Fixed #2724 by excluding bin_to_hex sink if using std::format

This reverts commit c3fa8f60e2.

.clang-format

@@ -104,5 +104,6 @@ SpacesInSquareBrackets: false
 Standard:        Cpp11
 TabWidth:        8
 UseTab:          Never
+IndentPPDirectives: AfterHash
 ...
 

.clang-tidy

@@ -2,7 +2,7 @@ Checks: 'cppcoreguidelines-*,
 performance-*,
 modernize-*,
 google-*,
-misc-*,
+misc-*
 cert-*,
 readability-*,
 clang-analyzer-*,

.github/workflows/ci.yml

@@ -0,0 +1,80 @@
+name: ci
+
+on: [push, pull_request]
+
+jobs:
+  build_linux:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    strategy:
+      fail-fast: false
+      matrix:
+        config:
+          - { compiler: gcc, version: 7, build_type: Release, cppstd: 11 }
+          - { compiler: gcc, version: 9, build_type: Release, cppstd: 17 }
+          - { compiler: gcc, version: 11, build_type: Debug, cppstd: 20 }
+          - { compiler: gcc, version: 12, build_type: Release, cppstd: 20 }
+          - { compiler: clang, version: 10, build_type: Release, cppstd: 11 }
+          - { compiler: clang, version: 10, build_type: Debug, cppstd: 17, asan: OFF }
+          - { compiler: clang, version: 12, build_type: Debug, cppstd: 17, asan: OFF }
+          - { compiler: clang, version: 15, build_type: Release, cppstd: 20, asan: OFF }
+    container:
+      image: ${{ matrix.config.compiler == 'clang' && 'teeks99/clang-ubuntu' || matrix.config.compiler }}:${{ matrix.config.version }}
+    name: "${{ matrix.config.compiler}} ${{ matrix.config.version }} (C++${{ matrix.config.cppstd }}, ${{ matrix.config.build_type }})"
+    steps:
+      - uses: actions/checkout@main
+      - name: Setup
+        run: |
+          apt-get update && apt-get install -y curl git pkg-config libsystemd-dev
+          CMAKE_VERSION="3.24.2"
+          curl -sSL https://github.com/Kitware/CMake/releases/download/v${CMAKE_VERSION}/cmake-${CMAKE_VERSION}-linux-x86_64.sh -o install-cmake.sh
+          chmod +x install-cmake.sh
+          ./install-cmake.sh --prefix=/usr/local --skip-license
+      - name: Setup Compiler
+        if: matrix.config.compiler == 'clang'
+        run: |
+          if [[ "${{ matrix.config.version }}" -ge 4 ]]; then
+            scripts/ci_setup_clang.sh "${{ matrix.config.version }}"
+            echo "CXXFLAGS=-stdlib=libc++" >> $GITHUB_ENV
+          fi
+          echo "CC=clang-${{ matrix.config.version }}" >> $GITHUB_ENV
+          echo "CXX=clang++-${{ matrix.config.version }}" >> $GITHUB_ENV
+      - name: Build
+        run: |
+          mkdir -p build && cd build
+          cmake .. \
+            -DCMAKE_BUILD_TYPE=${{ matrix.config.build_type }} \
+            -DCMAKE_CXX_STANDARD=${{ matrix.config.cppstd }} \
+            -DSPDLOG_BUILD_EXAMPLE=${{ matrix.config.examples || 'ON' }} \
+            -DSPDLOG_BUILD_EXAMPLE_HO=${{ matrix.config.examples || 'ON' }} \
+            -DSPDLOG_BUILD_WARNINGS=ON \
+            -DSPDLOG_BUILD_BENCH=OFF \
+            -DSPDLOG_BUILD_TESTS=ON \
+            -DSPDLOG_BUILD_TESTS_HO=OFF \
+            -DSPDLOG_SANITIZE_ADDRESS=${{ matrix.config.asan || 'ON' }}
+          make -j2
+          ctest -j2 --output-on-failure
+
+  build_osx:
+    runs-on: macOS-latest
+    name: "OS X Clang (C++11, Release)"
+    steps:
+      - uses: actions/checkout@main
+      - name: Build
+        run: |
+          mkdir -p build && cd build
+          cmake .. \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_CXX_STANDARD=11 \
+            -DSPDLOG_BUILD_EXAMPLE=ON \
+            -DSPDLOG_BUILD_EXAMPLE_HO=ON \
+            -DSPDLOG_BUILD_WARNINGS=ON \
+            -DSPDLOG_BUILD_BENCH=OFF \
+            -DSPDLOG_BUILD_TESTS=ON \
+            -DSPDLOG_BUILD_TESTS_HO=OFF \
+            -DSPDLOG_SANITIZE_ADDRESS=OFF
+          make -j2
+          ctest -j2 --output-on-failure
+

.gitignore

@@ -1,4 +1,6 @@
 # Auto generated files
+[Dd]ebug/
+[Rr]elease/
 build/*
 *.slo
 *.lo
@@ -55,6 +57,7 @@ example/*
 
 # generated files
 generated
+version.rc
 
 # Cmake
 CMakeCache.txt
@@ -67,9 +70,13 @@ install_manifest.txt
 /tests/tests.VC.db
 /tests/tests
 /tests/logs/*
+spdlogConfig.cmake
+spdlogConfigVersion.cmake
 
 # idea
 .idea/
+.cache/
+.vscode/
 cmake-build-*/
 *.db
 *.ipch
@@ -81,3 +88,7 @@ cmake-build-*/
 *.tcl
 *.user
 *.sln
+
+# macos
+*.DS_store
+*.xcodeproj/

.travis.yml

@@ -1,112 +0,0 @@
-# Adapted from various sources, including:
-# - Louis Dionne's Hana: https://github.com/ldionne/hana
-# - Paul Fultz II's FIT: https://github.com/pfultz2/Fit
-# - Eric Niebler's range-v3: https://github.com/ericniebler/range-v3
-sudo: required
-language: cpp
-
-# gcc 4.8
-addons: &gcc48
-  apt:
-    packages:
-      - g++-4.8
-    sources:
-      - ubuntu-toolchain-r-test
-
-# gcc 7.0
-addons: &gcc7
-  apt:
-    packages:
-      - g++-7
-    sources:
-      - ubuntu-toolchain-r-test
-
-# Clang 3.5
-addons: &clang35
-  apt:
-    packages:
-      - clang-3.5
-    sources:
-      - ubuntu-toolchain-r-test
-      - llvm-toolchain-precise-3.5
-      
-
-addons: &clang10
-  apt:
-    packages:
-      - clang-10
-      - lldb-10
-      - lld-10
-    sources:
-      - sourceline: "deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-10 main"
-        key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
-
-
-matrix:
-  include:
-    # Test gcc-4.8: C++11, Build=Debug/Release
-    - env: GCC_VERSION=4.8 BUILD_TYPE=Debug CPP=11
-      os: linux
-      addons: *gcc48
-
-    - env: GCC_VERSION=4.8 BUILD_TYPE=Release CPP=11
-      os: linux
-      addons: *gcc48
-
-    - env: GCC_VERSION=7 BUILD_TYPE=Release CPP=11
-      os: linux
-      addons: *gcc7
-
-    # Test clang-3.5: C++11, Build=Debug/Release
-    - env: CLANG_VERSION=3.5 BUILD_TYPE=Debug CPP=11
-      os: linux
-      addons: *clang35
-
-    - env: CLANG_VERSION=3.5 BUILD_TYPE=Release CPP=11
-      os: linux
-      addons: *clang35
-
-      # osx
-    - env: BUILD_TYPE=Release CPP=11 ASAN=Off TSAN=Off
-      os: osx
-
-    # Test clang-10.0: C++11, Build=Debug/Release
-    - env: CLANG_VERSION=10 BUILD_TYPE=Debug CPP=11
-      os: linux
-      dist: bionic
-      addons: *clang10
-
-    - env: CLANG_VERSION=10 BUILD_TYPE=Release CPP=11 ASAN=On
-      os: linux
-      dist: bionic
-      addons: *clang10
-
-
-before_script:
-  - if [ -n "$GCC_VERSION" ]; then export CXX="g++-${GCC_VERSION}" CC="gcc-${GCC_VERSION}"; fi
-  - if [ -n "$CLANG_VERSION" ]; then export CXX="clang++-${CLANG_VERSION}" CC="clang-${CLANG_VERSION}"; fi
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then export CXX="clang++" CC="clang"; fi
-  - which $CXX
-  - which $CC
-  - $CXX --version
-  - cmake --version
-
-script:
-  - cd ${TRAVIS_BUILD_DIR}
-  - mkdir -p build && cd build
-  - |
-    cmake .. \
-      --warn-uninitialized \
-      -DCMAKE_BUILD_TYPE=$BUILD_TYPE \
-      -DCMAKE_CXX_STANDARD=$CPP \
-      -DSPDLOG_BUILD_EXAMPLE=ON \
-      -DSPDLOG_BUILD_EXAMPLE_HO=ON \
-      -DSPDLOG_BUILD_WARNINGS=ON \
-      -DSPDLOG_BUILD_BENCH=OFF \
-      -DSPDLOG_BUILD_TESTS=ON \
-      -DSPDLOG_BUILD_TESTS_HO=OFF \
-      -DSPDLOG_SANITIZE_ADDRESS=$ASAN 
-      
-  - make VERBOSE=1 -j2
-  - ctest -j2 --output-on-failure
-  

CMakeLists.txt

@@ -1,6 +1,6 @@
 # Copyright(c) 2019 spdlog authors Distributed under the MIT License (http://opensource.org/licenses/MIT)
 
-cmake_minimum_required(VERSION 3.10)
+cmake_minimum_required(VERSION 3.10...3.21)
 
 # ---------------------------------------------------------------------------------------
 # Start spdlog project
@@ -25,14 +25,17 @@ endif()
 # ---------------------------------------------------------------------------------------
 # Compiler config
 # ---------------------------------------------------------------------------------------
-if(NOT CMAKE_CXX_STANDARD)
+if(SPDLOG_USE_STD_FORMAT)
+    set(CMAKE_CXX_STANDARD 20)
+    set(CMAKE_CXX_STANDARD_REQUIRED ON)
+elseif(NOT CMAKE_CXX_STANDARD)
     set(CMAKE_CXX_STANDARD 11)
     set(CMAKE_CXX_STANDARD_REQUIRED ON)
 endif()
 
-# make sure __cplusplus is defined when using msvc
+# make sure __cplusplus is defined when using msvc and enable parallel build
 if(MSVC)
-    string(APPEND CMAKE_CXX_FLAGS " /Zc:__cplusplus")
+    string(APPEND CMAKE_CXX_FLAGS " /Zc:__cplusplus /MP")
 endif()
 
 set(CMAKE_CXX_EXTENSIONS OFF)
@@ -61,6 +64,9 @@ option(SPDLOG_BUILD_SHARED "Build shared library" OFF)
 # precompiled headers option
 option(SPDLOG_ENABLE_PCH "Build static or shared library using precompiled header to speed up compilation time" OFF)
 
+# build position independent code
+option(SPDLOG_BUILD_PIC "Build position independent code (-fPIC)" OFF)
+
 # example options
 option(SPDLOG_BUILD_EXAMPLE "Build example" ${SPDLOG_MASTER_PROJECT})
 option(SPDLOG_BUILD_EXAMPLE_HO "Build header only example" OFF)
@@ -79,7 +85,9 @@ option(SPDLOG_SANITIZE_ADDRESS "Enable address sanitizer in tests" OFF)
 option(SPDLOG_BUILD_WARNINGS "Enable compiler warnings" OFF)
 
 # install options
+option(SPDLOG_SYSTEM_INCLUDES "Include as system headers (skip for clang-tidy)." OFF)
 option(SPDLOG_INSTALL "Generate the install target" ${SPDLOG_MASTER_PROJECT})
+option(SPDLOG_USE_STD_FORMAT "Use std::format instead of fmt library." OFF)
 option(SPDLOG_FMT_EXTERNAL "Use external fmt library instead of bundled" OFF)
 option(SPDLOG_FMT_EXTERNAL_HO "Use external fmt header-only library instead of bundled" OFF)
 option(SPDLOG_NO_EXCEPTIONS "Compile with -fno-exceptions. Call abort() on any spdlog exceptions" OFF)
@@ -88,14 +96,27 @@ if(SPDLOG_FMT_EXTERNAL AND SPDLOG_FMT_EXTERNAL_HO)
     message(FATAL_ERROR "SPDLOG_FMT_EXTERNAL and SPDLOG_FMT_EXTERNAL_HO are mutually exclusive")
 endif()
 
+if(SPDLOG_USE_STD_FORMAT AND SPDLOG_FMT_EXTERNAL_HO)
+    message(FATAL_ERROR "SPDLOG_USE_STD_FORMAT and SPDLOG_FMT_EXTERNAL_HO are mutually exclusive")
+endif()
+
+if(SPDLOG_USE_STD_FORMAT AND SPDLOG_FMT_EXTERNAL)
+    message(FATAL_ERROR "SPDLOG_USE_STD_FORMAT and SPDLOG_FMT_EXTERNAL are mutually exclusive")
+endif()
+
 # misc tweakme options
 if(WIN32)
     option(SPDLOG_WCHAR_SUPPORT "Support wchar api" OFF)
     option(SPDLOG_WCHAR_FILENAMES "Support wchar filenames" OFF)
+else()
+    set(SPDLOG_WCHAR_SUPPORT OFF CACHE BOOL "non supported option" FORCE)
+    set(SPDLOG_WCHAR_FILENAMES OFF CACHE BOOL "non supported option" FORCE)
 endif()
+
 if(${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
-    option(SPDLOG_CLOCK_COARSE
-           "Use the much faster (but much less accurate) CLOCK_REALTIME_COARSE instead of the regular clock," OFF)
+    option(SPDLOG_CLOCK_COARSE "Use CLOCK_REALTIME_COARSE instead of the regular clock," OFF)
+else()
+    set(SPDLOG_CLOCK_COARSE OFF CACHE BOOL "non supported option" FORCE)
 endif()
 
 option(SPDLOG_PREVENT_CHILD_FD "Prevent from child processes to inherit log file descriptors" OFF)
@@ -118,15 +139,19 @@ if(SPDLOG_TIDY)
     message(STATUS "Enabled clang-tidy")
 endif()
 
+if(SPDLOG_BUILD_PIC)
+    set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+endif()
+
 find_package(Threads REQUIRED)
 message(STATUS "Build type: " ${CMAKE_BUILD_TYPE})
 # ---------------------------------------------------------------------------------------
-# Static/Shared library (shared not supported in windows yet)
+# Static/Shared library
 # ---------------------------------------------------------------------------------------
 set(SPDLOG_SRCS src/spdlog.cpp src/stdout_sinks.cpp src/color_sinks.cpp src/file_sinks.cpp src/async.cpp src/cfg.cpp)
 
-if(NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
-    list(APPEND SPDLOG_SRCS src/fmt.cpp)
+if(NOT SPDLOG_USE_STD_FORMAT AND NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
+    list(APPEND SPDLOG_SRCS src/bundled_fmtlib_format.cpp)
 endif()
 
 if(SPDLOG_BUILD_SHARED OR BUILD_SHARED_LIBS)
@@ -137,10 +162,10 @@ if(SPDLOG_BUILD_SHARED OR BUILD_SHARED_LIBS)
     add_library(spdlog SHARED ${SPDLOG_SRCS} ${SPDLOG_ALL_HEADERS})
     target_compile_definitions(spdlog PUBLIC SPDLOG_SHARED_LIB)
     if(MSVC)
-        target_compile_options(spdlog PUBLIC 
-            $<$<AND:$<CXX_COMPILER_ID:MSVC>,$<NOT:$<COMPILE_LANGUAGE:CUDA>>>:/wd4251 /wd4275>)
+        target_compile_options(spdlog PUBLIC $<$<AND:$<CXX_COMPILER_ID:MSVC>,$<NOT:$<COMPILE_LANGUAGE:CUDA>>>:/wd4251
+                                             /wd4275>)
     endif()
-    if(NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
+    if(NOT SPDLOG_USE_STD_FORMAT AND NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
         target_compile_definitions(spdlog PRIVATE FMT_EXPORT PUBLIC FMT_SHARED)
     endif()
 else()
@@ -149,13 +174,19 @@ endif()
 
 add_library(spdlog::spdlog ALIAS spdlog)
 
+set(SPDLOG_INCLUDES_LEVEL "")
+if(SPDLOG_SYSTEM_INCLUDES)
+    set(SPDLOG_INCLUDES_LEVEL "SYSTEM")
+endif()
+
 target_compile_definitions(spdlog PUBLIC SPDLOG_COMPILED_LIB)
-target_include_directories(spdlog PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>"
-                                         "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>")
+target_include_directories(spdlog ${SPDLOG_INCLUDES_LEVEL} PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>"
+                                                                  "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>")
 target_link_libraries(spdlog PUBLIC Threads::Threads)
 spdlog_enable_warnings(spdlog)
 
-set_target_properties(spdlog PROPERTIES VERSION ${SPDLOG_VERSION} SOVERSION ${SPDLOG_VERSION_MAJOR})
+set_target_properties(spdlog PROPERTIES VERSION ${SPDLOG_VERSION} SOVERSION
+                                                                  ${SPDLOG_VERSION_MAJOR}.${SPDLOG_VERSION_MINOR})
 set_target_properties(spdlog PROPERTIES DEBUG_POSTFIX d)
 
 if(COMMAND target_precompile_headers AND SPDLOG_ENABLE_PCH)
@@ -169,8 +200,9 @@ endif()
 add_library(spdlog_header_only INTERFACE)
 add_library(spdlog::spdlog_header_only ALIAS spdlog_header_only)
 
-target_include_directories(spdlog_header_only INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>"
-                                                        "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>")
+target_include_directories(
+    spdlog_header_only ${SPDLOG_INCLUDES_LEVEL} INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>"
+                                                          "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>")
 target_link_libraries(spdlog_header_only INTERFACE Threads::Threads)
 
 # ---------------------------------------------------------------------------------------
@@ -198,10 +230,10 @@ endif()
 # ---------------------------------------------------------------------------------------
 # Add required libraries for Android CMake build
 # ---------------------------------------------------------------------------------------
-if (ANDROID)
+if(ANDROID)
     target_link_libraries(spdlog PUBLIC log)
     target_link_libraries(spdlog_header_only INTERFACE log)
-endif ()
+endif()
 
 # ---------------------------------------------------------------------------------------
 # Misc definitions according to tweak options
@@ -217,17 +249,27 @@ foreach(
     SPDLOG_NO_THREAD_ID
     SPDLOG_NO_TLS
     SPDLOG_NO_ATOMIC_LEVELS
-    SPDLOG_DISABLE_DEFAULT_LOGGER)
+    SPDLOG_DISABLE_DEFAULT_LOGGER
+    SPDLOG_USE_STD_FORMAT)
     if(${SPDLOG_OPTION})
         target_compile_definitions(spdlog PUBLIC ${SPDLOG_OPTION})
         target_compile_definitions(spdlog_header_only INTERFACE ${SPDLOG_OPTION})
     endif()
 endforeach()
 
-if(SPDLOG_NO_EXCEPTIONS AND NOT MSVC)
-    target_compile_options(spdlog PRIVATE -fno-exceptions)
+# ---------------------------------------------------------------------------------------
+# If exceptions are disabled, disable them in the bundled fmt as well
+# ---------------------------------------------------------------------------------------
+if(SPDLOG_NO_EXCEPTIONS)
+    if(NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
+        target_compile_definitions(spdlog PUBLIC FMT_EXCEPTIONS=0)
+    endif()
+    if(NOT MSVC)
+        target_compile_options(spdlog PRIVATE -fno-exceptions)
+    else()
+        target_compile_options(spdlog PRIVATE /EHsc)
+    endif()
 endif()
-
 # ---------------------------------------------------------------------------------------
 # Build binaries
 # ---------------------------------------------------------------------------------------
@@ -275,7 +317,7 @@ if(SPDLOG_INSTALL)
         ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
         RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 
-    if(NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
+    if(NOT SPDLOG_USE_STD_FORMAT AND NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
         install(DIRECTORY include/${PROJECT_NAME}/fmt/bundled/
                 DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME}/fmt/bundled/")
     endif()
@@ -283,6 +325,16 @@ if(SPDLOG_INSTALL)
     # ---------------------------------------------------------------------------------------
     # Install pkg-config file
     # ---------------------------------------------------------------------------------------
+    if(IS_ABSOLUTE "${CMAKE_INSTALL_INCLUDEDIR}")
+        set(PKG_CONFIG_INCLUDEDIR "${CMAKE_INSTALL_INCLUDEDIR}")
+    else()
+        set(PKG_CONFIG_INCLUDEDIR "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
+    endif()
+    if(IS_ABSOLUTE "${CMAKE_INSTALL_LIBDIR}")
+        set(PKG_CONFIG_LIBDIR "${CMAKE_INSTALL_LIBDIR}")
+    else()
+        set(PKG_CONFIG_LIBDIR "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
+    endif()
     get_target_property(PKG_CONFIG_DEFINES spdlog INTERFACE_COMPILE_DEFINITIONS)
     string(REPLACE ";" " -D" PKG_CONFIG_DEFINES "${PKG_CONFIG_DEFINES}")
     string(CONCAT PKG_CONFIG_DEFINES "-D" "${PKG_CONFIG_DEFINES}")
@@ -292,10 +344,11 @@ if(SPDLOG_INSTALL)
     # ---------------------------------------------------------------------------------------
     # Install CMake config files
     # ---------------------------------------------------------------------------------------
+    export(TARGETS spdlog NAMESPACE spdlog:: FILE "${CMAKE_CURRENT_BINARY_DIR}/${config_targets_file}")
     install(EXPORT spdlog DESTINATION ${export_dest_dir} NAMESPACE spdlog:: FILE ${config_targets_file})
 
     include(CMakePackageConfigHelpers)
-    configure_file("${project_config_in}" "${project_config_out}" @ONLY)
+    configure_package_config_file("${project_config_in}" "${project_config_out}" INSTALL_DESTINATION ${export_dest_dir})
 
     write_basic_package_version_file("${version_config_file}" COMPATIBILITY SameMajorVersion)
     install(FILES "${project_config_out}" "${version_config_file}" DESTINATION "${export_dest_dir}")
@@ -305,4 +358,3 @@ if(SPDLOG_INSTALL)
     # ---------------------------------------------------------------------------------------
     include(cmake/spdlogCPack.cmake)
 endif()
-

INSTALL

@@ -12,7 +12,7 @@ CMake:
   add_executable(example example.cpp)
   target_link_libraries(example spdlog::spdlog)
 
-Or copy src/spdlog.cpp to your build tree and pass the -DSPDLOG_COMPILED_LIB to the compiler.
+Or copy files src/*.cpp to your build tree and pass the -DSPDLOG_COMPILED_LIB to the compiler.
 
 Tested on:
 gcc 4.8.1 and above

README.md

@@ -1,59 +1,61 @@
 # spdlog
 
-Very fast, header-only/compiled, C++ logging library. [![Build Status](https://travis-ci.org/gabime/spdlog.svg?branch=v1.x)](https://travis-ci.org/gabime/spdlog)  [![Build status](https://ci.appveyor.com/api/projects/status/d2jnxclg20vd0o50?svg=true)](https://ci.appveyor.com/project/gabime/spdlog) [![Release](https://img.shields.io/github/release/gabime/spdlog.svg)](https://github.com/gabime/spdlog/releases/latest)
+Very fast, header-only/compiled, C++ logging library. [![ci](https://github.com/gabime/spdlog/actions/workflows/ci.yml/badge.svg)](https://github.com/gabime/spdlog/actions/workflows/ci.yml)  [![Build status](https://ci.appveyor.com/api/projects/status/d2jnxclg20vd0o50?svg=true&branch=v1.x)](https://ci.appveyor.com/project/gabime/spdlog) [![Release](https://img.shields.io/github/release/gabime/spdlog.svg)](https://github.com/gabime/spdlog/releases/latest)
 
-## Install 
-#### Header only version
-Copy the source [folder](https://github.com/gabime/spdlog/tree/v1.x/include/spdlog) to your build tree and use a C++11 compiler.
+## Install
+#### Header-only version
+Copy the include [folder](https://github.com/gabime/spdlog/tree/v1.x/include/spdlog) to your build tree and use a C++11 compiler.
 
-#### Static lib version (recommended - much faster compile times)
+#### Compiled version (recommended - much faster compile times)
 ```console
 $ git clone https://github.com/gabime/spdlog.git
 $ cd spdlog && mkdir build && cd build
 $ cmake .. && make -j
 ```
-      
-   see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/CMakeLists.txt) on how to use.
+
+see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/CMakeLists.txt) on how to use.
 
 ## Platforms
- * Linux, FreeBSD, OpenBSD, Solaris, AIX
- * Windows (msvc 2013+, cygwin)
- * macOS (clang 3.5+)
- * Android
+* Linux, FreeBSD, OpenBSD, Solaris, AIX
+* Windows (msvc 2013+, cygwin)
+* macOS (clang 3.5+)
+* Android
 
 ## Package managers:
+* Debian: `sudo apt install libspdlog-dev`
 * Homebrew: `brew install spdlog`
 * MacPorts: `sudo port install spdlog`
-* FreeBSD:  `cd /usr/ports/devel/spdlog/ && make install clean`
+* FreeBSD:  `pkg install spdlog`
 * Fedora: `dnf install spdlog`
 * Gentoo: `emerge dev-libs/spdlog`
 * Arch Linux: `pacman -S spdlog`
+* openSUSE: `sudo zypper in spdlog-devel`
 * vcpkg: `vcpkg install spdlog`
 * conan: `spdlog/[>=1.4.1]`
 * conda: `conda install -c conda-forge spdlog`
 * build2: ```depends: spdlog ^1.8.2```
 
 
-
 ## Features
 * Very fast (see [benchmarks](#benchmarks) below).
 * Headers only or compiled
-* Feature rich formatting, using the excellent [fmt](https://github.com/fmtlib/fmt) library.
+* Feature-rich formatting, using the excellent [fmt](https://github.com/fmtlib/fmt) library.
 * Asynchronous mode (optional)
 * [Custom](https://github.com/gabime/spdlog/wiki/3.-Custom-formatting) formatting.
 * Multi/Single threaded loggers.
 * Various log targets:
-    * Rotating log files.
-    * Daily log files.
-    * Console logging (colors supported).
-    * syslog.
-    * Windows event log.
-    * Windows debugger (```OutputDebugString(..)```).
-    * Easily extendable with custom log targets  (just implement a single function in the [sink](include/spdlog/sinks/sink.h) interface).
-* Log filtering - log levels can be modified in runtime as well as in compile time.
-* Support for loading log levels from argv or from environment var.
-* [Backtrace](#backtrace-support) support - store debug messages in a ring buffer and display later on demand.
- 
+  * Rotating log files.
+  * Daily log files.
+  * Console logging (colors supported).
+  * syslog.
+  * Windows event log.
+  * Windows debugger (```OutputDebugString(..)```).
+  * Log to Qt widgets ([example](#log-to-qt-with-nice-colors)).
+  * Easily [extendable](https://github.com/gabime/spdlog/wiki/4.-Sinks#implementing-your-own-sink) with custom log targets.
+* Log filtering - log levels can be modified at runtime as well as compile time.
+* Support for loading log levels from argv or environment var.
+* [Backtrace](#backtrace-support) support - store debug messages in a ring buffer and display them later on demand.
+
 ## Usage samples
 
 #### Basic usage
@@ -91,7 +93,7 @@ int main()
 #include "spdlog/sinks/stdout_color_sinks.h"
 void stdout_example()
 {
-    // create color multi threaded logger
+    // create a color multi-threaded logger
     auto console = spdlog::stdout_color_mt("console");    
     auto err_logger = spdlog::stderr_color_mt("stderr");    
     spdlog::get("console")->info("loggers can be retrieved from a global registry using the spdlog::get(logger_name)");
@@ -120,7 +122,7 @@ void basic_logfile_example()
 #include "spdlog/sinks/rotating_file_sink.h"
 void rotating_example()
 {
-    // Create a file rotating logger with 5mb size max and 3 rotated files
+    // Create a file rotating logger with 5 MB size max and 3 rotated files
     auto max_size = 1048576 * 5;
     auto max_files = 3;
     auto logger = spdlog::rotating_logger_mt("some_logger_name", "logs/rotating.txt", max_size, max_files);
@@ -134,7 +136,7 @@ void rotating_example()
 #include "spdlog/sinks/daily_file_sink.h"
 void daily_example()
 {
-    // Create a daily logger - a new file is created every day on 2:30am
+    // Create a daily logger - a new file is created every day at 2:30 am
     auto logger = spdlog::daily_logger_mt("daily_logger", "logs/daily.txt", 2, 30);
 }
 
@@ -143,10 +145,11 @@ void daily_example()
 ---
 #### Backtrace support
 ```c++
-// Loggers can store in a ring buffer all messages (including debug/trace) and display later on demand.
-// When needed, call dump_backtrace() to see them
+// Debug messages can be stored in a ring buffer instead of being logged immediately.
+// This is useful to display debug logs only when needed (e.g. when an error happens).
+// When needed, call dump_backtrace() to dump them to your log.
 
-spdlog::enable_backtrace(32); // Store the latest 32 messages in a buffer. Older messages will be dropped.
+spdlog::enable_backtrace(32); // Store the latest 32 messages in a buffer. 
 // or my_logger->enable_backtrace(32)..
 for(int i = 0; i < 100; i++)
 {
@@ -154,7 +157,6 @@ for(int i = 0; i < 100; i++)
 }
 // e.g. if some error happened:
 spdlog::dump_backtrace(); // log them now! show the last 32 messages
-
 // or my_logger->dump_backtrace(32)..
 ```
 
@@ -162,7 +164,7 @@ spdlog::dump_backtrace(); // log them now! show the last 32 messages
 #### Periodic flush
 ```c++
 // periodically flush all *registered* loggers every 3 seconds:
-// warning: only use if all your loggers are thread safe ("_mt" loggers)
+// warning: only use if all your loggers are thread-safe ("_mt" loggers)
 spdlog::flush_every(std::chrono::seconds(3));
 
 ```
@@ -190,7 +192,7 @@ void stopwatch_example()
 // {:X} - print in uppercase.
 // {:s} - don't separate each byte with space.
 // {:p} - don't print the position on each line start.
-// {:n} - don't split the output to lines.
+// {:n} - don't split the output into lines.
 // {:a} - show ASCII if :n is not set.
 
 #include "spdlog/fmt/bin_to_hex.h"
@@ -210,11 +212,11 @@ void binary_example()
 ```
 
 ---
-#### Logger with multi sinks - each with different format and log level
+#### Logger with multi sinks - each with a different format and log level
 ```c++
 
-// create logger with 2 targets with different log levels and formats.
-// the console will show only warnings or errors, while the file will log all.
+// create a logger with 2 targets, with different log levels and formats.
+// The console will show only warnings or errors, while the file will log all.
 void multi_sink_example()
 {
     auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
@@ -231,6 +233,27 @@ void multi_sink_example()
 }
 ```
 
+---
+#### User-defined callbacks about log events
+```c++
+
+// create a logger with a lambda function callback, the callback will be called
+// each time something is logged to the logger
+void callback_example()
+{
+    auto callback_sink = std::make_shared<spdlog::sinks::callback_sink_mt>([](const spdlog::details::log_msg &msg) {
+         // for example you can be notified by sending an email to yourself
+    });
+    callback_sink->set_level(spdlog::level::err);
+
+    auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
+    spdlog::logger logger("custom_callback_logger", {console_sink, callback_sink});
+
+    logger.info("some info log");
+    logger.error("critical issue"); // will notify you
+}
+```
+
 ---
 #### Asynchronous logging
 ```c++
@@ -248,7 +271,7 @@ void async_example()
 ```
 
 ---
-#### Asynchronous logger with multi sinks  
+#### Asynchronous logger with multi sinks
 ```c++
 #include "spdlog/sinks/stdout_color_sinks.h"
 #include "spdlog/sinks/rotating_file_sink.h"
@@ -265,29 +288,26 @@ void multi_sink_example2()
 ```
  
 ---
-#### User defined types
+#### User-defined types
 ```c++
-// user defined types logging by implementing operator<<
-#include "spdlog/fmt/ostr.h" // must be included
-struct my_type
+template<>
+struct fmt::formatter<my_type> : fmt::formatter<std::string>
 {
-    int i;
-    template<typename OStream>
-    friend OStream &operator<<(OStream &os, const my_type &c)
+    auto format(my_type my, format_context &ctx) const -> decltype(ctx.out())
     {
-        return os << "[my_type i=" << c.i << "]";
+        return format_to(ctx.out(), "[my_type i={}]", my.i);
     }
 };
 
 void user_defined_example()
 {
-    spdlog::get("console")->info("user defined type: {}", my_type{14});
+    spdlog::info("user defined type: {}", my_type(14));
 }
 
 ```
 
 ---
-#### User defined flags in the log pattern
+#### User-defined flags in the log pattern
 ```c++ 
 // Log patterns can contain custom flags.
 // the following example will add new flag '%*' - which will be bound to a <my_formatter_flag> instance.
@@ -329,7 +349,7 @@ void err_handler_example()
 ```
 
 ---
-#### syslog 
+#### syslog
 ```c++
 #include "spdlog/sinks/syslog_sink.h"
 void syslog_example()
@@ -340,7 +360,7 @@ void syslog_example()
 }
 ```
 ---
-#### Android example 
+#### Android example
 ```c++
 #include "spdlog/sinks/android_sink.h"
 void android_example()
@@ -352,14 +372,14 @@ void android_example()
 ```
 
 ---
-#### Load log levels from env variable or from argv
+#### Load log levels from the env variable or argv
 
