Fix coverity yml

* Bump fmt to 11.2.0

.github/workflows/coverity_scan.yml

@@ -0,0 +1,51 @@
+name: coverity-linux
+
+on: [pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  coverity_scan:
+    runs-on: ubuntu-latest
+    name: Coverity Scan
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y curl build-essential cmake pkg-config libsystemd-dev
+
+      - name: Download Coverity Tool
+        run: |
+          curl -s -L --output coverity_tool.tgz "https://scan.coverity.com/download/linux64?token=${{ secrets.COVERITY_TOKEN }}&project=gabime%2Fspdlog"
+          mkdir coverity_tool
+          tar -C coverity_tool --strip-components=1 -xf coverity_tool.tgz
+          echo "$PWD/coverity_tool/bin" >> $GITHUB_PATH
+
+      - name: Build with Coverity
+        run: |
+          mkdir build && cd build
+          cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_STANDARD=17
+          cd ..
+          cov-build --dir cov-int make -C build -j4
+
+      - name: Submit results to Coverity
+        run: |
+          tar czf cov-int.tgz cov-int
+          response=$(curl --silent --show-error --fail \
+            --form token="${{ secrets.COVERITY_TOKEN }}" \
+            --form file=@cov-int.tgz \
+            --form version="GitHub PR #${{ github.event.pull_request.number }}" \
+            --form description="CI run for PR" \
+            https://scan.coverity.com/builds?project=gabime%2Fspdlog)
+
+          echo "$response"
+
+          if echo "$response" | grep -qi "Build successfully submitted"; then
+            echo "Coverity upload succeeded"
+          else
+            echo "Coverity upload failed or was rejected"
+            exit 1
+          fi

.github/workflows/macos.yml

@@ -9,6 +9,15 @@ jobs:
   build:
     runs-on: macOS-latest
     name: "macOS Clang (C++11, Release)"
+    strategy:
+      fail-fast: true
+      matrix:
+        config:
+            - USE_STD_FORMAT: 'ON'
+              BUILD_EXAMPLE: 'OFF'
+            - USE_STD_FORMAT: 'OFF'
+              BUILD_EXAMPLE: 'ON'
+              
     steps:
       - uses: actions/checkout@v4
       - name: Build
@@ -17,12 +26,13 @@ jobs:
           cmake .. \
             -DCMAKE_BUILD_TYPE=Release \
             -DCMAKE_CXX_STANDARD=11 \
-            -DSPDLOG_BUILD_EXAMPLE=ON \
-            -DSPDLOG_BUILD_EXAMPLE_HO=ON \
+            -DSPDLOG_BUILD_EXAMPLE=${{ matrix.config.BUILD_EXAMPLE }} \
+            -DSPDLOG_BUILD_EXAMPLE_HO=${{ matrix.config.BUILD_EXAMPLE }} \
             -DSPDLOG_BUILD_WARNINGS=ON \
             -DSPDLOG_BUILD_BENCH=OFF \
             -DSPDLOG_BUILD_TESTS=ON \
             -DSPDLOG_BUILD_TESTS_HO=OFF \
+            -DSPDLOG_USE_STD_FORMAT=${{ matrix.config.USE_STD_FORMAT }} \
             -DSPDLOG_SANITIZE_ADDRESS=OFF
           make -j 4
           ctest -j 4 --output-on-failure

CMakeLists.txt

@@ -33,7 +33,6 @@ elseif(NOT CMAKE_CXX_STANDARD)
     set(CMAKE_CXX_STANDARD_REQUIRED ON)
 endif()
 
-
 set(CMAKE_CXX_EXTENSIONS OFF)
 
 if(CMAKE_SYSTEM_NAME MATCHES "CYGWIN" OR CMAKE_SYSTEM_NAME MATCHES "MSYS" OR CMAKE_SYSTEM_NAME MATCHES "MINGW")
@@ -133,6 +132,7 @@ option(
     "prevent spdlog from using of std::atomic log levels (use only if your code never modifies log levels concurrently"
     OFF)
 option(SPDLOG_DISABLE_DEFAULT_LOGGER "Disable default logger creation" OFF)
+option(SPDLOG_FWRITE_UNLOCKED "Use the unlocked variant of fwrite. Leave this on unless your libc doesn't have it" ON)
 