 ```c++
 #include "spdlog/cfg/env.h"
 int main (int argc, char *argv[])
 {
     spdlog::cfg::load_env_levels();
-    // or from command line:
+    // or from the command line:
     // ./example SPDLOG_LEVEL=info,mylogger=trace
     // #include "spdlog/cfg/argv.h" // for loading levels from argv
     // spdlog::cfg::load_argv_levels(argc, argv);
@@ -372,6 +392,51 @@ $ export SPDLOG_LEVEL=info,mylogger=trace
 $ ./example
 ```
 
+
+---
+#### Log file open/close event handlers
+```c++
+// You can get callbacks from spdlog before/after a log file has been opened or closed. 
+// This is useful for cleanup procedures or for adding something to the start/end of the log file.
+void file_events_example()
+{
+    // pass the spdlog::file_event_handlers to file sinks for open/close log file notifications
+    spdlog::file_event_handlers handlers;
+    handlers.before_open = [](spdlog::filename_t filename) { spdlog::info("Before opening {}", filename); };
+    handlers.after_open = [](spdlog::filename_t filename, std::FILE *fstream) { fputs("After opening\n", fstream); };
+    handlers.before_close = [](spdlog::filename_t filename, std::FILE *fstream) { fputs("Before closing\n", fstream); };
+    handlers.after_close = [](spdlog::filename_t filename) { spdlog::info("After closing {}", filename); };
+    auto my_logger = spdlog::basic_logger_st("some_logger", "logs/events-sample.txt", true, handlers);        
+}
+```
+
+---
+#### Replace the Default Logger
+```c++
+void replace_default_logger_example()
+{
+    auto new_logger = spdlog::basic_logger_mt("new_default_logger", "logs/new-default-log.txt", true);
+    spdlog::set_default_logger(new_logger);
+    spdlog::info("new logger log message");
+}
+```
+
+---
+#### Log to Qt with nice colors
+```c++
+#include "spdlog/spdlog.h"
+#include "spdlog/sinks/qt_sinks.h"
+MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
+{
+    setMinimumSize(640, 480);
+    auto log_widget = new QTextEdit(this);
+    setCentralWidget(log_widget);
+    int max_lines = 500; // keep the text widget to max 500 lines. remove old lines if needed.
+    auto logger = spdlog::qt_color_logger_mt("qt_logger", log_widget, max_lines);
+    logger->info("Some info message");
+}
+```
+
 ---
 ## Benchmarks
 

appveyor.yml

@@ -2,54 +2,72 @@ version: 1.0.{build}
 image: Visual Studio 2017
 environment:
   matrix:
-    - GENERATOR: '"Visual Studio 14 2015"'
-      BUILD_TYPE: Debug
-      BUILD_SHARED: 'OFF'
-      WCHAR: 'OFF'
-      WCHAR_FILES: 'OFF'
-      BUILD_EXAMPLE: 'ON'
-    - GENERATOR: '"Visual Studio 14 2015"'
-      BUILD_TYPE: Release
-      BUILD_SHARED: 'OFF'
-      WCHAR: 'ON'
-      WCHAR_FILES: 'OFF'
-      BUILD_EXAMPLE: 'ON'
-    - GENERATOR: '"Visual Studio 14 2015 Win64"'
-      BUILD_TYPE: Debug
-      BUILD_SHARED: 'OFF'
-      WCHAR: 'ON'
-      WCHAR_FILES: 'OFF'
-      BUILD_EXAMPLE: 'ON'
-    - GENERATOR: '"Visual Studio 14 2015 Win64"'
-      BUILD_TYPE: Release
-      BUILD_SHARED: 'OFF'
-      WCHAR: 'ON'
-      WCHAR_FILES: 'OFF'
-      BUILD_EXAMPLE: 'ON'
     - GENERATOR: '"Visual Studio 15 2017 Win64"'
       BUILD_TYPE: Debug
       BUILD_SHARED: 'OFF'
+      FATAL_ERRORS: 'OFF'
       WCHAR: 'ON'
       WCHAR_FILES: 'OFF'
       BUILD_EXAMPLE: 'ON'
+      USE_STD_FORMAT: 'OFF'
+      CXX_STANDARD: 11
     - GENERATOR: '"Visual Studio 15 2017 Win64"'
       BUILD_TYPE: Release
       BUILD_SHARED: 'OFF'
+      FATAL_ERRORS: 'OFF'
       WCHAR: 'OFF'
       WCHAR_FILES: 'OFF'
       BUILD_EXAMPLE: 'ON'
+      USE_STD_FORMAT: 'OFF'
+      CXX_STANDARD: 11
     - GENERATOR: '"Visual Studio 15 2017 Win64"'
       BUILD_TYPE: Release
       BUILD_SHARED: 'ON'
+      FATAL_ERRORS: 'OFF'
       WCHAR: 'OFF'
       WCHAR_FILES: 'OFF'
       BUILD_EXAMPLE: 'ON'
+      USE_STD_FORMAT: 'OFF'
+      CXX_STANDARD: 11
     - GENERATOR: '"Visual Studio 15 2017 Win64"'
       BUILD_TYPE: Release
       BUILD_SHARED: 'ON'
+      FATAL_ERRORS: 'OFF'
       WCHAR: 'ON'
       WCHAR_FILES: 'ON'
       BUILD_EXAMPLE: 'OFF'
+      USE_STD_FORMAT: 'OFF'
+      CXX_STANDARD: 11
+    - GENERATOR: '"Visual Studio 16 2019" -A x64'
+      BUILD_TYPE: Release
+      BUILD_SHARED: 'ON'
+      FATAL_ERRORS: 'ON'
+      WCHAR: 'OFF'
+      WCHAR_FILES: 'OFF'
+      BUILD_EXAMPLE: 'OFF'
+      USE_STD_FORMAT: 'OFF'
+      CXX_STANDARD: 17
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+    - GENERATOR: '"Visual Studio 17 2022" -A x64'
+      BUILD_TYPE: Release
+      BUILD_SHARED: 'ON'
+      FATAL_ERRORS: 'ON'
+      WCHAR: 'OFF'
+      WCHAR_FILES: 'OFF'
+      BUILD_EXAMPLE: 'OFF'
+      USE_STD_FORMAT: 'ON'
+      CXX_STANDARD: 20
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
+    - GENERATOR: '"Visual Studio 17 2022" -A x64'
+      BUILD_TYPE: Release
+      BUILD_SHARED: 'ON'
+      FATAL_ERRORS: 'ON'
+      WCHAR: 'ON'
+      WCHAR_FILES: 'ON'
+      BUILD_EXAMPLE: 'OFF'
+      USE_STD_FORMAT: 'ON'
+      CXX_STANDARD: 20
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
 build_script:
   - cmd: >-
       set
@@ -60,12 +78,12 @@ build_script:
 
       set PATH=%PATH%;C:\Program Files\Git\usr\bin
 
-      cmake -G %GENERATOR% -D CMAKE_BUILD_TYPE=%BUILD_TYPE% -D BUILD_SHARED_LIBS=%BUILD_SHARED% -D SPDLOG_WCHAR_SUPPORT=%WCHAR% -D SPDLOG_WCHAR_FILENAMES=%WCHAR_FILES% -D SPDLOG_BUILD_EXAMPLE=%BUILD_EXAMPLE% -D SPDLOG_BUILD_EXAMPLE_HO=%BUILD_EXAMPLE% -D SPDLOG_BUILD_TESTS=ON -D SPDLOG_BUILD_TESTS_HO=OFF -D SPDLOG_BUILD_WARNINGS=ON ..
+      cmake -G %GENERATOR% -D CMAKE_BUILD_TYPE=%BUILD_TYPE% -D BUILD_SHARED_LIBS=%BUILD_SHARED% -D SPDLOG_WCHAR_SUPPORT=%WCHAR% -D SPDLOG_WCHAR_FILENAMES=%WCHAR_FILES% -D SPDLOG_BUILD_EXAMPLE=%BUILD_EXAMPLE% -D SPDLOG_BUILD_EXAMPLE_HO=%BUILD_EXAMPLE% -D SPDLOG_BUILD_TESTS=ON -D SPDLOG_BUILD_TESTS_HO=OFF -D SPDLOG_BUILD_WARNINGS=%FATAL_ERRORS% -D SPDLOG_USE_STD_FORMAT=%USE_STD_FORMAT% -D CMAKE_CXX_STANDARD=%CXX_STANDARD% ..
 
       cmake --build . --config %BUILD_TYPE%
 
 before_test:
-  - set PATH=%PATH%;C:\projects\spdlog\build\%BUILD_TYPE%
+  - set PATH=%PATH%;C:\projects\spdlog\build\_deps\catch2-build\src\%BUILD_TYPE%;C:\projects\spdlog\build\%BUILD_TYPE%
   
 test_script:
   - C:\projects\spdlog\build\tests\%BUILD_TYPE%\spdlog-utests.exe

bench/CMakeLists.txt

@@ -10,18 +10,17 @@ endif()
 
 find_package(Threads REQUIRED)
 find_package(benchmark CONFIG)
-if (NOT benchmark_FOUND)
+if(NOT benchmark_FOUND)
     message(STATUS "Using CMake Version ${CMAKE_VERSION}")
-    if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.11.0")
-        # User can fetch googlebenchmark 			
+    if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.11.0")
+        # User can fetch googlebenchmark
         message(STATUS "Downloading GoogleBenchmark")
         include(FetchContent)
-        set(BENCHMARK_ENABLE_GTEST_TESTS OFF CACHE INTERNAL "")
-        # Do not build and run googlebenchmark tests
-        FetchContent_Declare(googlebenchmark
-            GIT_REPOSITORY https://github.com/google/benchmark.git
-            GIT_TAG v1.5.2)
 
+        # disable tests
+        set(BENCHMARK_ENABLE_TESTING OFF CACHE INTERNAL "")
+        # Do not build and run googlebenchmark tests
+        FetchContent_Declare(googlebenchmark GIT_REPOSITORY https://github.com/google/benchmark.git GIT_TAG v1.6.0)
         FetchContent_MakeAvailable(googlebenchmark)
     else()
         message(FATAL_ERROR "GoogleBenchmark is missing. Use CMake >= 3.11 or download it")

bench/async_bench.cpp

@@ -10,10 +10,12 @@
 #include "spdlog/async.h"
 #include "spdlog/sinks/basic_file_sink.h"
 
-#ifdef SPDLOG_FMT_EXTERNAL
-#include <fmt/locale.h>
+#if defined(SPDLOG_USE_STD_FORMAT)
+#    include <format>
+#elif defined(SPDLOG_FMT_EXTERNAL)
+#    include <fmt/format.h>
 #else
-#include "spdlog/fmt/bundled/locale.h"
+#    include "spdlog/fmt/bundled/format.h"
 #endif
 
 #include "utils.h"
@@ -32,9 +34,9 @@ using namespace utils;
 void bench_mt(int howmany, std::shared_ptr<spdlog::logger> log, int thread_count);
 
 #ifdef _MSC_VER
-#pragma warning(push)
-#pragma warning(disable : 4996) // disable fopen warning under msvc
-#endif // _MSC_VER
+#    pragma warning(push)
+#    pragma warning(disable : 4996) // disable fopen warning under msvc
+#endif                              // _MSC_VER
 
 int count_lines(const char *filename)
 {
@@ -64,7 +66,7 @@ void verify_file(const char *filename, int expected_count)
 }
 
 #ifdef _MSC_VER
-#pragma warning(pop)
+#    pragma warning(pop)
 #endif
 
 int main(int argc, char *argv[])
@@ -103,12 +105,11 @@ int main(int argc, char *argv[])
 
         auto slot_size = sizeof(spdlog::details::async_msg);
         spdlog::info("-------------------------------------------------");
-        spdlog::info(fmt::format(std::locale("en_US.UTF-8"), "Messages     : {:L}", howmany));
-        spdlog::info(fmt::format(std::locale("en_US.UTF-8"), "Threads      : {:L}", threads));
-        spdlog::info(fmt::format(std::locale("en_US.UTF-8"), "Queue        : {:L} slots", queue_size));
-        spdlog::info(fmt::format(
-            std::locale("en_US.UTF-8"), "Queue memory : {:L} x {:L} = {:L} KB ", queue_size, slot_size, (queue_size * slot_size) / 1024));
-        spdlog::info(fmt::format(std::locale("en_US.UTF-8"), "Total iters  : {:L}", iters));
+        spdlog::info("Messages     : {:L}", howmany);
+        spdlog::info("Threads      : {:L}", threads);
+        spdlog::info("Queue        : {:L} slots", queue_size);
+        spdlog::info("Queue memory : {:L} x {:L} = {:L} KB ", queue_size, slot_size, (queue_size * slot_size) / 1024);
+        spdlog::info("Total iters  : {:L}", iters);
         spdlog::info("-------------------------------------------------");
 
         const char *filename = "logs/basic_async.log";
@@ -161,7 +162,7 @@ void thread_fun(std::shared_ptr<spdlog::logger> logger, int howmany)
 void bench_mt(int howmany, std::shared_ptr<spdlog::logger> logger, int thread_count)
 {
     using std::chrono::high_resolution_clock;
-    vector<thread> threads;
+    vector<std::thread> threads;
     auto start = high_resolution_clock::now();
 
     int msgs_per_thread = howmany / thread_count;
@@ -181,5 +182,5 @@ void bench_mt(int howmany, std::shared_ptr<spdlog::logger> logger, int thread_co
 
     auto delta = high_resolution_clock::now() - start;
     auto delta_d = duration_cast<duration<double>>(delta).count();
-    spdlog::info(fmt::format(std::locale("en_US.UTF-8"), "Elapsed: {} secs\t {:L}/sec", delta_d, int(howmany / delta_d)));
+    spdlog::info("Elapsed: {} secs\t {:L}/sec", delta_d, int(howmany / delta_d));
 }

bench/bench.cpp

@@ -12,10 +12,12 @@
 #include "spdlog/sinks/null_sink.h"
 #include "spdlog/sinks/rotating_file_sink.h"
 
-#ifdef SPDLOG_FMT_EXTERNAL
-#include <fmt/locale.h>
+#if defined(SPDLOG_USE_STD_FORMAT)
+#    include <format>
+#elif defined(SPDLOG_FMT_EXTERNAL)
+#    include <fmt/format.h>
 #else
-#include "spdlog/fmt/bundled/locale.h"
+#    include "spdlog/fmt/bundled/format.h"
 #endif
 
 #include "utils.h"
@@ -38,7 +40,7 @@ static const int max_threads = 1000;
 void bench_threaded_logging(size_t threads, int iters)
 {
     spdlog::info("**************************************************************");
-    spdlog::info(fmt::format(std::locale("en_US.UTF-8"), "Multi threaded: {:L} threads, {:L} messages", threads, iters));
+    spdlog::info(spdlog::fmt_lib::format(std::locale("en_US.UTF-8"), "Multi threaded: {:L} threads, {:L} messages", threads, iters));
     spdlog::info("**************************************************************");
 
     auto basic_mt = spdlog::basic_logger_mt("basic_mt", "logs/basic_mt.log", true);
@@ -74,7 +76,7 @@ void bench_threaded_logging(size_t threads, int iters)
 void bench_single_threaded(int iters)
 {
     spdlog::info("**************************************************************");
-    spdlog::info(fmt::format(std::locale("en_US.UTF-8"), "Single threaded: {} messages", iters));
+    spdlog::info(spdlog::fmt_lib::format(std::locale("en_US.UTF-8"), "Single threaded: {} messages", iters));
     spdlog::info("**************************************************************");
 
     auto basic_st = spdlog::basic_logger_st("basic_st", "logs/basic_st.log", true);
@@ -128,7 +130,7 @@ int main(int argc, char *argv[])
 
         if (threads > max_threads)
         {
-            throw std::runtime_error(fmt::format("Number of threads exceeds maximum({}})", max_threads));
+            throw std::runtime_error(spdlog::fmt_lib::format("Number of threads exceeds maximum({})", max_threads));
         }
 
         bench_single_threaded(iters);
@@ -158,8 +160,8 @@ void bench(int howmany, std::shared_ptr<spdlog::logger> log)
     auto delta = high_resolution_clock::now() - start;
     auto delta_d = duration_cast<duration<double>>(delta).count();
 
-    spdlog::info(
-        fmt::format(std::locale("en_US.UTF-8"), "{:<30} Elapsed: {:0.2f} secs {:>16L}/sec", log->name(), delta_d, int(howmany / delta_d)));
+    spdlog::info(spdlog::fmt_lib::format(
+        std::locale("en_US.UTF-8"), "{:<30} Elapsed: {:0.2f} secs {:>16L}/sec", log->name(), delta_d, int(howmany / delta_d)));
     spdlog::drop(log->name());
 }
 
@@ -189,8 +191,8 @@ void bench_mt(int howmany, std::shared_ptr<spdlog::logger> log, size_t thread_co
 
     auto delta = high_resolution_clock::now() - start;
     auto delta_d = duration_cast<duration<double>>(delta).count();
-    spdlog::info(
-        fmt::format(std::locale("en_US.UTF-8"), "{:<30} Elapsed: {:0.2f} secs {:>16L}/sec", log->name(), delta_d, int(howmany / delta_d)));
+    spdlog::info(spdlog::fmt_lib::format(
+        std::locale("en_US.UTF-8"), "{:<30} Elapsed: {:0.2f} secs {:>16L}/sec", log->name(), delta_d, int(howmany / delta_d)));
     spdlog::drop(log->name());
 }
 

bench/latency.cpp

@@ -38,14 +38,13 @@ void bench_logger(benchmark::State &state, std::shared_ptr<spdlog::logger> logge
         logger->info("Hello logger: msg number {}...............", ++i);
     }
 }
-
-void bench_logger_fmt_string(benchmark::State &state, std::shared_ptr<spdlog::logger> logger)
+void bench_global_logger(benchmark::State &state, std::shared_ptr<spdlog::logger> logger)
 {
+    spdlog::set_default_logger(std::move(logger));
     int i = 0;
     for (auto _ : state)
     {
-        logger->info(FMT_STRING("Hello logger: msg number {}..............."), ++i);
-        ;
+        spdlog::info("Hello logger: msg number {}...............", ++i);
     }
 }
 
@@ -57,6 +56,17 @@ void bench_disabled_macro(benchmark::State &state, std::shared_ptr<spdlog::logge
     for (auto _ : state)
     {
         SPDLOG_LOGGER_DEBUG(logger, "Hello logger: msg number {}...............", i++);
+    }
+}
+
+void bench_disabled_macro_global_logger(benchmark::State &state, std::shared_ptr<spdlog::logger> logger)
+{
+    spdlog::set_default_logger(std::move(logger));
+    int i = 0;
+    benchmark::DoNotOptimize(i);      // prevent unused warnings
+    benchmark::DoNotOptimize(logger); // prevent unused warnings
+    for (auto _ : state)
+    {
         SPDLOG_DEBUG("Hello logger: msg number {}...............", i++);
     }
 }
@@ -89,7 +99,9 @@ int main(int argc, char *argv[])
     auto disabled_logger = std::make_shared<spdlog::logger>("bench", std::make_shared<null_sink_mt>());
     disabled_logger->set_level(spdlog::level::off);
     benchmark::RegisterBenchmark("disabled-at-compile-time", bench_disabled_macro, disabled_logger);
+    benchmark::RegisterBenchmark("disabled-at-compile-time (global logger)", bench_disabled_macro_global_logger, disabled_logger);
     benchmark::RegisterBenchmark("disabled-at-runtime", bench_logger, disabled_logger);
+    benchmark::RegisterBenchmark("disabled-at-runtime (global logger)", bench_global_logger, disabled_logger);
     // with backtrace of 64
     auto tracing_disabled_logger = std::make_shared<spdlog::logger>("bench", std::make_shared<null_sink_mt>());
     tracing_disabled_logger->enable_backtrace(64);
@@ -98,7 +110,7 @@ int main(int argc, char *argv[])
     auto null_logger_st = std::make_shared<spdlog::logger>("bench", std::make_shared<null_sink_st>());
     benchmark::RegisterBenchmark("null_sink_st (500_bytes c_str)", bench_c_string, std::move(null_logger_st));
     benchmark::RegisterBenchmark("null_sink_st", bench_logger, null_logger_st);
-    benchmark::RegisterBenchmark("null_sink_fmt_string", bench_logger_fmt_string, null_logger_st);
+    benchmark::RegisterBenchmark("null_sink_st (global logger)", bench_global_logger, null_logger_st);
     // with backtrace of 64
     auto tracing_null_logger_st = std::make_shared<spdlog::logger>("bench", std::make_shared<null_sink_st>());
     tracing_null_logger_st->enable_backtrace(64);

cmake/spdlog.pc.in

@@ -1,7 +1,7 @@
 prefix=@CMAKE_INSTALL_PREFIX@
 exec_prefix=${prefix}
-includedir=${prefix}/include
-libdir=${exec_prefix}/@CMAKE_INSTALL_LIBDIR@
+includedir=@PKG_CONFIG_INCLUDEDIR@
+libdir=@PKG_CONFIG_LIBDIR@
 
 Name: lib@PROJECT_NAME@
 Description: Fast C++ logging library.

cmake/spdlogConfig.cmake.in

@@ -1,15 +1,20 @@
 # Copyright(c) 2019 spdlog authors
 # Distributed under the MIT License (http://opensource.org/licenses/MIT)
 
+@PACKAGE_INIT@
+
 find_package(Threads REQUIRED)
 
 set(SPDLOG_FMT_EXTERNAL @SPDLOG_FMT_EXTERNAL@)
+set(SPDLOG_FMT_EXTERNAL_HO @SPDLOG_FMT_EXTERNAL_HO@)
 set(config_targets_file @config_targets_file@)
 
-if(SPDLOG_FMT_EXTERNAL)
+if(SPDLOG_FMT_EXTERNAL OR SPDLOG_FMT_EXTERNAL_HO)
     include(CMakeFindDependencyMacro)
     find_dependency(fmt CONFIG)
 endif()
 
 
 include("${CMAKE_CURRENT_LIST_DIR}/${config_targets_file}")
+
+check_required_components(spdlog)

cmake/utils.cmake

@@ -42,6 +42,7 @@ function(spdlog_enable_warnings target_name)
                     -Wextra
                     -Wconversion
                     -pedantic
+                    -Werror
                     -Wfatal-errors>
                     $<$<CXX_COMPILER_ID:MSVC>:${MSVC_OPTIONS}>)
     endif()
@@ -59,4 +60,3 @@ function(spdlog_enable_sanitizer target_name)
     target_compile_options(${target_name} PRIVATE -fno-omit-frame-pointer)
     target_link_libraries(${target_name} PRIVATE -fsanitize=address,undefined -fuse-ld=gold)
 endfunction()
-

example/CMakeLists.txt

@@ -12,7 +12,7 @@ endif()
 # Example of using pre-compiled library
 # ---------------------------------------------------------------------------------------
 add_executable(example example.cpp)
-target_link_libraries(example PRIVATE spdlog::spdlog)
+target_link_libraries(example PRIVATE spdlog::spdlog $<$<BOOL:${MINGW}>:ws2_32>)
 
 # ---------------------------------------------------------------------------------------
 # Example of using header-only library

example/example.cpp

@@ -5,24 +5,32 @@
 // spdlog usage example
 
 #include <cstdio>
+#include <chrono>
 
 void load_levels_example();
 void stdout_logger_example();
 void basic_example();
 void rotating_example();
 void daily_example();
+void callback_example();
 void async_example();
 void binary_example();
+void vector_example();
 void stopwatch_example();
 void trace_example();
 void multi_sink_example();
 void user_defined_example();
 void err_handler_example();
 void syslog_example();
+void udp_example();
 void custom_flags_example();
+void file_events_example();
+void replace_default_logger_example();
 
 #include "spdlog/spdlog.h"
-#include "spdlog/cfg/env.h" // support for loading levels from the environment variable
+#include "spdlog/cfg/env.h"  // support for loading levels from the environment variable
+#include "spdlog/fmt/ostr.h" // support for user defined types
+
 
 int main(int, char *[])
 {
@@ -66,14 +74,19 @@ int main(int, char *[])
         basic_example();
         rotating_example();
         daily_example();
+        callback_example();
         async_example();
         binary_example();
+        vector_example();
         multi_sink_example();
         user_defined_example();
         err_handler_example();
         trace_example();
         stopwatch_example();
+        udp_example();
         custom_flags_example();
+        file_events_example();
+        replace_default_logger_example();
 
         // Flush all *registered* loggers using a worker thread every 3 seconds.
         // note: registered loggers *must* be thread safe for this to work correctly!
@@ -109,7 +122,7 @@ void stdout_logger_example()
 void basic_example()
 {
     // Create basic file logger (not rotated).
-    auto my_logger = spdlog::basic_logger_mt("file_logger", "logs/basic-log.txt");
+    auto my_logger = spdlog::basic_logger_mt("file_logger", "logs/basic-log.txt", true);
 }
 
 #include "spdlog/sinks/rotating_file_sink.h"
@@ -126,10 +139,19 @@ void daily_example()
     auto daily_logger = spdlog::daily_logger_mt("daily_logger", "logs/daily.txt", 2, 30);
 }
 
+#include "spdlog/sinks/callback_sink.h"
+void callback_example()
+{
+    // Create the logger
+    auto logger = spdlog::callback_logger_mt("custom_callback_logger", [](const spdlog::details::log_msg & /*msg*/) {
+        // do what you need to do with msg
+    });
+}
+
 #include "spdlog/cfg/env.h"
 void load_levels_example()
 {
-    // Set the log level to "info" and mylogger to to "trace":
+    // Set the log level to "info" and mylogger to "trace":
     // SPDLOG_LEVEL=info,mylogger=trace && ./example
     spdlog::cfg::load_env_levels();
     // or from command line:
@@ -162,6 +184,7 @@ void async_example()
 // {:p} - don't print the position on each line start.
 // {:n} - don't split the output to lines.
 
+#if !defined SPDLOG_USE_STD_FORMAT || defined(_MSC_VER)
 #include "spdlog/fmt/bin_to_hex.h"
 void binary_example()
 {
@@ -179,6 +202,26 @@ void binary_example()
     // logger->info("hexdump style: {:a}", spdlog::to_hex(buf));
     // logger->info("hexdump style, 20 chars per line {:a}", spdlog::to_hex(buf, 20));
 }
+#else
+void binary_example() {
+    // not supported with std::format yet
+}
+#endif
+
+// Log a vector of numbers
+#ifndef SPDLOG_USE_STD_FORMAT
+#    include "spdlog/fmt/ranges.h"
+void vector_example()
+{
+    std::vector<int> vec = {1, 2, 3};
+    spdlog::info("Vector example: {}", vec);
+}
+
+#else
+void vector_example() {}
+#endif
+
+// ! DSPDLOG_USE_STD_FORMAT
 
 // Compile time log levels.
 // define SPDLOG_ACTIVE_LEVEL to required level (e.g. SPDLOG_LEVEL_TRACE)
@@ -204,6 +247,15 @@ void stopwatch_example()
     spdlog::info("Stopwatch: {} seconds", sw);
 }
 
+#include "spdlog/sinks/udp_sink.h"
+void udp_example()
+{
+    spdlog::sinks::udp_sink_config cfg("127.0.0.1", 11091);
+    auto my_logger = spdlog::udp_logger_mt("udplog", cfg);
+    my_logger->set_level(spdlog::level::debug);
+    my_logger->info("hello world");
+}
+
 // A logger with multiple sinks (stdout and file) - each with a different format and log level.
 void multi_sink_example()
 {
@@ -220,21 +272,38 @@ void multi_sink_example()
     logger.info("this message should not appear in the console, only in the file");
 }
 
-// User defined types logging by implementing operator<<
-#include "spdlog/fmt/ostr.h" // must be included
+// User defined types logging
 struct my_type
 {
-    int i;
-    template<typename OStream>
-    friend OStream &operator<<(OStream &os, const my_type &c)
+    int i = 0;
+    explicit my_type(int i)
+        : i(i){};
+};
+
+#ifndef SPDLOG_USE_STD_FORMAT // when using fmtlib
+template<>
+struct fmt::formatter<my_type> : fmt::formatter<std::string>
+{
+    auto format(my_type my, format_context &ctx) -> decltype(ctx.out())
     {
-        return os << "[my_type i=" << c.i << "]";
+        return fmt::format_to(ctx.out(), "[my_type i={}]", my.i);
     }
 };
 
+#else // when using std::format
+template<>
+struct std::formatter<my_type> : std::formatter<std::string>
+{
+    auto format(my_type my, format_context &ctx) const -> decltype(ctx.out())
+    {
+        return format_to(ctx.out(), "[my_type i={}]", my.i);
+    }
+};
+#endif
+
 void user_defined_example()
 {
-    spdlog::info("user defined type: {}", my_type{14});
+    spdlog::info("user defined type: {}", my_type(14));
 }
 
 // Custom error handler. Will be triggered on log failure.
@@ -246,7 +315,7 @@ void err_handler_example()
 
 // syslog example (linux/osx/freebsd)
 #ifndef _WIN32
-#include "spdlog/sinks/syslog_sink.h"
+#    include "spdlog/sinks/syslog_sink.h"
 void syslog_example()
 {
     std::string ident = "spdlog-example";
@@ -257,7 +326,7 @@ void syslog_example()
 
 // Android example.
 #if defined(__ANDROID__)
-#include "spdlog/sinks/android_sink.h"
+#    include "spdlog/sinks/android_sink.h"
 void android_example()
 {
     std::string tag = "spdlog-android";
@@ -290,5 +359,40 @@ void custom_flags_example()
     using spdlog::details::make_unique; // for pre c++14
     auto formatter = make_unique<spdlog::pattern_formatter>();
     formatter->add_flag<my_formatter_flag>('*').set_pattern("[%n] [%*] [%^%l%$] %v");
-    spdlog::set_formatter(std::move(formatter));
+    // set the new formatter using spdlog::set_formatter(formatter) or logger->set_formatter(formatter)
+    // spdlog::set_formatter(std::move(formatter));
+}
+
+void file_events_example()
+{
+    // pass the spdlog::file_event_handlers to file sinks for open/close log file notifications
+    spdlog::file_event_handlers handlers;
+    handlers.before_open = [](spdlog::filename_t filename) { spdlog::info("Before opening {}", filename); };
+    handlers.after_open = [](spdlog::filename_t filename, std::FILE *fstream) {
+        spdlog::info("After opening {}", filename);
+        fputs("After opening\n", fstream);
+    };
+    handlers.before_close = [](spdlog::filename_t filename, std::FILE *fstream) {
+        spdlog::info("Before closing {}", filename);
+        fputs("Before closing\n", fstream);
+    };
+    handlers.after_close = [](spdlog::filename_t filename) { spdlog::info("After closing {}", filename); };
+    auto file_sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>("logs/events-sample.txt", true, handlers);
+    spdlog::logger my_logger("some_logger", file_sink);
+    my_logger.info("Some log line");
+}
+
+void replace_default_logger_example()
+{
+    // store the old logger so we don't break other examples.
+    auto old_logger = spdlog::default_logger();
+
+    auto new_logger = spdlog::basic_logger_mt("new_default_logger", "logs/new-default-log.txt", true);
+    spdlog::set_default_logger(new_logger);
+    spdlog::set_level(spdlog::level::info);
+    spdlog::debug("This message should not be displayed!");
+    spdlog::set_level(spdlog::level::trace);
+    spdlog::debug("This message should be displayed..");
+
+    spdlog::set_default_logger(old_logger);
 }

include/spdlog/async.h

@@ -46,7 +46,7 @@ struct async_factory_impl
         auto tp = registry_inst.get_tp();
         if (tp == nullptr)
         {
-            tp = std::make_shared<details::thread_pool>(details::default_async_q_size, 1);
+            tp = std::make_shared<details::thread_pool>(details::default_async_q_size, 1U);
             registry_inst.set_tp(tp);
         }
 
@@ -73,16 +73,22 @@ inline std::shared_ptr<spdlog::logger> create_async_nb(std::string logger_name,
 }
 
 // set global thread pool.
-inline void init_thread_pool(size_t q_size, size_t thread_count, std::function<void()> on_thread_start)
+inline void init_thread_pool(
+    size_t q_size, size_t thread_count, std::function<void()> on_thread_start, std::function<void()> on_thread_stop)
 {
-    auto tp = std::make_shared<details::thread_pool>(q_size, thread_count, on_thread_start);
+    auto tp = std::make_shared<details::thread_pool>(q_size, thread_count, on_thread_start, on_thread_stop);
     details::registry::instance().set_tp(std::move(tp));
 }
 
-// set global thread pool.
+inline void init_thread_pool(size_t q_size, size_t thread_count, std::function<void()> on_thread_start)
+{
+    init_thread_pool(q_size, thread_count, on_thread_start, [] {});
+}
+
 inline void init_thread_pool(size_t q_size, size_t thread_count)
 {
-    init_thread_pool(q_size, thread_count, [] {});
+    init_thread_pool(
+        q_size, thread_count, [] {}, [] {});
 }
 
 // get the global thread pool.

include/spdlog/async_logger-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/async_logger.h>
+#    include <spdlog/async_logger.h>
 #endif
 
 #include <spdlog/sinks/sink.h>
@@ -24,29 +24,27 @@ SPDLOG_INLINE spdlog::async_logger::async_logger(
 {}
 
 // send the log message to the thread pool
-SPDLOG_INLINE void spdlog::async_logger::sink_it_(const details::log_msg &msg)
+SPDLOG_INLINE void spdlog::async_logger::sink_it_(const details::log_msg &msg){
+    SPDLOG_TRY{if (auto pool_ptr = thread_pool_.lock()){pool_ptr->post_log(shared_from_this(), msg, overflow_policy_);
+}
+else
 {
-    if (auto pool_ptr = thread_pool_.lock())
-    {
-        pool_ptr->post_log(shared_from_this(), msg, overflow_policy_);
-    }
-    else
-    {
-        throw_spdlog_ex("async log: thread pool doesn't exist anymore");
-    }
+    throw_spdlog_ex("async log: thread pool doesn't exist anymore");
+}
+}
+SPDLOG_LOGGER_CATCH(msg.source)
 }
 
 // send flush request to the thread pool
-SPDLOG_INLINE void spdlog::async_logger::flush_()
+SPDLOG_INLINE void spdlog::async_logger::flush_(){
+    SPDLOG_TRY{if (auto pool_ptr = thread_pool_.lock()){pool_ptr->post_flush(shared_from_this(), overflow_policy_);
+}
+else
 {
-    if (auto pool_ptr = thread_pool_.lock())
-    {
-        pool_ptr->post_flush(shared_from_this(), overflow_policy_);
-    }
-    else
-    {
-        throw_spdlog_ex("async flush: thread pool doesn't exist anymore");
-    }
+    throw_spdlog_ex("async flush: thread pool doesn't exist anymore");
+}
+}
+SPDLOG_LOGGER_CATCH(source_loc())
 }
 
 //
@@ -62,7 +60,7 @@ SPDLOG_INLINE void spdlog::async_logger::backend_sink_it_(const details::log_msg
             {
                 sink->log(msg);
             }
-            SPDLOG_LOGGER_CATCH()
+            SPDLOG_LOGGER_CATCH(msg.source)
         }
     }
 
@@ -80,7 +78,7 @@ SPDLOG_INLINE void spdlog::async_logger::backend_flush_()
         {
             sink->flush();
         }
-        SPDLOG_LOGGER_CATCH()
+        SPDLOG_LOGGER_CATCH(source_loc())
     }
 }
 

include/spdlog/async_logger.h

@@ -64,5 +64,5 @@ private:
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "async_logger-inl.h"
+#    include "async_logger-inl.h"
 #endif

include/spdlog/cfg/helpers-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/cfg/helpers.h>
+#    include <spdlog/cfg/helpers.h>
 #endif
 
 #include <spdlog/spdlog.h>

include/spdlog/cfg/helpers.h

@@ -25,5 +25,5 @@ SPDLOG_API void load_levels(const std::string &txt);
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "helpers-inl.h"
+#    include "helpers-inl.h"
 #endif // SPDLOG_HEADER_ONLY

include/spdlog/common-inl.h

@@ -4,16 +4,19 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/common.h>
+#    include <spdlog/common.h>
 #endif
 
+#include <algorithm>
+#include <iterator>
+
 namespace spdlog {
 namespace level {
 
 #if __cplusplus >= 201703L
 constexpr
 #endif
-static string_view_t level_string_views[] SPDLOG_LEVEL_NAMES;
+    static string_view_t level_string_views[] SPDLOG_LEVEL_NAMES;
 
 static const char *short_level_names[] SPDLOG_SHORT_LEVEL_NAMES;
 
@@ -22,11 +25,6 @@ SPDLOG_INLINE const string_view_t &to_string_view(spdlog::level::level_enum l) S
     return level_string_views[l];
 }
 
-SPDLOG_INLINE void set_string_view(spdlog::level::level_enum l, const string_view_t &s) SPDLOG_NOEXCEPT
-{
-    level_string_views[l] = s;
-}
-
 SPDLOG_INLINE const char *to_short_c_str(spdlog::level::level_enum l) SPDLOG_NOEXCEPT
 {
     return short_level_names[l];
@@ -34,15 +32,10 @@ SPDLOG_INLINE const char *to_short_c_str(spdlog::level::level_enum l) SPDLOG_NOE
 
 SPDLOG_INLINE spdlog::level::level_enum from_str(const std::string &name) SPDLOG_NOEXCEPT
 {
-    int level = 0;
-    for (const auto &level_str : level_string_views)
-    {
-        if (level_str == name)
-        {
-            return static_cast<level::level_enum>(level);
-        }
-        level++;
-    }
+    auto it = std::find(std::begin(level_string_views), std::end(level_string_views), name);
+    if (it != std::end(level_string_views))
+        return static_cast<level::level_enum>(std::distance(std::begin(level_string_views), it));
+
     // check also for "warn" and "err" before giving up..
     if (name == "warn")
     {
@@ -62,9 +55,13 @@ SPDLOG_INLINE spdlog_ex::spdlog_ex(std::string msg)
 
 SPDLOG_INLINE spdlog_ex::spdlog_ex(const std::string &msg, int last_errno)
 {
+#ifdef SPDLOG_USE_STD_FORMAT
+    msg_ = std::system_error(std::error_code(last_errno, std::generic_category()), msg).what();
+#else
     memory_buf_t outbuf;
-    fmt::format_system_error(outbuf, last_errno, msg);
+    fmt::format_system_error(outbuf, last_errno, msg.c_str());
     msg_ = fmt::to_string(outbuf);
+#endif
 }
 
 SPDLOG_INLINE const char *spdlog_ex::what() const SPDLOG_NOEXCEPT

include/spdlog/common.h

@@ -14,68 +14,101 @@
 #include <string>
 #include <type_traits>
 #include <functional>
+#include <cstdio>
+
+#ifdef SPDLOG_USE_STD_FORMAT
+#    include <version>
+#    if __cpp_lib_format >= 202207L
+#        include <format>
+#    else
+#        include <string_view>
+#    endif
+#endif
 
 #ifdef SPDLOG_COMPILED_LIB
-#undef SPDLOG_HEADER_ONLY
-#if defined(_WIN32) && defined(SPDLOG_SHARED_LIB)
-#ifdef spdlog_EXPORTS
-#define SPDLOG_API __declspec(dllexport)
-#else
-#define SPDLOG_API __declspec(dllimport)
-#endif
-#else // !defined(_WIN32) || !defined(SPDLOG_SHARED_LIB)
-#define SPDLOG_API
-#endif
-#define SPDLOG_INLINE
+#    undef SPDLOG_HEADER_ONLY
+#    if defined(SPDLOG_SHARED_LIB)
+#        if defined(_WIN32)
+#            ifdef spdlog_EXPORTS
+#                define SPDLOG_API __declspec(dllexport)
+#            else // !spdlog_EXPORTS
+#                define SPDLOG_API __declspec(dllimport)
+#            endif
+#        else // !defined(_WIN32)
+#            define SPDLOG_API __attribute__((visibility("default")))
+#        endif
+#    else // !defined(SPDLOG_SHARED_LIB)
+#        define SPDLOG_API
+#    endif
+#    define SPDLOG_INLINE
 #else // !defined(SPDLOG_COMPILED_LIB)
-#define SPDLOG_API
-#define SPDLOG_HEADER_ONLY
-#define SPDLOG_INLINE inline
+#    define SPDLOG_API
+#    define SPDLOG_HEADER_ONLY
+#    define SPDLOG_INLINE inline
 #endif // #ifdef SPDLOG_COMPILED_LIB
 
 #include <spdlog/fmt/fmt.h>
 
-// visual studio upto 2013 does not support noexcept nor constexpr
-#if defined(_MSC_VER) && (_MSC_VER < 1900)
-#define SPDLOG_NOEXCEPT _NOEXCEPT
-#define SPDLOG_CONSTEXPR
+#if !defined(SPDLOG_USE_STD_FORMAT) && FMT_VERSION >= 80000 // backward compatibility with fmt versions older than 8
+#    define SPDLOG_FMT_RUNTIME(format_string) fmt::runtime(format_string)
+#    define SPDLOG_FMT_STRING(format_string) FMT_STRING(format_string)
+#    if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+#        include <spdlog/fmt/xchar.h>
+#    endif
 #else
-#define SPDLOG_NOEXCEPT noexcept
-#define SPDLOG_CONSTEXPR constexpr
+#    define SPDLOG_FMT_RUNTIME(format_string) format_string
+#    define SPDLOG_FMT_STRING(format_string) format_string
+#endif
+
+// visual studio up to 2013 does not support noexcept nor constexpr
+#if defined(_MSC_VER) && (_MSC_VER < 1900)
+#    define SPDLOG_NOEXCEPT _NOEXCEPT
+#    define SPDLOG_CONSTEXPR
+#    define SPDLOG_CONSTEXPR_FUNC inline
+#else
+#    define SPDLOG_NOEXCEPT noexcept
+#    define SPDLOG_CONSTEXPR constexpr
+#    if __cplusplus >= 201402L
+#        define SPDLOG_CONSTEXPR_FUNC constexpr
+#    else
+#        define SPDLOG_CONSTEXPR_FUNC inline
+#    endif
 #endif
 
 #if defined(__GNUC__) || defined(__clang__)
-#define SPDLOG_DEPRECATED __attribute__((deprecated))
+#    define SPDLOG_DEPRECATED __attribute__((deprecated))
 #elif defined(_MSC_VER)
-#define SPDLOG_DEPRECATED __declspec(deprecated)
+#    define SPDLOG_DEPRECATED __declspec(deprecated)
 #else
-#define SPDLOG_DEPRECATED
+#    define SPDLOG_DEPRECATED
 #endif
 
 // disable thread local on msvc 2013
 #ifndef SPDLOG_NO_TLS
-#if (defined(_MSC_VER) && (_MSC_VER < 1900)) || defined(__cplusplus_winrt)
-#define SPDLOG_NO_TLS 1
-#endif
+#    if (defined(_MSC_VER) && (_MSC_VER < 1900)) || defined(__cplusplus_winrt)
+#        define SPDLOG_NO_TLS 1
+#    endif
 #endif
 
 #ifndef SPDLOG_FUNCTION
-#define SPDLOG_FUNCTION static_cast<const char *>(__FUNCTION__)
+#    define SPDLOG_FUNCTION static_cast<const char *>(__FUNCTION__)
 #endif
 
 #ifdef SPDLOG_NO_EXCEPTIONS
-#define SPDLOG_TRY
-#define SPDLOG_THROW(ex)                                                                                                                   \
-    do                                                                                                                                     \
-    {                                                                                                                                      \
-        printf("spdlog fatal error: %s\n", ex.what());                                                                                     \
-        std::abort();                                                                                                                      \
-    } while (0)
-#define SPDLOG_CATCH_ALL()
+#    define SPDLOG_TRY
+#    define SPDLOG_THROW(ex)                                                                                                               \
+        do                                                                                                                                 \
+        {                                                                                                                                  \
+            printf("spdlog fatal error: %s\n", ex.what());                                                                                 \
+            std::abort();                                                                                                                  \
+        } while (0)
+#    define SPDLOG_CATCH_STD
 #else
-#define SPDLOG_TRY try
-#define SPDLOG_THROW(ex) throw(ex)
-#define SPDLOG_CATCH_ALL() catch (...)
+#    define SPDLOG_TRY try
+#    define SPDLOG_THROW(ex) throw(ex)
+#    define SPDLOG_CATCH_STD                                                                                                               \
+        catch (const std::exception &)                                                                                                     \
+        {}
 #endif
 
 namespace spdlog {
@@ -89,35 +122,93 @@ class sink;
 #if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
 using filename_t = std::wstring;
 // allow macro expansion to occur in SPDLOG_FILENAME_T
-#define SPDLOG_FILENAME_T_INNER(s) L##s
-#define SPDLOG_FILENAME_T(s) SPDLOG_FILENAME_T_INNER(s)
+#    define SPDLOG_FILENAME_T_INNER(s) L##s
+#    define SPDLOG_FILENAME_T(s) SPDLOG_FILENAME_T_INNER(s)
 #else
 using filename_t = std::string;
-#define SPDLOG_FILENAME_T(s) s
+#    define SPDLOG_FILENAME_T(s) s
 #endif
 
 using log_clock = std::chrono::system_clock;
 using sink_ptr = std::shared_ptr<sinks::sink>;
 using sinks_init_list = std::initializer_list<sink_ptr>;
 using err_handler = std::function<void(const std::string &err_msg)>;
+#ifdef SPDLOG_USE_STD_FORMAT
+namespace fmt_lib = std;
+
+using string_view_t = std::string_view;
+using memory_buf_t = std::string;
+
+template<typename... Args>
+#    if __cpp_lib_format >= 202207L
+using format_string_t = std::format_string<Args...>;
+#    else
+using format_string_t = std::string_view;
+#    endif
+
+template<class T, class Char = char>
+struct is_convertible_to_basic_format_string : std::integral_constant<bool, std::is_convertible<T, std::basic_string_view<Char>>::value>
+{};
+
+#    if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+using wstring_view_t = std::wstring_view;
+using wmemory_buf_t = std::wstring;
+
+template<typename... Args>
+#        if __cpp_lib_format >= 202207L
+using wformat_string_t = std::wformat_string<Args...>;
+#        else
+using wformat_string_t = std::wstring_view;
+#        endif
+#    endif
+#    define SPDLOG_BUF_TO_STRING(x) x
+#else // use fmt lib instead of std::format
+namespace fmt_lib = fmt;
+
 using string_view_t = fmt::basic_string_view<char>;
-using wstring_view_t = fmt::basic_string_view<wchar_t>;
 using memory_buf_t = fmt::basic_memory_buffer<char, 250>;
+
+template<typename... Args>
+using format_string_t = fmt::format_string<Args...>;
+
+template<class T>
+using remove_cvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type;
+
+template<typename Char>
+#    if FMT_VERSION >= 90101
+using fmt_runtime_string = fmt::runtime_format_string<Char>;
+#    else
+using fmt_runtime_string = fmt::basic_runtime<Char>;
+#    endif
+
+// clang doesn't like SFINAE disabled constructor in std::is_convertible<> so have to repeat the condition from basic_format_string here,
+// in addition, fmt::basic_runtime<Char> is only convertible to basic_format_string<Char> but not basic_string_view<Char>
+template<class T, class Char = char>
+struct is_convertible_to_basic_format_string
+    : std::integral_constant<bool,
+          std::is_convertible<T, fmt::basic_string_view<Char>>::value || std::is_same<remove_cvref_t<T>, fmt_runtime_string<Char>>::value>
+{};
+
+#    if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+using wstring_view_t = fmt::basic_string_view<wchar_t>;
 using wmemory_buf_t = fmt::basic_memory_buffer<wchar_t, 250>;
 
+template<typename... Args>
+using wformat_string_t = fmt::wformat_string<Args...>;
+#    endif
+#    define SPDLOG_BUF_TO_STRING(x) fmt::to_string(x)
+#endif
+
 #ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
-#ifndef _WIN32
-#error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
-#else
-template<typename T>
-struct is_convertible_to_wstring_view : std::is_convertible<T, wstring_view_t>
+#    ifndef _WIN32
+#        error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
+#    endif // _WIN32
+#endif     // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+template<class T>
+struct is_convertible_to_any_format_string : std::integral_constant<bool, is_convertible_to_basic_format_string<T, char>::value ||
+                                                                              is_convertible_to_basic_format_string<T, wchar_t>::value>
 {};
-#endif // _WIN32
-#else
-template<typename>
-struct is_convertible_to_wstring_view : std::false_type
-{};
-#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
 
 #if defined(SPDLOG_NO_ATOMIC_LEVELS)
 using level_t = details::null_atomic_int;
@@ -134,12 +225,12 @@ using level_t = std::atomic<int>;
 #define SPDLOG_LEVEL_OFF 6
 
 #if !defined(SPDLOG_ACTIVE_LEVEL)
-#define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_INFO
+#    define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_INFO
 #endif
 
 // Log level enum
 namespace level {
-enum level_enum
+enum level_enum : int
 {
     trace = SPDLOG_LEVEL_TRACE,
     debug = SPDLOG_LEVEL_DEBUG,
@@ -151,23 +242,31 @@ enum level_enum
     n_levels
 };
 
+#define SPDLOG_LEVEL_NAME_TRACE spdlog::string_view_t("trace", 5)
+#define SPDLOG_LEVEL_NAME_DEBUG spdlog::string_view_t("debug", 5)
+#define SPDLOG_LEVEL_NAME_INFO spdlog::string_view_t("info", 4)
+#define SPDLOG_LEVEL_NAME_WARNING spdlog::string_view_t("warning", 7)
+#define SPDLOG_LEVEL_NAME_ERROR spdlog::string_view_t("error", 5)
+#define SPDLOG_LEVEL_NAME_CRITICAL spdlog::string_view_t("critical", 8)
+#define SPDLOG_LEVEL_NAME_OFF spdlog::string_view_t("off", 3)
+
 #if !defined(SPDLOG_LEVEL_NAMES)
-#define SPDLOG_LEVEL_NAMES                                                                                                                 \
-    {                                                                                                                                      \
-        "trace", "debug", "info", "warning", "error", "critical", "off"                                                                    \
-    }
+#    define SPDLOG_LEVEL_NAMES                                                                                                             \
+        {                                                                                                                                  \
+            SPDLOG_LEVEL_NAME_TRACE, SPDLOG_LEVEL_NAME_DEBUG, SPDLOG_LEVEL_NAME_INFO, SPDLOG_LEVEL_NAME_WARNING, SPDLOG_LEVEL_NAME_ERROR,  \
+                SPDLOG_LEVEL_NAME_CRITICAL, SPDLOG_LEVEL_NAME_OFF                                                                          \
+        }
 #endif
 
 #if !defined(SPDLOG_SHORT_LEVEL_NAMES)
 
-#define SPDLOG_SHORT_LEVEL_NAMES                                                                                                           \
-    {                                                                                                                                      \
-        "T", "D", "I", "W", "E", "C", "O"                                                                                                  \
-    }
+#    define SPDLOG_SHORT_LEVEL_NAMES                                                                                                       \
+        {                                                                                                                                  \
+            "T", "D", "I", "W", "E", "C", "O"                                                                                              \
+        }
 #endif
 
 SPDLOG_API const string_view_t &to_string_view(spdlog::level::level_enum l) SPDLOG_NOEXCEPT;
-SPDLOG_API void set_string_view(spdlog::level::level_enum l, const string_view_t &s) SPDLOG_NOEXCEPT;
 SPDLOG_API const char *to_short_c_str(spdlog::level::level_enum l) SPDLOG_NOEXCEPT;
 SPDLOG_API spdlog::level::level_enum from_str(const std::string &name) SPDLOG_NOEXCEPT;
 
@@ -228,12 +327,70 @@ struct source_loc
     const char *funcname{nullptr};
 };
 
+struct file_event_handlers
+{
+    file_event_handlers()
+        : before_open(nullptr)
+        , after_open(nullptr)
+        , before_close(nullptr)
+        , after_close(nullptr)
+    {}
+
+    std::function<void(const filename_t &filename)> before_open;
+    std::function<void(const filename_t &filename, std::FILE *file_stream)> after_open;
+    std::function<void(const filename_t &filename, std::FILE *file_stream)> before_close;
+    std::function<void(const filename_t &filename)> after_close;
+};
+
 namespace details {
+
+// to_string_view
+
+SPDLOG_CONSTEXPR_FUNC spdlog::string_view_t to_string_view(const memory_buf_t &buf) SPDLOG_NOEXCEPT
+{
+    return spdlog::string_view_t{buf.data(), buf.size()};
+}
+
+SPDLOG_CONSTEXPR_FUNC spdlog::string_view_t to_string_view(spdlog::string_view_t str) SPDLOG_NOEXCEPT
+{
+    return str;
+}
+
+#if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+SPDLOG_CONSTEXPR_FUNC spdlog::wstring_view_t to_string_view(const wmemory_buf_t &buf) SPDLOG_NOEXCEPT
+{
+    return spdlog::wstring_view_t{buf.data(), buf.size()};
+}
+
+SPDLOG_CONSTEXPR_FUNC spdlog::wstring_view_t to_string_view(spdlog::wstring_view_t str) SPDLOG_NOEXCEPT
+{
+    return str;
+}
+#endif
+
+#ifndef SPDLOG_USE_STD_FORMAT
+template<typename T, typename... Args>
+inline fmt::basic_string_view<T> to_string_view(fmt::basic_format_string<T, Args...> fmt)
+{
+    return fmt;
+}
+#elif __cpp_lib_format >= 202207L
+template<typename T, typename... Args>
+SPDLOG_CONSTEXPR_FUNC std::basic_string_view<T> to_string_view(std::basic_format_string<T, Args...> fmt) SPDLOG_NOEXCEPT
+{
+    return fmt.get();
+}
+#endif
+
 // make_unique support for pre c++14
 
 #if __cplusplus >= 201402L // C++14 and beyond
+using std::enable_if_t;
 using std::make_unique;
 #else
+template<bool B, class T = void>
+using enable_if_t = typename std::enable_if<B, T>::type;
+
 template<typename T, typename... Args>
 std::unique_ptr<T> make_unique(Args &&...args)
 {
@@ -241,9 +398,23 @@ std::unique_ptr<T> make_unique(Args &&...args)
     return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
 }
 #endif
+
+// to avoid useless casts (see https://github.com/nlohmann/json/issues/2893#issuecomment-889152324)
+template<typename T, typename U, enable_if_t<!std::is_same<T, U>::value, int> = 0>
+constexpr T conditional_static_cast(U value)
+{
+    return static_cast<T>(value);
+}
+
+template<typename T, typename U, enable_if_t<std::is_same<T, U>::value, int> = 0>
+constexpr T conditional_static_cast(U value)
+{
+    return value;
+}
+
 } // namespace details
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "common-inl.h"
+#    include "common-inl.h"
 #endif

include/spdlog/details/backtracer-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/details/backtracer.h>
+#    include <spdlog/details/backtracer.h>
 #endif
 namespace spdlog {
 namespace details {
@@ -54,6 +54,12 @@ SPDLOG_INLINE void backtracer::push_back(const log_msg &msg)
     messages_.push_back(log_msg_buffer{msg});
 }
 
+SPDLOG_INLINE bool backtracer::empty() const
+{
+    std::lock_guard<std::mutex> lock{mutex_};
+    return messages_.empty();
+}
+
 // pop all items in the q and apply the given fun on each of them.
 SPDLOG_INLINE void backtracer::foreach_pop(std::function<void(const details::log_msg &)> fun)
 {

include/spdlog/details/backtracer.h

@@ -32,6 +32,7 @@ public:
     void disable();
     bool enabled() const;
     void push_back(const log_msg &msg);
+    bool empty() const;
 
     // pop all items in the q and apply the given fun on each of them.
     void foreach_pop(std::function<void(const details::log_msg &)> fun);
@@ -41,5 +42,5 @@ public:
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "backtracer-inl.h"
-#endif
+#    include "backtracer-inl.h"
+#endif

include/spdlog/details/circular_q.h

@@ -121,6 +121,11 @@ public:
         return overrun_counter_;
     }
 
+    void reset_overrun_counter()
+    {
+        overrun_counter_ = 0;
+    }
+
 private:
     // copy from other&& and reset it to disabled state
     void copy_moveable(circular_q &&other) SPDLOG_NOEXCEPT

include/spdlog/details/file_helper-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/details/file_helper.h>
+#    include <spdlog/details/file_helper.h>
 #endif
 
 #include <spdlog/details/os.h>
@@ -20,6 +20,10 @@
 namespace spdlog {
 namespace details {
 
+SPDLOG_INLINE file_helper::file_helper(const file_event_handlers &event_handlers)
+    : event_handlers_(event_handlers)
+{}
+
 SPDLOG_INLINE file_helper::~file_helper()
 {
     close();
@@ -33,6 +37,10 @@ SPDLOG_INLINE void file_helper::open(const filename_t &fname, bool truncate)
     auto *mode = SPDLOG_FILENAME_T("ab");
     auto *trunc_mode = SPDLOG_FILENAME_T("wb");
 
+    if (event_handlers_.before_open)
+    {
+        event_handlers_.before_open(filename_);
+    }
     for (int tries = 0; tries < open_tries_; ++tries)
     {
         // create containing folder if not exists already.
@@ -52,6 +60,10 @@ SPDLOG_INLINE void file_helper::open(const filename_t &fname, bool truncate)
         }
         if (!os::fopen_s(&fd_, fname, mode))
         {
+            if (event_handlers_.after_open)
+            {
+                event_handlers_.after_open(filename_, fd_);
+            }
             return;
         }
 
@@ -72,15 +84,36 @@ SPDLOG_INLINE void file_helper::reopen(bool truncate)
 
 SPDLOG_INLINE void file_helper::flush()
 {
-    std::fflush(fd_);
+    if (std::fflush(fd_) != 0)
+    {
+        throw_spdlog_ex("Failed flush to file " + os::filename_to_str(filename_), errno);
+    }
+}
+
+SPDLOG_INLINE void file_helper::sync()
+{
+    if (!os::fsync(fd_))
+    {
+        throw_spdlog_ex("Failed to fsync file " + os::filename_to_str(filename_), errno);
+    }
 }
 
 SPDLOG_INLINE void file_helper::close()
 {
     if (fd_ != nullptr)
     {
+        if (event_handlers_.before_close)
+        {
+            event_handlers_.before_close(filename_, fd_);
+        }
+
         std::fclose(fd_);
         fd_ = nullptr;
+
+        if (event_handlers_.after_close)
+        {
+            event_handlers_.after_close(filename_);
+        }
     }
 }
 

include/spdlog/details/file_helper.h

@@ -16,7 +16,8 @@ namespace details {
 class SPDLOG_API file_helper
 {
 public:
-    explicit file_helper() = default;
+    file_helper() = default;
+    explicit file_helper(const file_event_handlers &event_handlers);
 
     file_helper(const file_helper &) = delete;
     file_helper &operator=(const file_helper &) = delete;
@@ -25,6 +26,7 @@ public:
     void open(const filename_t &fname, bool truncate = false);
     void reopen(bool truncate);
     void flush();
+    void sync();
     void close();
     void write(const memory_buf_t &buf);
     size_t size() const;
@@ -47,13 +49,14 @@ public:
 
 private:
     const int open_tries_ = 5;
-    const int open_interval_ = 10;
+    const unsigned int open_interval_ = 10;
     std::FILE *fd_{nullptr};
     filename_t filename_;
+    file_event_handlers event_handlers_;
 };
 } // namespace details
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "file_helper-inl.h"
+#    include "file_helper-inl.h"
 #endif

include/spdlog/details/fmt_helper.h

@@ -4,45 +4,93 @@
 
 #include <chrono>
 #include <type_traits>
+#include <iterator>
 #include <spdlog/fmt/fmt.h>
 #include <spdlog/common.h>
 
+#ifdef SPDLOG_USE_STD_FORMAT
+#    include <charconv>
+#    include <limits>
+#endif
+
 // Some fmt helpers to efficiently format and pad ints and strings
 namespace spdlog {
 namespace details {
 namespace fmt_helper {
 
-inline spdlog::string_view_t to_string_view(const memory_buf_t &buf) SPDLOG_NOEXCEPT
-{
-    return spdlog::string_view_t{buf.data(), buf.size()};
-}
-
 inline void append_string_view(spdlog::string_view_t view, memory_buf_t &dest)
 {
     auto *buf_ptr = view.data();
     dest.append(buf_ptr, buf_ptr + view.size());
 }
 
+#ifdef SPDLOG_USE_STD_FORMAT
+template<typename T>
+inline void append_int(T n, memory_buf_t &dest)
+{
+    // Buffer should be large enough to hold all digits (digits10 + 1) and a sign
+    SPDLOG_CONSTEXPR const auto BUF_SIZE = std::numeric_limits<T>::digits10 + 2;
+    char buf[BUF_SIZE];
+
+    auto [ptr, ec] = std::to_chars(buf, buf + BUF_SIZE, n, 10);
+    if (ec == std::errc())
+    {
+        dest.append(buf, ptr);
+    }
+    else
+    {
+        throw_spdlog_ex("Failed to format int", static_cast<int>(ec));
+    }
+}
+#else
 template<typename T>
 inline void append_int(T n, memory_buf_t &dest)
 {
     fmt::format_int i(n);
     dest.append(i.data(), i.data() + i.size());
 }
+#endif
+
+template<typename T>
+SPDLOG_CONSTEXPR_FUNC unsigned int count_digits_fallback(T n)
+{
+    // taken from fmt: https://github.com/fmtlib/fmt/blob/8.0.1/include/fmt/format.h#L899-L912
+    unsigned int count = 1;
+    for (;;)
+    {
+        // Integer division is slow so do it for a group of four digits instead
+        // of for every digit. The idea comes from the talk by Alexandrescu
+        // "Three Optimization Tips for C++". See speed-test for a comparison.
+        if (n < 10)
+            return count;
+        if (n < 100)
+            return count + 1;
+        if (n < 1000)
+            return count + 2;
+        if (n < 10000)
+            return count + 3;
+        n /= 10000u;
+        count += 4;
+    }
+}
 
 template<typename T>
 inline unsigned int count_digits(T n)
 {
     using count_type = typename std::conditional<(sizeof(T) > sizeof(uint32_t)), uint64_t, uint32_t>::type;
+#ifdef SPDLOG_USE_STD_FORMAT
+    return count_digits_fallback(static_cast<count_type>(n));
+#else
     return static_cast<unsigned int>(fmt::
 // fmt 7.0.0 renamed the internal namespace to detail.
 // See: https://github.com/fmtlib/fmt/issues/1538
-#if FMT_VERSION < 70000
+#    if FMT_VERSION < 70000
             internal
-#else
+#    else
             detail
-#endif
+#    endif
         ::count_digits(static_cast<count_type>(n)));
+#endif
 }
 
 inline void pad2(int n, memory_buf_t &dest)
@@ -54,7 +102,7 @@ inline void pad2(int n, memory_buf_t &dest)
     }
     else // unlikely, but just in case, let fmt deal with it
     {
-        fmt::format_to(dest, "{:02}", n);
+        fmt_lib::format_to(std::back_inserter(dest), SPDLOG_FMT_STRING("{:02}"), n);
     }
 }
 

include/spdlog/details/log_msg-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/details/log_msg.h>
+#    include <spdlog/details/log_msg.h>
 #endif
 
 #include <spdlog/details/os.h>

include/spdlog/details/log_msg.h

@@ -15,6 +15,7 @@ struct SPDLOG_API log_msg
     log_msg(source_loc loc, string_view_t logger_name, level::level_enum lvl, string_view_t msg);
     log_msg(string_view_t logger_name, level::level_enum lvl, string_view_t msg);
     log_msg(const log_msg &other) = default;
+    log_msg &operator=(const log_msg &other) = default;
 
     string_view_t logger_name;
     level::level_enum level{level::off};
@@ -32,5 +33,5 @@ struct SPDLOG_API log_msg
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "log_msg-inl.h"
+#    include "log_msg-inl.h"
 #endif

include/spdlog/details/log_msg_buffer-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/details/log_msg_buffer.h>
+#    include <spdlog/details/log_msg_buffer.h>
 #endif
 
 namespace spdlog {
@@ -26,9 +26,7 @@ SPDLOG_INLINE log_msg_buffer::log_msg_buffer(const log_msg_buffer &other)
     update_string_views();
 }
 
-SPDLOG_INLINE log_msg_buffer::log_msg_buffer(log_msg_buffer &&other) SPDLOG_NOEXCEPT 
-    : log_msg{other}
-    , buffer{std::move(other.buffer)}
+SPDLOG_INLINE log_msg_buffer::log_msg_buffer(log_msg_buffer &&other) SPDLOG_NOEXCEPT : log_msg{other}, buffer{std::move(other.buffer)}
 {
     update_string_views();
 }

include/spdlog/details/log_msg_buffer.h

@@ -29,5 +29,5 @@ public:
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "log_msg_buffer-inl.h"
+#    include "log_msg_buffer-inl.h"
 #endif

include/spdlog/details/mpmc_blocking_q.h

@@ -49,7 +49,7 @@ public:
         push_cv_.notify_one();
     }
 
-    // try to dequeue item. if no item found. wait upto timeout and try again
+    // dequeue with a timeout.
     // Return true, if succeeded dequeue item, false otherwise
     bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
     {
@@ -66,6 +66,18 @@ public:
         return true;
     }
 
+    // blocking dequeue without a timeout.
+    void dequeue(T &popped_item)
+    {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            push_cv_.wait(lock, [this] { return !this->q_.empty(); });
+            popped_item = std::move(q_.front());
+            q_.pop_front();
+        }
+        pop_cv_.notify_one();
+    }
+
 #else
     // apparently mingw deadlocks if the mutex is released before cv.notify_one(),
     // so release the mutex at the very end each function.
@@ -87,7 +99,7 @@ public:
         push_cv_.notify_one();
     }
 
-    // try to dequeue item. if no item found. wait upto timeout and try again
+    // dequeue with a timeout.
     // Return true, if succeeded dequeue item, false otherwise
     bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
     {
@@ -102,6 +114,16 @@ public:
         return true;
     }
 
+    // blocking dequeue without a timeout.
+    void dequeue(T &popped_item)
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        push_cv_.wait(lock, [this] { return !this->q_.empty(); });
+        popped_item = std::move(q_.front());
+        q_.pop_front();
+        pop_cv_.notify_one();
+    }
+
 #endif
 
     size_t overrun_counter()
@@ -116,6 +138,12 @@ public:
         return q_.size();
     }
 
+    void reset_overrun_counter()
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        q_.reset_overrun_counter();
+    }
+
 private:
     std::mutex queue_mutex_;
     std::condition_variable push_cv_;

include/spdlog/details/null_mutex.h

@@ -13,10 +13,6 @@ struct null_mutex
 {
     void lock() const {}
     void unlock() const {}
-    bool try_lock() const
-    {
-        return true;
-    }
 };
 
 struct null_atomic_int

include/spdlog/details/os-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/details/os.h>
+#    include <spdlog/details/os.h>
 #endif
 
 #include <spdlog/common.h>
@@ -23,45 +23,51 @@
 
 #ifdef _WIN32
 
-#include <io.h>      // _get_osfhandle and _isatty support
-#include <process.h> //  _get_pid support
-#include <spdlog/details/windows_include.h>
+#    include <io.h>      // for _get_osfhandle, _isatty, _fileno
+#    include <process.h> // for _get_pid
+#    include <spdlog/details/windows_include.h>
+#    include <fileapi.h> // for FlushFileBuffers
 
-#ifdef __MINGW32__
-#include <share.h>
-#endif
+#    ifdef __MINGW32__
+#        include <share.h>
+#    endif
 
-#if defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)
-#include <limits>
-#endif
+#    if defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)
+#        include <limits>
+#        include <cassert>
+#    endif
 
-#include <direct.h> // for _mkdir/_wmkdir
+#    include <direct.h> // for _mkdir/_wmkdir
 
 #else // unix
 
-#include <fcntl.h>
-#include <unistd.h>
+#    include <fcntl.h>
+#    include <unistd.h>
 
-#ifdef __linux__
-#include <sys/syscall.h> //Use gettid() syscall under linux to get thread id
+#    ifdef __linux__
+#        include <sys/syscall.h> //Use gettid() syscall under linux to get thread id
 
-#elif defined(_AIX)
-#include <pthread.h> // for pthread_getthreadid_np
+#    elif defined(_AIX)
+#        include <pthread.h> // for pthread_getthrds_np
 
-#elif defined(__DragonFly__) || defined(__FreeBSD__)
-#include <pthread_np.h> // for pthread_getthreadid_np
+#    elif defined(__DragonFly__) || defined(__FreeBSD__)
+#        include <pthread_np.h> // for pthread_getthreadid_np
 
-#elif defined(__NetBSD__)
-#include <lwp.h> // for _lwp_self
+#    elif defined(__NetBSD__)
+#        include <lwp.h> // for _lwp_self
 
-#elif defined(__sun)
-#include <thread.h> // for thr_self
-#endif
+#    elif defined(__sun)
+#        include <thread.h> // for thr_self
+#    endif
 
 #endif // unix
 
-#ifndef __has_feature      // Clang - feature checking macros.
-#define __has_feature(x) 0 // Compatibility with non-clang compilers.
+#if defined __APPLE__
+#    include <AvailabilityMacros.h>
+#endif
+
+#ifndef __has_feature          // Clang - feature checking macros.
+#    define __has_feature(x) 0 // Compatibility with non-clang compilers.
 #endif
 
 namespace spdlog {
@@ -123,12 +129,12 @@ SPDLOG_INLINE std::tm gmtime() SPDLOG_NOEXCEPT
 SPDLOG_INLINE bool fopen_s(FILE **fp, const filename_t &filename, const filename_t &mode)
 {
 #ifdef _WIN32
-#ifdef SPDLOG_WCHAR_FILENAMES
+#    ifdef SPDLOG_WCHAR_FILENAMES
     *fp = ::_wfsopen((filename.c_str()), mode.c_str(), _SH_DENYNO);
-#else
+#    else
     *fp = ::_fsopen((filename.c_str()), mode.c_str(), _SH_DENYNO);
-#endif
-#if defined(SPDLOG_PREVENT_CHILD_FD)
+#    endif
+#    if defined(SPDLOG_PREVENT_CHILD_FD)
     if (*fp != nullptr)
     {
         auto file_handle = reinterpret_cast<HANDLE>(_get_osfhandle(::_fileno(*fp)));
@@ -138,23 +144,23 @@ SPDLOG_INLINE bool fopen_s(FILE **fp, const filename_t &filename, const filename
             *fp = nullptr;
         }
     }
-#endif
+#    endif
 #else // unix
-#if defined(SPDLOG_PREVENT_CHILD_FD)
+#    if defined(SPDLOG_PREVENT_CHILD_FD)
     const int mode_flag = mode == SPDLOG_FILENAME_T("ab") ? O_APPEND : O_TRUNC;
     const int fd = ::open((filename.c_str()), O_CREAT | O_WRONLY | O_CLOEXEC | mode_flag, mode_t(0644));
     if (fd == -1)
     {
-        return false;
+        return true;
     }
     *fp = ::fdopen(fd, mode.c_str());
     if (*fp == nullptr)
     {
         ::close(fd);
     }
-#else
+#    else
     *fp = ::fopen((filename.c_str()), mode.c_str());
-#endif
+#    endif
 #endif
 
     return *fp == nullptr;
@@ -187,11 +193,11 @@ SPDLOG_INLINE int rename(const filename_t &filename1, const filename_t &filename
 SPDLOG_INLINE bool path_exists(const filename_t &filename) SPDLOG_NOEXCEPT
 {
 #ifdef _WIN32
-#ifdef SPDLOG_WCHAR_FILENAMES
+#    ifdef SPDLOG_WCHAR_FILENAMES
     auto attribs = ::GetFileAttributesW(filename.c_str());
-#else
+#    else
     auto attribs = ::GetFileAttributesA(filename.c_str());
-#endif
+#    endif
     return attribs != INVALID_FILE_ATTRIBUTES;
 #else // common linux/unix all have the stat system call
     struct stat buffer;
@@ -199,6 +205,12 @@ SPDLOG_INLINE bool path_exists(const filename_t &filename) SPDLOG_NOEXCEPT
 #endif
 }
 
+#ifdef _MSC_VER
+// avoid warning about unreachable statement at the end of filesize()
+#    pragma warning(push)
+#    pragma warning(disable : 4702)
+#endif
+
 // Return file size according to open FILE* object
 SPDLOG_INLINE size_t filesize(FILE *f)
 {
@@ -208,59 +220,63 @@ SPDLOG_INLINE size_t filesize(FILE *f)
     }
 #if defined(_WIN32) && !defined(__CYGWIN__)
     int fd = ::_fileno(f);
-#if _WIN64 // 64 bits
+#    if defined(_WIN64) // 64 bits
     __int64 ret = ::_filelengthi64(fd);
     if (ret >= 0)
     {
         return static_cast<size_t>(ret);
     }
 
-#else // windows 32 bits
+#    else // windows 32 bits
     long ret = ::_filelength(fd);
     if (ret >= 0)
     {
         return static_cast<size_t>(ret);
     }
-#endif
+#    endif
 
 #else // unix
-// OpenBSD doesn't compile with :: before the fileno(..)
-#if defined(__OpenBSD__)
+// OpenBSD and AIX doesn't compile with :: before the fileno(..)
+#    if defined(__OpenBSD__) || defined(_AIX)
     int fd = fileno(f);
-#else
+#    else
     int fd = ::fileno(f);
-#endif
-// 64 bits(but not in osx or cygwin, where fstat64 is deprecated)
-#if (defined(__linux__) || defined(__sun) || defined(_AIX)) && (defined(__LP64__) || defined(_LP64))
+#    endif
+// 64 bits(but not in osx, linux/musl or cygwin, where fstat64 is deprecated)
+#    if ((defined(__linux__) && defined(__GLIBC__)) || defined(__sun) || defined(_AIX)) && (defined(__LP64__) || defined(_LP64))
     struct stat64 st;
     if (::fstat64(fd, &st) == 0)
     {
         return static_cast<size_t>(st.st_size);
     }
-#else // other unix or linux 32 bits or cygwin
+#    else // other unix or linux 32 bits or cygwin
     struct stat st;
     if (::fstat(fd, &st) == 0)
     {
         return static_cast<size_t>(st.st_size);
     }
-#endif
+#    endif
 #endif
     throw_spdlog_ex("Failed getting file size from fd", errno);
     return 0; // will not be reached.
 }
 
+#ifdef _MSC_VER
+#    pragma warning(pop)
+#endif
+
 // Return utc offset in minutes or throw spdlog_ex on failure
 SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm)
 {
 
 #ifdef _WIN32
-#if _WIN32_WINNT < _WIN32_WINNT_WS08
+#    if _WIN32_WINNT < _WIN32_WINNT_WS08
     TIME_ZONE_INFORMATION tzinfo;
     auto rv = ::GetTimeZoneInformation(&tzinfo);
-#else
+#    else
     DYNAMIC_TIME_ZONE_INFORMATION tzinfo;
     auto rv = ::GetDynamicTimeZoneInformation(&tzinfo);
-#endif
+#    endif
     if (rv == TIME_ZONE_ID_INVALID)
         throw_spdlog_ex("Failed getting timezone info. ", errno);
 
@@ -276,7 +292,8 @@ SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm)
     return offset;
 #else
 
-#if defined(sun) || defined(__sun) || defined(_AIX) || (!defined(_BSD_SOURCE) && !defined(_GNU_SOURCE))
+#    if defined(sun) || defined(__sun) || defined(_AIX) || (defined(__NEWLIB__) && !defined(__TM_GMTOFF)) ||                               \
+        (!defined(_BSD_SOURCE) && !defined(_GNU_SOURCE))
     // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
     struct helper
     {
@@ -295,7 +312,7 @@ SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm)
                 ((local_year / 100 >> 2) - (gmt_year / 100 >> 2))
 
                 // + difference in years * 365 */
-                + (long int)(local_year - gmt_year) * 365);
+                + static_cast<long int>(local_year - gmt_year) * 365);
 
             long int hours = (24 * days) + (localtm.tm_hour - gmtm.tm_hour);
             long int mins = (60 * hours) + (localtm.tm_min - gmtm.tm_min);
@@ -306,9 +323,9 @@ SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm)
     };
 
     auto offset_seconds = helper::calculate_gmt_offset(tm);
-#else
+#    else
     auto offset_seconds = tm.tm_gmtoff;
-#endif
+#    endif
 
     return static_cast<int>(offset_seconds / 60);
 #endif
@@ -322,11 +339,18 @@ SPDLOG_INLINE size_t _thread_id() SPDLOG_NOEXCEPT
 #ifdef _WIN32
     return static_cast<size_t>(::GetCurrentThreadId());
 #elif defined(__linux__)
-#if defined(__ANDROID__) && defined(__ANDROID_API__) && (__ANDROID_API__ < 21)
-#define SYS_gettid __NR_gettid
-#endif
+#    if defined(__ANDROID__) && defined(__ANDROID_API__) && (__ANDROID_API__ < 21)
+#        define SYS_gettid __NR_gettid
+#    endif
     return static_cast<size_t>(::syscall(SYS_gettid));
-#elif defined(_AIX) || defined(__DragonFly__) || defined(__FreeBSD__)
+#elif defined(_AIX)
+    struct __pthrdsinfo buf;
+    int reg_size = 0;
+    pthread_t pt = pthread_self();
+    int retval = pthread_getthrds_np(&pt, PTHRDSINFO_QUERY_TID, &buf, sizeof(buf), NULL, &reg_size);
+    int tid = (!retval) ? buf.__pi_tid : 0;
+    return static_cast<size_t>(tid);
+#elif defined(__DragonFly__) || defined(__FreeBSD__)
     return static_cast<size_t>(::pthread_getthreadid_np());
 #elif defined(__NetBSD__)
     return static_cast<size_t>(::_lwp_self());
@@ -336,7 +360,22 @@ SPDLOG_INLINE size_t _thread_id() SPDLOG_NOEXCEPT
     return static_cast<size_t>(::thr_self());
 #elif __APPLE__
     uint64_t tid;
+    // There is no pthread_threadid_np prior to 10.6, and it is not supported on any PPC,
+    // including 10.6.8 Rosetta. __POWERPC__ is Apple-specific define encompassing ppc and ppc64.
+#    if (MAC_OS_X_VERSION_MAX_ALLOWED < 1060) || defined(__POWERPC__)
+    tid = pthread_mach_thread_np(pthread_self());
+#    elif MAC_OS_X_VERSION_MIN_REQUIRED < 1060
+    if (&pthread_threadid_np)
+    {
+        pthread_threadid_np(nullptr, &tid);
+    }
+    else
+    {
+        tid = pthread_mach_thread_np(pthread_self());
+    }
+#    else
     pthread_threadid_np(nullptr, &tid);
+#    endif
     return static_cast<size_t>(tid);
 #else // Default to standard C++11 (other Unix)
     return static_cast<size_t>(std::hash<std::thread::id>()(std::this_thread::get_id()));
@@ -356,7 +395,7 @@ SPDLOG_INLINE size_t thread_id() SPDLOG_NOEXCEPT
 
 // This is avoid msvc issue in sleep_for that happens if the clock changes.
 // See https://github.com/gabime/spdlog/issues/609
-SPDLOG_INLINE void sleep_for_millis(int milliseconds) SPDLOG_NOEXCEPT
+SPDLOG_INLINE void sleep_for_millis(unsigned int milliseconds) SPDLOG_NOEXCEPT
 {
 #if defined(_WIN32)
     ::Sleep(milliseconds);
@@ -371,7 +410,7 @@ SPDLOG_INLINE std::string filename_to_str(const filename_t &filename)
 {
     memory_buf_t buf;
     wstr_to_utf8buf(filename, buf);
-    return fmt::to_string(buf);
+    return SPDLOG_BUF_TO_STRING(buf);
 }
 #else
 SPDLOG_INLINE std::string filename_to_str(const filename_t &filename)
@@ -384,9 +423,9 @@ SPDLOG_INLINE int pid() SPDLOG_NOEXCEPT
 {
 
 #ifdef _WIN32
-    return static_cast<int>(::GetCurrentProcessId());
+    return conditional_static_cast<int>(::GetCurrentProcessId());
 #else
-    return static_cast<int>(::getpid());
+    return conditional_static_cast<int>(::getpid());
 #endif
 }
 
@@ -405,8 +444,8 @@ SPDLOG_INLINE bool is_color_terminal() SPDLOG_NOEXCEPT
             return true;
         }
 
-        static constexpr std::array<const char *, 15> terms = {{"ansi", "color", "console", "cygwin", "gnome", "konsole", "kterm", "linux",
-            "msys", "putty", "rxvt", "screen", "vt100", "xterm", "alacritty"}};
+        static constexpr std::array<const char *, 16> terms = {{"ansi", "color", "console", "cygwin", "gnome", "konsole", "kterm", "linux",
+            "msys", "putty", "rxvt", "screen", "vt100", "xterm", "alacritty", "vt102"}};
 
         const char *env_term_p = std::getenv("TERM");
         if (env_term_p == nullptr)
@@ -466,7 +505,7 @@ SPDLOG_INLINE void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target)
         }
     }
 
-    throw_spdlog_ex(fmt::format("WideCharToMultiByte failed. Last error: {}", ::GetLastError()));
+    throw_spdlog_ex(fmt_lib::format("WideCharToMultiByte failed. Last error: {}", ::GetLastError()));
 }
 
 SPDLOG_INLINE void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target)
@@ -483,25 +522,21 @@ SPDLOG_INLINE void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target)
         return;
     }
 
-    int result_size = static_cast<int>(target.capacity());
-    if (str_size + 1 > result_size)
-    {
-        result_size = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str.data(), str_size, NULL, 0);
-    }
+    // find the size to allocate for the result buffer
+    int result_size = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str.data(), str_size, NULL, 0);
 
     if (result_size > 0)
     {
         target.resize(result_size);
         result_size = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str.data(), str_size, target.data(), result_size);
-
         if (result_size > 0)
         {
-            target.resize(result_size);
+            assert(result_size == target.size());
             return;
         }
     }
 
-    throw_spdlog_ex(fmt::format("MultiByteToWideChar failed. Last error: {}", ::GetLastError()));
+    throw_spdlog_ex(fmt_lib::format("MultiByteToWideChar failed. Last error: {}", ::GetLastError()));
 }
 #endif // (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
 
@@ -509,11 +544,11 @@ SPDLOG_INLINE void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target)
 static SPDLOG_INLINE bool mkdir_(const filename_t &path)
 {
 #ifdef _WIN32
-#ifdef SPDLOG_WCHAR_FILENAMES
+#    ifdef SPDLOG_WCHAR_FILENAMES
     return ::_wmkdir(path.c_str()) == 0;
-#else
+#    else
     return ::_mkdir(path.c_str()) == 0;
-#endif
+#    endif
 #else
     return ::mkdir(path.c_str(), mode_t(0755)) == 0;
 #endif
@@ -521,7 +556,7 @@ static SPDLOG_INLINE bool mkdir_(const filename_t &path)
 
 // create the given directory - and all directories leading to it
 // return true on success or if the directory already exists
-SPDLOG_INLINE bool create_dir(filename_t path)
+SPDLOG_INLINE bool create_dir(const filename_t &path)
 {
     if (path_exists(path))
     {
@@ -560,7 +595,7 @@ SPDLOG_INLINE bool create_dir(filename_t path)
 // "abc/" => "abc"
 // "abc" => ""
 // "abc///" => "abc//"
-SPDLOG_INLINE filename_t dir_name(filename_t path)
+SPDLOG_INLINE filename_t dir_name(const filename_t &path)
 {
     auto pos = path.find_last_of(folder_seps_filename);
     return pos != filename_t::npos ? path.substr(0, pos) : filename_t{};
@@ -570,20 +605,31 @@ std::string SPDLOG_INLINE getenv(const char *field)
 {
 
 #if defined(_MSC_VER)
-#if defined(__cplusplus_winrt)
+#    if defined(__cplusplus_winrt)
     return std::string{}; // not supported under uwp
-#else
+#    else
     size_t len = 0;
     char buf[128];
     bool ok = ::getenv_s(&len, buf, sizeof(buf), field) == 0;
     return ok ? buf : std::string{};
-#endif
+#    endif
 #else // revert to getenv
     char *buf = ::getenv(field);
     return buf ? buf : std::string{};
 #endif
 }
 
+// Do fsync by FILE handlerpointer
+// Return true on success
+SPDLOG_INLINE bool fsync(FILE *fp)
+{
+#ifdef _WIN32
+    return FlushFileBuffers(reinterpret_cast<HANDLE>(_get_osfhandle(_fileno(fp)))) != 0;
+#else
+    return ::fsync(fileno(fp)) == 0;
+#endif
+}
+
 } // namespace os
 } // namespace details
 } // namespace spdlog

include/spdlog/details/os.h

@@ -22,22 +22,22 @@ SPDLOG_API std::tm gmtime() SPDLOG_NOEXCEPT;
 
 // eol definition
 #if !defined(SPDLOG_EOL)
-#ifdef _WIN32
-#define SPDLOG_EOL "\r\n"
-#else
-#define SPDLOG_EOL "\n"
-#endif
+#    ifdef _WIN32
+#        define SPDLOG_EOL "\r\n"
+#    else
+#        define SPDLOG_EOL "\n"
+#    endif
 #endif
 
 SPDLOG_CONSTEXPR static const char *default_eol = SPDLOG_EOL;
 
 // folder separator
 #if !defined(SPDLOG_FOLDER_SEPS)
-#ifdef _WIN32
-#define SPDLOG_FOLDER_SEPS "\\/"
-#else
-#define SPDLOG_FOLDER_SEPS "/"
-#endif
+#    ifdef _WIN32
+#        define SPDLOG_FOLDER_SEPS "\\/"
+#    else
+#        define SPDLOG_FOLDER_SEPS "/"
+#    endif
 #endif
 
 SPDLOG_CONSTEXPR static const char folder_seps[] = SPDLOG_FOLDER_SEPS;
@@ -74,7 +74,7 @@ SPDLOG_API size_t thread_id() SPDLOG_NOEXCEPT;
 
 // This is avoid msvc issue in sleep_for that happens if the clock changes.
 // See https://github.com/gabime/spdlog/issues/609
-SPDLOG_API void sleep_for_millis(int milliseconds) SPDLOG_NOEXCEPT;
+SPDLOG_API void sleep_for_millis(unsigned int milliseconds) SPDLOG_NOEXCEPT;
 
 SPDLOG_API std::string filename_to_str(const filename_t &filename);
 
@@ -99,20 +99,24 @@ SPDLOG_API void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target);
 // "abc/" => "abc"
 // "abc" => ""
 // "abc///" => "abc//"
-SPDLOG_API filename_t dir_name(filename_t path);
+SPDLOG_API filename_t dir_name(const filename_t &path);
 
 // Create a dir from the given path.
 // Return true if succeeded or if this dir already exists.
-SPDLOG_API bool create_dir(filename_t path);
+SPDLOG_API bool create_dir(const filename_t &path);
 
 // non thread safe, cross platform getenv/getenv_s
 // return empty string if field not found
 SPDLOG_API std::string getenv(const char *field);
 
+// Do fsync by FILE objectpointer.
+// Return true on success.
+SPDLOG_API bool fsync(FILE *fp);
+
 } // namespace os
 } // namespace details
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "os-inl.h"
+#    include "os-inl.h"
 #endif

include/spdlog/details/periodic_worker-inl.h

@@ -4,33 +4,12 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/details/periodic_worker.h>
+#    include <spdlog/details/periodic_worker.h>
 #endif
 
 namespace spdlog {
 namespace details {
 
-SPDLOG_INLINE periodic_worker::periodic_worker(const std::function<void()> &callback_fun, std::chrono::seconds interval)
-{
-    active_ = (interval > std::chrono::seconds::zero());
-    if (!active_)
-    {
-        return;
-    }
-
-    worker_thread_ = std::thread([this, callback_fun, interval]() {
-        for (;;)
-        {
-            std::unique_lock<std::mutex> lock(this->mutex_);
-            if (this->cv_.wait_for(lock, interval, [this] { return !this->active_; }))
-            {
-                return; // active_ == false, so exit this thread
-            }
-            callback_fun();
-        }
-    });
-}
-
 // stop the worker thread and join it
 SPDLOG_INLINE periodic_worker::~periodic_worker()
 {

include/spdlog/details/periodic_worker.h

@@ -20,7 +20,27 @@ namespace details {
 class SPDLOG_API periodic_worker
 {
 public:
-    periodic_worker(const std::function<void()> &callback_fun, std::chrono::seconds interval);
+    template<typename Rep, typename Period>
+    periodic_worker(const std::function<void()> &callback_fun, std::chrono::duration<Rep, Period> interval)
+    {
+        active_ = (interval > std::chrono::duration<Rep, Period>::zero());
+        if (!active_)
+        {
+            return;
+        }
+
+        worker_thread_ = std::thread([this, callback_fun, interval]() {
+            for (;;)
+            {
+                std::unique_lock<std::mutex> lock(this->mutex_);
+                if (this->cv_.wait_for(lock, interval, [this] { return !this->active_; }))
+                {
+                    return; // active_ == false, so exit this thread
+                }
+                callback_fun();
+            }
+        });
+    }
     periodic_worker(const periodic_worker &) = delete;
     periodic_worker &operator=(const periodic_worker &) = delete;
     // stop the worker thread and join it
@@ -36,5 +56,5 @@ private:
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "periodic_worker-inl.h"
+#    include "periodic_worker-inl.h"
 #endif

include/spdlog/details/registry-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/details/registry.h>
+#    include <spdlog/details/registry.h>
 #endif
 
 #include <spdlog/common.h>
@@ -14,11 +14,11 @@
 
 #ifndef SPDLOG_DISABLE_DEFAULT_LOGGER
 // support for the default stdout color logger
-#ifdef _WIN32
-#include <spdlog/sinks/wincolor_sink.h>
-#else
-#include <spdlog/sinks/ansicolor_sink.h>
-#endif
+#    ifdef _WIN32
+#        include <spdlog/sinks/wincolor_sink.h>
+#    else
+#        include <spdlog/sinks/ansicolor_sink.h>
+#    endif
 #endif // SPDLOG_DISABLE_DEFAULT_LOGGER
 
 #include <chrono>
@@ -36,11 +36,11 @@ SPDLOG_INLINE registry::registry()
 
 #ifndef SPDLOG_DISABLE_DEFAULT_LOGGER
     // create default logger (ansicolor_stdout_sink_mt or wincolor_stdout_sink_mt in windows).
-#ifdef _WIN32
+#    ifdef _WIN32
     auto color_sink = std::make_shared<sinks::wincolor_stdout_sink_mt>();
-#else
+#    else
     auto color_sink = std::make_shared<sinks::ansicolor_stdout_sink_mt>();
-#endif
+#    endif
 
     const char *default_logger_name = "";
     default_logger_ = std::make_shared<spdlog::logger>(default_logger_name, std::move(color_sink));
@@ -188,21 +188,14 @@ SPDLOG_INLINE void registry::flush_on(level::level_enum log_level)
     flush_level_ = log_level;
 }
 
-SPDLOG_INLINE void registry::flush_every(std::chrono::seconds interval)
-{
-    std::lock_guard<std::mutex> lock(flusher_mutex_);
-    auto clbk = [this]() { this->flush_all(); };
-    periodic_flusher_ = details::make_unique<periodic_worker>(clbk, interval);
-}
-
-SPDLOG_INLINE void registry::set_error_handler(void (*handler)(const std::string &msg))
+SPDLOG_INLINE void registry::set_error_handler(err_handler handler)
 {
     std::lock_guard<std::mutex> lock(logger_map_mutex_);
     for (auto &l : loggers_)
     {
         l.second->set_error_handler(handler);
     }
-    err_handler_ = handler;
+    err_handler_ = std::move(handler);
 }
 
 SPDLOG_INLINE void registry::apply_all(const std::function<void(const std::shared_ptr<logger>)> &fun)
@@ -226,8 +219,9 @@ SPDLOG_INLINE void registry::flush_all()
 SPDLOG_INLINE void registry::drop(const std::string &logger_name)
 {
     std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    auto is_default_logger = default_logger_ && default_logger_->name() == logger_name;
     loggers_.erase(logger_name);
-    if (default_logger_ && default_logger_->name() == logger_name)
+    if (is_default_logger)
     {
         default_logger_.reset();
     }
@@ -294,6 +288,14 @@ SPDLOG_INLINE registry &registry::instance()
     return s_instance;
 }
 
+SPDLOG_INLINE void registry::apply_logger_env_levels(std::shared_ptr<logger> new_logger)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    auto it = log_levels_.find(new_logger->name());
+    auto new_level = it != log_levels_.end() ? it->second : global_log_level_;
+    new_logger->set_level(new_level);
+}
+
 SPDLOG_INLINE void registry::throw_if_exists_(const std::string &logger_name)
 {
     if (loggers_.find(logger_name) != loggers_.end())

include/spdlog/details/registry.h

@@ -9,6 +9,7 @@
 // This class is thread safe
 
 #include <spdlog/common.h>
+#include <spdlog/details/periodic_worker.h>
 
 #include <chrono>
 #include <functional>
@@ -22,7 +23,6 @@ class logger;
 
 namespace details {
 class thread_pool;
-class periodic_worker;
 
 class SPDLOG_API registry
 {
@@ -61,9 +61,15 @@ public:
 
     void flush_on(level::level_enum log_level);
 
-    void flush_every(std::chrono::seconds interval);
+    template<typename Rep, typename Period>
+    void flush_every(std::chrono::duration<Rep, Period> interval)
+    {
+        std::lock_guard<std::mutex> lock(flusher_mutex_);
+        auto clbk = [this]() { this->flush_all(); };
+        periodic_flusher_ = details::make_unique<periodic_worker>(clbk, interval);
+    }
 
-    void set_error_handler(void (*handler)(const std::string &msg));
+    void set_error_handler(err_handler handler);
 
     void apply_all(const std::function<void(const std::shared_ptr<logger>)> &fun);
 
@@ -85,6 +91,8 @@ public:
 
     static registry &instance();
 
+    void apply_logger_env_levels(std::shared_ptr<logger> new_logger);
+
 private:
     registry();
     ~registry();
@@ -99,7 +107,7 @@ private:
     std::unique_ptr<formatter> formatter_;
     spdlog::level::level_enum global_log_level_ = level::info;
     level::level_enum flush_level_ = level::off;
-    void (*err_handler_)(const std::string &msg) = nullptr;
+    err_handler err_handler_;
     std::shared_ptr<thread_pool> tp_;
     std::unique_ptr<periodic_worker> periodic_flusher_;
     std::shared_ptr<logger> default_logger_;
@@ -111,5 +119,5 @@ private:
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "registry-inl.h"
+#    include "registry-inl.h"
 #endif

include/spdlog/details/synchronous_factory.h

@@ -21,4 +21,4 @@ struct synchronous_factory
         return new_logger;
     }
 };
-} // namespace spdlog
+} // namespace spdlog

include/spdlog/details/tcp_client-windows.h

@@ -25,20 +25,6 @@ class tcp_client
 {
     SOCKET socket_ = INVALID_SOCKET;
 
-    static bool winsock_initialized_()
-    {
-        SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
-        if (s == INVALID_SOCKET)
-        {
-            return false;
-        }
-        else
-        {
-            closesocket(s);
-            return true;
-        }
-    }
-
     static void init_winsock_()
     {
         WSADATA wsaData;
@@ -52,13 +38,24 @@ class tcp_client
     static void throw_winsock_error_(const std::string &msg, int last_error)
     {
         char buf[512];
-        ::FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, last_error,
+        ::FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, last_error,
             MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buf, (sizeof(buf) / sizeof(char)), NULL);
 
-        throw_spdlog_ex(fmt::format("tcp_sink - {}: {}", msg, buf));
+        throw_spdlog_ex(fmt_lib::format("tcp_sink - {}: {}", msg, buf));
     }
 
 public:
+    tcp_client()
+    {
+        init_winsock_();
+    }
+
+    ~tcp_client()
+    {
+        close();
+        ::WSACleanup();
+    }
+
     bool is_connected() const
     {
         return socket_ != INVALID_SOCKET;
@@ -68,7 +65,6 @@ public:
     {
         ::closesocket(socket_);
         socket_ = INVALID_SOCKET;
-        WSACleanup();
     }
 
     SOCKET fd() const
@@ -76,20 +72,9 @@ public:
         return socket_;
     }
 
-    ~tcp_client()
-    {
-        close();
-    }
-
     // try to connect or throw on failure
     void connect(const std::string &host, int port)
     {
-        // initialize winsock if needed
-        if (!winsock_initialized_())
-        {
-            init_winsock_();
-        }
-
         if (is_connected())
         {
             close();
@@ -98,7 +83,7 @@ public:
         {};
         ZeroMemory(&hints, sizeof(hints));
 
-        hints.ai_family = AF_INET;       // IPv4
+        hints.ai_family = AF_UNSPEC;     // To work with IPv4, IPv6, and so on
         hints.ai_socktype = SOCK_STREAM; // TCP
         hints.ai_flags = AI_NUMERICSERV; // port passed as as numeric value
         hints.ai_protocol = 0;
@@ -144,7 +129,7 @@ public:
 
         // set TCP_NODELAY
         int enable_flag = 1;
-        ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, (char *)&enable_flag, sizeof(enable_flag));
+        ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&enable_flag), sizeof(enable_flag));
     }
 
     // Send exactly n_bytes of the given data.

include/spdlog/details/tcp_client.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifdef _WIN32
-#error include tcp_client-windows.h instead
+#    error include tcp_client-windows.h instead
 #endif
 
 // tcp client helper
@@ -16,6 +16,7 @@
 #include <unistd.h>
 #include <netdb.h>
 #include <netinet/tcp.h>
+#include <netinet/in.h>
 
 #include <string>
 
@@ -57,7 +58,7 @@ public:
         struct addrinfo hints
         {};
         memset(&hints, 0, sizeof(struct addrinfo));
-        hints.ai_family = AF_INET;       // IPv4
+        hints.ai_family = AF_UNSPEC;     // To work with IPv4, IPv6, and so on
         hints.ai_socktype = SOCK_STREAM; // TCP
         hints.ai_flags = AI_NUMERICSERV; // port passed as as numeric value
         hints.ai_protocol = 0;
@@ -67,8 +68,7 @@ public:
         auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
         if (rv != 0)
         {
-            auto msg = fmt::format("::getaddrinfo failed: {}", gai_strerror(rv));
-            throw_spdlog_ex(msg);
+            throw_spdlog_ex(fmt_lib::format("::getaddrinfo failed: {}", gai_strerror(rv)));
         }
 
         // Try each address until we successfully connect(2).
@@ -103,15 +103,15 @@ public:
 
         // set TCP_NODELAY
         int enable_flag = 1;
-        ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, (char *)&enable_flag, sizeof(enable_flag));
+        ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&enable_flag), sizeof(enable_flag));
 
         // prevent sigpipe on systems where MSG_NOSIGNAL is not available
 #if defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
-        ::setsockopt(socket_, SOL_SOCKET, SO_NOSIGPIPE, (char *)&enable_flag, sizeof(enable_flag));
+        ::setsockopt(socket_, SOL_SOCKET, SO_NOSIGPIPE, reinterpret_cast<char *>(&enable_flag), sizeof(enable_flag));
 #endif
 
 #if !defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
-#error "tcp_sink would raise SIGPIPE since niether SO_NOSIGPIPE nor MSG_NOSIGNAL are available"
+#    error "tcp_sink would raise SIGPIPE since neither SO_NOSIGPIPE nor MSG_NOSIGNAL are available"
 #endif
     }
 

include/spdlog/details/thread_pool-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/details/thread_pool.h>
+#    include <spdlog/details/thread_pool.h>
 #endif
 
 #include <spdlog/common.h>
@@ -13,7 +13,8 @@
 namespace spdlog {
 namespace details {
 
-SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start)
+SPDLOG_INLINE thread_pool::thread_pool(
+    size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start, std::function<void()> on_thread_stop)
     : q_(q_max_items)
 {
     if (threads_n == 0 || threads_n > 1000)
@@ -23,15 +24,21 @@ SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items, size_t threads_n, std
     }
     for (size_t i = 0; i < threads_n; i++)
     {
-        threads_.emplace_back([this, on_thread_start] {
+        threads_.emplace_back([this, on_thread_start, on_thread_stop] {
             on_thread_start();
             this->thread_pool::worker_loop_();
+            on_thread_stop();
         });
     }
 }
 
+SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start)
+    : thread_pool(q_max_items, threads_n, on_thread_start, [] {})
+{}
+
 SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items, size_t threads_n)
-    : thread_pool(q_max_items, threads_n, [] {})
+    : thread_pool(
+          q_max_items, threads_n, [] {}, [] {})
 {}
 
 // message all threads to terminate gracefully join them
@@ -49,7 +56,7 @@ SPDLOG_INLINE thread_pool::~thread_pool()
             t.join();
         }
     }
-    SPDLOG_CATCH_ALL() {}
+    SPDLOG_CATCH_STD
 }
 
 void SPDLOG_INLINE thread_pool::post_log(async_logger_ptr &&worker_ptr, const details::log_msg &msg, async_overflow_policy overflow_policy)
@@ -68,6 +75,11 @@ size_t SPDLOG_INLINE thread_pool::overrun_counter()
     return q_.overrun_counter();
 }
 
+void SPDLOG_INLINE thread_pool::reset_overrun_counter()
+{
+    q_.reset_overrun_counter();
+}
+
 size_t SPDLOG_INLINE thread_pool::queue_size()
 {
     return q_.size();
@@ -96,11 +108,7 @@ void SPDLOG_INLINE thread_pool::worker_loop_()
 bool SPDLOG_INLINE thread_pool::process_next_msg_()
 {
     async_msg incoming_async_msg;
-    bool dequeued = q_.dequeue_for(incoming_async_msg, std::chrono::seconds(10));
-    if (!dequeued)
-    {
-        return true;
-    }
+    q_.dequeue(incoming_async_msg);
 
     switch (incoming_async_msg.msg_type)
     {

include/spdlog/details/thread_pool.h

@@ -27,7 +27,6 @@ enum class async_msg_type
     terminate
 };
 
-#include <spdlog/details/log_msg_buffer.h>
 // Async msg to move to/from the queue
 // Movable only. should never be copied
 struct async_msg : log_msg_buffer
@@ -85,10 +84,11 @@ public:
     using item_type = async_msg;
     using q_type = details::mpmc_blocking_queue<item_type>;
 
+    thread_pool(size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start, std::function<void()> on_thread_stop);
     thread_pool(size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start);
     thread_pool(size_t q_max_items, size_t threads_n);
 
-    // message all threads to terminate gracefully join them
+    // message all threads to terminate gracefully and join them
     ~thread_pool();
 
     thread_pool(const thread_pool &) = delete;
@@ -97,6 +97,7 @@ public:
     void post_log(async_logger_ptr &&worker_ptr, const details::log_msg &msg, async_overflow_policy overflow_policy);
     void post_flush(async_logger_ptr &&worker_ptr, async_overflow_policy overflow_policy);
     size_t overrun_counter();
+    void reset_overrun_counter();
     size_t queue_size();
 
 private:
@@ -117,5 +118,5 @@ private:
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "thread_pool-inl.h"
+#    include "thread_pool-inl.h"
 #endif

include/spdlog/details/udp_client-windows.h

@@ -0,0 +1,113 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Helper RAII over winsock udp client socket.
+// Will throw on construction if socket creation failed.
+
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+#include <spdlog/details/windows_include.h>
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string>
+
+#if defined(_MSC_VER)
+#    pragma comment(lib, "Ws2_32.lib")
+#    pragma comment(lib, "Mswsock.lib")
+#    pragma comment(lib, "AdvApi32.lib")
+#endif
+
+namespace spdlog {
+namespace details {
+class udp_client
+{
+    static constexpr int TX_BUFFER_SIZE = 1024 * 10;
+    SOCKET socket_ = INVALID_SOCKET;
+    sockaddr_in addr_ = {};
+
+    static void init_winsock_()
+    {
+        WSADATA wsaData;
+        auto rv = ::WSAStartup(MAKEWORD(2, 2), &wsaData);
+        if (rv != 0)
+        {
+            throw_winsock_error_("WSAStartup failed", ::WSAGetLastError());
+        }
+    }
+
+    static void throw_winsock_error_(const std::string &msg, int last_error)
+    {
+        char buf[512];
+        ::FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, last_error,
+            MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buf, (sizeof(buf) / sizeof(char)), NULL);
+
+        throw_spdlog_ex(fmt_lib::format("udp_sink - {}: {}", msg, buf));
+    }
+
+    void cleanup_()
+    {
+        if (socket_ != INVALID_SOCKET)
+        {
+            ::closesocket(socket_);
+        }
+        socket_ = INVALID_SOCKET;
+        ::WSACleanup();
+    }
+
+public:
+    udp_client(const std::string &host, uint16_t port)
+    {
+        init_winsock_();
+
+        addr_.sin_family = PF_INET;
+        addr_.sin_port = htons(port);
+        addr_.sin_addr.s_addr = INADDR_ANY;
+        if (InetPtonA(PF_INET, host.c_str(), &addr_.sin_addr.s_addr) != 1)
+        {
+            int last_error = ::WSAGetLastError();
+            ::WSACleanup();
+            throw_winsock_error_("error: Invalid address!", last_error);
+        }
+
+        socket_ = ::socket(PF_INET, SOCK_DGRAM, 0);
+        if (socket_ == INVALID_SOCKET)
+        {
+            int last_error = ::WSAGetLastError();
+            ::WSACleanup();
+            throw_winsock_error_("error: Create Socket failed", last_error);
+        }
+
+        int option_value = TX_BUFFER_SIZE;
+        if (::setsockopt(socket_, SOL_SOCKET, SO_SNDBUF, reinterpret_cast<const char *>(&option_value), sizeof(option_value)) < 0)
+        {
+            int last_error = ::WSAGetLastError();
+            cleanup_();
+            throw_winsock_error_("error: setsockopt(SO_SNDBUF) Failed!", last_error);
+        }
+    }
+
+    ~udp_client()
+    {
+        cleanup_();
+    }
+
+    SOCKET fd() const
+    {
+        return socket_;
+    }
+
+    void send(const char *data, size_t n_bytes)
+    {
+        socklen_t tolen = sizeof(struct sockaddr);
+        if (::sendto(socket_, data, static_cast<int>(n_bytes), 0, (struct sockaddr *)&addr_, tolen) == -1)
+        {
+            throw_spdlog_ex("sendto(2) failed", errno);
+        }
+    }
+};
+} // namespace details
+} // namespace spdlog

include/spdlog/details/udp_client.h

@@ -0,0 +1,94 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Helper RAII over unix udp client socket.
+// Will throw on construction if the socket creation failed.
+
+#ifdef _WIN32
+#    error "include udp_client-windows.h instead"
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+#include <cstring>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <netinet/udp.h>
+
+#include <string>
+
+namespace spdlog {
+namespace details {
+
+class udp_client
+{
+    static constexpr int TX_BUFFER_SIZE = 1024 * 10;
+    int socket_ = -1;
+    struct sockaddr_in sockAddr_;
+
+    void cleanup_()
+    {
+        if (socket_ != -1)
+        {
+            ::close(socket_);
+            socket_ = -1;
+        }
+    }
+
+public:
+    udp_client(const std::string &host, uint16_t port)
+    {
+        socket_ = ::socket(PF_INET, SOCK_DGRAM, 0);
+        if (socket_ < 0)
+        {
+            throw_spdlog_ex("error: Create Socket Failed!");
+        }
+
+        int option_value = TX_BUFFER_SIZE;
+        if (::setsockopt(socket_, SOL_SOCKET, SO_SNDBUF, reinterpret_cast<const char *>(&option_value), sizeof(option_value)) < 0)
+        {
+            cleanup_();
+            throw_spdlog_ex("error: setsockopt(SO_SNDBUF) Failed!");
+        }
+
+        sockAddr_.sin_family = AF_INET;
+        sockAddr_.sin_port = htons(port);
+
+        if (::inet_aton(host.c_str(), &sockAddr_.sin_addr) == 0)
+        {
+            cleanup_();
+            throw_spdlog_ex("error: Invalid address!");
+        }
+
+        ::memset(sockAddr_.sin_zero, 0x00, sizeof(sockAddr_.sin_zero));
+    }
+
+    ~udp_client()
+    {
+        cleanup_();
+    }
+
+    int fd() const
+    {
+        return socket_;
+    }
+
+    // Send exactly n_bytes of the given data.
+    // On error close the connection and throw.
+    void send(const char *data, size_t n_bytes)
+    {
+        ssize_t toslen = 0;
+        socklen_t tolen = sizeof(struct sockaddr);
+        if ((toslen = ::sendto(socket_, data, n_bytes, 0, (struct sockaddr *)&sockAddr_, tolen)) == -1)
+        {
+            throw_spdlog_ex("sendto(2) failed", errno);
+        }
+    }
+};
+} // namespace details
+} // namespace spdlog

include/spdlog/details/windows_include.h

@@ -1,11 +1,11 @@
 #pragma once
 
 #ifndef NOMINMAX
-#define NOMINMAX // prevent windows redefining min/max
+#    define NOMINMAX // prevent windows redefining min/max
 #endif
 
 #ifndef WIN32_LEAN_AND_MEAN
-#define WIN32_LEAN_AND_MEAN
+#    define WIN32_LEAN_AND_MEAN
 #endif
 
 #include <windows.h>

include/spdlog/fmt/bin_to_hex.h

@@ -6,10 +6,21 @@
 #pragma once
 
 #include <cctype>
+#include <spdlog/common.h>
+
+#if defined(__has_include)
+#    if __has_include(<version>)
+#        include <version>
+#    endif
+#endif
+
+#if __cpp_lib_span >= 202002L