 # clang-tidy
 option(SPDLOG_TIDY "run clang-tidy" OFF)
@@ -201,9 +201,9 @@ endif()
 # sanitizer support
 if(SPDLOG_SANITIZE_ADDRESS)
     spdlog_enable_addr_sanitizer(spdlog)
-elseif (SPDLOG_SANITIZE_THREAD)
+elseif(SPDLOG_SANITIZE_THREAD)
     spdlog_enable_thread_sanitizer(spdlog)
-endif ()
+endif()
 
 # ---------------------------------------------------------------------------------------
 # Header only version
@@ -238,6 +238,22 @@ if(SPDLOG_FMT_EXTERNAL OR SPDLOG_FMT_EXTERNAL_HO)
     set(PKG_CONFIG_REQUIRES fmt) # add dependency to pkg-config
 endif()
 
+# ---------------------------------------------------------------------------------------
+# Check if fwrite_unlocked/_fwrite_nolock is available
+# ---------------------------------------------------------------------------------------
+if(SPDLOG_FWRITE_UNLOCKED)
+    include(CheckSymbolExists)
+    if(WIN32)
+        check_symbol_exists(_fwrite_nolock "stdio.h" HAVE_FWRITE_UNLOCKED)
+    else()
+        check_symbol_exists(fwrite_unlocked "stdio.h" HAVE_FWRITE_UNLOCKED)
+    endif()
+    if(HAVE_FWRITE_UNLOCKED)
+        target_compile_definitions(spdlog PRIVATE SPDLOG_FWRITE_UNLOCKED)
+        target_compile_definitions(spdlog_header_only INTERFACE SPDLOG_FWRITE_UNLOCKED)
+    endif()
+endif()
+
 # ---------------------------------------------------------------------------------------
 # Add required libraries for Android CMake build
 # ---------------------------------------------------------------------------------------
@@ -274,8 +290,12 @@ if(MSVC)
     target_compile_options(spdlog PRIVATE "/Zc:__cplusplus")
     target_compile_options(spdlog_header_only INTERFACE "/Zc:__cplusplus")
     if(SPDLOG_MSVC_UTF8)
-	    target_compile_options(spdlog PUBLIC "/utf-8")
-	    target_compile_options(spdlog_header_only INTERFACE "/utf-8")    
+        # fmtlib requires the /utf-8 flag when building with msvc. see https://github.com/fmtlib/fmt/pull/4159 on the
+        # purpose of the additional
+        # "$<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>"
+        target_compile_options(spdlog PUBLIC $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>:/utf-8>)
+        target_compile_options(spdlog_header_only
+                               INTERFACE $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>:/utf-8>)
     endif()
 endif()
 
@@ -284,12 +304,13 @@ endif()
 # ---------------------------------------------------------------------------------------
 if(SPDLOG_NO_EXCEPTIONS)
     if(NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
-        target_compile_definitions(spdlog PUBLIC FMT_EXCEPTIONS=0)
+        target_compile_definitions(spdlog PUBLIC FMT_USE_EXCEPTIONS=0)
     endif()
     if(NOT MSVC)
         target_compile_options(spdlog PRIVATE -fno-exceptions)
     else()
         target_compile_options(spdlog PRIVATE /EHs-c-)
+        target_compile_definitions(spdlog PRIVATE _HAS_EXCEPTIONS=0)
     endif()
 endif()
 # ---------------------------------------------------------------------------------------

README.md

@@ -11,7 +11,7 @@ Fast C++ logging library
 
 ## 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.
+Copy the include [folder](include/spdlog) to your build tree and use a C++11 compiler.
 