+#    include <span>
+#endif
 
 //
 // Support for logging binary data as hex
-// format flags, any combination of the followng:
+// format flags, any combination of the following:
 // {:X} - print in uppercase.
 // {:s} - don't separate each byte with space.
 // {:p} - don't print the position on each line start.
@@ -38,11 +49,12 @@ public:
         , size_per_line_(size_per_line)
     {}
 
-    It begin() const
+    // do not use begin() and end() to avoid collision with fmt/ranges
+    It get_begin() const
     {
         return begin_;
     }
-    It end() const
+    It get_end() const
     {
         return end_;
     }
@@ -66,6 +78,20 @@ inline details::dump_info<typename Container::const_iterator> to_hex(const Conta
     return details::dump_info<Iter>(std::begin(container), std::end(container), size_per_line);
 }
 
+#if __cpp_lib_span >= 202002L
+
+template<typename Value, size_t Extent>
+inline details::dump_info<typename std::span<Value, Extent>::iterator> to_hex(
+    const std::span<Value, Extent> &container, size_t size_per_line = 32)
+{
+    using Container = std::span<Value, Extent>;
+    static_assert(sizeof(typename Container::value_type) == 1, "sizeof(Container::value_type) != 1");
+    using Iter = typename Container::iterator;
+    return details::dump_info<Iter>(std::begin(container), std::end(container), size_per_line);
+}
+
+#endif
+
 // create dump_info from ranges
 template<typename It>
 inline details::dump_info<It> to_hex(const It range_begin, const It range_end, size_t size_per_line = 32)
@@ -75,10 +101,16 @@ inline details::dump_info<It> to_hex(const It range_begin, const It range_end, s
 
 } // namespace spdlog
 
-namespace fmt {
+namespace
+#ifdef SPDLOG_USE_STD_FORMAT
+    std
+#else
+    fmt
+#endif
+{
 
 template<typename T>
-struct formatter<spdlog::details::dump_info<T>>
+struct formatter<spdlog::details::dump_info<T>, char>
 {
     const char delimiter = ' ';
     bool put_newlines = true;
@@ -89,7 +121,7 @@ struct formatter<spdlog::details::dump_info<T>>
 
     // parse the format string flags
     template<typename ParseContext>
-    auto parse(ParseContext &ctx) -> decltype(ctx.begin())
+    SPDLOG_CONSTEXPR_FUNC auto parse(ParseContext &ctx) -> decltype(ctx.begin())
     {
         auto it = ctx.begin();
         while (it != ctx.end() && *it != '}')
@@ -124,27 +156,27 @@ struct formatter<spdlog::details::dump_info<T>>
 
     // format the given bytes range as hex
     template<typename FormatContext, typename Container>
-    auto format(const spdlog::details::dump_info<Container> &the_range, FormatContext &ctx) -> decltype(ctx.out())
+    auto format(const spdlog::details::dump_info<Container> &the_range, FormatContext &ctx) const -> decltype(ctx.out())
     {
         SPDLOG_CONSTEXPR const char *hex_upper = "0123456789ABCDEF";
         SPDLOG_CONSTEXPR const char *hex_lower = "0123456789abcdef";
         const char *hex_chars = use_uppercase ? hex_upper : hex_lower;
 
-#if FMT_VERSION < 60000
+#if !defined(SPDLOG_USE_STD_FORMAT) && FMT_VERSION < 60000
         auto inserter = ctx.begin();
 #else
         auto inserter = ctx.out();
 #endif
 
         int size_per_line = static_cast<int>(the_range.size_per_line());
-        auto start_of_line = the_range.begin();
-        for (auto i = the_range.begin(); i != the_range.end(); i++)
+        auto start_of_line = the_range.get_begin();
+        for (auto i = the_range.get_begin(); i != the_range.get_end(); i++)
         {
             auto ch = static_cast<unsigned char>(*i);
 
-            if (put_newlines && (i == the_range.begin() || i - start_of_line >= size_per_line))
+            if (put_newlines && (i == the_range.get_begin() || i - start_of_line >= size_per_line))
             {
-                if (show_ascii && i != the_range.begin())
+                if (show_ascii && i != the_range.get_begin())
                 {
                     *inserter++ = delimiter;
                     *inserter++ = delimiter;
@@ -155,7 +187,7 @@ struct formatter<spdlog::details::dump_info<T>>
                     }
                 }
 
-                put_newline(inserter, static_cast<size_t>(i - the_range.begin()));
+                put_newline(inserter, static_cast<size_t>(i - the_range.get_begin()));
 
                 // put first byte without delimiter in front of it
                 *inserter++ = hex_chars[(ch >> 4) & 0x0f];
@@ -164,7 +196,7 @@ struct formatter<spdlog::details::dump_info<T>>
                 continue;
             }
 
-            if (put_delimiters)
+            if (put_delimiters && i != the_range.get_begin())
             {
                 *inserter++ = delimiter;
             }
@@ -174,9 +206,9 @@ struct formatter<spdlog::details::dump_info<T>>
         }
         if (show_ascii) // add ascii to last line
         {
-            if (the_range.end() - the_range.begin() > size_per_line)
+            if (the_range.get_end() - the_range.get_begin() > size_per_line)
             {
-                auto blank_num = size_per_line - (the_range.end() - start_of_line);
+                auto blank_num = size_per_line - (the_range.get_end() - start_of_line);
                 while (blank_num-- > 0)
                 {
                     *inserter++ = delimiter;
@@ -189,7 +221,7 @@ struct formatter<spdlog::details::dump_info<T>>
             }
             *inserter++ = delimiter;
             *inserter++ = delimiter;
-            for (auto j = start_of_line; j != the_range.end(); j++)
+            for (auto j = start_of_line; j != the_range.get_end(); j++)
             {
                 auto pc = static_cast<unsigned char>(*j);
                 *inserter++ = std::isprint(pc) ? static_cast<char>(*j) : '.';
@@ -200,7 +232,7 @@ struct formatter<spdlog::details::dump_info<T>>
 
     // put newline(and position header)
     template<typename It>
-    void put_newline(It inserter, std::size_t pos)
+    void put_newline(It inserter, std::size_t pos) const
     {
 #ifdef _WIN32
         *inserter++ = '\r';
@@ -209,8 +241,8 @@ struct formatter<spdlog::details::dump_info<T>>
 
         if (put_positions)
         {
-            fmt::format_to(inserter, "{:<04X}: ", pos);
+            spdlog::fmt_lib::format_to(inserter, SPDLOG_FMT_STRING("{:04X}: "), pos);
         }
     }
 };
-} // namespace fmt
+} // namespace std

include/spdlog/fmt/bundled/args.h

@@ -0,0 +1,234 @@
+// Formatting library for C++ - dynamic format arguments
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_ARGS_H_
+#define FMT_ARGS_H_
+
+#include <functional>  // std::reference_wrapper
+#include <memory>      // std::unique_ptr
+#include <vector>
+
+#include "core.h"
+
+FMT_BEGIN_NAMESPACE
+
+namespace detail {
+
+template <typename T> struct is_reference_wrapper : std::false_type {};
+template <typename T>
+struct is_reference_wrapper<std::reference_wrapper<T>> : std::true_type {};
+
+template <typename T> const T& unwrap(const T& v) { return v; }
+template <typename T> const T& unwrap(const std::reference_wrapper<T>& v) {
+  return static_cast<const T&>(v);
+}
+
+class dynamic_arg_list {
+  // Workaround for clang's -Wweak-vtables. Unlike for regular classes, for
+  // templates it doesn't complain about inability to deduce single translation
+  // unit for placing vtable. So storage_node_base is made a fake template.
+  template <typename = void> struct node {
+    virtual ~node() = default;
+    std::unique_ptr<node<>> next;
+  };
+
+  template <typename T> struct typed_node : node<> {
+    T value;
+
+    template <typename Arg>
+    FMT_CONSTEXPR typed_node(const Arg& arg) : value(arg) {}
+
+    template <typename Char>
+    FMT_CONSTEXPR typed_node(const basic_string_view<Char>& arg)
+        : value(arg.data(), arg.size()) {}
+  };
+
+  std::unique_ptr<node<>> head_;
+
+ public:
+  template <typename T, typename Arg> const T& push(const Arg& arg) {
+    auto new_node = std::unique_ptr<typed_node<T>>(new typed_node<T>(arg));
+    auto& value = new_node->value;
+    new_node->next = std::move(head_);
+    head_ = std::move(new_node);
+    return value;
+  }
+};
+}  // namespace detail
+
+/**
+  \rst
+  A dynamic version of `fmt::format_arg_store`.
+  It's equipped with a storage to potentially temporary objects which lifetimes
+  could be shorter than the format arguments object.
+
+  It can be implicitly converted into `~fmt::basic_format_args` for passing
+  into type-erased formatting functions such as `~fmt::vformat`.
+  \endrst
+ */
+template <typename Context>
+class dynamic_format_arg_store
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+    // Workaround a GCC template argument substitution bug.
+    : public basic_format_args<Context>
+#endif
+{
+ private:
+  using char_type = typename Context::char_type;
+
+  template <typename T> struct need_copy {
+    static constexpr detail::type mapped_type =
+        detail::mapped_type_constant<T, Context>::value;
+
+    enum {
+      value = !(detail::is_reference_wrapper<T>::value ||
+                std::is_same<T, basic_string_view<char_type>>::value ||
+                std::is_same<T, detail::std_string_view<char_type>>::value ||
+                (mapped_type != detail::type::cstring_type &&
+                 mapped_type != detail::type::string_type &&
+                 mapped_type != detail::type::custom_type))
+    };
+  };
+
+  template <typename T>
+  using stored_type = conditional_t<
+      std::is_convertible<T, std::basic_string<char_type>>::value &&
+          !detail::is_reference_wrapper<T>::value,
+      std::basic_string<char_type>, T>;
+
+  // Storage of basic_format_arg must be contiguous.
+  std::vector<basic_format_arg<Context>> data_;
+  std::vector<detail::named_arg_info<char_type>> named_info_;
+
+  // Storage of arguments not fitting into basic_format_arg must grow
+  // without relocation because items in data_ refer to it.
+  detail::dynamic_arg_list dynamic_args_;
+
+  friend class basic_format_args<Context>;
+
+  unsigned long long get_types() const {
+    return detail::is_unpacked_bit | data_.size() |
+           (named_info_.empty()
+                ? 0ULL
+                : static_cast<unsigned long long>(detail::has_named_args_bit));
+  }
+
+  const basic_format_arg<Context>* data() const {
+    return named_info_.empty() ? data_.data() : data_.data() + 1;
+  }
+
+  template <typename T> void emplace_arg(const T& arg) {
+    data_.emplace_back(detail::make_arg<Context>(arg));
+  }
+
+  template <typename T>
+  void emplace_arg(const detail::named_arg<char_type, T>& arg) {
+    if (named_info_.empty()) {
+      constexpr const detail::named_arg_info<char_type>* zero_ptr{nullptr};
+      data_.insert(data_.begin(), {zero_ptr, 0});
+    }
+    data_.emplace_back(detail::make_arg<Context>(detail::unwrap(arg.value)));
+    auto pop_one = [](std::vector<basic_format_arg<Context>>* data) {
+      data->pop_back();
+    };
+    std::unique_ptr<std::vector<basic_format_arg<Context>>, decltype(pop_one)>
+        guard{&data_, pop_one};
+    named_info_.push_back({arg.name, static_cast<int>(data_.size() - 2u)});
+    data_[0].value_.named_args = {named_info_.data(), named_info_.size()};
+    guard.release();
+  }
+
+ public:
+  constexpr dynamic_format_arg_store() = default;
+
+  /**
+    \rst
+    Adds an argument into the dynamic store for later passing to a formatting
+    function.
+
+    Note that custom types and string types (but not string views) are copied
+    into the store dynamically allocating memory if necessary.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      store.push_back(42);
+      store.push_back("abc");
+      store.push_back(1.5f);
+      std::string result = fmt::vformat("{} and {} and {}", store);
+    \endrst
+  */
+  template <typename T> void push_back(const T& arg) {
+    if (detail::const_check(need_copy<T>::value))
+      emplace_arg(dynamic_args_.push<stored_type<T>>(arg));
+    else
+      emplace_arg(detail::unwrap(arg));
+  }
+
+  /**
+    \rst
+    Adds a reference to the argument into the dynamic store for later passing to
+    a formatting function.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      char band[] = "Rolling Stones";
+      store.push_back(std::cref(band));
+      band[9] = 'c'; // Changing str affects the output.
+      std::string result = fmt::vformat("{}", store);
+      // result == "Rolling Scones"
+    \endrst
+  */
+  template <typename T> void push_back(std::reference_wrapper<T> arg) {
+    static_assert(
+        need_copy<T>::value,
+        "objects of built-in types and string views are always copied");
+    emplace_arg(arg.get());
+  }
+
+  /**
+    Adds named argument into the dynamic store for later passing to a formatting
+    function. ``std::reference_wrapper`` is supported to avoid copying of the
+    argument. The name is always copied into the store.
+  */
+  template <typename T>
+  void push_back(const detail::named_arg<char_type, T>& arg) {
+    const char_type* arg_name =
+        dynamic_args_.push<std::basic_string<char_type>>(arg.name).c_str();
+    if (detail::const_check(need_copy<T>::value)) {
+      emplace_arg(
+          fmt::arg(arg_name, dynamic_args_.push<stored_type<T>>(arg.value)));
+    } else {
+      emplace_arg(fmt::arg(arg_name, arg.value));
+    }
+  }
+
+  /** Erase all elements from the store */
+  void clear() {
+    data_.clear();
+    named_info_.clear();
+    dynamic_args_ = detail::dynamic_arg_list();
+  }
+
+  /**
+    \rst
+    Reserves space to store at least *new_cap* arguments including
+    *new_cap_named* named arguments.
+    \endrst
+  */
+  void reserve(size_t new_cap, size_t new_cap_named) {
+    FMT_ASSERT(new_cap >= new_cap_named,
+               "Set of arguments includes set of named arguments");
+    data_.reserve(new_cap);
+    named_info_.reserve(new_cap_named);
+  }
+};
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_ARGS_H_

include/spdlog/fmt/bundled/color.h

@@ -11,6 +11,7 @@
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT_BEGIN
 
 enum class color : uint32_t {
   alice_blue = 0xF0F8FF,               // rgb(240,248,255)
@@ -177,9 +178,13 @@ enum class terminal_color : uint8_t {
 
 enum class emphasis : uint8_t {
   bold = 1,
-  italic = 1 << 1,
-  underline = 1 << 2,
-  strikethrough = 1 << 3
+  faint = 1 << 1,
+  italic = 1 << 2,
+  underline = 1 << 3,
+  blink = 1 << 4,
+  reverse = 1 << 5,
+  conceal = 1 << 6,
+  strikethrough = 1 << 7,
 };
 
 // rgb is a struct for red, green and blue colors.
@@ -198,21 +203,20 @@ struct rgb {
   uint8_t b;
 };
 
-namespace detail {
+FMT_BEGIN_DETAIL_NAMESPACE
 
 // color is a struct of either a rgb color or a terminal color.
 struct color_type {
-  FMT_CONSTEXPR color_type() FMT_NOEXCEPT : is_rgb(), value{} {}
-  FMT_CONSTEXPR color_type(color rgb_color) FMT_NOEXCEPT : is_rgb(true),
-                                                           value{} {
+  FMT_CONSTEXPR color_type() noexcept : is_rgb(), value{} {}
+  FMT_CONSTEXPR color_type(color rgb_color) noexcept : is_rgb(true), value{} {
     value.rgb_color = static_cast<uint32_t>(rgb_color);
   }
-  FMT_CONSTEXPR color_type(rgb rgb_color) FMT_NOEXCEPT : is_rgb(true), value{} {
+  FMT_CONSTEXPR color_type(rgb rgb_color) noexcept : is_rgb(true), value{} {
     value.rgb_color = (static_cast<uint32_t>(rgb_color.r) << 16) |
                       (static_cast<uint32_t>(rgb_color.g) << 8) | rgb_color.b;
   }
-  FMT_CONSTEXPR color_type(terminal_color term_color) FMT_NOEXCEPT : is_rgb(),
-                                                                     value{} {
+  FMT_CONSTEXPR color_type(terminal_color term_color) noexcept
+      : is_rgb(), value{} {
     value.term_color = static_cast<uint8_t>(term_color);
   }
   bool is_rgb;
@@ -221,15 +225,14 @@ struct color_type {
     uint32_t rgb_color;
   } value;
 };
-}  // namespace detail
 
-// Experimental text formatting support.
+FMT_END_DETAIL_NAMESPACE
+
+/** A text style consisting of foreground and background colors and emphasis. */
 class text_style {
  public:
-  FMT_CONSTEXPR text_style(emphasis em = emphasis()) FMT_NOEXCEPT
-      : set_foreground_color(),
-        set_background_color(),
-        ems(em) {}
+  FMT_CONSTEXPR text_style(emphasis em = emphasis()) noexcept
+      : set_foreground_color(), set_background_color(), ems(em) {}
 
   FMT_CONSTEXPR text_style& operator|=(const text_style& rhs) {
     if (!set_foreground_color) {
@@ -260,63 +263,32 @@ class text_style {
     return lhs |= rhs;
   }
 
-  FMT_CONSTEXPR text_style& operator&=(const text_style& rhs) {
-    if (!set_foreground_color) {
-      set_foreground_color = rhs.set_foreground_color;
-      foreground_color = rhs.foreground_color;
-    } else if (rhs.set_foreground_color) {
-      if (!foreground_color.is_rgb || !rhs.foreground_color.is_rgb)
-        FMT_THROW(format_error("can't AND a terminal color"));
-      foreground_color.value.rgb_color &= rhs.foreground_color.value.rgb_color;
-    }
-
-    if (!set_background_color) {
-      set_background_color = rhs.set_background_color;
-      background_color = rhs.background_color;
-    } else if (rhs.set_background_color) {
-      if (!background_color.is_rgb || !rhs.background_color.is_rgb)
-        FMT_THROW(format_error("can't AND a terminal color"));
-      background_color.value.rgb_color &= rhs.background_color.value.rgb_color;
-    }
-
-    ems = static_cast<emphasis>(static_cast<uint8_t>(ems) &
-                                static_cast<uint8_t>(rhs.ems));
-    return *this;
-  }
-
-  friend FMT_CONSTEXPR text_style operator&(text_style lhs,
-                                            const text_style& rhs) {
-    return lhs &= rhs;
-  }
-
-  FMT_CONSTEXPR bool has_foreground() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR bool has_foreground() const noexcept {
     return set_foreground_color;
   }
-  FMT_CONSTEXPR bool has_background() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR bool has_background() const noexcept {
     return set_background_color;
   }
-  FMT_CONSTEXPR bool has_emphasis() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR bool has_emphasis() const noexcept {
     return static_cast<uint8_t>(ems) != 0;
   }
-  FMT_CONSTEXPR detail::color_type get_foreground() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR detail::color_type get_foreground() const noexcept {
     FMT_ASSERT(has_foreground(), "no foreground specified for this style");
     return foreground_color;
   }
-  FMT_CONSTEXPR detail::color_type get_background() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR detail::color_type get_background() const noexcept {
     FMT_ASSERT(has_background(), "no background specified for this style");
     return background_color;
   }
-  FMT_CONSTEXPR emphasis get_emphasis() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR emphasis get_emphasis() const noexcept {
     FMT_ASSERT(has_emphasis(), "no emphasis specified for this style");
     return ems;
   }
 
  private:
   FMT_CONSTEXPR text_style(bool is_foreground,
-                           detail::color_type text_color) FMT_NOEXCEPT
-      : set_foreground_color(),
-        set_background_color(),
-        ems() {
+                           detail::color_type text_color) noexcept
+      : set_foreground_color(), set_background_color(), ems() {
     if (is_foreground) {
       foreground_color = text_color;
       set_foreground_color = true;
@@ -326,10 +298,9 @@ class text_style {
     }
   }
 
-  friend FMT_CONSTEXPR_DECL text_style fg(detail::color_type foreground)
-      FMT_NOEXCEPT;
-  friend FMT_CONSTEXPR_DECL text_style bg(detail::color_type background)
-      FMT_NOEXCEPT;
+  friend FMT_CONSTEXPR text_style fg(detail::color_type foreground) noexcept;
+
+  friend FMT_CONSTEXPR text_style bg(detail::color_type background) noexcept;
 
   detail::color_type foreground_color;
   detail::color_type background_color;
@@ -338,27 +309,29 @@ class text_style {
   emphasis ems;
 };
 
-FMT_CONSTEXPR text_style fg(detail::color_type foreground) FMT_NOEXCEPT {
-  return text_style(/*is_foreground=*/true, foreground);
+/** Creates a text style from the foreground (text) color. */
+FMT_CONSTEXPR inline text_style fg(detail::color_type foreground) noexcept {
+  return text_style(true, foreground);
 }
 
-FMT_CONSTEXPR text_style bg(detail::color_type background) FMT_NOEXCEPT {
-  return text_style(/*is_foreground=*/false, background);
+/** Creates a text style from the background color. */
+FMT_CONSTEXPR inline text_style bg(detail::color_type background) noexcept {
+  return text_style(false, background);
 }
 
-FMT_CONSTEXPR text_style operator|(emphasis lhs, emphasis rhs) FMT_NOEXCEPT {
+FMT_CONSTEXPR inline text_style operator|(emphasis lhs, emphasis rhs) noexcept {
   return text_style(lhs) | rhs;
 }
 
-namespace detail {
+FMT_BEGIN_DETAIL_NAMESPACE
 
 template <typename Char> struct ansi_color_escape {
   FMT_CONSTEXPR ansi_color_escape(detail::color_type text_color,
-                                  const char* esc) FMT_NOEXCEPT {
+                                  const char* esc) noexcept {
     // If we have a terminal color, we need to output another escape code
     // sequence.
     if (!text_color.is_rgb) {
-      bool is_background = esc == detail::data::background_color;
+      bool is_background = esc == string_view("\x1b[48;2;");
       uint32_t value = text_color.value.term_color;
       // Background ASCII codes are the same as the foreground ones but with
       // 10 more.
@@ -389,17 +362,19 @@ template <typename Char> struct ansi_color_escape {
     to_esc(color.b, buffer + 15, 'm');
     buffer[19] = static_cast<Char>(0);
   }
-  FMT_CONSTEXPR ansi_color_escape(emphasis em) FMT_NOEXCEPT {
-    uint8_t em_codes[4] = {};
-    uint8_t em_bits = static_cast<uint8_t>(em);
-    if (em_bits & static_cast<uint8_t>(emphasis::bold)) em_codes[0] = 1;
-    if (em_bits & static_cast<uint8_t>(emphasis::italic)) em_codes[1] = 3;
-    if (em_bits & static_cast<uint8_t>(emphasis::underline)) em_codes[2] = 4;
-    if (em_bits & static_cast<uint8_t>(emphasis::strikethrough))
-      em_codes[3] = 9;
+  FMT_CONSTEXPR ansi_color_escape(emphasis em) noexcept {
+    uint8_t em_codes[num_emphases] = {};
+    if (has_emphasis(em, emphasis::bold)) em_codes[0] = 1;
+    if (has_emphasis(em, emphasis::faint)) em_codes[1] = 2;
+    if (has_emphasis(em, emphasis::italic)) em_codes[2] = 3;
+    if (has_emphasis(em, emphasis::underline)) em_codes[3] = 4;
+    if (has_emphasis(em, emphasis::blink)) em_codes[4] = 5;
+    if (has_emphasis(em, emphasis::reverse)) em_codes[5] = 7;
+    if (has_emphasis(em, emphasis::conceal)) em_codes[6] = 8;
+    if (has_emphasis(em, emphasis::strikethrough)) em_codes[7] = 9;
 
     size_t index = 0;
-    for (int i = 0; i < 4; ++i) {
+    for (size_t i = 0; i < num_emphases; ++i) {
       if (!em_codes[i]) continue;
       buffer[index++] = static_cast<Char>('\x1b');
       buffer[index++] = static_cast<Char>('[');
@@ -408,67 +383,76 @@ template <typename Char> struct ansi_color_escape {
     }
     buffer[index++] = static_cast<Char>(0);
   }
-  FMT_CONSTEXPR operator const Char*() const FMT_NOEXCEPT { return buffer; }
+  FMT_CONSTEXPR operator const Char*() const noexcept { return buffer; }
 
-  FMT_CONSTEXPR const Char* begin() const FMT_NOEXCEPT { return buffer; }
-  FMT_CONSTEXPR const Char* end() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR const Char* begin() const noexcept { return buffer; }
+  FMT_CONSTEXPR_CHAR_TRAITS const Char* end() const noexcept {
     return buffer + std::char_traits<Char>::length(buffer);
   }
 
  private:
-  Char buffer[7u + 3u * 4u + 1u];
+  static constexpr size_t num_emphases = 8;
+  Char buffer[7u + 3u * num_emphases + 1u];
 
   static FMT_CONSTEXPR void to_esc(uint8_t c, Char* out,
-                                   char delimiter) FMT_NOEXCEPT {
+                                   char delimiter) noexcept {
     out[0] = static_cast<Char>('0' + c / 100);
     out[1] = static_cast<Char>('0' + c / 10 % 10);
     out[2] = static_cast<Char>('0' + c % 10);
     out[3] = static_cast<Char>(delimiter);
   }
+  static FMT_CONSTEXPR bool has_emphasis(emphasis em, emphasis mask) noexcept {
+    return static_cast<uint8_t>(em) & static_cast<uint8_t>(mask);
+  }
 };
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_foreground_color(
-    detail::color_type foreground) FMT_NOEXCEPT {
-  return ansi_color_escape<Char>(foreground, detail::data::foreground_color);
+    detail::color_type foreground) noexcept {
+  return ansi_color_escape<Char>(foreground, "\x1b[38;2;");
 }
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_background_color(
-    detail::color_type background) FMT_NOEXCEPT {
-  return ansi_color_escape<Char>(background, detail::data::background_color);
+    detail::color_type background) noexcept {
+  return ansi_color_escape<Char>(background, "\x1b[48;2;");
 }
 
 template <typename Char>
-FMT_CONSTEXPR ansi_color_escape<Char> make_emphasis(emphasis em) FMT_NOEXCEPT {
+FMT_CONSTEXPR ansi_color_escape<Char> make_emphasis(emphasis em) noexcept {
   return ansi_color_escape<Char>(em);
 }
 
-template <typename Char>
-inline void fputs(const Char* chars, FILE* stream) FMT_NOEXCEPT {
-  std::fputs(chars, stream);
+template <typename Char> inline void fputs(const Char* chars, FILE* stream) {
+  int result = std::fputs(chars, stream);
+  if (result < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
 }
 
-template <>
-inline void fputs<wchar_t>(const wchar_t* chars, FILE* stream) FMT_NOEXCEPT {
-  std::fputws(chars, stream);
+template <> inline void fputs<wchar_t>(const wchar_t* chars, FILE* stream) {
+  int result = std::fputws(chars, stream);
+  if (result < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
 }
 
-template <typename Char> inline void reset_color(FILE* stream) FMT_NOEXCEPT {
-  fputs(detail::data::reset_color, stream);
+template <typename Char> inline void reset_color(FILE* stream) {
+  fputs("\x1b[0m", stream);
 }
 
-template <> inline void reset_color<wchar_t>(FILE* stream) FMT_NOEXCEPT {
-  fputs(detail::data::wreset_color, stream);
+template <> inline void reset_color<wchar_t>(FILE* stream) {
+  fputs(L"\x1b[0m", stream);
 }
 
-template <typename Char>
-inline void reset_color(buffer<Char>& buffer) FMT_NOEXCEPT {
-  const char* begin = data::reset_color;
-  const char* end = begin + sizeof(data::reset_color) - 1;
-  buffer.append(begin, end);
+template <typename Char> inline void reset_color(buffer<Char>& buffer) {
+  auto reset_color = string_view("\x1b[0m");
+  buffer.append(reset_color.begin(), reset_color.end());
 }
 
+template <typename T> struct styled_arg {
+  const T& value;
+  text_style style;
+};
+
 template <typename Char>
 void vformat_to(buffer<Char>& buf, const text_style& ts,
                 basic_string_view<Char> format_str,
@@ -489,18 +473,23 @@ void vformat_to(buffer<Char>& buf, const text_style& ts,
     auto background = detail::make_background_color<Char>(ts.get_background());
     buf.append(background.begin(), background.end());
   }
-  detail::vformat_to(buf, format_str, args);
+  detail::vformat_to(buf, format_str, args, {});
   if (has_style) detail::reset_color<Char>(buf);
 }
-}  // namespace detail
+
+FMT_END_DETAIL_NAMESPACE
 
 template <typename S, typename Char = char_t<S>>
 void vprint(std::FILE* f, const text_style& ts, const S& format,
             basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buf;
-  detail::vformat_to(buf, ts, to_string_view(format), args);
-  buf.push_back(Char(0));
-  detail::fputs(buf.data(), f);
+  detail::vformat_to(buf, ts, detail::to_string_view(format), args);
+  if (detail::is_utf8()) {
+    detail::print(f, basic_string_view<Char>(buf.begin(), buf.size()));
+  } else {
+    buf.push_back(Char(0));
+    detail::fputs(buf.data(), f);
+  }
 }
 
 /**
@@ -519,15 +508,19 @@ template <typename S, typename... Args,
 void print(std::FILE* f, const text_style& ts, const S& format_str,
            const Args&... args) {
   vprint(f, ts, format_str,
-         fmt::make_args_checked<Args...>(format_str, args...));
+         fmt::make_format_args<buffer_context<char_t<S>>>(args...));
 }
 
 /**
+  \rst
   Formats a string and prints it to stdout using ANSI escape sequences to
   specify text formatting.
-  Example:
+
+  **Example**::
+
     fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
                "Elapsed time: {0:.2f} seconds", 1.23);
+  \endrst
  */
 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_string<S>::value)>
@@ -540,7 +533,7 @@ inline std::basic_string<Char> vformat(
     const text_style& ts, const S& format_str,
     basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buf;
-  detail::vformat_to(buf, ts, to_string_view(format_str), args);
+  detail::vformat_to(buf, ts, detail::to_string_view(format_str), args);
   return fmt::to_string(buf);
 }
 
@@ -559,8 +552,8 @@ inline std::basic_string<Char> vformat(
 template <typename S, typename... Args, typename Char = char_t<S>>
 inline std::basic_string<Char> format(const text_style& ts, const S& format_str,
                                       const Args&... args) {
-  return vformat(ts, to_string_view(format_str),
-                 fmt::make_args_checked<Args...>(format_str, args...));
+  return fmt::vformat(ts, detail::to_string_view(format_str),
+                      fmt::make_format_args<buffer_context<Char>>(args...));
 }
 
 /**
@@ -571,7 +564,7 @@ template <typename OutputIt, typename Char,
 OutputIt vformat_to(
     OutputIt out, const text_style& ts, basic_string_view<Char> format_str,
     basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  decltype(detail::get_buffer<Char>(out)) buf(detail::get_buffer_init(out));
+  auto&& buf = detail::get_buffer<Char>(out);
   detail::vformat_to(buf, ts, format_str, args);
   return detail::get_iterator(buf);
 }
@@ -594,10 +587,65 @@ template <typename OutputIt, typename S, typename... Args,
 inline auto format_to(OutputIt out, const text_style& ts, const S& format_str,
                       Args&&... args) ->
     typename std::enable_if<enable, OutputIt>::type {
-  return vformat_to(out, ts, to_string_view(format_str),
-                    fmt::make_args_checked<Args...>(format_str, args...));
+  return vformat_to(out, ts, detail::to_string_view(format_str),
+                    fmt::make_format_args<buffer_context<char_t<S>>>(args...));
 }
 
+template <typename T, typename Char>
+struct formatter<detail::styled_arg<T>, Char> : formatter<T, Char> {
+  template <typename FormatContext>
+  auto format(const detail::styled_arg<T>& arg, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    const auto& ts = arg.style;
+    const auto& value = arg.value;
+    auto out = ctx.out();
+
+    bool has_style = false;
+    if (ts.has_emphasis()) {
+      has_style = true;
+      auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
+      out = std::copy(emphasis.begin(), emphasis.end(), out);
+    }
+    if (ts.has_foreground()) {
+      has_style = true;
+      auto foreground =
+          detail::make_foreground_color<Char>(ts.get_foreground());
+      out = std::copy(foreground.begin(), foreground.end(), out);
+    }
+    if (ts.has_background()) {
+      has_style = true;
+      auto background =
+          detail::make_background_color<Char>(ts.get_background());
+      out = std::copy(background.begin(), background.end(), out);
+    }
+    out = formatter<T, Char>::format(value, ctx);
+    if (has_style) {
+      auto reset_color = string_view("\x1b[0m");
+      out = std::copy(reset_color.begin(), reset_color.end(), out);
+    }
+    return out;
+  }
+};
+
+/**
+  \rst
+  Returns an argument that will be formatted using ANSI escape sequences,
+  to be used in a formatting function.
+
+  **Example**::
+
+    fmt::print("Elapsed time: {0:.2f} seconds",
+               fmt::styled(1.23, fmt::fg(fmt::color::green) |
+                                 fmt::bg(fmt::color::blue)));
+  \endrst
+ */
+template <typename T>
+FMT_CONSTEXPR auto styled(const T& value, text_style ts)
+    -> detail::styled_arg<remove_cvref_t<T>> {
+  return detail::styled_arg<remove_cvref_t<T>>{value, ts};
+}
+
+FMT_MODULE_EXPORT_END
 FMT_END_NAMESPACE
 
 #endif  // FMT_COLOR_H_

include/spdlog/fmt/bundled/compile.h

@@ -8,13 +8,95 @@
 #ifndef FMT_COMPILE_H_
 #define FMT_COMPILE_H_
 
-#include <vector>
-
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
+template <typename Char, typename InputIt>
+FMT_CONSTEXPR inline counting_iterator copy_str(InputIt begin, InputIt end,
+                                                counting_iterator it) {
+  return it + (end - begin);
+}
+
+template <typename OutputIt> class truncating_iterator_base {
+ protected:
+  OutputIt out_;
+  size_t limit_;
+  size_t count_ = 0;
+
+  truncating_iterator_base() : out_(), limit_(0) {}
+
+  truncating_iterator_base(OutputIt out, size_t limit)
+      : out_(out), limit_(limit) {}
+
+ public:
+  using iterator_category = std::output_iterator_tag;
+  using value_type = typename std::iterator_traits<OutputIt>::value_type;
+  using difference_type = std::ptrdiff_t;
+  using pointer = void;
+  using reference = void;
+  FMT_UNCHECKED_ITERATOR(truncating_iterator_base);
+
+  OutputIt base() const { return out_; }
+  size_t count() const { return count_; }
+};
+
+// An output iterator that truncates the output and counts the number of objects
+// written to it.
+template <typename OutputIt,
+          typename Enable = typename std::is_void<
+              typename std::iterator_traits<OutputIt>::value_type>::type>
+class truncating_iterator;
+
+template <typename OutputIt>
+class truncating_iterator<OutputIt, std::false_type>
+    : public truncating_iterator_base<OutputIt> {
+  mutable typename truncating_iterator_base<OutputIt>::value_type blackhole_;
+
+ public:
+  using value_type = typename truncating_iterator_base<OutputIt>::value_type;
+
+  truncating_iterator() = default;
+
+  truncating_iterator(OutputIt out, size_t limit)
+      : truncating_iterator_base<OutputIt>(out, limit) {}
+
+  truncating_iterator& operator++() {
+    if (this->count_++ < this->limit_) ++this->out_;
+    return *this;
+  }
+
+  truncating_iterator operator++(int) {
+    auto it = *this;
+    ++*this;
+    return it;
+  }
+
+  value_type& operator*() const {
+    return this->count_ < this->limit_ ? *this->out_ : blackhole_;
+  }
+};
+
+template <typename OutputIt>
+class truncating_iterator<OutputIt, std::true_type>
+    : public truncating_iterator_base<OutputIt> {
+ public:
+  truncating_iterator() = default;
+
+  truncating_iterator(OutputIt out, size_t limit)
+      : truncating_iterator_base<OutputIt>(out, limit) {}
+
+  template <typename T> truncating_iterator& operator=(T val) {
+    if (this->count_++ < this->limit_) *this->out_++ = val;
+    return *this;
+  }
+
+  truncating_iterator& operator++() { return *this; }
+  truncating_iterator& operator++(int) { return *this; }
+  truncating_iterator& operator*() { return *this; }
+};
+
 // A compile-time string which is compiled into fast formatting code.
 class compiled_string {};
 
@@ -34,336 +116,30 @@ struct is_compiled_string : std::is_base_of<compiled_string, S> {};
     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
   \endrst
  */
-#define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::detail::compiled_string)
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
+#  define FMT_COMPILE(s) \
+    FMT_STRING_IMPL(s, fmt::detail::compiled_string, explicit)
+#else
+#  define FMT_COMPILE(s) FMT_STRING(s)
+#endif
+
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+template <typename Char, size_t N,
+          fmt::detail_exported::fixed_string<Char, N> Str>
+struct udl_compiled_string : compiled_string {
+  using char_type = Char;
+  explicit constexpr operator basic_string_view<char_type>() const {
+    return {Str.data, N - 1};
+  }
+};
+#endif
 
 template <typename T, typename... Tail>
 const T& first(const T& value, const Tail&...) {
   return value;
 }
 
-// Part of a compiled format string. It can be either literal text or a
-// replacement field.
-template <typename Char> struct format_part {
-  enum class kind { arg_index, arg_name, text, replacement };
-
-  struct replacement {
-    arg_ref<Char> arg_id;
-    dynamic_format_specs<Char> specs;
-  };
-
-  kind part_kind;
-  union value {
-    int arg_index;
-    basic_string_view<Char> str;
-    replacement repl;
-
-    FMT_CONSTEXPR value(int index = 0) : arg_index(index) {}
-    FMT_CONSTEXPR value(basic_string_view<Char> s) : str(s) {}
-    FMT_CONSTEXPR value(replacement r) : repl(r) {}
-  } val;
-  // Position past the end of the argument id.
-  const Char* arg_id_end = nullptr;
-
-  FMT_CONSTEXPR format_part(kind k = kind::arg_index, value v = {})
-      : part_kind(k), val(v) {}
-
-  static FMT_CONSTEXPR format_part make_arg_index(int index) {
-    return format_part(kind::arg_index, index);
-  }
-  static FMT_CONSTEXPR format_part make_arg_name(basic_string_view<Char> name) {
-    return format_part(kind::arg_name, name);
-  }
-  static FMT_CONSTEXPR format_part make_text(basic_string_view<Char> text) {
-    return format_part(kind::text, text);
-  }
-  static FMT_CONSTEXPR format_part make_replacement(replacement repl) {
-    return format_part(kind::replacement, repl);
-  }
-};
-
-template <typename Char> struct part_counter {
-  unsigned num_parts = 0;
-
-  FMT_CONSTEXPR void on_text(const Char* begin, const Char* end) {
-    if (begin != end) ++num_parts;
-  }
-
-  FMT_CONSTEXPR int on_arg_id() { return ++num_parts, 0; }
-  FMT_CONSTEXPR int on_arg_id(int) { return ++num_parts, 0; }
-  FMT_CONSTEXPR int on_arg_id(basic_string_view<Char>) {
-    return ++num_parts, 0;
-  }
-
-  FMT_CONSTEXPR void on_replacement_field(int, const Char*) {}
-
-  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
-                                            const Char* end) {
-    // Find the matching brace.
-    unsigned brace_counter = 0;
-    for (; begin != end; ++begin) {
-      if (*begin == '{') {
-        ++brace_counter;
-      } else if (*begin == '}') {
-        if (brace_counter == 0u) break;
-        --brace_counter;
-      }
-    }
-    return begin;
-  }
-
-  FMT_CONSTEXPR void on_error(const char*) {}
-};
-
-// Counts the number of parts in a format string.
-template <typename Char>
-FMT_CONSTEXPR unsigned count_parts(basic_string_view<Char> format_str) {
-  part_counter<Char> counter;
-  parse_format_string<true>(format_str, counter);
-  return counter.num_parts;
-}
-
-template <typename Char, typename PartHandler>
-class format_string_compiler : public error_handler {
- private:
-  using part = format_part<Char>;
-
-  PartHandler handler_;
-  part part_;
-  basic_string_view<Char> format_str_;
-  basic_format_parse_context<Char> parse_context_;
-
- public:
-  FMT_CONSTEXPR format_string_compiler(basic_string_view<Char> format_str,
-                                       PartHandler handler)
-      : handler_(handler),
-        format_str_(format_str),
-        parse_context_(format_str) {}
-
-  FMT_CONSTEXPR void on_text(const Char* begin, const Char* end) {
-    if (begin != end)
-      handler_(part::make_text({begin, to_unsigned(end - begin)}));
-  }
-
-  FMT_CONSTEXPR int on_arg_id() {
-    part_ = part::make_arg_index(parse_context_.next_arg_id());
-    return 0;
-  }
-
-  FMT_CONSTEXPR int on_arg_id(int id) {
-    parse_context_.check_arg_id(id);
-    part_ = part::make_arg_index(id);
-    return 0;
-  }
-
-  FMT_CONSTEXPR int on_arg_id(basic_string_view<Char> id) {
-    part_ = part::make_arg_name(id);
-    return 0;
-  }
-
-  FMT_CONSTEXPR void on_replacement_field(int, const Char* ptr) {
-    part_.arg_id_end = ptr;
-    handler_(part_);
-  }
-
-  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
-                                            const Char* end) {
-    auto repl = typename part::replacement();
-    dynamic_specs_handler<basic_format_parse_context<Char>> handler(
-        repl.specs, parse_context_);
-    auto it = parse_format_specs(begin, end, handler);
-    if (*it != '}') on_error("missing '}' in format string");
-    repl.arg_id = part_.part_kind == part::kind::arg_index
-                      ? arg_ref<Char>(part_.val.arg_index)
-                      : arg_ref<Char>(part_.val.str);
-    auto part = part::make_replacement(repl);
-    part.arg_id_end = begin;
-    handler_(part);
-    return it;
-  }
-};
-
-// Compiles a format string and invokes handler(part) for each parsed part.
-template <bool IS_CONSTEXPR, typename Char, typename PartHandler>
-FMT_CONSTEXPR void compile_format_string(basic_string_view<Char> format_str,
-                                         PartHandler handler) {
-  parse_format_string<IS_CONSTEXPR>(
-      format_str,
-      format_string_compiler<Char, PartHandler>(format_str, handler));
-}
-
-template <typename OutputIt, typename Context, typename Id>
-void format_arg(
-    basic_format_parse_context<typename Context::char_type>& parse_ctx,
-    Context& ctx, Id arg_id) {
-  ctx.advance_to(visit_format_arg(
-      arg_formatter<OutputIt, typename Context::char_type>(ctx, &parse_ctx),
-      ctx.arg(arg_id)));
-}
-
-// vformat_to is defined in a subnamespace to prevent ADL.
-namespace cf {
-template <typename Context, typename OutputIt, typename CompiledFormat>
-auto vformat_to(OutputIt out, CompiledFormat& cf,
-                basic_format_args<Context> args) -> typename Context::iterator {
-  using char_type = typename Context::char_type;
-  basic_format_parse_context<char_type> parse_ctx(
-      to_string_view(cf.format_str_));
-  Context ctx(out, args);
-
-  const auto& parts = cf.parts();
-  for (auto part_it = std::begin(parts); part_it != std::end(parts);
-       ++part_it) {
-    const auto& part = *part_it;
-    const auto& value = part.val;
-
-    using format_part_t = format_part<char_type>;
-    switch (part.part_kind) {
-    case format_part_t::kind::text: {
-      const auto text = value.str;
-      auto output = ctx.out();
-      auto&& it = reserve(output, text.size());
-      it = std::copy_n(text.begin(), text.size(), it);
-      ctx.advance_to(output);
-      break;
-    }
-
-    case format_part_t::kind::arg_index:
-      advance_to(parse_ctx, part.arg_id_end);
-      detail::format_arg<OutputIt>(parse_ctx, ctx, value.arg_index);
-      break;
-
-    case format_part_t::kind::arg_name:
-      advance_to(parse_ctx, part.arg_id_end);
-      detail::format_arg<OutputIt>(parse_ctx, ctx, value.str);
-      break;
-
-    case format_part_t::kind::replacement: {
-      const auto& arg_id_value = value.repl.arg_id.val;
-      const auto arg = value.repl.arg_id.kind == arg_id_kind::index
-                           ? ctx.arg(arg_id_value.index)
-                           : ctx.arg(arg_id_value.name);
-
-      auto specs = value.repl.specs;
-
-      handle_dynamic_spec<width_checker>(specs.width, specs.width_ref, ctx);
-      handle_dynamic_spec<precision_checker>(specs.precision,
-                                             specs.precision_ref, ctx);
-
-      error_handler h;
-      numeric_specs_checker<error_handler> checker(h, arg.type());
-      if (specs.align == align::numeric) checker.require_numeric_argument();
-      if (specs.sign != sign::none) checker.check_sign();
-      if (specs.alt) checker.require_numeric_argument();
-      if (specs.precision >= 0) checker.check_precision();
-
-      advance_to(parse_ctx, part.arg_id_end);
-      ctx.advance_to(
-          visit_format_arg(arg_formatter<OutputIt, typename Context::char_type>(
-                               ctx, nullptr, &specs),
-                           arg));
-      break;
-    }
-    }
-  }
-  return ctx.out();
-}
-}  // namespace cf
-
-struct basic_compiled_format {};
-
-template <typename S, typename = void>
-struct compiled_format_base : basic_compiled_format {
-  using char_type = char_t<S>;
-  using parts_container = std::vector<detail::format_part<char_type>>;
-
-  parts_container compiled_parts;
-
-  explicit compiled_format_base(basic_string_view<char_type> format_str) {
-    compile_format_string<false>(format_str,
-                                 [this](const format_part<char_type>& part) {
-                                   compiled_parts.push_back(part);
-                                 });
-  }
-
-  const parts_container& parts() const { return compiled_parts; }
-};
-
-template <typename Char, unsigned N> struct format_part_array {
-  format_part<Char> data[N] = {};
-  FMT_CONSTEXPR format_part_array() = default;
-};
-
-template <typename Char, unsigned N>
-FMT_CONSTEXPR format_part_array<Char, N> compile_to_parts(
-    basic_string_view<Char> format_str) {
-  format_part_array<Char, N> parts;
-  unsigned counter = 0;
-  // This is not a lambda for compatibility with older compilers.
-  struct {
-    format_part<Char>* parts;
-    unsigned* counter;
-    FMT_CONSTEXPR void operator()(const format_part<Char>& part) {
-      parts[(*counter)++] = part;
-    }
-  } collector{parts.data, &counter};
-  compile_format_string<true>(format_str, collector);
-  if (counter < N) {
-    parts.data[counter] =
-        format_part<Char>::make_text(basic_string_view<Char>());
-  }
-  return parts;
-}
-
-template <typename T> constexpr const T& constexpr_max(const T& a, const T& b) {
-  return (a < b) ? b : a;
-}
-
-template <typename S>
-struct compiled_format_base<S, enable_if_t<is_compile_string<S>::value>>
-    : basic_compiled_format {
-  using char_type = char_t<S>;
-
-  FMT_CONSTEXPR explicit compiled_format_base(basic_string_view<char_type>) {}
-
-// Workaround for old compilers. Format string compilation will not be
-// performed there anyway.
-#if FMT_USE_CONSTEXPR
-  static FMT_CONSTEXPR_DECL const unsigned num_format_parts =
-      constexpr_max(count_parts(to_string_view(S())), 1u);
-#else
-  static const unsigned num_format_parts = 1;
-#endif
-
-  using parts_container = format_part<char_type>[num_format_parts];
-
-  const parts_container& parts() const {
-    static FMT_CONSTEXPR_DECL const auto compiled_parts =
-        compile_to_parts<char_type, num_format_parts>(
-            detail::to_string_view(S()));
-    return compiled_parts.data;
-  }
-};
-
-template <typename S, typename... Args>
-class compiled_format : private compiled_format_base<S> {
- public:
-  using typename compiled_format_base<S>::char_type;
-
- private:
-  basic_string_view<char_type> format_str_;
-
-  template <typename Context, typename OutputIt, typename CompiledFormat>
-  friend auto cf::vformat_to(OutputIt out, CompiledFormat& cf,
-                             basic_format_args<Context> args) ->
-      typename Context::iterator;
-
- public:
-  compiled_format() = delete;
-  explicit constexpr compiled_format(basic_string_view<char_type> format_str)
-      : compiled_format_base<S>(format_str), format_str_(format_str) {}
-};
-
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 template <typename... Args> struct type_list {};
 
 // Returns a reference to the argument at index N from [first, rest...].
@@ -374,13 +150,20 @@ constexpr const auto& get([[maybe_unused]] const T& first,
   if constexpr (N == 0)
     return first;
   else
-    return get<N - 1>(rest...);
+    return detail::get<N - 1>(rest...);
+}
+
+template <typename Char, typename... Args>
+constexpr int get_arg_index_by_name(basic_string_view<Char> name,
+                                    type_list<Args...>) {
+  return get_arg_index_by_name<Args...>(name);
 }
 
 template <int N, typename> struct get_type_impl;
 
 template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
-  using type = remove_cvref_t<decltype(get<N>(std::declval<Args>()...))>;
+  using type =
+      remove_cvref_t<decltype(detail::get<N>(std::declval<Args>()...))>;
 };
 
 template <int N, typename T>
@@ -393,7 +176,7 @@ template <typename Char> struct text {
   using char_type = Char;
 
   template <typename OutputIt, typename... Args>
-  OutputIt format(OutputIt out, const Args&...) const {
+  constexpr OutputIt format(OutputIt out, const Args&...) const {
     return write<Char>(out, data);
   }
 };
@@ -412,11 +195,22 @@ template <typename Char> struct code_unit {
   using char_type = Char;
 
   template <typename OutputIt, typename... Args>
-  OutputIt format(OutputIt out, const Args&...) const {
+  constexpr OutputIt format(OutputIt out, const Args&...) const {
     return write<Char>(out, value);
   }
 };
 
+// This ensures that the argument type is convertible to `const T&`.
+template <typename T, int N, typename... Args>
+constexpr const T& get_arg_checked(const Args&... args) {
+  const auto& arg = detail::get<N>(args...);
+  if constexpr (detail::is_named_arg<remove_cvref_t<decltype(arg)>>()) {
+    return arg.value;
+  } else {
+    return arg;
+  }
+}
+
 template <typename Char>
 struct is_compiled_format<code_unit<Char>> : std::true_type {};
 
@@ -425,29 +219,58 @@ template <typename Char, typename T, int N> struct field {
   using char_type = Char;
 
   template <typename OutputIt, typename... Args>
-  OutputIt format(OutputIt out, const Args&... args) const {
-    // This ensures that the argument type is convertile to `const T&`.
-    const T& arg = get<N>(args...);
-    return write<Char>(out, arg);
+  constexpr OutputIt format(OutputIt out, const Args&... args) const {
+    return write<Char>(out, get_arg_checked<T, N>(args...));
   }
 };
 
 template <typename Char, typename T, int N>
 struct is_compiled_format<field<Char, T, N>> : std::true_type {};
 
+// A replacement field that refers to argument with name.
+template <typename Char> struct runtime_named_field {
+  using char_type = Char;
+  basic_string_view<Char> name;
+
+  template <typename OutputIt, typename T>
+  constexpr static bool try_format_argument(
+      OutputIt& out,
+      // [[maybe_unused]] due to unused-but-set-parameter warning in GCC 7,8,9
+      [[maybe_unused]] basic_string_view<Char> arg_name, const T& arg) {
+    if constexpr (is_named_arg<typename std::remove_cv<T>::type>::value) {
+      if (arg_name == arg.name) {
+        out = write<Char>(out, arg.value);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  template <typename OutputIt, typename... Args>
+  constexpr OutputIt format(OutputIt out, const Args&... args) const {
+    bool found = (try_format_argument(out, name, args) || ...);
+    if (!found) {
+      FMT_THROW(format_error("argument with specified name is not found"));
+    }
+    return out;
+  }
+};
+
+template <typename Char>
+struct is_compiled_format<runtime_named_field<Char>> : std::true_type {};
+
 // A replacement field that refers to argument N and has format specifiers.
 template <typename Char, typename T, int N> struct spec_field {
   using char_type = Char;
-  mutable formatter<T, Char> fmt;
+  formatter<T, Char> fmt;
 
   template <typename OutputIt, typename... Args>
-  OutputIt format(OutputIt out, const Args&... args) const {
-    // This ensures that the argument type is convertile to `const T&`.
-    const T& arg = get<N>(args...);
+  constexpr FMT_INLINE OutputIt format(OutputIt out,
+                                       const Args&... args) const {
     const auto& vargs =
-        make_format_args<basic_format_context<OutputIt, Char>>(args...);
+        fmt::make_format_args<basic_format_context<OutputIt, Char>>(args...);
     basic_format_context<OutputIt, Char> ctx(out, vargs);
-    return fmt.format(arg, ctx);
+    return fmt.format(get_arg_checked<T, N>(args...), ctx);
   }
 };
 
@@ -460,7 +283,7 @@ template <typename L, typename R> struct concat {
   using char_type = typename L::char_type;
 
   template <typename OutputIt, typename... Args>
-  OutputIt format(OutputIt out, const Args&... args) const {
+  constexpr OutputIt format(OutputIt out, const Args&... args) const {
     out = lhs.format(out, args...);
     return rhs.format(out, args...);
   }
@@ -508,14 +331,87 @@ template <typename T, typename Char> struct parse_specs_result {
   int next_arg_id;
 };
 
+constexpr int manual_indexing_id = -1;
+
 template <typename T, typename Char>
 constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
-                                                  size_t pos, int arg_id) {
+                                                  size_t pos, int next_arg_id) {
   str.remove_prefix(pos);
-  auto ctx = basic_format_parse_context<Char>(str, {}, arg_id + 1);
+  auto ctx = compile_parse_context<Char>(str, max_value<int>(), nullptr, {},
+                                         next_arg_id);
   auto f = formatter<T, Char>();
   auto end = f.parse(ctx);
-  return {f, pos + (end - str.data()) + 1, ctx.next_arg_id()};
+  return {f, pos + fmt::detail::to_unsigned(end - str.data()),
+          next_arg_id == 0 ? manual_indexing_id : ctx.next_arg_id()};
+}
+
+template <typename Char> struct arg_id_handler {
+  arg_ref<Char> arg_id;
+
+  constexpr int operator()() {
+    FMT_ASSERT(false, "handler cannot be used with automatic indexing");
+    return 0;
+  }
+  constexpr int operator()(int id) {
+    arg_id = arg_ref<Char>(id);
+    return 0;
+  }
+  constexpr int operator()(basic_string_view<Char> id) {
+    arg_id = arg_ref<Char>(id);
+    return 0;
+  }
+
+  constexpr void on_error(const char* message) {
+    FMT_THROW(format_error(message));
+  }
+};
+
+template <typename Char> struct parse_arg_id_result {
+  arg_ref<Char> arg_id;
+  const Char* arg_id_end;
+};
+
+template <int ID, typename Char>
+constexpr auto parse_arg_id(const Char* begin, const Char* end) {
+  auto handler = arg_id_handler<Char>{arg_ref<Char>{}};
+  auto arg_id_end = parse_arg_id(begin, end, handler);
+  return parse_arg_id_result<Char>{handler.arg_id, arg_id_end};
+}
+
+template <typename T, typename Enable = void> struct field_type {
+  using type = remove_cvref_t<T>;
+};
+
+template <typename T>
+struct field_type<T, enable_if_t<detail::is_named_arg<T>::value>> {
+  using type = remove_cvref_t<decltype(T::value)>;
+};
+
+template <typename T, typename Args, size_t END_POS, int ARG_INDEX, int NEXT_ID,
+          typename S>
+constexpr auto parse_replacement_field_then_tail(S format_str) {
+  using char_type = typename S::char_type;
+  constexpr auto str = basic_string_view<char_type>(format_str);
+  constexpr char_type c = END_POS != str.size() ? str[END_POS] : char_type();
+  if constexpr (c == '}') {
+    return parse_tail<Args, END_POS + 1, NEXT_ID>(
+        field<char_type, typename field_type<T>::type, ARG_INDEX>(),
+        format_str);
+  } else if constexpr (c != ':') {
+    FMT_THROW(format_error("expected ':'"));
+  } else {
+    constexpr auto result = parse_specs<typename field_type<T>::type>(
+        str, END_POS + 1, NEXT_ID == manual_indexing_id ? 0 : NEXT_ID);
+    if constexpr (result.end >= str.size() || str[result.end] != '}') {
+      FMT_THROW(format_error("expected '}'"));
+      return 0;
+    } else {
+      return parse_tail<Args, result.end + 1, result.next_arg_id>(
+          spec_field<char_type, typename field_type<T>::type, ARG_INDEX>{
+              result.fmt},
+          format_str);
+    }
+  }
 }
 
 // Compiles a non-empty format string and returns the compiled representation
@@ -523,27 +419,59 @@ constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
 template <typename Args, size_t POS, int ID, typename S>
 constexpr auto compile_format_string(S format_str) {
   using char_type = typename S::char_type;
-  constexpr basic_string_view<char_type> str = format_str;
+  constexpr auto str = basic_string_view<char_type>(format_str);
   if constexpr (str[POS] == '{') {
-    if (POS + 1 == str.size())
-      throw format_error("unmatched '{' in format string");
+    if constexpr (POS + 1 == str.size())
+      FMT_THROW(format_error("unmatched '{' in format string"));
     if constexpr (str[POS + 1] == '{') {
       return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
-    } else if constexpr (str[POS + 1] == '}') {
-      using type = get_type<ID, Args>;
-      return parse_tail<Args, POS + 2, ID + 1>(field<char_type, type, ID>(),
-                                               format_str);
-    } else if constexpr (str[POS + 1] == ':') {
-      using type = get_type<ID, Args>;
-      constexpr auto result = parse_specs<type>(str, POS + 2, ID);
-      return parse_tail<Args, result.end, result.next_arg_id>(
-          spec_field<char_type, type, ID>{result.fmt}, format_str);
+    } else if constexpr (str[POS + 1] == '}' || str[POS + 1] == ':') {
+      static_assert(ID != manual_indexing_id,
+                    "cannot switch from manual to automatic argument indexing");
+      constexpr auto next_id =
+          ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
+      return parse_replacement_field_then_tail<get_type<ID, Args>, Args,
+                                               POS + 1, ID, next_id>(
+          format_str);
     } else {
-      return unknown_format();
+      constexpr auto arg_id_result =
+          parse_arg_id<ID>(str.data() + POS + 1, str.data() + str.size());
+      constexpr auto arg_id_end_pos = arg_id_result.arg_id_end - str.data();
+      constexpr char_type c =
+          arg_id_end_pos != str.size() ? str[arg_id_end_pos] : char_type();
+      static_assert(c == '}' || c == ':', "missing '}' in format string");
+      if constexpr (arg_id_result.arg_id.kind == arg_id_kind::index) {
+        static_assert(
+            ID == manual_indexing_id || ID == 0,
+            "cannot switch from automatic to manual argument indexing");
+        constexpr auto arg_index = arg_id_result.arg_id.val.index;
+        return parse_replacement_field_then_tail<get_type<arg_index, Args>,
+                                                 Args, arg_id_end_pos,
+                                                 arg_index, manual_indexing_id>(
+            format_str);
+      } else if constexpr (arg_id_result.arg_id.kind == arg_id_kind::name) {
+        constexpr auto arg_index =
+            get_arg_index_by_name(arg_id_result.arg_id.val.name, Args{});
+        if constexpr (arg_index != invalid_arg_index) {
+          constexpr auto next_id =
+              ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
+          return parse_replacement_field_then_tail<
+              decltype(get_type<arg_index, Args>::value), Args, arg_id_end_pos,
+              arg_index, next_id>(format_str);
+        } else {
+          if constexpr (c == '}') {
+            return parse_tail<Args, arg_id_end_pos + 1, ID>(
+                runtime_named_field<char_type>{arg_id_result.arg_id.val.name},
+                format_str);
+          } else if constexpr (c == ':') {
+            return unknown_format();  // no type info for specs parsing
+          }
+        }
+      }
     }
   } else if constexpr (str[POS] == '}') {
-    if (POS + 1 == str.size())
-      throw format_error("unmatched '}' in format string");
+    if constexpr (POS + 1 == str.size())
+      FMT_THROW(format_error("unmatched '}' in format string"));
     return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
   } else {
     constexpr auto end = parse_text(str, POS + 1);
@@ -558,144 +486,126 @@ constexpr auto compile_format_string(S format_str) {
 }
 
 template <typename... Args, typename S,
-          FMT_ENABLE_IF(is_compile_string<S>::value ||
-                        detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 constexpr auto compile(S format_str) {
-  constexpr basic_string_view<typename S::char_type> str = format_str;
+  constexpr auto str = basic_string_view<typename S::char_type>(format_str);
   if constexpr (str.size() == 0) {
     return detail::make_text(str, 0, 0);
   } else {
     constexpr auto result =
         detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
             format_str);
-    if constexpr (std::is_same<remove_cvref_t<decltype(result)>,
-                               detail::unknown_format>()) {
-      return detail::compiled_format<S, Args...>(to_string_view(format_str));
-    } else {
-      return result;
-    }
+    return result;
   }
 }
-#else
-template <typename... Args, typename S,
-          FMT_ENABLE_IF(is_compile_string<S>::value)>
-constexpr auto compile(S format_str) -> detail::compiled_format<S, Args...> {
-  return detail::compiled_format<S, Args...>(to_string_view(format_str));
-}
-#endif  // __cpp_if_constexpr
-
-// Compiles the format string which must be a string literal.
-template <typename... Args, typename Char, size_t N>
-auto compile(const Char (&format_str)[N])
-    -> detail::compiled_format<const Char*, Args...> {
-  return detail::compiled_format<const Char*, Args...>(
-      basic_string_view<Char>(format_str, N - 1));
-}
+#endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 }  // namespace detail
 
-// DEPRECATED! use FMT_COMPILE instead.
-template <typename... Args>
-FMT_DEPRECATED auto compile(const Args&... args)
-    -> decltype(detail::compile(args...)) {
-  return detail::compile(args...);
-}
+FMT_MODULE_EXPORT_BEGIN
 
-#if FMT_USE_CONSTEXPR
-#  ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 
 template <typename CompiledFormat, typename... Args,
           typename Char = typename CompiledFormat::char_type,
           FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
 FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
                                           const Args&... args) {
-  basic_memory_buffer<Char> buffer;
-  cf.format(detail::buffer_appender<Char>(buffer), args...);
-  return to_string(buffer);
+  auto s = std::basic_string<Char>();
+  cf.format(std::back_inserter(s), args...);
+  return s;
 }
 
 template <typename OutputIt, typename CompiledFormat, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
-OutputIt format_to(OutputIt out, const CompiledFormat& cf,
-                   const Args&... args) {
+constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
+                                        const Args&... args) {
   return cf.format(out, args...);
 }
-#  endif  // __cpp_if_constexpr
-#endif    // FMT_USE_CONSTEXPR
-
-template <typename CompiledFormat, typename... Args,
-          typename Char = typename CompiledFormat::char_type,
-          FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format,
-                                        CompiledFormat>::value)>
-std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) {
-  basic_memory_buffer<Char> buffer;
-  using context = buffer_context<Char>;
-  detail::cf::vformat_to<context>(detail::buffer_appender<Char>(buffer), cf,
-                                  make_format_args<context>(args...));
-  return to_string(buffer);
-}
 
 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
                                                            Args&&... args) {
-#ifdef __cpp_if_constexpr
   if constexpr (std::is_same<typename S::char_type, char>::value) {
-    constexpr basic_string_view<typename S::char_type> str = S();
-    if (str.size() == 2 && str[0] == '{' && str[1] == '}')
-      return fmt::to_string(detail::first(args...));
+    constexpr auto str = basic_string_view<typename S::char_type>(S());
+    if constexpr (str.size() == 2 && str[0] == '{' && str[1] == '}') {
+      const auto& first = detail::first(args...);
+      if constexpr (detail::is_named_arg<
+                        remove_cvref_t<decltype(first)>>::value) {
+        return fmt::to_string(first.value);
+      } else {
+        return fmt::to_string(first);
+      }
+    }
   }
+  constexpr auto compiled = detail::compile<Args...>(S());
+  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
+                             detail::unknown_format>()) {
+    return fmt::format(
+        static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
+  } else {
+    return fmt::format(compiled, std::forward<Args>(args)...);
+  }
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
+  constexpr auto compiled = detail::compile<Args...>(S());
+  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
+                             detail::unknown_format>()) {
+    return fmt::format_to(
+        out, static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
+  } else {
+    return fmt::format_to(out, compiled, std::forward<Args>(args)...);
+  }
+}
 #endif
-  constexpr auto compiled = detail::compile<Args...>(S());
-  return format(compiled, std::forward<Args>(args)...);
-}
-
-template <typename OutputIt, typename CompiledFormat, typename... Args,
-          FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format,
-                                        CompiledFormat>::value)>
-OutputIt format_to(OutputIt out, const CompiledFormat& cf,
-                   const Args&... args) {
-  using char_type = typename CompiledFormat::char_type;
-  using context = format_context_t<OutputIt, char_type>;
-  return detail::cf::vformat_to<context>(out, cf,
-                                         make_format_args<context>(args...));
-}
 
 template <typename OutputIt, typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
-OutputIt format_to(OutputIt out, const S&, const Args&... args) {
-  constexpr auto compiled = detail::compile<Args...>(S());
-  return format_to(out, compiled, args...);
-}
-
-template <typename OutputIt, typename CompiledFormat, typename... Args>
-auto format_to_n(OutputIt out, size_t n, const CompiledFormat& cf,
-                 const Args&... args) ->
-    typename std::enable_if<
-        detail::is_output_iterator<OutputIt,
-                                   typename CompiledFormat::char_type>::value &&
-            std::is_base_of<detail::basic_compiled_format,
-                            CompiledFormat>::value,
-        format_to_n_result<OutputIt>>::type {
-  auto it =
-      format_to(detail::truncating_iterator<OutputIt>(out, n), cf, args...);
+format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
+                                         const S& format_str, Args&&... args) {
+  auto it = fmt::format_to(detail::truncating_iterator<OutputIt>(out, n),
+                           format_str, std::forward<Args>(args)...);
   return {it.base(), it.count()};
 }
 
-template <typename OutputIt, typename S, typename... Args,
+template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
-format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n, const S&,
-                                         const Args&... args) {
-  constexpr auto compiled = detail::compile<Args...>(S());
-  auto it = format_to(detail::truncating_iterator<OutputIt>(out, n), compiled,
-                      args...);
-  return {it.base(), it.count()};
+FMT_CONSTEXPR20 size_t formatted_size(const S& format_str,
+                                      const Args&... args) {
+  return fmt::format_to(detail::counting_iterator(), format_str, args...)
+      .count();
 }
 
-template <typename CompiledFormat, typename... Args>
-size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
-  return format_to(detail::counting_iterator(), cf, args...).count();
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+void print(std::FILE* f, const S& format_str, const Args&... args) {
+  memory_buffer buffer;
+  fmt::format_to(std::back_inserter(buffer), format_str, args...);
+  detail::print(f, {buffer.data(), buffer.size()});
 }
 
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+void print(const S& format_str, const Args&... args) {
+  print(stdout, format_str, args...);
+}
+
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+inline namespace literals {
+template <detail_exported::fixed_string Str> constexpr auto operator""_cf() {
+  using char_t = remove_cvref_t<decltype(Str.data[0])>;
+  return detail::udl_compiled_string<char_t, sizeof(Str.data) / sizeof(char_t),
+                                     Str>();
+}
+}  // namespace literals
+#endif
+
+FMT_MODULE_EXPORT_END
 FMT_END_NAMESPACE
 
 #endif  // FMT_COMPILE_H_

include/spdlog/fmt/bundled/locale.h

@@ -1,64 +1,2 @@
-// Formatting library for C++ - std::locale support
-//
-// Copyright (c) 2012 - present, Victor Zverovich
-// All rights reserved.
-//
-// For the license information refer to format.h.
-
-#ifndef FMT_LOCALE_H_
-#define FMT_LOCALE_H_
-
-#include <locale>
-
-#include "format.h"
-
-FMT_BEGIN_NAMESPACE
-
-namespace detail {
-template <typename Char>
-std::basic_string<Char> vformat(
-    const std::locale& loc, basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buffer;
-  detail::vformat_to(buffer, format_str, args, detail::locale_ref(loc));
-  return fmt::to_string(buffer);
-}
-}  // namespace detail
-
-template <typename S, typename Char = char_t<S>>
-inline std::basic_string<Char> vformat(
-    const std::locale& loc, const S& format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  return detail::vformat(loc, to_string_view(format_str), args);
-}
-
-template <typename S, typename... Args, typename Char = char_t<S>>
-inline std::basic_string<Char> format(const std::locale& loc,
-                                      const S& format_str, Args&&... args) {
-  return detail::vformat(loc, to_string_view(format_str),
-                         fmt::make_args_checked<Args...>(format_str, args...));
-}
-
-template <typename S, typename OutputIt, typename... Args,
-          typename Char = char_t<S>,
-          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
-inline OutputIt vformat_to(
-    OutputIt out, const std::locale& loc, const S& format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  decltype(detail::get_buffer<Char>(out)) buf(detail::get_buffer_init(out));
-  vformat_to(buf, to_string_view(format_str), args, detail::locale_ref(loc));
-  return detail::get_iterator(buf);
-}
-
-template <typename OutputIt, typename S, typename... Args,
-          bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value>
-inline auto format_to(OutputIt out, const std::locale& loc,
-                      const S& format_str, Args&&... args) ->
-    typename std::enable_if<enable, OutputIt>::type {
-  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
-  return vformat_to(out, loc, to_string_view(format_str), vargs);
-}
-
-FMT_END_NAMESPACE
-
-#endif  // FMT_LOCALE_H_
+#include "xchar.h"
+#warning fmt/locale.h is deprecated, include fmt/format.h or fmt/xchar.h instead

include/spdlog/fmt/bundled/os.h

@@ -8,16 +8,10 @@
 #ifndef FMT_OS_H_
 #define FMT_OS_H_
 
-#if defined(__MINGW32__) || defined(__CYGWIN__)
-// Workaround MinGW bug https://sourceforge.net/p/mingw/bugs/2024/.
-#  undef __STRICT_ANSI__
-#endif
-
 #include <cerrno>
-#include <clocale>  // for locale_t
 #include <cstddef>
 #include <cstdio>
-#include <cstdlib>  // for strtod_l
+#include <system_error>  // std::system_error
 
 #if defined __APPLE__ || defined(__FreeBSD__)
 #  include <xlocale.h>  // for LC_NUMERIC_MASK on OS X
@@ -25,17 +19,20 @@
 
 #include "format.h"
 
+#ifndef FMT_USE_FCNTL
 // UWP doesn't provide _pipe.
-#if FMT_HAS_INCLUDE("winapifamily.h")
-#  include <winapifamily.h>
-#endif
-#if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
-     defined(__linux__)) &&                              \
-    (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
-#  include <fcntl.h>  // for O_RDONLY
-#  define FMT_USE_FCNTL 1
-#else
-#  define FMT_USE_FCNTL 0
+#  if FMT_HAS_INCLUDE("winapifamily.h")
+#    include <winapifamily.h>
+#  endif
+#  if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
+       defined(__linux__)) &&                              \
+      (!defined(WINAPI_FAMILY) ||                          \
+       (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
+#    include <fcntl.h>  // for O_RDONLY
+#    define FMT_USE_FCNTL 1
+#  else
+#    define FMT_USE_FCNTL 0
+#  endif
 #endif
 
 #ifndef FMT_POSIX
@@ -74,6 +71,7 @@
 #define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
 
 FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT_BEGIN
 
 /**
   \rst
@@ -122,19 +120,28 @@ template <typename Char> class basic_cstring_view {
 using cstring_view = basic_cstring_view<char>;
 using wcstring_view = basic_cstring_view<wchar_t>;
 
-// An error code.
-class error_code {
- private:
-  int value_;
+template <typename Char> struct formatter<std::error_code, Char> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
 
- public:
-  explicit error_code(int value = 0) FMT_NOEXCEPT : value_(value) {}
-
-  int get() const FMT_NOEXCEPT { return value_; }
+  template <typename FormatContext>
+  FMT_CONSTEXPR auto format(const std::error_code& ec, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::write_bytes(out, ec.category().name(),
+                              basic_format_specs<Char>());
+    out = detail::write<Char>(out, Char(':'));
+    out = detail::write<Char>(out, ec.value());
+    return out;
+  }
 };
 
 #ifdef _WIN32
-namespace detail {
+FMT_API const std::error_category& system_category() noexcept;
+
+FMT_BEGIN_DETAIL_NAMESPACE
 // A converter from UTF-16 to UTF-8.
 // It is only provided for Windows since other systems support UTF-8 natively.
 class utf16_to_utf8 {
@@ -143,7 +150,7 @@ class utf16_to_utf8 {
 
  public:
   utf16_to_utf8() {}
-  FMT_API explicit utf16_to_utf8(wstring_view s);
+  FMT_API explicit utf16_to_utf8(basic_string_view<wchar_t> s);
   operator string_view() const { return string_view(&buffer_[0], size()); }
   size_t size() const { return buffer_.size() - 1; }
   const char* c_str() const { return &buffer_[0]; }
@@ -152,59 +159,67 @@ class utf16_to_utf8 {
   // Performs conversion returning a system error code instead of
   // throwing exception on conversion error. This method may still throw
   // in case of memory allocation error.
-  FMT_API int convert(wstring_view s);
+  FMT_API int convert(basic_string_view<wchar_t> s);
 };
 
 FMT_API void format_windows_error(buffer<char>& out, int error_code,
-                                  string_view message) FMT_NOEXCEPT;
-}  // namespace detail
+                                  const char* message) noexcept;
+FMT_END_DETAIL_NAMESPACE
 
-/** A Windows error. */
-class windows_error : public system_error {
- private:
-  FMT_API void init(int error_code, string_view format_str, format_args args);
+FMT_API std::system_error vwindows_error(int error_code, string_view format_str,
+                                         format_args args);
 
- public:
-  /**
-   \rst
-   Constructs a :class:`fmt::windows_error` object with the description
-   of the form
+/**
+ \rst
+ Constructs a :class:`std::system_error` object with the description
+ of the form
 
-   .. parsed-literal::
-     *<message>*: *<system-message>*
+ .. parsed-literal::
+   *<message>*: *<system-message>*
 
-   where *<message>* is the formatted message and *<system-message>* is the
-   system message corresponding to the error code.
-   *error_code* is a Windows error code as given by ``GetLastError``.
-   If *error_code* is not a valid error code such as -1, the system message
-   will look like "error -1".
+ where *<message>* is the formatted message and *<system-message>* is the
+ system message corresponding to the error code.
+ *error_code* is a Windows error code as given by ``GetLastError``.
+ If *error_code* is not a valid error code such as -1, the system message
+ will look like "error -1".
 
-   **Example**::
+ **Example**::
 
-     // This throws a windows_error with the description
-     //   cannot open file 'madeup': The system cannot find the file specified.
-     // or similar (system message may vary).
-     const char *filename = "madeup";
-     LPOFSTRUCT of = LPOFSTRUCT();
-     HFILE file = OpenFile(filename, &of, OF_READ);
-     if (file == HFILE_ERROR) {
-       throw fmt::windows_error(GetLastError(),
-                                "cannot open file '{}'", filename);
-     }
-   \endrst
-  */
-  template <typename... Args>
-  windows_error(int error_code, string_view message, const Args&... args) {
-    init(error_code, message, make_format_args(args...));
-  }
-};
+   // This throws a system_error with the description
+   //   cannot open file 'madeup': The system cannot find the file specified.
+   // or similar (system message may vary).
+   const char *filename = "madeup";
+   LPOFSTRUCT of = LPOFSTRUCT();
+   HFILE file = OpenFile(filename, &of, OF_READ);
+   if (file == HFILE_ERROR) {
+     throw fmt::windows_error(GetLastError(),
+                              "cannot open file '{}'", filename);
+   }
+ \endrst
+*/
+template <typename... Args>
+std::system_error windows_error(int error_code, string_view message,
+                                const Args&... args) {
+  return vwindows_error(error_code, message, fmt::make_format_args(args...));
+}
 
 // Reports a Windows error without throwing an exception.
 // Can be used to report errors from destructors.
-FMT_API void report_windows_error(int error_code,
-                                  string_view message) FMT_NOEXCEPT;
+FMT_API void report_windows_error(int error_code, const char* message) noexcept;
+#else
+inline const std::error_category& system_category() noexcept {
+  return std::system_category();
+}
 #endif  // _WIN32
 
+// std::system is not available on some platforms such as iOS (#2248).
+#ifdef __OSX__
+template <typename S, typename... Args, typename Char = char_t<S>>
+void say(const S& format_str, Args&&... args) {
+  std::system(format("say \"{}\"", format(format_str, args...)).c_str());
+}
+#endif
+
 // A buffered file.
 class buffered_file {
  private:
@@ -219,13 +234,13 @@ class buffered_file {
   void operator=(const buffered_file&) = delete;
 
   // Constructs a buffered_file object which doesn't represent any file.
-  buffered_file() FMT_NOEXCEPT : file_(nullptr) {}
+  buffered_file() noexcept : file_(nullptr) {}
 
   // Destroys the object closing the file it represents if any.
-  FMT_API ~buffered_file() FMT_NOEXCEPT;
+  FMT_API ~buffered_file() noexcept;
 
  public:
-  buffered_file(buffered_file&& other) FMT_NOEXCEPT : file_(other.file_) {
+  buffered_file(buffered_file&& other) noexcept : file_(other.file_) {
     other.file_ = nullptr;
   }
 
@@ -243,11 +258,9 @@ class buffered_file {
   FMT_API void close();
 
   // Returns the pointer to a FILE object representing this file.
-  FILE* get() const FMT_NOEXCEPT { return file_; }
+  FILE* get() const noexcept { return file_; }
 
-  // We place parentheses around fileno to workaround a bug in some versions
-  // of MinGW that define fileno as a macro.
-  FMT_API int(fileno)() const;
+  FMT_API int descriptor() const;
 
   void vprint(string_view format_str, format_args args) {
     fmt::vprint(file_, format_str, args);
@@ -255,18 +268,18 @@ class buffered_file {
 
   template <typename... Args>
   inline void print(string_view format_str, const Args&... args) {
-    vprint(format_str, make_format_args(args...));
+    vprint(format_str, fmt::make_format_args(args...));
   }
 };
 
 #if FMT_USE_FCNTL
 // A file. Closed file is represented by a file object with descriptor -1.
-// Methods that are not declared with FMT_NOEXCEPT may throw
+// Methods that are not declared with noexcept may throw
 // fmt::system_error in case of failure. Note that some errors such as
 // closing the file multiple times will cause a crash on Windows rather
 // than an exception. You can get standard behavior by overriding the
 // invalid parameter handler with _set_invalid_parameter_handler.
-class file {
+class FMT_API file {
  private:
   int fd_;  // File descriptor.
 
@@ -280,22 +293,24 @@ class file {
     WRONLY = FMT_POSIX(O_WRONLY),  // Open for writing only.
     RDWR = FMT_POSIX(O_RDWR),      // Open for reading and writing.
     CREATE = FMT_POSIX(O_CREAT),   // Create if the file doesn't exist.
-    APPEND = FMT_POSIX(O_APPEND)   // Open in append mode.
+    APPEND = FMT_POSIX(O_APPEND),  // Open in append mode.
+    TRUNC = FMT_POSIX(O_TRUNC)     // Truncate the content of the file.
   };
 
   // Constructs a file object which doesn't represent any file.
-  file() FMT_NOEXCEPT : fd_(-1) {}
+  file() noexcept : fd_(-1) {}
 
   // Opens a file and constructs a file object representing this file.
-  FMT_API file(cstring_view path, int oflag);
+  file(cstring_view path, int oflag);
 
  public:
   file(const file&) = delete;
   void operator=(const file&) = delete;
 
-  file(file&& other) FMT_NOEXCEPT : fd_(other.fd_) { other.fd_ = -1; }
+  file(file&& other) noexcept : fd_(other.fd_) { other.fd_ = -1; }
 
-  file& operator=(file&& other) FMT_NOEXCEPT {
+  // Move assignment is not noexcept because close may throw.
+  file& operator=(file&& other) {
     close();
     fd_ = other.fd_;
     other.fd_ = -1;
@@ -303,51 +318,52 @@ class file {
   }
 
   // Destroys the object closing the file it represents if any.
-  FMT_API ~file() FMT_NOEXCEPT;
+  ~file() noexcept;
 
   // Returns the file descriptor.
-  int descriptor() const FMT_NOEXCEPT { return fd_; }
+  int descriptor() const noexcept { return fd_; }
 
   // Closes the file.
-  FMT_API void close();
+  void close();
 
   // Returns the file size. The size has signed type for consistency with
   // stat::st_size.
-  FMT_API long long size() const;
+  long long size() const;
 
   // Attempts to read count bytes from the file into the specified buffer.
-  FMT_API size_t read(void* buffer, size_t count);
+  size_t read(void* buffer, size_t count);
 
   // Attempts to write count bytes from the specified buffer to the file.
-  FMT_API size_t write(const void* buffer, size_t count);
+  size_t write(const void* buffer, size_t count);
 
   // Duplicates a file descriptor with the dup function and returns
   // the duplicate as a file object.
-  FMT_API static file dup(int fd);
+  static file dup(int fd);
 
   // Makes fd be the copy of this file descriptor, closing fd first if
   // necessary.
-  FMT_API void dup2(int fd);
+  void dup2(int fd);
 
   // Makes fd be the copy of this file descriptor, closing fd first if
   // necessary.
-  FMT_API void dup2(int fd, error_code& ec) FMT_NOEXCEPT;
+  void dup2(int fd, std::error_code& ec) noexcept;
 
   // Creates a pipe setting up read_end and write_end file objects for reading
   // and writing respectively.
-  FMT_API static void pipe(file& read_end, file& write_end);
+  static void pipe(file& read_end, file& write_end);
 
   // Creates a buffered_file object associated with this file and detaches
   // this file object from the file.
-  FMT_API buffered_file fdopen(const char* mode);
+  buffered_file fdopen(const char* mode);
 };
 
 // Returns the memory page size.
 long getpagesize();
 
-namespace detail {
+FMT_BEGIN_DETAIL_NAMESPACE
 
 struct buffer_size {
+  buffer_size() = default;
   size_t value = 0;
   buffer_size operator=(size_t val) const {
     auto bs = buffer_size();
@@ -357,14 +373,14 @@ struct buffer_size {
 };
 
 struct ostream_params {
-  int oflag = file::WRONLY | file::CREATE;
+  int oflag = file::WRONLY | file::CREATE | file::TRUNC;
   size_t buffer_size = BUFSIZ > 32768 ? BUFSIZ : 32768;
 
   ostream_params() {}
 
   template <typename... T>
-  ostream_params(T... params, int oflag) : ostream_params(params...) {
-    this->oflag = oflag;
+  ostream_params(T... params, int new_oflag) : ostream_params(params...) {
+    oflag = new_oflag;
   }
 
   template <typename... T>
@@ -372,23 +388,27 @@ struct ostream_params {
       : ostream_params(params...) {
     this->buffer_size = bs.value;
   }
+
+// Intel has a bug that results in failure to deduce a constructor
+// for empty parameter packs.
+#  if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 2000
+  ostream_params(int new_oflag) : oflag(new_oflag) {}
+  ostream_params(detail::buffer_size bs) : buffer_size(bs.value) {}
+#  endif
 };
-}  // namespace detail
 
-static constexpr detail::buffer_size buffer_size;
+FMT_END_DETAIL_NAMESPACE
 
-// A fast output stream which is not thread-safe.
-class ostream final : private detail::buffer<char> {
+// Added {} below to work around default constructor error known to
+// occur in Xcode versions 7.2.1 and 8.2.1.
+constexpr detail::buffer_size buffer_size{};
+
+/** A fast output stream which is not thread-safe. */
+class FMT_API ostream final : private detail::buffer<char> {
  private:
   file file_;
 
-  void flush() {
-    if (size() == 0) return;
-    file_.write(data(), size());
-    clear();
-  }
-
-  FMT_API void grow(size_t) override final;
+  void grow(size_t) override;
 
   ostream(cstring_view path, const detail::ostream_params& params)
       : file_(path, params.oflag) {
@@ -399,6 +419,7 @@ class ostream final : private detail::buffer<char> {
   ostream(ostream&& other)
       : detail::buffer<char>(other.data(), other.size(), other.capacity()),
         file_(std::move(other.file_)) {
+    other.clear();
     other.set(nullptr, 0);
   }
   ~ostream() {
@@ -406,6 +427,12 @@ class ostream final : private detail::buffer<char> {
     delete[] data();
   }
 
+  void flush() {
+    if (size() == 0) return;
+    file_.write(data(), size());
+    clear();
+  }
+
   template <typename... T>
   friend ostream output_file(cstring_view path, T... params);
 
@@ -414,16 +441,30 @@ class ostream final : private detail::buffer<char> {
     file_.close();
   }
 
-  template <typename S, typename... Args>
-  void print(const S& format_str, const Args&... args) {
-    format_to(detail::buffer_appender<char>(*this), format_str, args...);
+  /**
+    Formats ``args`` according to specifications in ``fmt`` and writes the
+    output to the file.
+   */
+  template <typename... T> void print(format_string<T...> fmt, T&&... args) {
+    vformat_to(detail::buffer_appender<char>(*this), fmt,
+               fmt::make_format_args(args...));
   }
 };
 
 /**
-  Opens a file for writing. Supported parameters passed in `params`:
-  * ``<integer>``: Output flags (``file::WRONLY | file::CREATE`` by default)
+  \rst
+  Opens a file for writing. Supported parameters passed in *params*:
+
+  * ``<integer>``: Flags passed to `open
+    <https://pubs.opengroup.org/onlinepubs/007904875/functions/open.html>`_
+    (``file::WRONLY | file::CREATE | file::TRUNC`` by default)
   * ``buffer_size=<integer>``: Output buffer size
+
+  **Example**::
+
+    auto out = fmt::output_file("guide.txt");
+    out.print("Don't {}", "Panic");
+  \endrst
  */
 template <typename... T>
 inline ostream output_file(cstring_view path, T... params) {
@@ -431,50 +472,7 @@ inline ostream output_file(cstring_view path, T... params) {
 }
 #endif  // FMT_USE_FCNTL
 
-#ifdef FMT_LOCALE
-// A "C" numeric locale.
-class locale {
- private:
-#  ifdef _WIN32
-  using locale_t = _locale_t;
-
-  static void freelocale(locale_t loc) { _free_locale(loc); }
-
-  static double strtod_l(const char* nptr, char** endptr, _locale_t loc) {
-    return _strtod_l(nptr, endptr, loc);
-  }
-#  endif
-
-  locale_t locale_;
-
- public:
-  using type = locale_t;
-  locale(const locale&) = delete;
-  void operator=(const locale&) = delete;
-
-  locale() {
-#  ifndef _WIN32
-    locale_ = FMT_SYSTEM(newlocale(LC_NUMERIC_MASK, "C", nullptr));
-#  else
-    locale_ = _create_locale(LC_NUMERIC, "C");
-#  endif
-    if (!locale_) FMT_THROW(system_error(errno, "cannot create locale"));
-  }
-  ~locale() { freelocale(locale_); }
-
-  type get() const { return locale_; }
-
-  // Converts string to floating-point number and advances str past the end
-  // of the parsed input.
-  double strtod(const char*& str) const {
-    char* end = nullptr;
-    double result = strtod_l(str, &end, locale_);
-    str = end;
-    return result;
-  }
-};
-using Locale FMT_DEPRECATED_ALIAS = locale;
-#endif  // FMT_LOCALE
+FMT_MODULE_EXPORT_END
 FMT_END_NAMESPACE
 
 #endif  // FMT_OS_H_

include/spdlog/fmt/bundled/ostream.h

@@ -8,87 +8,104 @@
 #ifndef FMT_OSTREAM_H_
 #define FMT_OSTREAM_H_
 
+#include <fstream>
 #include <ostream>
+#if defined(_WIN32) && defined(__GLIBCXX__)
+#  include <ext/stdio_filebuf.h>
+#  include <ext/stdio_sync_filebuf.h>
+#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
+#  include <__std_stream>
+#endif
 
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
 
-template <typename Char> class basic_printf_parse_context;
 template <typename OutputIt, typename Char> class basic_printf_context;
 
 namespace detail {
 
-template <class Char> class formatbuf : public std::basic_streambuf<Char> {
- private:
-  using int_type = typename std::basic_streambuf<Char>::int_type;
-  using traits_type = typename std::basic_streambuf<Char>::traits_type;
-
-  buffer<Char>& buffer_;
-
- public:
-  formatbuf(buffer<Char>& buf) : buffer_(buf) {}
-
- protected:
-  // The put-area is actually always empty. This makes the implementation
-  // simpler and has the advantage that the streambuf and the buffer are always
-  // in sync and sputc never writes into uninitialized memory. The obvious
-  // disadvantage is that each call to sputc always results in a (virtual) call
-  // to overflow. There is no disadvantage here for sputn since this always
-  // results in a call to xsputn.
-
-  int_type overflow(int_type ch = traits_type::eof()) FMT_OVERRIDE {
-    if (!traits_type::eq_int_type(ch, traits_type::eof()))
-      buffer_.push_back(static_cast<Char>(ch));
-    return ch;
-  }
-
-  std::streamsize xsputn(const Char* s, std::streamsize count) FMT_OVERRIDE {
-    buffer_.append(s, s + count);
-    return count;
-  }
-};
-
-struct converter {
-  template <typename T, FMT_ENABLE_IF(is_integral<T>::value)> converter(T);
-};
-
-template <typename Char> struct test_stream : std::basic_ostream<Char> {
- private:
-  void_t<> operator<<(converter);
-};
-
-// Hide insertion operators for built-in types.
-template <typename Char, typename Traits>
-void_t<> operator<<(std::basic_ostream<Char, Traits>&, Char);
-template <typename Char, typename Traits>
-void_t<> operator<<(std::basic_ostream<Char, Traits>&, char);
-template <typename Traits>
-void_t<> operator<<(std::basic_ostream<char, Traits>&, char);
-template <typename Traits>
-void_t<> operator<<(std::basic_ostream<char, Traits>&, signed char);
-template <typename Traits>
-void_t<> operator<<(std::basic_ostream<char, Traits>&, unsigned char);
-
-// Checks if T has a user-defined operator<< (e.g. not a member of
-// std::ostream).
-template <typename T, typename Char> class is_streamable {
+// Checks if T has a user-defined operator<<.
+template <typename T, typename Char, typename Enable = void>
+class is_streamable {
  private:
   template <typename U>
-  static bool_constant<!std::is_same<decltype(std::declval<test_stream<Char>&>()
-                                              << std::declval<U>()),
-                                     void_t<>>::value>
-  test(int);
+  static auto test(int)
+      -> bool_constant<sizeof(std::declval<std::basic_ostream<Char>&>()
+                              << std::declval<U>()) != 0>;
 
-  template <typename> static std::false_type test(...);
+  template <typename> static auto test(...) -> std::false_type;
 
   using result = decltype(test<T>(0));
 
  public:
+  is_streamable() = default;
+
   static const bool value = result::value;
 };
 
+// Formatting of built-in types and arrays is intentionally disabled because
+// it's handled by standard (non-ostream) formatters.
+template <typename T, typename Char>
+struct is_streamable<
+    T, Char,
+    enable_if_t<
+        std::is_arithmetic<T>::value || std::is_array<T>::value ||
+        std::is_pointer<T>::value || std::is_same<T, char8_type>::value ||
+        std::is_convertible<T, fmt::basic_string_view<Char>>::value ||
+        std::is_same<T, std_string_view<Char>>::value ||
+        (std::is_convertible<T, int>::value && !std::is_enum<T>::value)>>
+    : std::false_type {};
+
+// Generate a unique explicit instantion in every translation unit using a tag
+// type in an anonymous namespace.
+namespace {
+struct file_access_tag {};
+}  // namespace
+template <class Tag, class BufType, FILE* BufType::*FileMemberPtr>
+class file_access {
+  friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
+};
+
+#if FMT_MSC_VERSION
+template class file_access<file_access_tag, std::filebuf,
+                           &std::filebuf::_Myfile>;
+auto get_file(std::filebuf&) -> FILE*;
+#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
+template class file_access<file_access_tag, std::__stdoutbuf<char>,
+                           &std::__stdoutbuf<char>::__file_>;
+auto get_file(std::__stdoutbuf<char>&) -> FILE*;
+#endif
+
+inline bool write_ostream_unicode(std::ostream& os, fmt::string_view data) {
+#if FMT_MSC_VERSION
+  if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
+    if (FILE* f = get_file(*buf)) return write_console(f, data);
+#elif defined(_WIN32) && defined(__GLIBCXX__)
+  auto* rdbuf = os.rdbuf();
+  FILE* c_file;
+  if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
+    c_file = fbuf->file();
+  else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
+    c_file = fbuf->file();
+  else
+    return false;
+  if (c_file) return write_console(c_file, data);
+#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
+  if (auto* buf = dynamic_cast<std::__stdoutbuf<char>*>(os.rdbuf()))
+    if (FILE* f = get_file(*buf)) return write_console(f, data);
+#else
+  ignore_unused(os, data);
+#endif
+  return false;
+}
+inline bool write_ostream_unicode(std::wostream&,
+                                  fmt::basic_string_view<wchar_t>) {
+  return false;
+}
+
 // Write the content of buf to os.
+// It is a separate function rather than a part of vprint to simplify testing.
 template <typename Char>
 void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
   const Char* buf_data = buf.data();
@@ -106,54 +123,86 @@ void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
 template <typename Char, typename T>
 void format_value(buffer<Char>& buf, const T& value,
                   locale_ref loc = locale_ref()) {
-  formatbuf<Char> format_buf(buf);
-  std::basic_ostream<Char> output(&format_buf);
+  auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf);
+  auto&& output = std::basic_ostream<Char>(&format_buf);
 #if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
   if (loc) output.imbue(loc.get<std::locale>());
 #endif
   output << value;
   output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
-  buf.try_resize(buf.size());
 }
 
+template <typename T> struct streamed_view { const T& value; };
+
+}  // namespace detail
+
+// Formats an object of type T that has an overloaded ostream operator<<.
+template <typename Char>
+struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
+  void set_debug_format() = delete;
+
+  template <typename T, typename OutputIt>
+  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) const
+      -> OutputIt {
+    auto buffer = basic_memory_buffer<Char>();
+    format_value(buffer, value, ctx.locale());
+    return formatter<basic_string_view<Char>, Char>::format(
+        {buffer.data(), buffer.size()}, ctx);
+  }
+};
+
+using ostream_formatter = basic_ostream_formatter<char>;
+
+template <typename T, typename Char>
+struct formatter<detail::streamed_view<T>, Char>
+    : basic_ostream_formatter<Char> {
+  template <typename OutputIt>
+  auto format(detail::streamed_view<T> view,
+              basic_format_context<OutputIt, Char>& ctx) const -> OutputIt {
+    return basic_ostream_formatter<Char>::format(view.value, ctx);
+  }
+};
+
+/**
+  \rst
+  Returns a view that formats `value` via an ostream ``operator<<``.
+
+  **Example**::
+
+    fmt::print("Current thread id: {}\n",
+               fmt::streamed(std::this_thread::get_id()));
+  \endrst
+ */
+template <typename T>
+auto streamed(const T& value) -> detail::streamed_view<T> {
+  return {value};
+}
+
+namespace detail {
+
 // Formats an object of type T that has an overloaded ostream operator<<.
 template <typename T, typename Char>
 struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
-    : private formatter<basic_string_view<Char>, Char> {
-  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
-      -> decltype(ctx.begin()) {
-    return formatter<basic_string_view<Char>, Char>::parse(ctx);
-  }
-  template <typename ParseCtx,
-            FMT_ENABLE_IF(std::is_same<
-                          ParseCtx, basic_printf_parse_context<Char>>::value)>
-  auto parse(ParseCtx& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-
-  template <typename OutputIt>
-  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx)
-      -> OutputIt {
-    basic_memory_buffer<Char> buffer;
-    format_value(buffer, value, ctx.locale());
-    basic_string_view<Char> str(buffer.data(), buffer.size());
-    return formatter<basic_string_view<Char>, Char>::format(str, ctx);
-  }
-  template <typename OutputIt>
-  auto format(const T& value, basic_printf_context<OutputIt, Char>& ctx)
-      -> OutputIt {
-    basic_memory_buffer<Char> buffer;
-    format_value(buffer, value, ctx.locale());
-    return std::copy(buffer.begin(), buffer.end(), ctx.out());
-  }
+    : basic_ostream_formatter<Char> {
+  using basic_ostream_formatter<Char>::format;
 };
+
+inline void vprint_directly(std::ostream& os, string_view format_str,
+                            format_args args) {
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, format_str, args);
+  detail::write_buffer(os, buffer);
+}
+
 }  // namespace detail
 
-template <typename Char>
-void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
+FMT_MODULE_EXPORT template <typename Char>
+void vprint(std::basic_ostream<Char>& os,
+            basic_string_view<type_identity_t<Char>> format_str,
             basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buffer;
+  auto buffer = basic_memory_buffer<Char>();
   detail::vformat_to(buffer, format_str, args);
+  if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()})) return;
   detail::write_buffer(os, buffer);
 }
 
@@ -166,12 +215,23 @@ void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
     fmt::print(cerr, "Don't {}!", "panic");
   \endrst
  */
-template <typename S, typename... Args,
-          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
-void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) {
-  vprint(os, to_string_view(format_str),
-         fmt::make_args_checked<Args...>(format_str, args...));
+FMT_MODULE_EXPORT template <typename... T>
+void print(std::ostream& os, format_string<T...> fmt, T&&... args) {
+  const auto& vargs = fmt::make_format_args(args...);
+  if (detail::is_utf8())
+    vprint(os, fmt, vargs);
+  else
+    detail::vprint_directly(os, fmt, vargs);
 }
+
+FMT_MODULE_EXPORT
+template <typename... Args>
+void print(std::wostream& os,
+           basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
+           Args&&... args) {
+  vprint(os, fmt, fmt::make_format_args<buffer_context<wchar_t>>(args...));
+}
+
 FMT_END_NAMESPACE
 
 #endif  // FMT_OSTREAM_H_

include/spdlog/fmt/bundled/posix.h

@@ -1,2 +0,0 @@
-#include "os.h"
-#warning "fmt/posix.h is deprecated; use fmt/os.h instead"

include/spdlog/fmt/bundled/printf.h

@@ -11,10 +11,52 @@
 #include <algorithm>  // std::max
 #include <limits>     // std::numeric_limits
 
-#include "ostream.h"
+#include "format.h"
 
 FMT_BEGIN_NAMESPACE
-namespace detail {
+FMT_MODULE_EXPORT_BEGIN
+
+template <typename T> struct printf_formatter { printf_formatter() = delete; };
+
+template <typename Char>
+class basic_printf_parse_context : public basic_format_parse_context<Char> {
+  using basic_format_parse_context<Char>::basic_format_parse_context;
+};
+
+template <typename OutputIt, typename Char> class basic_printf_context {
+ private:
+  OutputIt out_;
+  basic_format_args<basic_printf_context> args_;
+
+ public:
+  using char_type = Char;
+  using format_arg = basic_format_arg<basic_printf_context>;
+  using parse_context_type = basic_printf_parse_context<Char>;
+  template <typename T> using formatter_type = printf_formatter<T>;
+
+  /**
+    \rst
+    Constructs a ``printf_context`` object. References to the arguments are
+    stored in the context object so make sure they have appropriate lifetimes.
+    \endrst
+   */
+  basic_printf_context(OutputIt out,
+                       basic_format_args<basic_printf_context> args)
+      : out_(out), args_(args) {}
+
+  OutputIt out() { return out_; }
+  void advance_to(OutputIt it) { out_ = it; }
+
+  detail::locale_ref locale() { return {}; }
+
+  format_arg arg(int id) const { return args_.get(id); }
+
+  FMT_CONSTEXPR void on_error(const char* message) {
+    detail::error_handler().on_error(message);
+  }
+};
+
+FMT_BEGIN_DETAIL_NAMESPACE
 
 // Checks if a value fits in int - used to avoid warnings about comparing
 // signed and unsigned integers.
@@ -178,81 +220,38 @@ template <typename Char> class printf_width_handler {
   }
 };
 
-template <typename Char, typename Context>
-void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
-             basic_format_args<Context> args) {
-  Context(buffer_appender<Char>(buf), format, args).format();
-}
-}  // namespace detail
-
-// For printing into memory_buffer.
-template <typename Char, typename Context>
-FMT_DEPRECATED void printf(detail::buffer<Char>& buf,
-                           basic_string_view<Char> format,
-                           basic_format_args<Context> args) {
-  return detail::vprintf(buf, format, args);
-}
-using detail::vprintf;
-
-template <typename Char>
-class basic_printf_parse_context : public basic_format_parse_context<Char> {
-  using basic_format_parse_context<Char>::basic_format_parse_context;
-};
-template <typename OutputIt, typename Char> class basic_printf_context;
-
-/**
-  \rst
-  The ``printf`` argument formatter.
-  \endrst
- */
+// The ``printf`` argument formatter.
 template <typename OutputIt, typename Char>
-class printf_arg_formatter : public detail::arg_formatter_base<OutputIt, Char> {
- public:
-  using iterator = OutputIt;
-
+class printf_arg_formatter : public arg_formatter<Char> {
  private:
-  using char_type = Char;
-  using base = detail::arg_formatter_base<OutputIt, Char>;
+  using base = arg_formatter<Char>;
   using context_type = basic_printf_context<OutputIt, Char>;
+  using format_specs = basic_format_specs<Char>;
 
   context_type& context_;
 
-  void write_null_pointer(char) {
-    this->specs()->type = 0;
-    this->write("(nil)");
-  }
-
-  void write_null_pointer(wchar_t) {
-    this->specs()->type = 0;
-    this->write(L"(nil)");
+  OutputIt write_null_pointer(bool is_string = false) {
+    auto s = this->specs;
+    s.type = presentation_type::none;
+    return write_bytes(this->out, is_string ? "(null)" : "(nil)", s);
   }
 
  public:
-  using format_specs = typename base::format_specs;
+  printf_arg_formatter(OutputIt iter, format_specs& s, context_type& ctx)
+      : base{iter, s, locale_ref()}, context_(ctx) {}
 
-  /**
-    \rst
-    Constructs an argument formatter object.
-    *buffer* is a reference to the output buffer and *specs* contains format
-    specifier information for standard argument types.
-    \endrst
-   */
-  printf_arg_formatter(iterator iter, format_specs& specs, context_type& ctx)
-      : base(iter, &specs, detail::locale_ref()), context_(ctx) {}
+  OutputIt operator()(monostate value) { return base::operator()(value); }
 
-  template <typename T, FMT_ENABLE_IF(fmt::detail::is_integral<T>::value)>
-  iterator operator()(T value) {
-    // MSVC2013 fails to compile separate overloads for bool and char_type so
-    // use std::is_same instead.
-    if (std::is_same<T, bool>::value) {
-      format_specs& fmt_specs = *this->specs();
-      if (fmt_specs.type != 's') return base::operator()(value ? 1 : 0);
-      fmt_specs.type = 0;
-      this->write(value != 0);
-    } else if (std::is_same<T, char_type>::value) {
-      format_specs& fmt_specs = *this->specs();
-      if (fmt_specs.type && fmt_specs.type != 'c')
+  template <typename T, FMT_ENABLE_IF(detail::is_integral<T>::value)>
+  OutputIt operator()(T value) {
+    // MSVC2013 fails to compile separate overloads for bool and Char so use
+    // std::is_same instead.
+    if (std::is_same<T, Char>::value) {
+      format_specs fmt_specs = this->specs;
+      if (fmt_specs.type != presentation_type::none &&
+          fmt_specs.type != presentation_type::chr) {
         return (*this)(static_cast<int>(value));
+      }
       fmt_specs.sign = sign::none;
       fmt_specs.alt = false;
       fmt_specs.fill[0] = ' ';  // Ignore '0' flag for char types.
@@ -260,138 +259,49 @@ class printf_arg_formatter : public detail::arg_formatter_base<OutputIt, Char> {
       // ignored for non-numeric types
       if (fmt_specs.align == align::none || fmt_specs.align == align::numeric)
         fmt_specs.align = align::right;
-      return base::operator()(value);
-    } else {
-      return base::operator()(value);
+      return write<Char>(this->out, static_cast<Char>(value), fmt_specs);
     }
-    return this->out();
+    return base::operator()(value);
   }
 
   template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
-  iterator operator()(T value) {
+  OutputIt operator()(T value) {
     return base::operator()(value);
   }
 
   /** Formats a null-terminated C string. */
-  iterator operator()(const char* value) {
-    if (value)
-      base::operator()(value);
-    else if (this->specs()->type == 'p')
-      write_null_pointer(char_type());
-    else
-      this->write("(null)");
-    return this->out();
+  OutputIt operator()(const char* value) {
+    if (value) return base::operator()(value);
+    return write_null_pointer(this->specs.type != presentation_type::pointer);
   }
 
   /** Formats a null-terminated wide C string. */
-  iterator operator()(const wchar_t* value) {
-    if (value)
-      base::operator()(value);
-    else if (this->specs()->type == 'p')
-      write_null_pointer(char_type());
-    else
-      this->write(L"(null)");
-    return this->out();
+  OutputIt operator()(const wchar_t* value) {
+    if (value) return base::operator()(value);
+    return write_null_pointer(this->specs.type != presentation_type::pointer);
   }
 
-  iterator operator()(basic_string_view<char_type> value) {
+  OutputIt operator()(basic_string_view<Char> value) {
     return base::operator()(value);
   }
 
-  iterator operator()(monostate value) { return base::operator()(value); }
-
   /** Formats a pointer. */
-  iterator operator()(const void* value) {
-    if (value) return base::operator()(value);
-    this->specs()->type = 0;
-    write_null_pointer(char_type());
-    return this->out();
+  OutputIt operator()(const void* value) {
+    return value ? base::operator()(value) : write_null_pointer();
   }
 
   /** Formats an argument of a custom (user-defined) type. */
-  iterator operator()(typename basic_format_arg<context_type>::handle handle) {
-    handle.format(context_.parse_context(), context_);
-    return this->out();
+  OutputIt operator()(typename basic_format_arg<context_type>::handle handle) {
+    auto parse_ctx =
+        basic_printf_parse_context<Char>(basic_string_view<Char>());
+    handle.format(parse_ctx, context_);
+    return this->out;
   }
 };
 
-template <typename T> struct printf_formatter {
-  printf_formatter() = delete;
-
-  template <typename ParseContext>
-  auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-
-  template <typename FormatContext>
-  auto format(const T& value, FormatContext& ctx) -> decltype(ctx.out()) {
-    detail::format_value(detail::get_container(ctx.out()), value);
-    return ctx.out();
-  }
-};
-
-/**
- This template formats data and writes the output through an output iterator.
- */
-template <typename OutputIt, typename Char> class basic_printf_context {
- public:
-  /** The character type for the output. */
-  using char_type = Char;
-  using iterator = OutputIt;
-  using format_arg = basic_format_arg<basic_printf_context>;
-  using parse_context_type = basic_printf_parse_context<Char>;
-  template <typename T> using formatter_type = printf_formatter<T>;
-
- private:
-  using format_specs = basic_format_specs<char_type>;
-
-  OutputIt out_;
-  basic_format_args<basic_printf_context> args_;
-  parse_context_type parse_ctx_;
-
-  static void parse_flags(format_specs& specs, const Char*& it,
-                          const Char* end);
-
-  // Returns the argument with specified index or, if arg_index is -1, the next
-  // argument.
-  format_arg get_arg(int arg_index = -1);
-
-  // Parses argument index, flags and width and returns the argument index.
-  int parse_header(const Char*& it, const Char* end, format_specs& specs);
-
- public:
-  /**
-   \rst
-   Constructs a ``printf_context`` object. References to the arguments are
-   stored in the context object so make sure they have appropriate lifetimes.
-   \endrst
-   */
-  basic_printf_context(OutputIt out, basic_string_view<char_type> format_str,
-                       basic_format_args<basic_printf_context> args)
-      : out_(out), args_(args), parse_ctx_(format_str) {}
-
-  OutputIt out() { return out_; }
-  void advance_to(OutputIt it) { out_ = it; }
-
-  detail::locale_ref locale() { return {}; }
-
-  format_arg arg(int id) const { return args_.get(id); }
-
-  parse_context_type& parse_context() { return parse_ctx_; }
-
-  FMT_CONSTEXPR void on_error(const char* message) {
-    parse_ctx_.on_error(message);
-  }
-
-  /** Formats stored arguments and writes the output to the range. */
-  template <typename ArgFormatter = printf_arg_formatter<OutputIt, Char>>
-  OutputIt format();
-};
-
-template <typename OutputIt, typename Char>
-void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
-                                                       const Char*& it,
-                                                       const Char* end) {
+template <typename Char>
+void parse_flags(basic_format_specs<Char>& specs, const Char*& it,
+                 const Char* end) {
   for (; it != end; ++it) {
     switch (*it) {
     case '-':
@@ -417,35 +327,24 @@ void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
   }
 }
 
-template <typename OutputIt, typename Char>
-typename basic_printf_context<OutputIt, Char>::format_arg
-basic_printf_context<OutputIt, Char>::get_arg(int arg_index) {
-  if (arg_index < 0)
-    arg_index = parse_ctx_.next_arg_id();
-  else
-    parse_ctx_.check_arg_id(--arg_index);
-  return detail::get_arg(*this, arg_index);
-}
-
-template <typename OutputIt, typename Char>
-int basic_printf_context<OutputIt, Char>::parse_header(const Char*& it,
-                                                       const Char* end,
-                                                       format_specs& specs) {
+template <typename Char, typename GetArg>
+int parse_header(const Char*& it, const Char* end,
+                 basic_format_specs<Char>& specs, GetArg get_arg) {
   int arg_index = -1;
-  char_type c = *it;
+  Char c = *it;
   if (c >= '0' && c <= '9') {
     // Parse an argument index (if followed by '$') or a width possibly
     // preceded with '0' flag(s).
-    detail::error_handler eh;
-    int value = parse_nonnegative_int(it, end, eh);
+    int value = parse_nonnegative_int(it, end, -1);
     if (it != end && *it == '$') {  // value is an argument index
       ++it;
-      arg_index = value;
+      arg_index = value != -1 ? value : max_value<int>();
     } else {
       if (c == '0') specs.fill[0] = '0';
       if (value != 0) {
         // Nonzero value means that we parsed width and don't need to
         // parse it or flags again, so return now.
+        if (value == -1) FMT_THROW(format_error("number is too big"));
         specs.width = value;
         return arg_index;
       }
@@ -455,58 +354,76 @@ int basic_printf_context<OutputIt, Char>::parse_header(const Char*& it,
   // Parse width.
   if (it != end) {
     if (*it >= '0' && *it <= '9') {
-      detail::error_handler eh;
-      specs.width = parse_nonnegative_int(it, end, eh);
+      specs.width = parse_nonnegative_int(it, end, -1);
+      if (specs.width == -1) FMT_THROW(format_error("number is too big"));
     } else if (*it == '*') {
       ++it;
       specs.width = static_cast<int>(visit_format_arg(
-          detail::printf_width_handler<char_type>(specs), get_arg()));
+          detail::printf_width_handler<Char>(specs), get_arg(-1)));
     }
   }
   return arg_index;
 }
 
-template <typename OutputIt, typename Char>
-template <typename ArgFormatter>
-OutputIt basic_printf_context<OutputIt, Char>::format() {
-  auto out = this->out();
-  const Char* start = parse_ctx_.begin();
-  const Char* end = parse_ctx_.end();
+template <typename Char, typename Context>
+void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
+             basic_format_args<Context> args) {
+  using OutputIt = buffer_appender<Char>;
+  auto out = OutputIt(buf);
+  auto context = basic_printf_context<OutputIt, Char>(out, args);
+  auto parse_ctx = basic_printf_parse_context<Char>(format);
+
+  // Returns the argument with specified index or, if arg_index is -1, the next
+  // argument.
+  auto get_arg = [&](int arg_index) {
+    if (arg_index < 0)
+      arg_index = parse_ctx.next_arg_id();
+    else
+      parse_ctx.check_arg_id(--arg_index);
+    return detail::get_arg(context, arg_index);
+  };
+
+  const Char* start = parse_ctx.begin();
+  const Char* end = parse_ctx.end();
   auto it = start;
   while (it != end) {
-    char_type c = *it++;
-    if (c != '%') continue;
+    if (!detail::find<false, Char>(it, end, '%', it)) {
+      it = end;  // detail::find leaves it == nullptr if it doesn't find '%'
+      break;
+    }
+    Char c = *it++;
     if (it != end && *it == c) {
-      out = std::copy(start, it, out);
+      out = detail::write(
+          out, basic_string_view<Char>(start, detail::to_unsigned(it - start)));
       start = ++it;
       continue;
     }
-    out = std::copy(start, it - 1, out);
+    out = detail::write(out, basic_string_view<Char>(
+                                 start, detail::to_unsigned(it - 1 - start)));
 
-    format_specs specs;
+    basic_format_specs<Char> specs;
     specs.align = align::right;
 
     // Parse argument index, flags and width.
-    int arg_index = parse_header(it, end, specs);
-    if (arg_index == 0) on_error("argument not found");
+    int arg_index = parse_header(it, end, specs, get_arg);
+    if (arg_index == 0) parse_ctx.on_error("argument not found");
 
     // Parse precision.
     if (it != end && *it == '.') {
       ++it;
       c = it != end ? *it : 0;
       if ('0' <= c && c <= '9') {
-        detail::error_handler eh;
-        specs.precision = parse_nonnegative_int(it, end, eh);
+        specs.precision = parse_nonnegative_int(it, end, 0);
       } else if (c == '*') {
         ++it;
         specs.precision = static_cast<int>(
-            visit_format_arg(detail::printf_precision_handler(), get_arg()));
+            visit_format_arg(detail::printf_precision_handler(), get_arg(-1)));
       } else {
         specs.precision = 0;
       }
     }
 
-    format_arg arg = get_arg(arg_index);
+    auto arg = get_arg(arg_index);
     // For d, i, o, u, x, and X conversion specifiers, if a precision is
     // specified, the '0' flag is ignored
     if (specs.precision >= 0 && arg.is_integral())
@@ -516,9 +433,10 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
       auto str = visit_format_arg(detail::get_cstring<Char>(), arg);
       auto str_end = str + specs.precision;
       auto nul = std::find(str, str_end, Char());
-      arg = detail::make_arg<basic_printf_context>(basic_string_view<Char>(
-          str,
-          detail::to_unsigned(nul != str_end ? nul - str : specs.precision)));
+      arg = detail::make_arg<basic_printf_context<OutputIt, Char>>(
+          basic_string_view<Char>(
+              str, detail::to_unsigned(nul != str_end ? nul - str
+                                                      : specs.precision)));
     }
     if (specs.alt && visit_format_arg(detail::is_zero_int(), arg))
       specs.alt = false;
@@ -532,7 +450,7 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
 
     // Parse length and convert the argument to the required type.
     c = it != end ? *it++ : 0;
-    char_type t = it != end ? *it : 0;
+    Char t = it != end ? *it : 0;
     using detail::convert_arg;
     switch (c) {
     case 'h':
@@ -573,28 +491,34 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
 
     // Parse type.
     if (it == end) FMT_THROW(format_error("invalid format string"));
-    specs.type = static_cast<char>(*it++);
+    char type = static_cast<char>(*it++);
     if (arg.is_integral()) {
       // Normalize type.
-      switch (specs.type) {
+      switch (type) {
       case 'i':
       case 'u':
-        specs.type = 'd';
+        type = 'd';
         break;
       case 'c':
-        visit_format_arg(detail::char_converter<basic_printf_context>(arg),
-                         arg);
+        visit_format_arg(
+            detail::char_converter<basic_printf_context<OutputIt, Char>>(arg),
+            arg);
         break;
       }
     }
+    specs.type = parse_presentation_type(type);
+    if (specs.type == presentation_type::none)
+      parse_ctx.on_error("invalid type specifier");
 
     start = it;
 
     // Format argument.
-    out = visit_format_arg(ArgFormatter(out, specs, *this), arg);
+    out = visit_format_arg(
+        detail::printf_arg_formatter<OutputIt, Char>(out, specs, context), arg);
   }
-  return std::copy(start, it, out);
+  detail::write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
 }
+FMT_END_DETAIL_NAMESPACE
 
 template <typename Char>
 using basic_printf_context_t =
@@ -612,9 +536,9 @@ using wprintf_args = basic_format_args<wprintf_context>;
   arguments and can be implicitly converted to `~fmt::printf_args`.
   \endrst
  */
-template <typename... Args>
-inline format_arg_store<printf_context, Args...> make_printf_args(
-    const Args&... args) {
+template <typename... T>
+inline auto make_printf_args(const T&... args)
+    -> format_arg_store<printf_context, T...> {
   return {args...};
 }
 
@@ -624,18 +548,19 @@ inline format_arg_store<printf_context, Args...> make_printf_args(
   arguments and can be implicitly converted to `~fmt::wprintf_args`.
   \endrst
  */
-template <typename... Args>
-inline format_arg_store<wprintf_context, Args...> make_wprintf_args(
-    const Args&... args) {
+template <typename... T>
+inline auto make_wprintf_args(const T&... args)
+    -> format_arg_store<wprintf_context, T...> {
   return {args...};
 }
 
 template <typename S, typename Char = char_t<S>>
-inline std::basic_string<Char> vsprintf(
-    const S& format,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
+inline auto vsprintf(
+    const S& fmt,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
+    -> std::basic_string<Char> {
   basic_memory_buffer<Char> buffer;
-  vprintf(buffer, to_string_view(format), args);
+  vprintf(buffer, detail::to_string_view(fmt), args);
   return to_string(buffer);
 }
 
@@ -648,19 +573,21 @@ inline std::basic_string<Char> vsprintf(
     std::string message = fmt::sprintf("The answer is %d", 42);
   \endrst
 */
-template <typename S, typename... Args,
+template <typename S, typename... T,
           typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
-inline std::basic_string<Char> sprintf(const S& format, const Args&... args) {
+inline auto sprintf(const S& fmt, const T&... args) -> std::basic_string<Char> {
   using context = basic_printf_context_t<Char>;
-  return vsprintf(to_string_view(format), make_format_args<context>(args...));
+  return vsprintf(detail::to_string_view(fmt),
+                  fmt::make_format_args<context>(args...));
 }
 
 template <typename S, typename Char = char_t<S>>
-inline int vfprintf(
-    std::FILE* f, const S& format,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
+inline auto vfprintf(
+    std::FILE* f, const S& fmt,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
+    -> int {
   basic_memory_buffer<Char> buffer;
-  vprintf(buffer, to_string_view(format), args);
+  vprintf(buffer, detail::to_string_view(fmt), args);
   size_t size = buffer.size();
   return std::fwrite(buffer.data(), sizeof(Char), size, f) < size
              ? -1
@@ -676,19 +603,19 @@ inline int vfprintf(
     fmt::fprintf(stderr, "Don't %s!", "panic");
   \endrst
  */
-template <typename S, typename... Args,
-          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
-inline int fprintf(std::FILE* f, const S& format, const Args&... args) {
+template <typename S, typename... T, typename Char = char_t<S>>
+inline auto fprintf(std::FILE* f, const S& fmt, const T&... args) -> int {
   using context = basic_printf_context_t<Char>;
-  return vfprintf(f, to_string_view(format),
-                  make_format_args<context>(args...));
+  return vfprintf(f, detail::to_string_view(fmt),
+                  fmt::make_format_args<context>(args...));
 }
 
 template <typename S, typename Char = char_t<S>>
-inline int vprintf(
-    const S& format,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
-  return vfprintf(stdout, to_string_view(format), args);
+inline auto vprintf(
+    const S& fmt,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
+    -> int {
+  return vfprintf(stdout, detail::to_string_view(fmt), args);
 }
 
 /**
@@ -700,52 +627,14 @@ inline int vprintf(
     fmt::printf("Elapsed time: %.2f seconds", 1.23);
   \endrst
  */
-template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_string<S>::value)>
-inline int printf(const S& format_str, const Args&... args) {
-  using context = basic_printf_context_t<char_t<S>>;
-  return vprintf(to_string_view(format_str),
-                 make_format_args<context>(args...));
+template <typename S, typename... T, FMT_ENABLE_IF(detail::is_string<S>::value)>
+inline auto printf(const S& fmt, const T&... args) -> int {
+  return vprintf(
+      detail::to_string_view(fmt),
+      fmt::make_format_args<basic_printf_context_t<char_t<S>>>(args...));
 }
 
-template <typename S, typename Char = char_t<S>>
-inline int vfprintf(
-    std::basic_ostream<Char>& os, const S& format,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, to_string_view(format), args);
-  detail::write_buffer(os, buffer);
-  return static_cast<int>(buffer.size());
-}
-
-/** Formats arguments and writes the output to the range. */
-template <typename ArgFormatter, typename Char,
-          typename Context =
-              basic_printf_context<typename ArgFormatter::iterator, Char>>
-typename ArgFormatter::iterator vprintf(
-    detail::buffer<Char>& out, basic_string_view<Char> format_str,
-    basic_format_args<type_identity_t<Context>> args) {
-  typename ArgFormatter::iterator iter(out);
-  Context(iter, format_str, args).template format<ArgFormatter>();
-  return iter;
-}
-
-/**
-  \rst
-  Prints formatted data to the stream *os*.
-
-  **Example**::
-
-    fmt::fprintf(cerr, "Don't %s!", "panic");
-  \endrst
- */
-template <typename S, typename... Args, typename Char = char_t<S>>
-inline int fprintf(std::basic_ostream<Char>& os, const S& format_str,
-                   const Args&... args) {
-  using context = basic_printf_context_t<Char>;
-  return vfprintf(os, to_string_view(format_str),
-                  make_format_args<context>(args...));
-}
+FMT_MODULE_EXPORT_END
 FMT_END_NAMESPACE
 
 #endif  // FMT_PRINTF_H_

include/spdlog/fmt/bundled/ranges.h

@@ -13,47 +13,13 @@
 #define FMT_RANGES_H_
 
 #include <initializer_list>
+#include <tuple>
 #include <type_traits>
 
 #include "format.h"
 
-// output only up to N items from the range.
-#ifndef FMT_RANGE_OUTPUT_LENGTH_LIMIT
-#  define FMT_RANGE_OUTPUT_LENGTH_LIMIT 256
-#endif
-
 FMT_BEGIN_NAMESPACE
 
-template <typename Char> struct formatting_base {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-};
-
-template <typename Char, typename Enable = void>
-struct formatting_range : formatting_base<Char> {
-  static FMT_CONSTEXPR_DECL const size_t range_length_limit =
-      FMT_RANGE_OUTPUT_LENGTH_LIMIT;  // output only up to N items from the
-                                      // range.
-  Char prefix;
-  Char delimiter;
-  Char postfix;
-  formatting_range() : prefix('{'), delimiter(','), postfix('}') {}
-  static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
-  static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
-};
-
-template <typename Char, typename Enable = void>
-struct formatting_tuple : formatting_base<Char> {
-  Char prefix;
-  Char delimiter;
-  Char postfix;
-  formatting_tuple() : prefix('('), delimiter(','), postfix(')') {}
-  static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
-  static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
-};
-
 namespace detail {
 
 template <typename RangeT, typename OutputIterator>
@@ -75,47 +41,145 @@ OutputIterator copy(char ch, OutputIterator out) {
   return out;
 }
 
-/// Return true value if T has std::string interface, like std::string_view.
-template <typename T> class is_like_std_string {
+template <typename OutputIterator>
+OutputIterator copy(wchar_t ch, OutputIterator out) {
+  *out++ = ch;
+  return out;
+}
+
+// Returns true if T has a std::string-like interface, like std::string_view.
+template <typename T> class is_std_string_like {
   template <typename U>
   static auto check(U* p)
       -> decltype((void)p->find('a'), p->length(), (void)p->data(), int());
   template <typename> static void check(...);
 
  public:
-  static FMT_CONSTEXPR_DECL const bool value =
-      is_string<T>::value || !std::is_void<decltype(check<T>(nullptr))>::value;
+  static constexpr const bool value =
+      is_string<T>::value ||
+      std::is_convertible<T, std_string_view<char>>::value ||
+      !std::is_void<decltype(check<T>(nullptr))>::value;
 };
 
 template <typename Char>
-struct is_like_std_string<fmt::basic_string_view<Char>> : std::true_type {};
+struct is_std_string_like<fmt::basic_string_view<Char>> : std::true_type {};
+
+template <typename T> class is_map {
+  template <typename U> static auto check(U*) -> typename U::mapped_type;
+  template <typename> static void check(...);
+
+ public:
+#ifdef FMT_FORMAT_MAP_AS_LIST
+  static constexpr const bool value = false;
+#else
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+#endif
+};
+
+template <typename T> class is_set {
+  template <typename U> static auto check(U*) -> typename U::key_type;
+  template <typename> static void check(...);
+
+ public:
+#ifdef FMT_FORMAT_SET_AS_LIST
+  static constexpr const bool value = false;
+#else
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value && !is_map<T>::value;
+#endif
+};
 
 template <typename... Ts> struct conditional_helper {};
 
 template <typename T, typename _ = void> struct is_range_ : std::false_type {};
 
-#if !FMT_MSC_VER || FMT_MSC_VER > 1800
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION > 1800
+
+#  define FMT_DECLTYPE_RETURN(val)  \
+    ->decltype(val) { return val; } \
+    static_assert(                  \
+        true, "")  // This makes it so that a semicolon is required after the
+                   // macro, which helps clang-format handle the formatting.
+
+// C array overload
+template <typename T, std::size_t N>
+auto range_begin(const T (&arr)[N]) -> const T* {
+  return arr;
+}
+template <typename T, std::size_t N>
+auto range_end(const T (&arr)[N]) -> const T* {
+  return arr + N;
+}
+
+template <typename T, typename Enable = void>
+struct has_member_fn_begin_end_t : std::false_type {};
+
 template <typename T>
-struct is_range_<
-    T, conditional_t<false,
-                     conditional_helper<decltype(std::declval<T>().begin()),
-                                        decltype(std::declval<T>().end())>,
-                     void>> : std::true_type {};
+struct has_member_fn_begin_end_t<T, void_t<decltype(std::declval<T>().begin()),
+                                           decltype(std::declval<T>().end())>>
+    : std::true_type {};
+
+// Member function overload
+template <typename T>
+auto range_begin(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).begin());
+template <typename T>
+auto range_end(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).end());
+
+// ADL overload. Only participates in overload resolution if member functions
+// are not found.
+template <typename T>
+auto range_begin(T&& rng)
+    -> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
+                   decltype(begin(static_cast<T&&>(rng)))> {
+  return begin(static_cast<T&&>(rng));
+}
+template <typename T>
+auto range_end(T&& rng) -> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
+                                       decltype(end(static_cast<T&&>(rng)))> {
+  return end(static_cast<T&&>(rng));
+}
+
+template <typename T, typename Enable = void>
+struct has_const_begin_end : std::false_type {};
+template <typename T, typename Enable = void>
+struct has_mutable_begin_end : std::false_type {};
+
+template <typename T>
+struct has_const_begin_end<
+    T,
+    void_t<
+        decltype(detail::range_begin(std::declval<const remove_cvref_t<T>&>())),
+        decltype(detail::range_end(std::declval<const remove_cvref_t<T>&>()))>>
+    : std::true_type {};
+
+template <typename T>
+struct has_mutable_begin_end<
+    T, void_t<decltype(detail::range_begin(std::declval<T>())),
+              decltype(detail::range_end(std::declval<T>())),
+              enable_if_t<std::is_copy_constructible<T>::value>>>
+    : std::true_type {};
+
+template <typename T>
+struct is_range_<T, void>
+    : std::integral_constant<bool, (has_const_begin_end<T>::value ||
+                                    has_mutable_begin_end<T>::value)> {};
+#  undef FMT_DECLTYPE_RETURN
 #endif
 
-/// tuple_size and tuple_element check.
+// tuple_size and tuple_element check.
 template <typename T> class is_tuple_like_ {
   template <typename U>
   static auto check(U* p) -> decltype(std::tuple_size<U>::value, int());
   template <typename> static void check(...);
 
  public:
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       !std::is_void<decltype(check<T>(nullptr))>::value;
 };
 
 // Check for integer_sequence
-#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900
+#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VERSION >= 1900
 template <typename T, T... N>
 using integer_sequence = std::integer_sequence<T, N...>;
 template <size_t... N> using index_sequence = std::index_sequence<N...>;
@@ -138,8 +202,33 @@ template <size_t N>
 using make_index_sequence = make_integer_sequence<size_t, N>;
 #endif
 
+template <typename T>
+using tuple_index_sequence = make_index_sequence<std::tuple_size<T>::value>;
+
+template <typename T, typename C, bool = is_tuple_like_<T>::value>
+class is_tuple_formattable_ {
+ public:
+  static constexpr const bool value = false;
+};
+template <typename T, typename C> class is_tuple_formattable_<T, C, true> {
+  template <std::size_t... I>
+  static std::true_type check2(index_sequence<I...>,
+                               integer_sequence<bool, (I == I)...>);
+  static std::false_type check2(...);
+  template <std::size_t... I>
+  static decltype(check2(
+      index_sequence<I...>{},
+      integer_sequence<
+          bool, (is_formattable<typename std::tuple_element<I, T>::type,
+                                C>::value)...>{})) check(index_sequence<I...>);
+
+ public:
+  static constexpr const bool value =
+      decltype(check(tuple_index_sequence<T>{}))::value;
+};
+
 template <class Tuple, class F, size_t... Is>
-void for_each(index_sequence<Is...>, Tuple&& tup, F&& f) FMT_NOEXCEPT {
+void for_each(index_sequence<Is...>, Tuple&& tup, F&& f) noexcept {
   using std::get;
   // using free function get<I>(T) now.
   const int _[] = {0, ((void)f(get<Is>(tup)), 0)...};
@@ -157,194 +246,435 @@ template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) {
   for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
 }
 
+#if FMT_MSC_VERSION && FMT_MSC_VERSION < 1920
+// Older MSVC doesn't get the reference type correctly for arrays.
+template <typename R> struct range_reference_type_impl {
+  using type = decltype(*detail::range_begin(std::declval<R&>()));
+};
+
+template <typename T, std::size_t N> struct range_reference_type_impl<T[N]> {
+  using type = T&;
+};
+
+template <typename T>
+using range_reference_type = typename range_reference_type_impl<T>::type;
+#else
 template <typename Range>
-using value_type = remove_cvref_t<decltype(*std::declval<Range>().begin())>;
+using range_reference_type =
+    decltype(*detail::range_begin(std::declval<Range&>()));
+#endif
 
-template <typename Arg, FMT_ENABLE_IF(!is_like_std_string<
-                                      typename std::decay<Arg>::type>::value)>
-FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
-  return add_space ? " {}" : "{}";
+// We don't use the Range's value_type for anything, but we do need the Range's
+// reference type, with cv-ref stripped.
+template <typename Range>
+using uncvref_type = remove_cvref_t<range_reference_type<Range>>;
+
+template <typename Range>
+using uncvref_first_type =
+    remove_cvref_t<decltype(std::declval<range_reference_type<Range>>().first)>;
+
+template <typename Range>
+using uncvref_second_type = remove_cvref_t<
+    decltype(std::declval<range_reference_type<Range>>().second)>;
+
+template <typename OutputIt> OutputIt write_delimiter(OutputIt out) {
+  *out++ = ',';
+  *out++ = ' ';
+  return out;
 }
 
-template <typename Arg, FMT_ENABLE_IF(is_like_std_string<
-                                      typename std::decay<Arg>::type>::value)>
-FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
-  return add_space ? " \"{}\"" : "\"{}\"";
+template <typename Char, typename OutputIt>
+auto write_range_entry(OutputIt out, basic_string_view<Char> str) -> OutputIt {
+  return write_escaped_string(out, str);
 }
 
-FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char*) {
-  return add_space ? " \"{}\"" : "\"{}\"";
-}
-FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t*) {
-  return add_space ? L" \"{}\"" : L"\"{}\"";
+template <typename Char, typename OutputIt, typename T,
+          FMT_ENABLE_IF(std::is_convertible<T, std_string_view<char>>::value)>
+inline auto write_range_entry(OutputIt out, const T& str) -> OutputIt {
+  auto sv = std_string_view<Char>(str);
+  return write_range_entry<Char>(out, basic_string_view<Char>(sv));
 }
 
-FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char) {
-  return add_space ? " '{}'" : "'{}'";
+template <typename Char, typename OutputIt, typename Arg,
+          FMT_ENABLE_IF(std::is_same<Arg, Char>::value)>
+OutputIt write_range_entry(OutputIt out, const Arg v) {
+  return write_escaped_char(out, v);
 }
-FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) {
-  return add_space ? L" '{}'" : L"'{}'";
+
+template <
+    typename Char, typename OutputIt, typename Arg,
+    FMT_ENABLE_IF(!is_std_string_like<typename std::decay<Arg>::type>::value &&
+                  !std::is_same<Arg, Char>::value)>
+OutputIt write_range_entry(OutputIt out, const Arg& v) {
+  return write<Char>(out, v);
 }
+
 }  // namespace detail
 
 template <typename T> struct is_tuple_like {
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value;
 };
 
+template <typename T, typename C> struct is_tuple_formattable {
+  static constexpr const bool value =
+      detail::is_tuple_formattable_<T, C>::value;
+};
+
 template <typename TupleT, typename Char>
-struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
+struct formatter<TupleT, Char,
+                 enable_if_t<fmt::is_tuple_like<TupleT>::value &&
+                             fmt::is_tuple_formattable<TupleT, Char>::value>> {
  private:
-  // C++11 generic lambda for format()
+  basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
+  basic_string_view<Char> opening_bracket_ =
+      detail::string_literal<Char, '('>{};
+  basic_string_view<Char> closing_bracket_ =
+      detail::string_literal<Char, ')'>{};
+
+  // C++11 generic lambda for format().
   template <typename FormatContext> struct format_each {
     template <typename T> void operator()(const T& v) {
-      if (i > 0) {
-        if (formatting.add_prepostfix_space) {
-          *out++ = ' ';
-        }
-        out = detail::copy(formatting.delimiter, out);
-      }
-      out = format_to(out,
-                      detail::format_str_quoted(
-                          (formatting.add_delimiter_spaces && i > 0), v),
-                      v);
+      if (i > 0) out = detail::copy_str<Char>(separator, out);
+      out = detail::write_range_entry<Char>(out, v);
       ++i;
     }
-
-    formatting_tuple<Char>& formatting;
-    size_t& i;
-    typename std::add_lvalue_reference<decltype(
-        std::declval<FormatContext>().out())>::type out;
+    int i;
+    typename FormatContext::iterator& out;
+    basic_string_view<Char> separator;
   };
 
  public:
-  formatting_tuple<Char> formatting;
+  FMT_CONSTEXPR formatter() {}
 
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return formatting.parse(ctx);
+  FMT_CONSTEXPR void set_separator(basic_string_view<Char> sep) {
+    separator_ = sep;
   }
 
-  template <typename FormatContext = format_context>
-  auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) {
-    auto out = ctx.out();
-    size_t i = 0;
-    detail::copy(formatting.prefix, out);
-
-    detail::for_each(values, format_each<FormatContext>{formatting, i, out});
-    if (formatting.add_prepostfix_space) {
-      *out++ = ' ';
-    }
-    detail::copy(formatting.postfix, out);
-
-    return ctx.out();
-  }
-};
-
-template <typename T, typename Char> struct is_range {
-  static FMT_CONSTEXPR_DECL const bool value =
-      detail::is_range_<T>::value && !detail::is_like_std_string<T>::value &&
-      !std::is_convertible<T, std::basic_string<Char>>::value &&
-      !std::is_constructible<detail::std_string_view<Char>, T>::value;
-};
-
-template <typename T, typename Char>
-struct formatter<
-    T, Char,
-    enable_if_t<fmt::is_range<T, Char>::value
-// Workaround a bug in MSVC 2017 and earlier.
-#if !FMT_MSC_VER || FMT_MSC_VER >= 1927
-                &&
-                (has_formatter<detail::value_type<T>, format_context>::value ||
-                 detail::has_fallback_formatter<detail::value_type<T>,
-                                                format_context>::value)
-#endif
-                >> {
-  formatting_range<Char> formatting;
-
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return formatting.parse(ctx);
+  FMT_CONSTEXPR void set_brackets(basic_string_view<Char> open,
+                                  basic_string_view<Char> close) {
+    opening_bracket_ = open;
+    closing_bracket_ = close;
   }
 
-  template <typename FormatContext>
-  typename FormatContext::iterator format(const T& values, FormatContext& ctx) {
-    auto out = detail::copy(formatting.prefix, ctx.out());
-    size_t i = 0;
-    auto it = values.begin();
-    auto end = values.end();
-    for (; it != end; ++it) {
-      if (i > 0) {
-        if (formatting.add_prepostfix_space) *out++ = ' ';
-        out = detail::copy(formatting.delimiter, out);
-      }
-      out = format_to(out,
-                      detail::format_str_quoted(
-                          (formatting.add_delimiter_spaces && i > 0), *it),
-                      *it);
-      if (++i > formatting.range_length_limit) {
-        out = format_to(out, " ... <other elements>");
-        break;
-      }
-    }
-    if (formatting.add_prepostfix_space) *out++ = ' ';
-    return detail::copy(formatting.postfix, out);
-  }
-};
-
-template <typename Char, typename... T> struct tuple_arg_join : detail::view {
-  const std::tuple<T...>& tuple;
-  basic_string_view<Char> sep;
-
-  tuple_arg_join(const std::tuple<T...>& t, basic_string_view<Char> s)
-      : tuple{t}, sep{s} {}
-};
-
-template <typename Char, typename... T>
-struct formatter<tuple_arg_join<Char, T...>, Char> {
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
     return ctx.begin();
   }
 
+  template <typename FormatContext = format_context>
+  auto format(const TupleT& values, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::copy_str<Char>(opening_bracket_, out);
+    detail::for_each(values, format_each<FormatContext>{0, out, separator_});
+    out = detail::copy_str<Char>(closing_bracket_, out);
+    return out;
+  }
+};
+
+template <typename T, typename Char> struct is_range {
+  static constexpr const bool value =
+      detail::is_range_<T>::value && !detail::is_std_string_like<T>::value &&
+      !std::is_convertible<T, std::basic_string<Char>>::value &&
+      !std::is_convertible<T, detail::std_string_view<Char>>::value;
+};
+
+namespace detail {
+template <typename Context> struct range_mapper {
+  using mapper = arg_mapper<Context>;
+
+  template <typename T,
+            FMT_ENABLE_IF(has_formatter<remove_cvref_t<T>, Context>::value)>
+  static auto map(T&& value) -> T&& {
+    return static_cast<T&&>(value);
+  }
+  template <typename T,
+            FMT_ENABLE_IF(!has_formatter<remove_cvref_t<T>, Context>::value)>
+  static auto map(T&& value)
+      -> decltype(mapper().map(static_cast<T&&>(value))) {
+    return mapper().map(static_cast<T&&>(value));
+  }
+};
+
+template <typename Char, typename Element>
+using range_formatter_type = conditional_t<
+    is_formattable<Element, Char>::value,
+    formatter<remove_cvref_t<decltype(range_mapper<buffer_context<Char>>{}.map(
+                  std::declval<Element>()))>,
+              Char>,
+    fallback_formatter<Element, Char>>;
+
+template <typename R>
+using maybe_const_range =
+    conditional_t<has_const_begin_end<R>::value, const R, R>;
+
+// Workaround a bug in MSVC 2015 and earlier.
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
+template <typename R, typename Char>
+struct is_formattable_delayed
+    : disjunction<
+          is_formattable<uncvref_type<maybe_const_range<R>>, Char>,
+          has_fallback_formatter<uncvref_type<maybe_const_range<R>>, Char>> {};
+#endif
+
+}  // namespace detail
+
+template <typename T, typename Char, typename Enable = void>
+struct range_formatter;
+
+template <typename T, typename Char>
+struct range_formatter<
+    T, Char,
+    enable_if_t<conjunction<
+        std::is_same<T, remove_cvref_t<T>>,
+        disjunction<is_formattable<T, Char>,
+                    detail::has_fallback_formatter<T, Char>>>::value>> {
+ private:
+  detail::range_formatter_type<Char, T> underlying_;
+  bool custom_specs_ = false;
+  basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
+  basic_string_view<Char> opening_bracket_ =
+      detail::string_literal<Char, '['>{};
+  basic_string_view<Char> closing_bracket_ =
+      detail::string_literal<Char, ']'>{};
+
+  template <class U>
+  FMT_CONSTEXPR static auto maybe_set_debug_format(U& u, int)
+      -> decltype(u.set_debug_format()) {
+    u.set_debug_format();
+  }
+
+  template <class U>
+  FMT_CONSTEXPR static void maybe_set_debug_format(U&, ...) {}
+
+  FMT_CONSTEXPR void maybe_set_debug_format() {
+    maybe_set_debug_format(underlying_, 0);
+  }
+
+ public:
+  FMT_CONSTEXPR range_formatter() {}
+
+  FMT_CONSTEXPR auto underlying() -> detail::range_formatter_type<Char, T>& {
+    return underlying_;
+  }
+
+  FMT_CONSTEXPR void set_separator(basic_string_view<Char> sep) {
+    separator_ = sep;
+  }
+
+  FMT_CONSTEXPR void set_brackets(basic_string_view<Char> open,
+                                  basic_string_view<Char> close) {
+    opening_bracket_ = open;
+    closing_bracket_ = close;
+  }
+
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    auto it = ctx.begin();
+    auto end = ctx.end();
+    if (it == end || *it == '}') {
+      maybe_set_debug_format();
+      return it;
+    }
+
+    if (*it == 'n') {
+      set_brackets({}, {});
+      ++it;
+    }
+
+    if (*it == '}') {
+      maybe_set_debug_format();
+      return it;
+    }
+
+    if (*it != ':')
+      FMT_THROW(format_error("no other top-level range formatters supported"));
+
+    custom_specs_ = true;
+    ++it;
+    ctx.advance_to(it);
+    return underlying_.parse(ctx);
+  }
+
+  template <typename R, class FormatContext>
+  auto format(R&& range, FormatContext& ctx) const -> decltype(ctx.out()) {
+    detail::range_mapper<buffer_context<Char>> mapper;
+    auto out = ctx.out();
+    out = detail::copy_str<Char>(opening_bracket_, out);
+    int i = 0;
+    auto it = detail::range_begin(range);
+    auto end = detail::range_end(range);
+    for (; it != end; ++it) {
+      if (i > 0) out = detail::copy_str<Char>(separator_, out);
+      ;
+      ctx.advance_to(out);
+      out = underlying_.format(mapper.map(*it), ctx);
+      ++i;
+    }
+    out = detail::copy_str<Char>(closing_bracket_, out);
+    return out;
+  }
+};
+
+enum class range_format { disabled, map, set, sequence, string, debug_string };
+
+namespace detail {
+template <typename T> struct range_format_kind_ {
+  static constexpr auto value = std::is_same<range_reference_type<T>, T>::value
+                                    ? range_format::disabled
+                                : is_map<T>::value ? range_format::map
+                                : is_set<T>::value ? range_format::set
+                                                   : range_format::sequence;
+};
+
+template <range_format K, typename R, typename Char, typename Enable = void>
+struct range_default_formatter;
+
+template <range_format K>
+using range_format_constant = std::integral_constant<range_format, K>;
+
+template <range_format K, typename R, typename Char>
+struct range_default_formatter<
+    K, R, Char,
+    enable_if_t<(K == range_format::sequence || K == range_format::map ||
+                 K == range_format::set)>> {
+  using range_type = detail::maybe_const_range<R>;
+  range_formatter<detail::uncvref_type<range_type>, Char> underlying_;
+
+  FMT_CONSTEXPR range_default_formatter() { init(range_format_constant<K>()); }
+
+  FMT_CONSTEXPR void init(range_format_constant<range_format::set>) {
+    underlying_.set_brackets(detail::string_literal<Char, '{'>{},
+                             detail::string_literal<Char, '}'>{});
+  }
+
+  FMT_CONSTEXPR void init(range_format_constant<range_format::map>) {
+    underlying_.set_brackets(detail::string_literal<Char, '{'>{},
+                             detail::string_literal<Char, '}'>{});
+    underlying_.underlying().set_brackets({}, {});
+    underlying_.underlying().set_separator(
+        detail::string_literal<Char, ':', ' '>{});
+  }
+
+  FMT_CONSTEXPR void init(range_format_constant<range_format::sequence>) {}
+
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return underlying_.parse(ctx);
+  }
+
   template <typename FormatContext>
-  typename FormatContext::iterator format(
-      const tuple_arg_join<Char, T...>& value, FormatContext& ctx) {
-    return format(value, ctx, detail::make_index_sequence<sizeof...(T)>{});
+  auto format(range_type& range, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return underlying_.format(range, ctx);
+  }
+};
+}  // namespace detail
+
+template <typename T, typename Char, typename Enable = void>
+struct range_format_kind
+    : conditional_t<
+          is_range<T, Char>::value, detail::range_format_kind_<T>,
+          std::integral_constant<range_format, range_format::disabled>> {};
+
+template <typename R, typename Char>
+struct formatter<
+    R, Char,
+    enable_if_t<conjunction<bool_constant<range_format_kind<R, Char>::value !=
+                                          range_format::disabled>
+// Workaround a bug in MSVC 2015 and earlier.
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
+                            ,
+                            detail::is_formattable_delayed<R, Char>
+#endif
+                            >::value>>
+    : detail::range_default_formatter<range_format_kind<R, Char>::value, R,
+                                      Char> {
+};
+
+template <typename Char, typename... T> struct tuple_join_view : detail::view {
+  const std::tuple<T...>& tuple;
+  basic_string_view<Char> sep;
+
+  tuple_join_view(const std::tuple<T...>& t, basic_string_view<Char> s)
+      : tuple(t), sep{s} {}
+};
+
+template <typename Char, typename... T>
+using tuple_arg_join = tuple_join_view<Char, T...>;
+
+// Define FMT_TUPLE_JOIN_SPECIFIERS to enable experimental format specifiers
+// support in tuple_join. It is disabled by default because of issues with
+// the dynamic width and precision.
+#ifndef FMT_TUPLE_JOIN_SPECIFIERS
+#  define FMT_TUPLE_JOIN_SPECIFIERS 0
+#endif
+
+template <typename Char, typename... T>
+struct formatter<tuple_join_view<Char, T...>, Char> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return do_parse(ctx, std::integral_constant<size_t, sizeof...(T)>());
+  }
+
+  template <typename FormatContext>
+  auto format(const tuple_join_view<Char, T...>& value,
+              FormatContext& ctx) const -> typename FormatContext::iterator {
+    return do_format(value, ctx,
+                     std::integral_constant<size_t, sizeof...(T)>());
   }
 
  private:
-  template <typename FormatContext, size_t... N>
-  typename FormatContext::iterator format(
-      const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
-      detail::index_sequence<N...>) {
-    return format_args(value, ctx, std::get<N>(value.tuple)...);
+  std::tuple<formatter<typename std::decay<T>::type, Char>...> formatters_;
+
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto do_parse(ParseContext& ctx,
+                              std::integral_constant<size_t, 0>)
+      -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename ParseContext, size_t N>
+  FMT_CONSTEXPR auto do_parse(ParseContext& ctx,
+                              std::integral_constant<size_t, N>)
+      -> decltype(ctx.begin()) {
+    auto end = ctx.begin();
+#if FMT_TUPLE_JOIN_SPECIFIERS
+    end = std::get<sizeof...(T) - N>(formatters_).parse(ctx);
+    if (N > 1) {
+      auto end1 = do_parse(ctx, std::integral_constant<size_t, N - 1>());
+      if (end != end1)
+        FMT_THROW(format_error("incompatible format specs for tuple elements"));
+    }
+#endif
+    return end;
   }
 
   template <typename FormatContext>
-  typename FormatContext::iterator format_args(
-      const tuple_arg_join<Char, T...>&, FormatContext& ctx) {
-    // NOTE: for compilers that support C++17, this empty function instantiation
-    // can be replaced with a constexpr branch in the variadic overload.
+  auto do_format(const tuple_join_view<Char, T...>&, FormatContext& ctx,
+                 std::integral_constant<size_t, 0>) const ->
+      typename FormatContext::iterator {
     return ctx.out();
   }
 
-  template <typename FormatContext, typename Arg, typename... Args>
-  typename FormatContext::iterator format_args(
-      const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
-      const Arg& arg, const Args&... args) {
-    using base = formatter<typename std::decay<Arg>::type, Char>;
-    auto out = ctx.out();
-    out = base{}.format(arg, ctx);
-    if (sizeof...(Args) > 0) {
+  template <typename FormatContext, size_t N>
+  auto do_format(const tuple_join_view<Char, T...>& value, FormatContext& ctx,
+                 std::integral_constant<size_t, N>) const ->
+      typename FormatContext::iterator {
+    auto out = std::get<sizeof...(T) - N>(formatters_)
+                   .format(std::get<sizeof...(T) - N>(value.tuple), ctx);
+    if (N > 1) {
       out = std::copy(value.sep.begin(), value.sep.end(), out);
       ctx.advance_to(out);
-      return format_args(value, ctx, args...);
+      return do_format(value, ctx, std::integral_constant<size_t, N - 1>());
     }
     return out;
   }
 };
 
+FMT_MODULE_EXPORT_BEGIN
+
 /**
   \rst
   Returns an object that formats `tuple` with elements separated by `sep`.
@@ -357,14 +687,15 @@ struct formatter<tuple_arg_join<Char, T...>, Char> {
   \endrst
  */
 template <typename... T>
-FMT_CONSTEXPR tuple_arg_join<char, T...> join(const std::tuple<T...>& tuple,
-                                              string_view sep) {
+FMT_CONSTEXPR auto join(const std::tuple<T...>& tuple, string_view sep)
+    -> tuple_join_view<char, T...> {
   return {tuple, sep};
 }
 
 template <typename... T>
-FMT_CONSTEXPR tuple_arg_join<wchar_t, T...> join(const std::tuple<T...>& tuple,
-                                                 wstring_view sep) {
+FMT_CONSTEXPR auto join(const std::tuple<T...>& tuple,
+                        basic_string_view<wchar_t> sep)
+    -> tuple_join_view<wchar_t, T...> {
   return {tuple, sep};
 }
 
@@ -380,17 +711,12 @@ FMT_CONSTEXPR tuple_arg_join<wchar_t, T...> join(const std::tuple<T...>& tuple,
   \endrst
  */
 template <typename T>
-arg_join<const T*, const T*, char> join(std::initializer_list<T> list,
-                                        string_view sep) {
-  return join(std::begin(list), std::end(list), sep);
-}
-
-template <typename T>
-arg_join<const T*, const T*, wchar_t> join(std::initializer_list<T> list,
-                                           wstring_view sep) {
+auto join(std::initializer_list<T> list, string_view sep)
+    -> join_view<const T*, const T*> {
   return join(std::begin(list), std::end(list), sep);
 }
 
+FMT_MODULE_EXPORT_END
 FMT_END_NAMESPACE
 
 #endif  // FMT_RANGES_H_

include/spdlog/fmt/bundled/std.h

@@ -0,0 +1,171 @@
+// Formatting library for C++ - formatters for standard library types
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_STD_H_
+#define FMT_STD_H_
+
+#include <thread>
+#include <type_traits>
+#include <utility>
+
+#include "ostream.h"
+
+#if FMT_HAS_INCLUDE(<version>)
+#  include <version>
+#endif
+// Checking FMT_CPLUSPLUS for warning suppression in MSVC.
+#if FMT_CPLUSPLUS >= 201703L
+#  if FMT_HAS_INCLUDE(<filesystem>)
+#    include <filesystem>
+#  endif
+#  if FMT_HAS_INCLUDE(<variant>)
+#    include <variant>
+#  endif
+#endif
+
+#ifdef __cpp_lib_filesystem
+FMT_BEGIN_NAMESPACE
+
+namespace detail {
+
+template <typename Char>
+void write_escaped_path(basic_memory_buffer<Char>& quoted,
+                        const std::filesystem::path& p) {
+  write_escaped_string<Char>(std::back_inserter(quoted), p.string<Char>());
+}
+#  ifdef _WIN32
+template <>
+inline void write_escaped_path<char>(basic_memory_buffer<char>& quoted,
+                                     const std::filesystem::path& p) {
+  auto s = p.u8string();
+  write_escaped_string<char>(
+      std::back_inserter(quoted),
+      string_view(reinterpret_cast<const char*>(s.c_str()), s.size()));
+}
+#  endif
+template <>
+inline void write_escaped_path<std::filesystem::path::value_type>(
+    basic_memory_buffer<std::filesystem::path::value_type>& quoted,
+    const std::filesystem::path& p) {
+  write_escaped_string<std::filesystem::path::value_type>(
+      std::back_inserter(quoted), p.native());
+}
+
+}  // namespace detail
+
+template <typename Char>
+struct formatter<std::filesystem::path, Char>
+    : formatter<basic_string_view<Char>> {
+  template <typename FormatContext>
+  auto format(const std::filesystem::path& p, FormatContext& ctx) const ->
+      typename FormatContext::iterator {
+    basic_memory_buffer<Char> quoted;
+    detail::write_escaped_path(quoted, p);
+    return formatter<basic_string_view<Char>>::format(
+        basic_string_view<Char>(quoted.data(), quoted.size()), ctx);
+  }
+};
+FMT_END_NAMESPACE
+#endif
+
+FMT_BEGIN_NAMESPACE
+template <typename Char>
+struct formatter<std::thread::id, Char> : basic_ostream_formatter<Char> {};
+FMT_END_NAMESPACE
+
+#ifdef __cpp_lib_variant
+FMT_BEGIN_NAMESPACE
+template <typename Char> struct formatter<std::monostate, Char> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const std::monostate&, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::write<Char>(out, "monostate");
+    return out;
+  }
+};
+
+namespace detail {
+
+template <typename T>
+using variant_index_sequence =
+    std::make_index_sequence<std::variant_size<T>::value>;
+
+// variant_size and variant_alternative check.
+template <typename T, typename U = void>
+struct is_variant_like_ : std::false_type {};
+template <typename T>
+struct is_variant_like_<T, std::void_t<decltype(std::variant_size<T>::value)>>
+    : std::true_type {};
+
+// formattable element check
+template <typename T, typename C> class is_variant_formattable_ {
+  template <std::size_t... I>
+  static std::conjunction<
+      is_formattable<std::variant_alternative_t<I, T>, C>...>
+      check(std::index_sequence<I...>);
+
+ public:
+  static constexpr const bool value =
+      decltype(check(variant_index_sequence<T>{}))::value;
+};
+
+template <typename Char, typename OutputIt, typename T>
+auto write_variant_alternative(OutputIt out, const T& v) -> OutputIt {
+  if constexpr (is_string<T>::value)
+    return write_escaped_string<Char>(out, detail::to_string_view(v));
+  else if constexpr (std::is_same_v<T, Char>)
+    return write_escaped_char(out, v);
+  else
+    return write<Char>(out, v);
+}
+
+}  // namespace detail
+
+template <typename T> struct is_variant_like {
+  static constexpr const bool value = detail::is_variant_like_<T>::value;
+};
+
+template <typename T, typename C> struct is_variant_formattable {
+  static constexpr const bool value =
+      detail::is_variant_formattable_<T, C>::value;
+};
+
+template <typename Variant, typename Char>
+struct formatter<
+    Variant, Char,
+    std::enable_if_t<std::conjunction_v<
+        is_variant_like<Variant>, is_variant_formattable<Variant, Char>>>> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const Variant& value, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+
+    out = detail::write<Char>(out, "variant(");
+    std::visit(
+        [&](const auto& v) {
+          out = detail::write_variant_alternative<Char>(out, v);
+        },
+        value);
+    *out++ = ')';
+    return out;
+  }
+};
+FMT_END_NAMESPACE
+#endif
+
+#endif  // FMT_STD_H_

include/spdlog/fmt/bundled/xchar.h

@@ -0,0 +1,229 @@
+// Formatting library for C++ - optional wchar_t and exotic character support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_XCHAR_H_
+#define FMT_XCHAR_H_
+
+#include <cwchar>
+
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+template <typename T>
+using is_exotic_char = bool_constant<!std::is_same<T, char>::value>;
+}
+
+FMT_MODULE_EXPORT_BEGIN
+
+using wstring_view = basic_string_view<wchar_t>;
+using wformat_parse_context = basic_format_parse_context<wchar_t>;
+using wformat_context = buffer_context<wchar_t>;
+using wformat_args = basic_format_args<wformat_context>;
+using wmemory_buffer = basic_memory_buffer<wchar_t>;
+
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+// Workaround broken conversion on older gcc.
+template <typename... Args> using wformat_string = wstring_view;
+inline auto runtime(wstring_view s) -> wstring_view { return s; }
+#else
+template <typename... Args>
+using wformat_string = basic_format_string<wchar_t, type_identity_t<Args>...>;
+inline auto runtime(wstring_view s) -> basic_runtime<wchar_t> { return {{s}}; }
+#endif
+
+template <> struct is_char<wchar_t> : std::true_type {};
+template <> struct is_char<detail::char8_type> : std::true_type {};
+template <> struct is_char<char16_t> : std::true_type {};
+template <> struct is_char<char32_t> : std::true_type {};
+
+template <typename... Args>
+constexpr format_arg_store<wformat_context, Args...> make_wformat_args(
+    const Args&... args) {
+  return {args...};
+}
+
+inline namespace literals {
+#if FMT_USE_USER_DEFINED_LITERALS && !FMT_USE_NONTYPE_TEMPLATE_ARGS
+constexpr detail::udl_arg<wchar_t> operator"" _a(const wchar_t* s, size_t) {
+  return {s};
+}
+#endif
+}  // namespace literals
+
+template <typename It, typename Sentinel>
+auto join(It begin, Sentinel end, wstring_view sep)
+    -> join_view<It, Sentinel, wchar_t> {
+  return {begin, end, sep};
+}
+
+template <typename Range>
+auto join(Range&& range, wstring_view sep)
+    -> join_view<detail::iterator_t<Range>, detail::sentinel_t<Range>,
+                 wchar_t> {
+  return join(std::begin(range), std::end(range), sep);
+}
+
+template <typename T>
+auto join(std::initializer_list<T> list, wstring_view sep)
+    -> join_view<const T*, const T*, wchar_t> {
+  return join(std::begin(list), std::end(list), sep);
+}
+
+template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
+auto vformat(basic_string_view<Char> format_str,
+             basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> std::basic_string<Char> {
+  basic_memory_buffer<Char> buffer;
+  detail::vformat_to(buffer, format_str, args);
+  return to_string(buffer);
+}
+
+template <typename... T>
+auto format(wformat_string<T...> fmt, T&&... args) -> std::wstring {
+  return vformat(fmt::wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+// Pass char_t as a default template parameter instead of using
+// std::basic_string<char_t<S>> to reduce the symbol size.
+template <typename S, typename... Args, typename Char = char_t<S>,
+          FMT_ENABLE_IF(!std::is_same<Char, char>::value &&
+                        !std::is_same<Char, wchar_t>::value)>
+auto format(const S& format_str, Args&&... args) -> std::basic_string<Char> {
+  return vformat(detail::to_string_view(format_str),
+                 fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename Locale, typename S, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto vformat(
+    const Locale& loc, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> std::basic_string<Char> {
+  return detail::vformat(loc, detail::to_string_view(format_str), args);
+}
+
+template <typename Locale, typename S, typename... Args,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format(const Locale& loc, const S& format_str, Args&&... args)
+    -> std::basic_string<Char> {
+  return detail::vformat(loc, detail::to_string_view(format_str),
+                         fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename OutputIt, typename S, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+auto vformat_to(OutputIt out, const S& format_str,
+                basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> OutputIt {
+  auto&& buf = detail::get_buffer<Char>(out);
+  detail::vformat_to(buf, detail::to_string_view(format_str), args);
+  return detail::get_iterator(buf);
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format_to(OutputIt out, const S& fmt, Args&&... args) -> OutputIt {
+  return vformat_to(out, detail::to_string_view(fmt),
+                    fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename Locale, typename S, typename OutputIt, typename... Args,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_locale<Locale>::value&&
+                                detail::is_exotic_char<Char>::value)>
+inline auto vformat_to(
+    OutputIt out, const Locale& loc, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) -> OutputIt {
+  auto&& buf = detail::get_buffer<Char>(out);
+  vformat_to(buf, detail::to_string_view(format_str), args,
+             detail::locale_ref(loc));
+  return detail::get_iterator(buf);
+}
+
+template <
+    typename OutputIt, typename Locale, typename S, typename... Args,
+    typename Char = char_t<S>,
+    bool enable = detail::is_output_iterator<OutputIt, Char>::value&&
+        detail::is_locale<Locale>::value&& detail::is_exotic_char<Char>::value>
+inline auto format_to(OutputIt out, const Locale& loc, const S& format_str,
+                      Args&&... args) ->
+    typename std::enable_if<enable, OutputIt>::type {
+  return vformat_to(out, loc, to_string_view(format_str),
+                    fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename OutputIt, typename Char, typename... Args,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto vformat_to_n(
+    OutputIt out, size_t n, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> format_to_n_result<OutputIt> {
+  detail::iterator_buffer<OutputIt, Char, detail::fixed_buffer_traits> buf(out,
+                                                                           n);
+  detail::vformat_to(buf, format_str, args);
+  return {buf.out(), buf.count()};
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format_to_n(OutputIt out, size_t n, const S& fmt,
+                        const Args&... args) -> format_to_n_result<OutputIt> {
+  return vformat_to_n(out, n, detail::to_string_view(fmt),
+                      fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename S, typename... Args, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)>
+inline auto formatted_size(const S& fmt, Args&&... args) -> size_t {
+  detail::counting_buffer<Char> buf;
+  detail::vformat_to(buf, detail::to_string_view(fmt),
+                     fmt::make_format_args<buffer_context<Char>>(args...));
+  return buf.count();
+}
+
+inline void vprint(std::FILE* f, wstring_view fmt, wformat_args args) {
+  wmemory_buffer buffer;
+  detail::vformat_to(buffer, fmt, args);
+  buffer.push_back(L'\0');
+  if (std::fputws(buffer.data(), f) == -1)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
+}
+
+inline void vprint(wstring_view fmt, wformat_args args) {
+  vprint(stdout, fmt, args);
+}
+
+template <typename... T>
+void print(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
+  return vprint(f, wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+template <typename... T> void print(wformat_string<T...> fmt, T&&... args) {
+  return vprint(wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+/**
+  Converts *value* to ``std::wstring`` using the default format for type *T*.
+ */
+template <typename T> inline auto to_wstring(const T& value) -> std::wstring {
+  return format(FMT_STRING(L"{}"), value);
+}
+FMT_MODULE_EXPORT_END
+FMT_END_NAMESPACE
+
+#endif  // FMT_XCHAR_H_

include/spdlog/fmt/chrono.h

@@ -8,13 +8,15 @@
 // include bundled or external copy of fmtlib's chrono support
 //
 
-#if !defined(SPDLOG_FMT_EXTERNAL)
-#ifdef SPDLOG_HEADER_ONLY
-#ifndef FMT_HEADER_ONLY
-#define FMT_HEADER_ONLY
-#endif
-#endif
-#include <spdlog/fmt/bundled/chrono.h>
-#else
-#include <fmt/chrono.h>
+#if !defined(SPDLOG_USE_STD_FORMAT)
+#    if !defined(SPDLOG_FMT_EXTERNAL)
+#        ifdef SPDLOG_HEADER_ONLY
+#            ifndef FMT_HEADER_ONLY
+#                define FMT_HEADER_ONLY
+#            endif
+#        endif
+#        include <spdlog/fmt/bundled/chrono.h>
+#    else
+#        include <fmt/chrono.h>
+#    endif
 #endif

include/spdlog/fmt/compile.h

@@ -0,0 +1,22 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's compile-time support
+//
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+#    if !defined(SPDLOG_FMT_EXTERNAL)
+#        ifdef SPDLOG_HEADER_ONLY
+#            ifndef FMT_HEADER_ONLY
+#                define FMT_HEADER_ONLY
+#            endif
+#        endif
+#        include <spdlog/fmt/bundled/compile.h>
+#    else
+#        include <fmt/compile.h>
+#    endif
+#endif

include/spdlog/fmt/fmt.h

@@ -10,18 +10,24 @@
 // By default spdlog include its own copy.
 //
 
-#if !defined(SPDLOG_FMT_EXTERNAL)
-#if !defined(SPDLOG_COMPILED_LIB) && !defined(FMT_HEADER_ONLY)
-#define FMT_HEADER_ONLY
-#endif
-#ifndef FMT_USE_WINDOWS_H
-#define FMT_USE_WINDOWS_H 0
-#endif
+#if defined(SPDLOG_USE_STD_FORMAT) // SPDLOG_USE_STD_FORMAT is defined - use std::format
+#    include <format>
+#elif !defined(SPDLOG_FMT_EXTERNAL)
+#    if !defined(SPDLOG_COMPILED_LIB) && !defined(FMT_HEADER_ONLY)
+#        define FMT_HEADER_ONLY
+#    endif
+#    ifndef FMT_USE_WINDOWS_H
+#        define FMT_USE_WINDOWS_H 0
+#    endif
 // enable the 'n' flag in for backward compatibility with fmt 6.x
-#define FMT_DEPRECATED_N_SPECIFIER
-#include <spdlog/fmt/bundled/core.h>
-#include <spdlog/fmt/bundled/format.h>
+#    define FMT_DEPRECATED_N_SPECIFIER
+// enable ostream formatting for backward compatibility with fmt 8.x
+#    define FMT_DEPRECATED_OSTREAM
+
+#    include <spdlog/fmt/bundled/core.h>
+#    include <spdlog/fmt/bundled/format.h>
+
 #else // SPDLOG_FMT_EXTERNAL is defined - use external fmtlib
-#include <fmt/core.h>
-#include <fmt/format.h>
-#endif
+#    include <fmt/core.h>
+#    include <fmt/format.h>
+#endif

include/spdlog/fmt/ostr.h

@@ -8,13 +8,15 @@
 // include bundled or external copy of fmtlib's ostream support
 //
 
-#if !defined(SPDLOG_FMT_EXTERNAL)
-#ifdef SPDLOG_HEADER_ONLY
-#ifndef FMT_HEADER_ONLY
-#define FMT_HEADER_ONLY
-#endif
-#endif
-#include <spdlog/fmt/bundled/ostream.h>
-#else
-#include <fmt/ostream.h>
+#if !defined(SPDLOG_USE_STD_FORMAT)
+#    if !defined(SPDLOG_FMT_EXTERNAL)
+#        ifdef SPDLOG_HEADER_ONLY
+#            ifndef FMT_HEADER_ONLY
+#                define FMT_HEADER_ONLY
+#            endif
+#        endif
+#        include <spdlog/fmt/bundled/ostream.h>
+#    else
+#        include <fmt/ostream.h>
+#    endif
 #endif

include/spdlog/fmt/ranges.h

@@ -0,0 +1,22 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's ranges support
+//
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+#    if !defined(SPDLOG_FMT_EXTERNAL)
+#        ifdef SPDLOG_HEADER_ONLY
+#            ifndef FMT_HEADER_ONLY
+#                define FMT_HEADER_ONLY
+#            endif
+#        endif
+#        include <spdlog/fmt/bundled/ranges.h>
+#    else
+#        include <fmt/ranges.h>
+#    endif
+#endif

include/spdlog/fmt/std.h

@@ -0,0 +1,23 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's std support (for formatting e.g. std::filesystem::path, std::thread::id, std::monostate,
+// std::variant, ...)
+//
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+#    if !defined(SPDLOG_FMT_EXTERNAL)
+#        ifdef SPDLOG_HEADER_ONLY
+#            ifndef FMT_HEADER_ONLY
+#                define FMT_HEADER_ONLY
+#            endif
+#        endif
+#        include <spdlog/fmt/bundled/std.h>
+#    else
+#        include <fmt/std.h>
+#    endif
+#endif

include/spdlog/fmt/xchar.h

@@ -0,0 +1,22 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's xchar support
+//
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+#    if !defined(SPDLOG_FMT_EXTERNAL)
+#        ifdef SPDLOG_HEADER_ONLY
+#            ifndef FMT_HEADER_ONLY
+#                define FMT_HEADER_ONLY
+#            endif
+#        endif
+#        include <spdlog/fmt/bundled/xchar.h>
+#    else
+#        include <fmt/xchar.h>
+#    endif
+#endif

include/spdlog/fwd.h

@@ -11,4 +11,8 @@ namespace sinks {
 class sink;
 }
 
+namespace level {
+enum level_enum : int;
+}
+
 } // namespace spdlog

include/spdlog/logger-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/logger.h>
+#    include <spdlog/logger.h>
 #endif
 
 #include <spdlog/sinks/sink.h>
@@ -185,7 +185,7 @@ SPDLOG_INLINE void logger::sink_it_(const details::log_msg &msg)
             {
                 sink->log(msg);
             }
-            SPDLOG_LOGGER_CATCH()
+            SPDLOG_LOGGER_CATCH(msg.source)
         }
     }
 
@@ -203,14 +203,14 @@ SPDLOG_INLINE void logger::flush_()
         {
             sink->flush();
         }
-        SPDLOG_LOGGER_CATCH()
+        SPDLOG_LOGGER_CATCH(source_loc())
     }
 }
 
 SPDLOG_INLINE void logger::dump_backtrace_()
 {
     using details::log_msg;
-    if (tracer_.enabled())
+    if (tracer_.enabled() && !tracer_.empty())
     {
         sink_it_(log_msg{name(), level::info, "****************** Backtrace Start ******************"});
         tracer_.foreach_pop([this](const log_msg &msg) { this->sink_it_(msg); });
@@ -248,9 +248,9 @@ SPDLOG_INLINE void logger::err_handler_(const std::string &msg)
         char date_buf[64];
         std::strftime(date_buf, sizeof(date_buf), "%Y-%m-%d %H:%M:%S", &tm_time);
 #if defined(USING_R) && defined(R_R_H) // if in R environment
-        REprintf("[*** LOG ERROR #%04zu ***] [%s] [%s] {%s}\n", err_counter, date_buf, name().c_str(), msg.c_str());
+        REprintf("[*** LOG ERROR #%04zu ***] [%s] [%s] %s\n", err_counter, date_buf, name().c_str(), msg.c_str());
 #else
-        std::fprintf(stderr, "[*** LOG ERROR #%04zu ***] [%s] [%s] {%s}\n", err_counter, date_buf, name().c_str(), msg.c_str());
+        std::fprintf(stderr, "[*** LOG ERROR #%04zu ***] [%s] [%s] %s\n", err_counter, date_buf, name().c_str(), msg.c_str());
 #endif
     }
 }

include/spdlog/logger.h

@@ -19,22 +19,34 @@
 #include <spdlog/details/backtracer.h>
 
 #ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
-#include <spdlog/details/os.h>
+#    ifndef _WIN32
+#        error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
+#    endif
+#    include <spdlog/details/os.h>
 #endif
 
 #include <vector>
+
 #ifndef SPDLOG_NO_EXCEPTIONS
-#define SPDLOG_LOGGER_CATCH()                                                                                                              \
-    catch (const std::exception &ex)                                                                                                       \
-    {                                                                                                                                      \
-        err_handler_(ex.what());                                                                                                           \
-    }                                                                                                                                      \
-    catch (...)                                                                                                                            \
-    {                                                                                                                                      \
-        err_handler_("Unknown exception in logger");                                                                                       \
-    }
+#    define SPDLOG_LOGGER_CATCH(location)                                                                                                  \
+        catch (const std::exception &ex)                                                                                                   \
+        {                                                                                                                                  \
+            if (location.filename)                                                                                                         \
+            {                                                                                                                              \
+                err_handler_(fmt_lib::format(SPDLOG_FMT_STRING("{} [{}({})]"), ex.what(), location.filename, location.line));              \
+            }                                                                                                                              \
+            else                                                                                                                           \
+            {                                                                                                                              \
+                err_handler_(ex.what());                                                                                                   \
+            }                                                                                                                              \
+        }                                                                                                                                  \
+        catch (...)                                                                                                                        \
+        {                                                                                                                                  \
+            err_handler_("Rethrowing unknown exception in logger");                                                                        \
+            throw;                                                                                                                         \
+        }
 #else
-#define SPDLOG_LOGGER_CATCH()
+#    define SPDLOG_LOGGER_CATCH(location)
 #endif
 
 namespace spdlog {
@@ -70,77 +82,31 @@ public:
     logger(const logger &other);
     logger(logger &&other) SPDLOG_NOEXCEPT;
     logger &operator=(logger other) SPDLOG_NOEXCEPT;
-
     void swap(spdlog::logger &other) SPDLOG_NOEXCEPT;
 
-    // FormatString is a type derived from fmt::compile_string
-    template<typename FormatString, typename std::enable_if<fmt::is_compile_string<FormatString>::value, int>::type = 0, typename... Args>
-    void log(source_loc loc, level::level_enum lvl, const FormatString &fmt, Args&&...args)
-    {
-        log_(loc, lvl, fmt, std::forward<Args>(args)...);
-    }
-
-    // FormatString is NOT a type derived from fmt::compile_string but is a string_view_t or can be implicitly converted to one
     template<typename... Args>
-    void log(source_loc loc, level::level_enum lvl, string_view_t fmt, Args&&...args)
+    void log(source_loc loc, level::level_enum lvl, format_string_t<Args...> fmt, Args &&...args)
     {
-        log_(loc, lvl, fmt, std::forward<Args>(args)...);
+        log_(loc, lvl, details::to_string_view(fmt), std::forward<Args>(args)...);
     }
 
-    template<typename FormatString, typename... Args>
-    void log(level::level_enum lvl, const FormatString &fmt, Args&&...args)
+    template<typename... Args>
+    void log(level::level_enum lvl, format_string_t<Args...> fmt, Args &&...args)
     {
         log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
     }
 
-    template<typename FormatString, typename... Args>
-    void trace(const FormatString &fmt, Args&&...args)
-    {
-        log(level::trace, fmt, std::forward<Args>(args)...);
-    }
-
-    template<typename FormatString, typename... Args>
-    void debug(const FormatString &fmt, Args&&...args)
-    {
-        log(level::debug, fmt, std::forward<Args>(args)...);
-    }
-
-    template<typename FormatString, typename... Args>
-    void info(const FormatString &fmt, Args&&...args)
-    {
-        log(level::info, fmt, std::forward<Args>(args)...);
-    }
-
-    template<typename FormatString, typename... Args>
-    void warn(const FormatString &fmt, Args&&...args)
-    {
-        log(level::warn, fmt, std::forward<Args>(args)...);
-    }
-
-    template<typename FormatString, typename... Args>
-    void error(const FormatString &fmt, Args&&...args)
-    {
-        log(level::err, fmt, std::forward<Args>(args)...);
-    }
-
-    template<typename FormatString, typename... Args>
-    void critical(const FormatString &fmt, Args&&...args)
-    {
-        log(level::critical, fmt, std::forward<Args>(args)...);
-    }
-
     template<typename T>
     void log(level::level_enum lvl, const T &msg)
     {
         log(source_loc{}, lvl, msg);
     }
 
-    // T can be statically converted to string_view and isn't a fmt::compile_string
-    template<class T, typename std::enable_if<
-                          std::is_convertible<const T &, spdlog::string_view_t>::value && !fmt::is_compile_string<T>::value, int>::type = 0>
+    // T cannot be statically converted to format string (including string_view/wstring_view)
+    template<class T, typename std::enable_if<!is_convertible_to_any_format_string<const T &>::value, int>::type = 0>
     void log(source_loc loc, level::level_enum lvl, const T &msg)
     {
-        log(loc, lvl, string_view_t{msg});
+        log(loc, lvl, "{}", msg);
     }
 
     void log(log_clock::time_point log_time, source_loc loc, level::level_enum lvl, string_view_t msg)
@@ -174,15 +140,127 @@ public:
         log(source_loc{}, lvl, msg);
     }
 
-    // T cannot be statically converted to string_view or wstring_view
-    template<class T, typename std::enable_if<!std::is_convertible<const T &, spdlog::string_view_t>::value &&
-                                                  !is_convertible_to_wstring_view<const T &>::value,
-                          int>::type = 0>
-    void log(source_loc loc, level::level_enum lvl, const T &msg)
+    template<typename... Args>
+    void trace(format_string_t<Args...> fmt, Args &&...args)
     {
-        log(loc, lvl, "{}", msg);
+        log(level::trace, fmt, std::forward<Args>(args)...);
     }
 
+    template<typename... Args>
+    void debug(format_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::debug, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void info(format_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::info, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void warn(format_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::warn, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void error(format_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::err, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void critical(format_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::critical, fmt, std::forward<Args>(args)...);
+    }
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+    template<typename... Args>
+    void log(source_loc loc, level::level_enum lvl, wformat_string_t<Args...> fmt, Args &&...args)
+    {
+        log_(loc, lvl, details::to_string_view(fmt), std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void log(level::level_enum lvl, wformat_string_t<Args...> fmt, Args &&...args)
+    {
+        log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
+    }
+
+    void log(log_clock::time_point log_time, source_loc loc, level::level_enum lvl, wstring_view_t msg)
+    {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled)
+        {
+            return;
+        }
+
+        memory_buf_t buf;
+        details::os::wstr_to_utf8buf(wstring_view_t(msg.data(), msg.size()), buf);
+        details::log_msg log_msg(log_time, loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+        log_it_(log_msg, log_enabled, traceback_enabled);
+    }
+
+    void log(source_loc loc, level::level_enum lvl, wstring_view_t msg)
+    {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled)
+        {
+            return;
+        }
+
+        memory_buf_t buf;
+        details::os::wstr_to_utf8buf(wstring_view_t(msg.data(), msg.size()), buf);
+        details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+        log_it_(log_msg, log_enabled, traceback_enabled);
+    }
+
+    void log(level::level_enum lvl, wstring_view_t msg)
+    {
+        log(source_loc{}, lvl, msg);
+    }
+
+    template<typename... Args>
+    void trace(wformat_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::trace, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void debug(wformat_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::debug, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void info(wformat_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::info, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void warn(wformat_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::warn, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void error(wformat_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::err, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void critical(wformat_string_t<Args...> fmt, Args &&...args)
+    {
+        log(level::critical, fmt, std::forward<Args>(args)...);
+    }
+#endif
+
     template<typename T>
     void trace(const T &msg)
     {
@@ -219,57 +297,6 @@ public:
         log(level::critical, msg);
     }
 
-#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
-#ifndef _WIN32
-#error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
-#else
-
-    template<typename... Args>
-    void log(source_loc loc, level::level_enum lvl, wstring_view_t fmt, Args&&...args)
-    {
-        bool log_enabled = should_log(lvl);
-        bool traceback_enabled = tracer_.enabled();
-        if (!log_enabled && !traceback_enabled)
-        {
-            return;
-        }
-        SPDLOG_TRY
-        {
-            // format to wmemory_buffer and convert to utf8
-            fmt::wmemory_buffer wbuf;
-            fmt::format_to(wbuf, fmt, std::forward<Args>(args)...);
-
-            memory_buf_t buf;
-            details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
-            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
-            log_it_(log_msg, log_enabled, traceback_enabled);
-        }
-        SPDLOG_LOGGER_CATCH()
-    }
-
-    // T can be statically converted to wstring_view
-    template<class T, typename std::enable_if<is_convertible_to_wstring_view<const T &>::value, int>::type = 0>
-    void log(source_loc loc, level::level_enum lvl, const T &msg)
-    {
-        bool log_enabled = should_log(lvl);
-        bool traceback_enabled = tracer_.enabled();
-        if (!log_enabled && !traceback_enabled)
-        {
-            return;
-        }
-
-        SPDLOG_TRY
-        {
-            memory_buf_t buf;
-            details::os::wstr_to_utf8buf(msg, buf);
-            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
-            log_it_(log_msg, log_enabled, traceback_enabled);
-        }
-        SPDLOG_LOGGER_CATCH()
-    }
-#endif // _WIN32
-#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
-
     // return true logging is enabled for the given level.
     bool should_log(level::level_enum msg_level) const
     {
@@ -292,6 +319,10 @@ public:
     // each sink will get a separate instance of the formatter object.
     void set_formatter(std::unique_ptr<formatter> f);
 
+    // set formatting for the sinks in this logger.
+    // equivalent to
+    //     set_formatter(make_unique<pattern_formatter>(pattern, time_type))
+    // Note: each sink will get a new instance of a formatter object, replacing the old one.
     void set_pattern(std::string pattern, pattern_time_type time_type = pattern_time_type::local);
 
     // backtrace support.
@@ -325,8 +356,8 @@ protected:
     details::backtracer tracer_;
 
     // common implementation for after templated public api has been resolved
-    template<typename FormatString, typename... Args>
-    void log_(source_loc loc, level::level_enum lvl, const FormatString &fmt, Args&&...args)
+    template<typename... Args>
+    void log_(source_loc loc, level::level_enum lvl, string_view_t fmt, Args &&...args)
     {
         bool log_enabled = should_log(lvl);
         bool traceback_enabled = tracer_.enabled();
@@ -337,13 +368,43 @@ protected:
         SPDLOG_TRY
         {
             memory_buf_t buf;
-            fmt::format_to(buf, fmt, std::forward<Args>(args)...);
+#ifdef SPDLOG_USE_STD_FORMAT
+            fmt_lib::vformat_to(std::back_inserter(buf), fmt, fmt_lib::make_format_args(args...));
+#else
+            fmt::vformat_to(fmt::appender(buf), fmt, fmt::make_format_args(args...));
+#endif
+
             details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
             log_it_(log_msg, log_enabled, traceback_enabled);
         }
-        SPDLOG_LOGGER_CATCH()
+        SPDLOG_LOGGER_CATCH(loc)
     }
 
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+    template<typename... Args>
+    void log_(source_loc loc, level::level_enum lvl, wstring_view_t fmt, Args &&...args)
+    {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled)
+        {
+            return;
+        }
+        SPDLOG_TRY
+        {
+            // format to wmemory_buffer and convert to utf8
+            wmemory_buf_t wbuf;
+            fmt_lib::vformat_to(std::back_inserter(wbuf), fmt, fmt_lib::make_format_args<fmt_lib::wformat_context>(args...));
+
+            memory_buf_t buf;
+            details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
+            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+            log_it_(log_msg, log_enabled, traceback_enabled);
+        }
+        SPDLOG_LOGGER_CATCH(loc)
+    }
+#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
     // log the given message (if the given log level is high enough),
     // and save backtrace (if backtrace is enabled).
     void log_it_(const details::log_msg &log_msg, bool log_enabled, bool traceback_enabled);
@@ -362,5 +423,5 @@ void swap(logger &a, logger &b);
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "logger-inl.h"
+#    include "logger-inl.h"
 #endif

include/spdlog/pattern_formatter-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/pattern_formatter.h>
+#    include <spdlog/pattern_formatter.h>
 #endif
 
 #include <spdlog/details/fmt_helper.h>
@@ -766,6 +766,7 @@ public:
     {
         if (msg.source.empty())
         {
+            ScopedPadder p(0, padinfo_, dest);
             return;
         }
 
@@ -800,6 +801,7 @@ public:
     {
         if (msg.source.empty())
         {
+            ScopedPadder p(0, padinfo_, dest);
             return;
         }
         size_t text_size = padinfo_.enabled() ? std::char_traits<char>::length(msg.source.filename) : 0;
@@ -817,9 +819,9 @@ public:
     {}
 
 #ifdef _MSC_VER
-#pragma warning(push)
-#pragma warning(disable : 4127) // consider using 'if constexpr' instead
-#endif // _MSC_VER
+#    pragma warning(push)
+#    pragma warning(disable : 4127) // consider using 'if constexpr' instead
+#endif                              // _MSC_VER
     static const char *basename(const char *filename)
     {
         // if the size is 2 (1 character + null terminator) we can use the more efficient strrchr
@@ -831,21 +833,22 @@ public:
         }
         else
         {
-            const std::reverse_iterator<const char*> begin(filename + std::strlen(filename));
-            const std::reverse_iterator<const char*> end(filename);
+            const std::reverse_iterator<const char *> begin(filename + std::strlen(filename));
+            const std::reverse_iterator<const char *> end(filename);
 
             const auto it = std::find_first_of(begin, end, std::begin(os::folder_seps), std::end(os::folder_seps) - 1);
             return it != end ? it.base() : filename;
         }
     }
 #ifdef _MSC_VER
-#pragma warning(pop)
+#    pragma warning(pop)
 #endif // _MSC_VER
 
     void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
     {
         if (msg.source.empty())
         {
+            ScopedPadder p(0, padinfo_, dest);
             return;
         }
         auto filename = basename(msg.source.filename);
@@ -867,6 +870,7 @@ public:
     {
         if (msg.source.empty())
         {
+            ScopedPadder p(0, padinfo_, dest);
             return;
         }
 
@@ -889,6 +893,7 @@ public:
     {
         if (msg.source.empty())
         {
+            ScopedPadder p(0, padinfo_, dest);
             return;
         }
         size_t text_size = padinfo_.enabled() ? std::char_traits<char>::length(msg.source.funcname) : 0;
@@ -925,7 +930,7 @@ private:
 };
 
 // Full info formatter
-// pattern: [%Y-%m-%d %H:%M:%S.%e] [%n] [%l] %v
+// pattern: [%Y-%m-%d %H:%M:%S.%e] [%n] [%l] [%s:%#] %v
 class full_formatter final : public flag_formatter
 {
 public:
@@ -1019,6 +1024,7 @@ SPDLOG_INLINE pattern_formatter::pattern_formatter(
     : pattern_(std::move(pattern))
     , eol_(std::move(eol))
     , pattern_time_type_(time_type)
+    , need_localtime_(false)
     , last_log_secs_(0)
     , custom_handlers_(std::move(custom_user_flags))
 {
@@ -1031,6 +1037,7 @@ SPDLOG_INLINE pattern_formatter::pattern_formatter(pattern_time_type time_type,
     : pattern_("%+")
     , eol_(std::move(eol))
     , pattern_time_type_(time_type)
+    , need_localtime_(true)
     , last_log_secs_(0)
 {
     std::memset(&cached_tm_, 0, sizeof(cached_tm_));
@@ -1044,16 +1051,25 @@ SPDLOG_INLINE std::unique_ptr<formatter> pattern_formatter::clone() const
     {
         cloned_custom_formatters[it.first] = it.second->clone();
     }
-    return details::make_unique<pattern_formatter>(pattern_, pattern_time_type_, eol_, std::move(cloned_custom_formatters));
+    auto cloned = details::make_unique<pattern_formatter>(pattern_, pattern_time_type_, eol_, std::move(cloned_custom_formatters));
+    cloned->need_localtime(need_localtime_);
+#if defined(__GNUC__) && __GNUC__ < 5
+    return std::move(cloned);
+#else
+    return cloned;
+#endif
 }
 
 SPDLOG_INLINE void pattern_formatter::format(const details::log_msg &msg, memory_buf_t &dest)
 {
-    auto secs = std::chrono::duration_cast<std::chrono::seconds>(msg.time.time_since_epoch());
-    if (secs != last_log_secs_)
+    if (need_localtime_)
     {
-        cached_tm_ = get_time_(msg);
-        last_log_secs_ = secs;
+        const auto secs = std::chrono::duration_cast<std::chrono::seconds>(msg.time.time_since_epoch());
+        if (secs != last_log_secs_)
+        {
+            cached_tm_ = get_time_(msg);
+            last_log_secs_ = secs;
+        }
     }
 
     for (auto &f : formatters_)
@@ -1067,9 +1083,15 @@ SPDLOG_INLINE void pattern_formatter::format(const details::log_msg &msg, memory
 SPDLOG_INLINE void pattern_formatter::set_pattern(std::string pattern)
 {
     pattern_ = std::move(pattern);
+    need_localtime_ = false;
     compile_pattern_(pattern_);
 }
 
+SPDLOG_INLINE void pattern_formatter::need_localtime(bool need)
+{
+    need_localtime_ = need;
+}
+
 SPDLOG_INLINE std::tm pattern_formatter::get_time_(const details::log_msg &msg)
 {
     if (pattern_time_type_ == pattern_time_type::local)
@@ -1097,6 +1119,7 @@ SPDLOG_INLINE void pattern_formatter::handle_flag_(char flag, details::padding_i
     {
     case ('+'): // default formatter
         formatters_.push_back(details::make_unique<details::full_formatter>(padding));
+        need_localtime_ = true;
         break;
 
     case 'n': // logger name
@@ -1121,60 +1144,74 @@ SPDLOG_INLINE void pattern_formatter::handle_flag_(char flag, details::padding_i
 
     case ('a'): // weekday
         formatters_.push_back(details::make_unique<details::a_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('A'): // short weekday
         formatters_.push_back(details::make_unique<details::A_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('b'):
     case ('h'): // month
         formatters_.push_back(details::make_unique<details::b_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('B'): // short month
         formatters_.push_back(details::make_unique<details::B_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('c'): // datetime
         formatters_.push_back(details::make_unique<details::c_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('C'): // year 2 digits
         formatters_.push_back(details::make_unique<details::C_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('Y'): // year 4 digits
         formatters_.push_back(details::make_unique<details::Y_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('D'):
     case ('x'): // datetime MM/DD/YY
         formatters_.push_back(details::make_unique<details::D_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('m'): // month 1-12
         formatters_.push_back(details::make_unique<details::m_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('d'): // day of month 1-31
         formatters_.push_back(details::make_unique<details::d_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('H'): // hours 24
         formatters_.push_back(details::make_unique<details::H_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('I'): // hours 12
         formatters_.push_back(details::make_unique<details::I_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('M'): // minutes
         formatters_.push_back(details::make_unique<details::M_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('S'): // seconds
         formatters_.push_back(details::make_unique<details::S_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('e'): // milliseconds
@@ -1195,23 +1232,28 @@ SPDLOG_INLINE void pattern_formatter::handle_flag_(char flag, details::padding_i
 
     case ('p'): // am/pm
         formatters_.push_back(details::make_unique<details::p_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('r'): // 12 hour clock 02:55:02 pm
         formatters_.push_back(details::make_unique<details::r_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('R'): // 24-hour HH:MM time
         formatters_.push_back(details::make_unique<details::R_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('T'):
     case ('X'): // ISO 8601 time format (HH:MM:SS)
         formatters_.push_back(details::make_unique<details::T_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('z'): // timezone
         formatters_.push_back(details::make_unique<details::z_formatter<Padder>>(padding));
+        need_localtime_ = true;
         break;
 
     case ('P'): // pid
@@ -1342,7 +1384,6 @@ SPDLOG_INLINE details::padding_info pattern_formatter::handle_padspec_(std::stri
     {
         truncate = false;
     }
-
     return details::padding_info{std::min<size_t>(width, max_width), side, truncate};
 }
 

include/spdlog/pattern_formatter.h

@@ -68,7 +68,7 @@ class SPDLOG_API custom_flag_formatter : public details::flag_formatter
 public:
     virtual std::unique_ptr<custom_flag_formatter> clone() const = 0;
 
-    void set_padding_info(details::padding_info padding)
+    void set_padding_info(const details::padding_info &padding)
     {
         flag_formatter::padinfo_ = padding;
     }
@@ -92,17 +92,19 @@ public:
     void format(const details::log_msg &msg, memory_buf_t &dest) override;
 
     template<typename T, typename... Args>
-    pattern_formatter &add_flag(char flag, Args&&...args)
+    pattern_formatter &add_flag(char flag, Args &&...args)
     {
         custom_handlers_[flag] = details::make_unique<T>(std::forward<Args>(args)...);
         return *this;
     }
     void set_pattern(std::string pattern);
+    void need_localtime(bool need = true);
 
 private:
     std::string pattern_;
     std::string eol_;
     pattern_time_type pattern_time_type_;
+    bool need_localtime_;
     std::tm cached_tm_;
     std::chrono::seconds last_log_secs_;
     std::vector<std::unique_ptr<details::flag_formatter>> formatters_;
@@ -122,5 +124,5 @@ private:
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "pattern_formatter-inl.h"
+#    include "pattern_formatter-inl.h"
 #endif

include/spdlog/sinks/android_sink.h

@@ -5,29 +5,31 @@
 
 #ifdef __ANDROID__
 
-#include <spdlog/details/fmt_helper.h>
-#include <spdlog/details/null_mutex.h>
-#include <spdlog/details/os.h>
-#include <spdlog/sinks/base_sink.h>
-#include <spdlog/details/synchronous_factory.h>
+#    include <spdlog/details/fmt_helper.h>
+#    include <spdlog/details/null_mutex.h>
+#    include <spdlog/details/os.h>
+#    include <spdlog/sinks/base_sink.h>
+#    include <spdlog/details/synchronous_factory.h>
 
-#include <android/log.h>
-#include <chrono>
-#include <mutex>
-#include <string>
-#include <thread>
+#    include <android/log.h>
+#    include <chrono>
+#    include <mutex>
+#    include <string>
+#    include <thread>
+#    include <type_traits>
 
-#if !defined(SPDLOG_ANDROID_RETRIES)
-#define SPDLOG_ANDROID_RETRIES 2
-#endif
+#    if !defined(SPDLOG_ANDROID_RETRIES)
+#        define SPDLOG_ANDROID_RETRIES 2
+#    endif
 
 namespace spdlog {
 namespace sinks {
 
 /*
- * Android sink (logging using __android_log_write)
+ * Android sink
+ * (logging using __android_log_write or __android_log_buf_write depending on the specified BufferID)
  */
-template<typename Mutex>
+template<typename Mutex, int BufferID = log_id::LOG_ID_MAIN>
 class android_sink final : public base_sink<Mutex>
 {
 public:
@@ -53,24 +55,43 @@ protected:
         const char *msg_output = formatted.data();
 
         // See system/core/liblog/logger_write.c for explanation of return value
-        int ret = __android_log_write(priority, tag_.c_str(), msg_output);
+        int ret = android_log(priority, tag_.c_str(), msg_output);
+        if (ret == -EPERM)
+        {
+            return; // !__android_log_is_loggable
+        }
         int retry_count = 0;
         while ((ret == -11 /*EAGAIN*/) && (retry_count < SPDLOG_ANDROID_RETRIES))
         {
             details::os::sleep_for_millis(5);
-            ret = __android_log_write(priority, tag_.c_str(), msg_output);
+            ret = android_log(priority, tag_.c_str(), msg_output);
             retry_count++;
         }
 
         if (ret < 0)
         {
-            throw_spdlog_ex("__android_log_write() failed", ret);
+            throw_spdlog_ex("logging to Android failed", ret);
         }
     }
 
     void flush_() override {}
 
 private:
+    // There might be liblog versions used, that do not support __android_log_buf_write. So we only compile and link against
+    // __android_log_buf_write, if user explicitly provides a non-default log buffer. Otherwise, when using the default log buffer, always
+    // log via __android_log_write.
+    template<int ID = BufferID>
+    typename std::enable_if<ID == static_cast<int>(log_id::LOG_ID_MAIN), int>::type android_log(int prio, const char *tag, const char *text)
+    {
+        return __android_log_write(prio, tag, text);
+    }
+
+    template<int ID = BufferID>
+    typename std::enable_if<ID != static_cast<int>(log_id::LOG_ID_MAIN), int>::type android_log(int prio, const char *tag, const char *text)
+    {
+        return __android_log_buf_write(ID, prio, tag, text);
+    }
+
     static android_LogPriority convert_to_android_(spdlog::level::level_enum level)
     {
         switch (level)
@@ -98,6 +119,12 @@ private:
 
 using android_sink_mt = android_sink<std::mutex>;
 using android_sink_st = android_sink<details::null_mutex>;
+
+template<int BufferId = log_id::LOG_ID_MAIN>
+using android_sink_buf_mt = android_sink<std::mutex, BufferId>;
+template<int BufferId = log_id::LOG_ID_MAIN>
+using android_sink_buf_st = android_sink<details::null_mutex, BufferId>;
+
 } // namespace sinks
 
 // Create and register android syslog logger
@@ -116,4 +143,4 @@ inline std::shared_ptr<logger> android_logger_st(const std::string &logger_name,
 
 } // namespace spdlog
 
-#endif // __ANDROID__
+#endif // __ANDROID__

include/spdlog/sinks/ansicolor_sink-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/sinks/ansicolor_sink.h>
+#    include <spdlog/sinks/ansicolor_sink.h>
 #endif
 
 #include <spdlog/pattern_formatter.h>
@@ -21,20 +21,20 @@ SPDLOG_INLINE ansicolor_sink<ConsoleMutex>::ansicolor_sink(FILE *target_file, co
 
 {
     set_color_mode(mode);
-    colors_[level::trace] = to_string_(white);
-    colors_[level::debug] = to_string_(cyan);
-    colors_[level::info] = to_string_(green);
-    colors_[level::warn] = to_string_(yellow_bold);
-    colors_[level::err] = to_string_(red_bold);
-    colors_[level::critical] = to_string_(bold_on_red);
-    colors_[level::off] = to_string_(reset);
+    colors_.at(level::trace) = to_string_(white);
+    colors_.at(level::debug) = to_string_(cyan);
+    colors_.at(level::info) = to_string_(green);
+    colors_.at(level::warn) = to_string_(yellow_bold);
+    colors_.at(level::err) = to_string_(red_bold);
+    colors_.at(level::critical) = to_string_(bold_on_red);
+    colors_.at(level::off) = to_string_(reset);
 }
 
 template<typename ConsoleMutex>
 SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_color(level::level_enum color_level, string_view_t color)
 {
     std::lock_guard<mutex_t> lock(mutex_);
-    colors_[color_level] = to_string_(color);
+    colors_.at(static_cast<size_t>(color_level)) = to_string_(color);
 }
 
 template<typename ConsoleMutex>
@@ -52,7 +52,7 @@ SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::log(const details::log_msg &msg
         // before color range
         print_range_(formatted, 0, msg.color_range_start);
         // in color range
-        print_ccode_(colors_[msg.level]);
+        print_ccode_(colors_.at(static_cast<size_t>(msg.level)));
         print_range_(formatted, msg.color_range_start, msg.color_range_end);
         print_ccode_(reset);
         // after color range

include/spdlog/sinks/ansicolor_sink.h

@@ -114,5 +114,5 @@ using ansicolor_stderr_sink_st = ansicolor_stderr_sink<details::console_nullmute
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "ansicolor_sink-inl.h"
+#    include "ansicolor_sink-inl.h"
 #endif

include/spdlog/sinks/base_sink-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/sinks/base_sink.h>
+#    include <spdlog/sinks/base_sink.h>
 #endif
 
 #include <spdlog/common.h>

include/spdlog/sinks/base_sink.h

@@ -16,7 +16,7 @@
 namespace spdlog {
 namespace sinks {
 template<typename Mutex>
-class base_sink : public sink
+class SPDLOG_API base_sink : public sink
 {
 public:
     base_sink();
@@ -48,5 +48,5 @@ protected:
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "base_sink-inl.h"
+#    include "base_sink-inl.h"
 #endif

include/spdlog/sinks/basic_file_sink-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/sinks/basic_file_sink.h>
+#    include <spdlog/sinks/basic_file_sink.h>
 #endif
 
 #include <spdlog/common.h>
@@ -14,7 +14,8 @@ namespace spdlog {
 namespace sinks {
 
 template<typename Mutex>
-SPDLOG_INLINE basic_file_sink<Mutex>::basic_file_sink(const filename_t &filename, bool truncate)
+SPDLOG_INLINE basic_file_sink<Mutex>::basic_file_sink(const filename_t &filename, bool truncate, const file_event_handlers &event_handlers)
+    : file_helper_{event_handlers}
 {
     file_helper_.open(filename, truncate);
 }

include/spdlog/sinks/basic_file_sink.h

@@ -20,7 +20,7 @@ template<typename Mutex>
 class basic_file_sink final : public base_sink<Mutex>
 {
 public:
-    explicit basic_file_sink(const filename_t &filename, bool truncate = false);
+    explicit basic_file_sink(const filename_t &filename, bool truncate = false, const file_event_handlers &event_handlers = {});
     const filename_t &filename() const;
 
 protected:
@@ -40,19 +40,21 @@ using basic_file_sink_st = basic_file_sink<details::null_mutex>;
 // factory functions
 //
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> basic_logger_mt(const std::string &logger_name, const filename_t &filename, bool truncate = false)
+inline std::shared_ptr<logger> basic_logger_mt(
+    const std::string &logger_name, const filename_t &filename, bool truncate = false, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::basic_file_sink_mt>(logger_name, filename, truncate);
+    return Factory::template create<sinks::basic_file_sink_mt>(logger_name, filename, truncate, event_handlers);
 }
 
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> basic_logger_st(const std::string &logger_name, const filename_t &filename, bool truncate = false)
+inline std::shared_ptr<logger> basic_logger_st(
+    const std::string &logger_name, const filename_t &filename, bool truncate = false, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::basic_file_sink_st>(logger_name, filename, truncate);
+    return Factory::template create<sinks::basic_file_sink_st>(logger_name, filename, truncate, event_handlers);
 }
 
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "basic_file_sink-inl.h"
-#endif
+#    include "basic_file_sink-inl.h"
+#endif

include/spdlog/sinks/callback_sink.h

@@ -0,0 +1,61 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <mutex>
+#include <string>
+
+namespace spdlog {
+
+// callbacks type
+typedef std::function<void(const details::log_msg &msg)> custom_log_callback;
+
+namespace sinks {
+/*
+ * Trivial callback sink, gets a callback function and calls it on each log
+ */
+template<typename Mutex>
+class callback_sink final : public base_sink<Mutex>
+{
+public:
+    explicit callback_sink(const custom_log_callback &callback)
+        : callback_{callback}
+    {}
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        callback_(msg);
+    }
+    void flush_() override{};
+
+private:
+    custom_log_callback callback_;
+};
+
+using callback_sink_mt = callback_sink<std::mutex>;
+using callback_sink_st = callback_sink<details::null_mutex>;
+
+} // namespace sinks
+
+//
+// factory functions
+//
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> callback_logger_mt(const std::string &logger_name, const custom_log_callback &callback)
+{
+    return Factory::template create<sinks::callback_sink_mt>(logger_name, callback);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> callback_logger_st(const std::string &logger_name, const custom_log_callback &callback)
+{
+    return Factory::template create<sinks::callback_sink_st>(logger_name, callback);
+}
+
+} // namespace spdlog

include/spdlog/sinks/daily_file_sink.h

@@ -13,9 +13,10 @@
 #include <spdlog/details/circular_q.h>
 #include <spdlog/details/synchronous_factory.h>
 
+#include <sstream>
+#include <iomanip>
 #include <chrono>
 #include <cstdio>
-#include <ctime>
 #include <mutex>
 #include <string>
 
@@ -32,25 +33,29 @@ struct daily_filename_calculator
     {
         filename_t basename, ext;
         std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
-        return fmt::format(
-            SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}{}"), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1, now_tm.tm_mday, ext);
+        return fmt_lib::format(SPDLOG_FMT_STRING(SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}{}")), basename, now_tm.tm_year + 1900,
+            now_tm.tm_mon + 1, now_tm.tm_mday, ext);
     }
 };
 
 /*
  * Generator of daily log file names with strftime format.
- * Usages:  
+ * Usages:
  *    auto sink =  std::make_shared<spdlog::sinks::daily_file_format_sink_mt>("myapp-%Y-%m-%d:%H:%M:%S.log", hour, minute);"
  *    auto logger = spdlog::daily_logger_format_mt("loggername, "myapp-%Y-%m-%d:%X.log", hour,  minute)"
- *  
+ *
  */
 struct daily_filename_format_calculator
 {
-    static filename_t calc_filename (const filename_t &filename, const tm &now_tm)
+    static filename_t calc_filename(const filename_t &file_path, const tm &now_tm)
     {
-         // generate fmt datetime format string, e.g. {:%Y-%m-%d}.
-        filename_t fmt_filename = fmt::format(SPDLOG_FILENAME_T ("{{:{}}}"), filename);
-        return fmt::format(fmt_filename, now_tm);
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+        std::wstringstream stream;
+#else
+        std::stringstream stream;
+#endif
+        stream << std::put_time(&now_tm, file_path.c_str());
+        return stream.str();
     }
 };
 
@@ -64,10 +69,12 @@ class daily_file_sink final : public base_sink<Mutex>
 {
 public:
     // create daily file sink which rotates on given time
-    daily_file_sink(filename_t base_filename, int rotation_hour, int rotation_minute, bool truncate = false, uint16_t max_files = 0)
+    daily_file_sink(filename_t base_filename, int rotation_hour, int rotation_minute, bool truncate = false, uint16_t max_files = 0,
+        const file_event_handlers &event_handlers = {})
         : base_filename_(std::move(base_filename))
         , rotation_h_(rotation_hour)
         , rotation_m_(rotation_minute)
+        , file_helper_{event_handlers}
         , truncate_(truncate)
         , max_files_(max_files)
         , filenames_q_()
@@ -209,30 +216,32 @@ using daily_file_format_sink_st = daily_file_sink<details::null_mutex, daily_fil
 // factory functions
 //
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> daily_logger_mt(
-    const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0, bool truncate = false, uint16_t max_files = 0)
+inline std::shared_ptr<logger> daily_logger_mt(const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0,
+    bool truncate = false, uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::daily_file_sink_mt>(logger_name, filename, hour, minute, truncate, max_files);
+    return Factory::template create<sinks::daily_file_sink_mt>(logger_name, filename, hour, minute, truncate, max_files, event_handlers);
 }
 
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> daily_logger_format_mt(
-    const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0, bool truncate = false, uint16_t max_files = 0)
+inline std::shared_ptr<logger> daily_logger_format_mt(const std::string &logger_name, const filename_t &filename, int hour = 0,
+    int minute = 0, bool truncate = false, uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::daily_file_format_sink_mt>(logger_name, filename, hour, minute, truncate, max_files);
+    return Factory::template create<sinks::daily_file_format_sink_mt>(
+        logger_name, filename, hour, minute, truncate, max_files, event_handlers);
 }
 
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> daily_logger_st(
-    const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0, bool truncate = false, uint16_t max_files = 0)
+inline std::shared_ptr<logger> daily_logger_st(const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0,
+    bool truncate = false, uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::daily_file_sink_st>(logger_name, filename, hour, minute, truncate, max_files);
+    return Factory::template create<sinks::daily_file_sink_st>(logger_name, filename, hour, minute, truncate, max_files, event_handlers);
 }
 
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> daily_logger_format_st(
-    const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0, bool truncate = false, uint16_t max_files = 0)
+inline std::shared_ptr<logger> daily_logger_format_st(const std::string &logger_name, const filename_t &filename, int hour = 0,
+    int minute = 0, bool truncate = false, uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::daily_file_format_sink_st>(logger_name, filename, hour, minute, truncate, max_files);
+    return Factory::template create<sinks::daily_file_format_sink_st>(
+        logger_name, filename, hour, minute, truncate, max_files, event_handlers);
 }
 } // namespace spdlog

include/spdlog/sinks/dist_sink.h

@@ -31,16 +31,16 @@ public:
     dist_sink(const dist_sink &) = delete;
     dist_sink &operator=(const dist_sink &) = delete;
 
-    void add_sink(std::shared_ptr<sink> sink)
+    void add_sink(std::shared_ptr<sink> sub_sink)
     {
         std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
-        sinks_.push_back(sink);
+        sinks_.push_back(sub_sink);
     }
 
-    void remove_sink(std::shared_ptr<sink> sink)
+    void remove_sink(std::shared_ptr<sink> sub_sink)
     {
         std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
-        sinks_.erase(std::remove(sinks_.begin(), sinks_.end(), sink), sinks_.end());
+        sinks_.erase(std::remove(sinks_.begin(), sinks_.end(), sub_sink), sinks_.end());
     }
 
     void set_sinks(std::vector<std::shared_ptr<sink>> sinks)
@@ -57,20 +57,20 @@ public:
 protected:
     void sink_it_(const details::log_msg &msg) override
     {
-        for (auto &sink : sinks_)
+        for (auto &sub_sink : sinks_)
         {
-            if (sink->should_log(msg.level))
+            if (sub_sink->should_log(msg.level))
             {
-                sink->log(msg);
+                sub_sink->log(msg);
             }
         }
     }
 
     void flush_() override
     {
-        for (auto &sink : sinks_)
+        for (auto &sub_sink : sinks_)
         {
-            sink->flush();
+            sub_sink->flush();
         }
     }
 
@@ -82,9 +82,9 @@ protected:
     void set_formatter_(std::unique_ptr<spdlog::formatter> sink_formatter) override
     {
         base_sink<Mutex>::formatter_ = std::move(sink_formatter);
-        for (auto &sink : sinks_)
+        for (auto &sub_sink : sinks_)
         {
-            sink->set_formatter(base_sink<Mutex>::formatter_->clone());
+            sub_sink->set_formatter(base_sink<Mutex>::formatter_->clone());
         }
     }
     std::vector<std::shared_ptr<sink>> sinks_;

include/spdlog/sinks/dup_filter_sink.h

@@ -7,6 +7,7 @@
 #include <spdlog/details/null_mutex.h>
 #include <spdlog/details/log_msg.h>
 
+#include <cstdio>
 #include <mutex>
 #include <string>
 #include <chrono>
@@ -19,7 +20,7 @@
 //     #include <spdlog/sinks/dup_filter_sink.h>
 //
 //     int main() {
-//         auto dup_filter = std::make_shared<dup_filter_sink_st>(std::chrono::seconds(5));
+//         auto dup_filter = std::make_shared<dup_filter_sink_st>(std::chrono::seconds(5), level::info);
 //         dup_filter->add_sink(std::make_shared<stdout_color_sink_mt>());
 //         spdlog::logger l("logger", dup_filter);
 //         l.info("Hello");
@@ -40,8 +41,9 @@ class dup_filter_sink : public dist_sink<Mutex>
 {
 public:
     template<class Rep, class Period>
-    explicit dup_filter_sink(std::chrono::duration<Rep, Period> max_skip_duration)
+    explicit dup_filter_sink(std::chrono::duration<Rep, Period> max_skip_duration, level::level_enum notification_level = level::info)
         : max_skip_duration_{max_skip_duration}
+        , log_level_{notification_level}
     {}
 
 protected:
@@ -49,6 +51,7 @@ protected:
     log_clock::time_point last_msg_time_;
     std::string last_msg_payload_;
     size_t skip_counter_ = 0;
+    level::level_enum log_level_;
 
     void sink_it_(const details::log_msg &msg) override
     {
@@ -62,10 +65,13 @@ protected:
         // log the "skipped.." message
         if (skip_counter_ > 0)
         {
-            memory_buf_t buf;
-            fmt::format_to(buf, "Skipped {} duplicate messages..", skip_counter_);
-            details::log_msg skipped_msg{msg.logger_name, level::info, string_view_t{buf.data(), buf.size()}};
-            dist_sink<Mutex>::sink_it_(skipped_msg);
+            char buf[64];
+            auto msg_size = ::snprintf(buf, sizeof(buf), "Skipped %u duplicate messages..", static_cast<unsigned>(skip_counter_));
+            if (msg_size > 0 && static_cast<size_t>(msg_size) < sizeof(buf))
+            {
+                details::log_msg skipped_msg{msg.source, msg.logger_name, log_level_, string_view_t{buf, static_cast<size_t>(msg_size)}};
+                dist_sink<Mutex>::sink_it_(skipped_msg);
+            }
         }
 
         // log current message

include/spdlog/sinks/hourly_file_sink.h

@@ -31,8 +31,8 @@ struct hourly_filename_calculator
     {
         filename_t basename, ext;
         std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
-        return fmt::format(
-            SPDLOG_FILENAME_T("{}_{:04d}{:02d}{:02d}_{:02d}{}"), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1, now_tm.tm_mday, now_tm.tm_hour, ext);
+        return fmt_lib::format(SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}_{:02d}{}"), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1,
+            now_tm.tm_mday, now_tm.tm_hour, ext);
     }
 };
 
@@ -46,8 +46,10 @@ class hourly_file_sink final : public base_sink<Mutex>
 {
 public:
     // create hourly file sink which rotates on given time
-    hourly_file_sink(filename_t base_filename, bool truncate = false, uint16_t max_files = 0)
+    hourly_file_sink(
+        filename_t base_filename, bool truncate = false, uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
         : base_filename_(std::move(base_filename))
+        , file_helper_{event_handlers}
         , truncate_(truncate)
         , max_files_(max_files)
         , filenames_q_()
@@ -55,6 +57,7 @@ public:
         auto now = log_clock::now();
         auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(now));
         file_helper_.open(filename, truncate_);
+        remove_init_file_ = file_helper_.size() == 0;
         rotation_tp_ = next_rotation_tp_();
 
         if (max_files_ > 0)
@@ -76,10 +79,16 @@ protected:
         bool should_rotate = time >= rotation_tp_;
         if (should_rotate)
         {
+            if (remove_init_file_)
+            {
+                file_helper_.close();
+                details::os::remove(file_helper_.filename());
+            }
             auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(time));
             file_helper_.open(filename, truncate_);
             rotation_tp_ = next_rotation_tp_();
         }
+        remove_init_file_ = false;
         memory_buf_t formatted;
         base_sink<Mutex>::formatter_->format(msg, formatted);
         file_helper_.write(formatted);
@@ -168,6 +177,7 @@ private:
     bool truncate_;
     uint16_t max_files_;
     details::circular_q<filename_t> filenames_q_;
+    bool remove_init_file_;
 };
 
 using hourly_file_sink_mt = hourly_file_sink<std::mutex>;
@@ -179,16 +189,16 @@ using hourly_file_sink_st = hourly_file_sink<details::null_mutex>;
 // factory functions
 //
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> hourly_logger_mt(
-    const std::string &logger_name, const filename_t &filename, bool truncate = false, uint16_t max_files = 0)
+inline std::shared_ptr<logger> hourly_logger_mt(const std::string &logger_name, const filename_t &filename, bool truncate = false,
+    uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::hourly_file_sink_mt>(logger_name, filename, truncate, max_files);
+    return Factory::template create<sinks::hourly_file_sink_mt>(logger_name, filename, truncate, max_files, event_handlers);
 }
 
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> hourly_logger_st(
-    const std::string &logger_name, const filename_t &filename, bool truncate = false, uint16_t max_files = 0)
+inline std::shared_ptr<logger> hourly_logger_st(const std::string &logger_name, const filename_t &filename, bool truncate = false,
+    uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::hourly_file_sink_st>(logger_name, filename, truncate, max_files);
+    return Factory::template create<sinks::hourly_file_sink_st>(logger_name, filename, truncate, max_files, event_handlers);
 }
 } // namespace spdlog

include/spdlog/sinks/kafka_sink.h

@@ -0,0 +1,133 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+//
+// Custom sink for kafka
+// Building and using requires librdkafka library.
+// For building librdkafka library check the url below
+// https://github.com/confluentinc/librdkafka
+//
+
+#include <spdlog/common.h>
+#include "spdlog/details/log_msg.h"
+#include "spdlog/sinks/base_sink.h"
+#include "spdlog/details/synchronous_factory.h"
+#include "spdlog/details/null_mutex.h"
+#include "spdlog/async.h"
+#include <mutex>
+
+// kafka header
+#include <librdkafka/rdkafkacpp.h>
+
+namespace spdlog {
+namespace sinks {
+
+struct kafka_sink_config
+{
+    std::string server_addr;
+    std::string produce_topic;
+    int32_t flush_timeout_ms = 1000;
+
+    kafka_sink_config(std::string addr, std::string topic, int flush_timeout_ms = 1000)
+        : server_addr{std::move(addr)}
+        , produce_topic{std::move(topic)}
+        , flush_timeout_ms(flush_timeout_ms)
+    {}
+};
+
+template<typename Mutex>
+class kafka_sink : public base_sink<Mutex>
+{
+public:
+    kafka_sink(kafka_sink_config config)
+        : config_{std::move(config)}
+    {
+        try
+        {
+            std::string errstr;
+            conf_.reset(RdKafka::Conf::create(RdKafka::Conf::CONF_GLOBAL));
+            RdKafka::Conf::ConfResult confRes = conf_->set("bootstrap.servers", config_.server_addr, errstr);
+            if (confRes != RdKafka::Conf::CONF_OK)
+            {
+                throw_spdlog_ex(fmt_lib::format("conf set bootstrap.servers failed err:{}", errstr));
+            }
+
+            tconf_.reset(RdKafka::Conf::create(RdKafka::Conf::CONF_TOPIC));
+            if (tconf_ == nullptr)
+            {
+                throw_spdlog_ex(fmt_lib::format("create topic config failed"));
+            }
+
+            producer_.reset(RdKafka::Producer::create(conf_.get(), errstr));
+            if (producer_ == nullptr)
+            {
+                throw_spdlog_ex(fmt_lib::format("create producer failed err:{}", errstr));
+            }
+            topic_.reset(RdKafka::Topic::create(producer_.get(), config_.produce_topic, tconf_.get(), errstr));
+            if (topic_ == nullptr)
+            {
+                throw_spdlog_ex(fmt_lib::format("create topic failed err:{}", errstr));
+            }
+        }
+        catch (const std::exception &e)
+        {
+            throw_spdlog_ex(fmt_lib::format("error create kafka instance: {}", e.what()));
+        }
+    }
+
+    ~kafka_sink()
+    {
+        producer_->flush(config_.flush_timeout_ms);
+    }
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        producer_->produce(topic_.get(), 0, RdKafka::Producer::RK_MSG_COPY, (void *)msg.payload.data(), msg.payload.size(), NULL, NULL);
+    }
+
+    void flush_() override
+    {
+        producer_->flush(config_.flush_timeout_ms);
+    }
+
+private:
+    kafka_sink_config config_;
+    std::unique_ptr<RdKafka::Producer> producer_ = nullptr;
+    std::unique_ptr<RdKafka::Conf> conf_ = nullptr;
+    std::unique_ptr<RdKafka::Conf> tconf_ = nullptr;
+    std::unique_ptr<RdKafka::Topic> topic_ = nullptr;
+};
+
+using kafka_sink_mt = kafka_sink<std::mutex>;
+using kafka_sink_st = kafka_sink<spdlog::details::null_mutex>;
+
+} // namespace sinks
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> kafka_logger_mt(const std::string &logger_name, spdlog::sinks::kafka_sink_config config)
+{
+    return Factory::template create<sinks::kafka_sink_mt>(logger_name, config);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> kafka_logger_st(const std::string &logger_name, spdlog::sinks::kafka_sink_config config)
+{
+    return Factory::template create<sinks::kafka_sink_st>(logger_name, config);
+}
+
+template<typename Factory = spdlog::async_factory>
+inline std::shared_ptr<spdlog::logger> kafka_logger_async_mt(std::string logger_name, spdlog::sinks::kafka_sink_config config)
+{
+    return Factory::template create<sinks::kafka_sink_mt>(logger_name, config);
+}
+
+template<typename Factory = spdlog::async_factory>
+inline std::shared_ptr<spdlog::logger> kafka_logger_async_st(std::string logger_name, spdlog::sinks::kafka_sink_config config)
+{
+    return Factory::template create<sinks::kafka_sink_st>(logger_name, config);
+}
+
+} // namespace spdlog

include/spdlog/sinks/mongo_sink.h

@@ -0,0 +1,107 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+//
+// Custom sink for mongodb
+// Building and using requires mongocxx library.
+// For building mongocxx library check the url below
+// http://mongocxx.org/mongocxx-v3/installation/
+//
+
+#include "spdlog/common.h"
+#include "spdlog/details/log_msg.h"
+#include "spdlog/sinks/base_sink.h"
+#include <spdlog/details/synchronous_factory.h>
+
+#include <bsoncxx/builder/stream/document.hpp>
+#include <bsoncxx/types.hpp>
+#include <bsoncxx/view_or_value.hpp>
+
+#include <mongocxx/client.hpp>
+#include <mongocxx/instance.hpp>
+#include <mongocxx/uri.hpp>
+
+namespace spdlog {
+namespace sinks {
+template<typename Mutex>
+class mongo_sink : public base_sink<Mutex>
+{
+public:
+    mongo_sink(const std::string &db_name, const std::string &collection_name, const std::string &uri = "mongodb://localhost:27017")
+    try : mongo_sink(std::make_shared<mongocxx::instance>(), db_name, collection_name, uri)
+    {}
+    catch (const std::exception &e)
+    {
+        throw_spdlog_ex(fmt_lib::format("Error opening database: {}", e.what()));
+    }
+
+    mongo_sink(std::shared_ptr<mongocxx::instance> instance, const std::string &db_name, const std::string &collection_name,
+        const std::string &uri = "mongodb://localhost:27017")
+        : instance_(std::move(instance))
+        , db_name_(db_name)
+        , coll_name_(collection_name)
+    {
+        try
+        {
+            client_ = spdlog::details::make_unique<mongocxx::client>(mongocxx::uri{uri});
+        }
+        catch (const std::exception &e)
+        {
+            throw_spdlog_ex(fmt_lib::format("Error opening database: {}", e.what()));
+        }
+    }
+
+    ~mongo_sink()
+    {
+        flush_();
+    }
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        using bsoncxx::builder::stream::document;
+        using bsoncxx::builder::stream::finalize;
+
+        if (client_ != nullptr)
+        {
+            auto doc = document{} << "timestamp" << bsoncxx::types::b_date(msg.time) << "level" << level::to_string_view(msg.level).data()
+                                  << "level_num" << msg.level << "message" << std::string(msg.payload.begin(), msg.payload.end())
+                                  << "logger_name" << std::string(msg.logger_name.begin(), msg.logger_name.end()) << "thread_id"
+                                  << static_cast<int>(msg.thread_id) << finalize;
+            client_->database(db_name_).collection(coll_name_).insert_one(doc.view());
+        }
+    }
+
+    void flush_() override {}
+
+private:
+    std::shared_ptr<mongocxx::instance> instance_;
+    std::string db_name_;
+    std::string coll_name_;
+    std::unique_ptr<mongocxx::client> client_ = nullptr;
+};
+
+#include "spdlog/details/null_mutex.h"
+#include <mutex>
+using mongo_sink_mt = mongo_sink<std::mutex>;
+using mongo_sink_st = mongo_sink<spdlog::details::null_mutex>;
+
+} // namespace sinks
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> mongo_logger_mt(const std::string &logger_name, const std::string &db_name,
+    const std::string &collection_name, const std::string &uri = "mongodb://localhost:27017")
+{
+    return Factory::template create<sinks::mongo_sink_mt>(logger_name, db_name, collection_name, uri);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> mongo_logger_st(const std::string &logger_name, const std::string &db_name,
+    const std::string &collection_name, const std::string &uri = "mongodb://localhost:27017")
+{
+    return Factory::template create<sinks::mongo_sink_st>(logger_name, db_name, collection_name, uri);
+}
+
+} // namespace spdlog

include/spdlog/sinks/msvc_sink.h

@@ -1,19 +1,26 @@
-// Copyright(c) 2016 Alexander Dalshov.
+// Copyright(c) 2016 Alexander Dalshov & spdlog contributors.
 // Distributed under the MIT License (http://opensource.org/licenses/MIT)
 
 #pragma once
 
 #if defined(_WIN32)
 
-#include <spdlog/details/null_mutex.h>
-#include <spdlog/sinks/base_sink.h>
-
-#include <mutex>
-#include <string>
+#    include <spdlog/details/null_mutex.h>
+#    if defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+#        include <spdlog/details/os.h>
+#    endif
+#    include <spdlog/sinks/base_sink.h>
 
+#    include <mutex>
+#    include <string>
 
 // Avoid including windows.h (https://stackoverflow.com/a/30741042)
+#    if defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+extern "C" __declspec(dllimport) void __stdcall OutputDebugStringW(const wchar_t *lpOutputString);
+#    else
 extern "C" __declspec(dllimport) void __stdcall OutputDebugStringA(const char *lpOutputString);
+#    endif
+extern "C" __declspec(dllimport) int __stdcall IsDebuggerPresent();
 
 namespace spdlog {
 namespace sinks {
@@ -25,16 +32,31 @@ class msvc_sink : public base_sink<Mutex>
 {
 public:
     msvc_sink() = default;
+    msvc_sink(bool check_debugger_present)
+        : check_debugger_present_{check_debugger_present} {};
 
 protected:
     void sink_it_(const details::log_msg &msg) override
     {
+        if (check_debugger_present_ && !IsDebuggerPresent())
+        {
+            return;
+        }
         memory_buf_t formatted;
         base_sink<Mutex>::formatter_->format(msg, formatted);
-        OutputDebugStringA(fmt::to_string(formatted).c_str());
+        formatted.push_back('\0'); // add a null terminator for OutputDebugString
+#    if defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+        wmemory_buf_t wformatted;
+        details::os::utf8_to_wstrbuf(string_view_t(formatted.data(), formatted.size()), wformatted);
+        OutputDebugStringW(wformatted.data());
+#    else
+        OutputDebugStringA(formatted.data());
+#    endif
     }
 
     void flush_() override {}
+
+    bool check_debugger_present_ = true;
 };
 
 using msvc_sink_mt = msvc_sink<std::mutex>;

include/spdlog/sinks/qt_sinks.h

@@ -0,0 +1,292 @@
+// Copyright(c) 2015-present, Gabi Melman, mguludag and spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+//
+// Custom sink for QPlainTextEdit or QTextEdit and its childs(QTextBrowser...
+// etc) Building and using requires Qt library.
+//
+// Warning: the qt_sink won't be notified if the target widget is destroyed.
+// If the widget's lifetime can be shorter than the logger's one, you should provide some permanent QObject,
+// and then use a standard signal/slot.
+//
+
+#include "spdlog/common.h"
+#include "spdlog/details/log_msg.h"
+#include "spdlog/details/synchronous_factory.h"
+#include "spdlog/sinks/base_sink.h"
+#include <array>
+
+#include <QTextEdit>
+#include <QPlainTextEdit>
+
+//
+// qt_sink class
+//
+namespace spdlog {
+namespace sinks {
+template<typename Mutex>
+class qt_sink : public base_sink<Mutex>
+{
+public:
+    qt_sink(QObject *qt_object, std::string meta_method)
+        : qt_object_(qt_object)
+        , meta_method_(std::move(meta_method))
+    {
+        if (!qt_object_)
+        {
+            throw_spdlog_ex("qt_sink: qt_object is null");
+        }
+    }
+
+    ~qt_sink()
+    {
+        flush_();
+    }
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        memory_buf_t formatted;
+        base_sink<Mutex>::formatter_->format(msg, formatted);
+        const string_view_t str = string_view_t(formatted.data(), formatted.size());
+        QMetaObject::invokeMethod(qt_object_, meta_method_.c_str(), Qt::AutoConnection,
+            Q_ARG(QString, QString::fromUtf8(str.data(), static_cast<int>(str.size())).trimmed()));
+    }
+
+    void flush_() override {}
+
+private:
+    QObject *qt_object_ = nullptr;
+    std::string meta_method_;
+};
+
+// QT color sink to QTextEdit.
+// Color location is determined by the sink log pattern like in the rest of spdlog sinks.
+// Colors can be modified if needed using sink->set_color(level, qtTextCharFormat).
+// max_lines is the maximum number of lines that the sink will hold before removing the oldest lines.
+// Note: Only ascii (latin1) is supported by this sink.
+template<typename Mutex>
+class qt_color_sink : public base_sink<Mutex>
+{
+public:
+    qt_color_sink(QTextEdit *qt_text_edit, int max_lines)
+        : qt_text_edit_(qt_text_edit)
+        , max_lines_(max_lines)
+    {
+        if (!qt_text_edit_)
+        {
+            throw_spdlog_ex("qt_color_text_sink: text_edit is null");
+        }
+
+        default_color_ = qt_text_edit_->currentCharFormat();
+        // set colors
+        QTextCharFormat format;
+        // trace
+        format.setForeground(Qt::gray);
+        colors_.at(level::trace) = format;
+        // debug
+        format.setForeground(Qt::cyan);
+        colors_.at(level::debug) = format;
+        // info
+        format.setForeground(Qt::green);
+        colors_.at(level::info) = format;
+        // warn
+        format.setForeground(Qt::yellow);
+        colors_.at(level::warn) = format;
+        // err
+        format.setForeground(Qt::red);
+        colors_.at(level::err) = format;
+        // critical
+        format.setForeground(Qt::white);
+        format.setBackground(Qt::red);
+        colors_.at(level::critical) = format;
+    }
+
+    ~qt_color_sink()
+    {
+        flush_();
+    }
+
+    void set_default_color(QTextCharFormat format)
+    {
+        // std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        default_color_ = format;
+    }
+
+    void set_level_color(level::level_enum color_level, QTextCharFormat format)
+    {
+        // std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        colors_.at(static_cast<size_t>(color_level)) = format;
+    }
+
+    QTextCharFormat &get_level_color(level::level_enum color_level)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        return colors_.at(static_cast<size_t>(color_level));
+    }
+
+    QTextCharFormat &get_default_color()
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        return default_color_;
+    }
+
+protected:
+    struct invoke_params
+    {
+        invoke_params(int max_lines, QTextEdit *q_text_edit, QString payload, QTextCharFormat default_color, QTextCharFormat level_color,
+            int color_range_start, int color_range_end)
+            : max_lines(max_lines)
+            , q_text_edit(q_text_edit)
+            , payload(std::move(payload))
+            , default_color(default_color)
+            , level_color(level_color)
+            , color_range_start(color_range_start)
+            , color_range_end(color_range_end)
+        {}
+        int max_lines;
+        QTextEdit *q_text_edit;
+        QString payload;
+        QTextCharFormat default_color;
+        QTextCharFormat level_color;
+        int color_range_start;
+        int color_range_end;
+    };
+
+    void sink_it_(const details::log_msg &msg) override
+    {
+        memory_buf_t formatted;
+        base_sink<Mutex>::formatter_->format(msg, formatted);
+
+        const string_view_t str = string_view_t(formatted.data(), formatted.size());
+        // apply the color to the color range in the formatted message.
+        auto payload = QString::fromLatin1(str.data(), static_cast<int>(str.size()));
+
+        invoke_params params{max_lines_,             // max lines
+            qt_text_edit_,                           // text edit to append to
+            std::move(payload),                      // text to append
+            default_color_,                          // default color
+            colors_.at(msg.level),                   // color to apply
+            static_cast<int>(msg.color_range_start), // color range start
+            static_cast<int>(msg.color_range_end)};  // color range end
+
+        QMetaObject::invokeMethod(
+            qt_text_edit_, [params]() { invoke_method_(params); }, Qt::AutoConnection);
+    }
+
+    void flush_() override {}
+
+    // Add colored text to the text edit widget. This method is invoked in the GUI thread.
+    // It is a static method to ensure that it is handled correctly even if the sink is destroyed prematurely
+    // before it is invoked.
+
+    static void invoke_method_(invoke_params params)
+    {
+        auto *document = params.q_text_edit->document();
+        QTextCursor cursor(document);
+
+        // remove first blocks if number of blocks exceeds max_lines
+        while (document->blockCount() > params.max_lines)
+        {
+            cursor.select(QTextCursor::BlockUnderCursor);
+            cursor.removeSelectedText();
+            cursor.deleteChar(); // delete the newline after the block
+        }
+
+        cursor.movePosition(QTextCursor::End);
+        cursor.setCharFormat(params.default_color);
+
+        // if color range not specified or not not valid, just append the text with default color
+        if (params.color_range_end <= params.color_range_start)
+        {
+            cursor.insertText(params.payload);
+            return;
+        }
+
+        // insert the text before the color range
+        cursor.insertText(params.payload.left(params.color_range_start));
+
+        // insert the colorized text
+        cursor.setCharFormat(params.level_color);
+        cursor.insertText(params.payload.mid(params.color_range_start, params.color_range_end - params.color_range_start));
+
+        // insert the text after the color range with default format
+        cursor.setCharFormat(params.default_color);
+        cursor.insertText(params.payload.mid(params.color_range_end));
+    }
+
+    QTextEdit *qt_text_edit_;
+    int max_lines_;
+    QTextCharFormat default_color_;
+    std::array<QTextCharFormat, level::n_levels> colors_;
+};
+
+#include "spdlog/details/null_mutex.h"
+#include <mutex>
+
+using qt_sink_mt = qt_sink<std::mutex>;
+using qt_sink_st = qt_sink<details::null_mutex>;
+using qt_color_sink_mt = qt_color_sink<std::mutex>;
+using qt_color_sink_st = qt_color_sink<details::null_mutex>;
+} // namespace sinks
+
+//
+// Factory functions
+//
+
+// log to QTextEdit
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> qt_logger_mt(const std::string &logger_name, QTextEdit *qt_object, const std::string &meta_method = "append")
+{
+    return Factory::template create<sinks::qt_sink_mt>(logger_name, qt_object, meta_method);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> qt_logger_st(const std::string &logger_name, QTextEdit *qt_object, const std::string &meta_method = "append")
+{
+    return Factory::template create<sinks::qt_sink_st>(logger_name, qt_object, meta_method);
+}
+
+// log to QPlainTextEdit
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> qt_logger_mt(
+    const std::string &logger_name, QPlainTextEdit *qt_object, const std::string &meta_method = "appendPlainText")
+{
+    return Factory::template create<sinks::qt_sink_mt>(logger_name, qt_object, meta_method);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> qt_logger_st(
+    const std::string &logger_name, QPlainTextEdit *qt_object, const std::string &meta_method = "appendPlainText")
+{
+    return Factory::template create<sinks::qt_sink_st>(logger_name, qt_object, meta_method);
+}
+// log to QObject
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> qt_logger_mt(const std::string &logger_name, QObject *qt_object, const std::string &meta_method)
+{
+    return Factory::template create<sinks::qt_sink_mt>(logger_name, qt_object, meta_method);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> qt_logger_st(const std::string &logger_name, QObject *qt_object, const std::string &meta_method)
+{
+    return Factory::template create<sinks::qt_sink_st>(logger_name, qt_object, meta_method);
+}
+
+// log to QTextEdit with colorize output
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> qt_color_logger_mt(const std::string &logger_name, QTextEdit *qt_text_edit, int max_lines)
+{
+    return Factory::template create<sinks::qt_color_sink_mt>(logger_name, qt_text_edit, max_lines);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> qt_color_logger_st(const std::string &logger_name, QTextEdit *qt_text_edit, int max_lines)
+{
+    return Factory::template create<sinks::qt_color_sink_st>(logger_name, qt_text_edit, max_lines);
+}
+
+} // namespace spdlog

include/spdlog/sinks/ringbuffer_sink.h

@@ -50,7 +50,7 @@ public:
         {
             memory_buf_t formatted;
             base_sink<Mutex>::formatter_->format(q_.at(i), formatted);
-            ret.push_back(fmt::to_string(formatted));
+            ret.push_back(SPDLOG_BUF_TO_STRING(formatted));
         }
         return ret;
     }

include/spdlog/sinks/rotating_file_sink-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/sinks/rotating_file_sink.h>
+#    include <spdlog/sinks/rotating_file_sink.h>
 #endif
 
 #include <spdlog/common.h>
@@ -25,16 +25,27 @@ namespace sinks {
 
 template<typename Mutex>
 SPDLOG_INLINE rotating_file_sink<Mutex>::rotating_file_sink(
-    filename_t base_filename, std::size_t max_size, std::size_t max_files, bool rotate_on_open)
+    filename_t base_filename, std::size_t max_size, std::size_t max_files, bool rotate_on_open, const file_event_handlers &event_handlers)
     : base_filename_(std::move(base_filename))
     , max_size_(max_size)
     , max_files_(max_files)
+    , file_helper_{event_handlers}
 {
+    if (max_size == 0)
+    {
+        throw_spdlog_ex("rotating sink constructor: max_size arg cannot be zero");
+    }
+
+    if (max_files > 200000)
+    {
+        throw_spdlog_ex("rotating sink constructor: max_files arg cannot exceed 200000");
+    }
     file_helper_.open(calc_filename(base_filename_, 0));
     current_size_ = file_helper_.size(); // expensive. called only once
     if (rotate_on_open && current_size_ > 0)
     {
         rotate_();
+        current_size_ = 0;
     }
 }
 
@@ -50,7 +61,7 @@ SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::calc_filename(const filename
 
     filename_t basename, ext;
     std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
-    return fmt::format(SPDLOG_FILENAME_T("{}.{}{}"), basename, index, ext);
+    return fmt_lib::format(SPDLOG_FILENAME_T("{}.{}{}"), basename, index, ext);
 }
 
 template<typename Mutex>
@@ -65,13 +76,22 @@ SPDLOG_INLINE void rotating_file_sink<Mutex>::sink_it_(const details::log_msg &m
 {
     memory_buf_t formatted;
     base_sink<Mutex>::formatter_->format(msg, formatted);
-    current_size_ += formatted.size();
-    if (current_size_ > max_size_)
+    auto new_size = current_size_ + formatted.size();
+
+    // rotate if the new estimated file size exceeds max size.
+    // rotate only if the real size > 0 to better deal with full disk (see issue #2261).
+    // we only check the real size when new_size > max_size_ because it is relatively expensive.
+    if (new_size > max_size_)
     {
-        rotate_();
-        current_size_ = formatted.size();
+        file_helper_.flush();
+        if (file_helper_.size() > 0)
+        {
+            rotate_();
+            new_size = formatted.size();
+        }
     }
     file_helper_.write(formatted);
+    current_size_ = new_size;
 }
 
 template<typename Mutex>
@@ -90,6 +110,7 @@ SPDLOG_INLINE void rotating_file_sink<Mutex>::rotate_()
 {
     using details::os::filename_to_str;
     using details::os::path_exists;
+
     file_helper_.close();
     for (auto i = max_files_; i > 0; --i)
     {

include/spdlog/sinks/rotating_file_sink.h

@@ -22,7 +22,8 @@ template<typename Mutex>
 class rotating_file_sink final : public base_sink<Mutex>
 {
 public:
-    rotating_file_sink(filename_t base_filename, std::size_t max_size, std::size_t max_files, bool rotate_on_open = false);
+    rotating_file_sink(filename_t base_filename, std::size_t max_size, std::size_t max_files, bool rotate_on_open = false,
+        const file_event_handlers &event_handlers = {});
     static filename_t calc_filename(const filename_t &filename, std::size_t index);
     filename_t filename();
 
@@ -59,20 +60,22 @@ using rotating_file_sink_st = rotating_file_sink<details::null_mutex>;
 //
 
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> rotating_logger_mt(
-    const std::string &logger_name, const filename_t &filename, size_t max_file_size, size_t max_files, bool rotate_on_open = false)
+inline std::shared_ptr<logger> rotating_logger_mt(const std::string &logger_name, const filename_t &filename, size_t max_file_size,
+    size_t max_files, bool rotate_on_open = false, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::rotating_file_sink_mt>(logger_name, filename, max_file_size, max_files, rotate_on_open);
+    return Factory::template create<sinks::rotating_file_sink_mt>(
+        logger_name, filename, max_file_size, max_files, rotate_on_open, event_handlers);
 }
 
 template<typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> rotating_logger_st(
-    const std::string &logger_name, const filename_t &filename, size_t max_file_size, size_t max_files, bool rotate_on_open = false)
+inline std::shared_ptr<logger> rotating_logger_st(const std::string &logger_name, const filename_t &filename, size_t max_file_size,
+    size_t max_files, bool rotate_on_open = false, const file_event_handlers &event_handlers = {})
 {
-    return Factory::template create<sinks::rotating_file_sink_st>(logger_name, filename, max_file_size, max_files, rotate_on_open);
+    return Factory::template create<sinks::rotating_file_sink_st>(
+        logger_name, filename, max_file_size, max_files, rotate_on_open, event_handlers);
 }
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "rotating_file_sink-inl.h"
+#    include "rotating_file_sink-inl.h"
 #endif

include/spdlog/sinks/sink-inl.h

@@ -4,7 +4,7 @@
 #pragma once
 
 #ifndef SPDLOG_HEADER_ONLY
-#include <spdlog/sinks/sink.h>
+#    include <spdlog/sinks/sink.h>
 #endif
 
 #include <spdlog/common.h>