 #### Compiled version (recommended - much faster compile times)
 ```console
@@ -19,7 +19,7 @@ $ git clone https://github.com/gabime/spdlog.git
 $ cd spdlog && mkdir build && cd build
 $ cmake .. && cmake --build .
 ```
-see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/CMakeLists.txt) on how to use.
+see example [CMakeLists.txt](example/CMakeLists.txt) on how to use.
 
 ## Platforms
 * Linux, FreeBSD, OpenBSD, Solaris, AIX
@@ -36,6 +36,7 @@ see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/
 * Gentoo: `emerge dev-libs/spdlog`
 * Arch Linux: `pacman -S spdlog`
 * openSUSE: `sudo zypper in spdlog-devel`
+* ALT Linux: `apt-get install libspdlog-devel`
 * vcpkg: `vcpkg install spdlog`
 * conan: `conan install --requires=spdlog/[*]`
 * conda: `conda install -c conda-forge spdlog`
@@ -47,7 +48,7 @@ see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/
 * Headers only or compiled
 * 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.
+* [Custom](https://github.com/gabime/spdlog/wiki/Custom-formatting) formatting.
 * Multi/Single threaded loggers.
 * Various log targets:
   * Rotating log files.
@@ -57,7 +58,7 @@ see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/
   * 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.
+  * Easily [extendable](https://github.com/gabime/spdlog/wiki/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.
@@ -303,7 +304,7 @@ struct fmt::formatter<my_type> : fmt::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);
+        return fmt::format_to(ctx.out(), "[my_type i={}]", my.i);
     }
 };
 
@@ -387,6 +388,9 @@ void android_example()
 int main (int argc, char *argv[])
 {
     spdlog::cfg::load_env_levels();
+    // or specify the env variable name:
+    // MYAPP_LEVEL=info,mylogger=trace && ./example
+    // spdlog::cfg::load_env_levels("MYAPP_LEVEL");
     // or from the command line:
     // ./example SPDLOG_LEVEL=info,mylogger=trace
     // #include "spdlog/cfg/argv.h" // for loading levels from argv
@@ -463,7 +467,7 @@ void mdc_example()
 ---
 ## Benchmarks
 
-Below are some [benchmarks](https://github.com/gabime/spdlog/blob/v1.x/bench/bench.cpp) done in Ubuntu 64 bit, Intel i7-4770 CPU @ 3.40GHz
+Below are some [benchmarks](bench/bench.cpp) done in Ubuntu 64 bit, Intel i7-4770 CPU @ 3.40GHz
 
 #### Synchronous mode
 ```
@@ -515,7 +519,8 @@ Below are some [benchmarks](https://github.com/gabime/spdlog/blob/v1.x/bench/ben
 ```
 
 ## Documentation
-Documentation can be found in the [wiki](https://github.com/gabime/spdlog/wiki/1.-QuickStart) pages.
+
+Documentation can be found in the [wiki](https://github.com/gabime/spdlog/wiki) pages.
 
 ---
 

cmake/pch.h.in

@@ -10,7 +10,6 @@
 
 // details/file_helper-inl.h
 // details/os-inl.h
-// fmt/bundled/core.h
 // fmt/bundled/posix.h
 // logger-inl.h
 // sinks/daily_file_sink.h
@@ -23,7 +22,6 @@
 
 // details/os-inl.h
 // details/pattern_formatter-inl.h
-// fmt/bundled/core.h
 // fmt/bundled/format-inl.h
 #include <cstring>
 
@@ -73,7 +71,6 @@
 // details/registry.h
 // details/tcp_client-windows.h
 // details/tcp_client.h
-// fmt/bundled/core.h
 // sinks/android_sink.h
 // sinks/ansicolor_sink.h
 // sinks/basic_file_sink.h
@@ -150,7 +147,6 @@
 
 // common.h
 // details/fmt_helper.h
-// fmt/bundled/core.h
 // fmt/bundled/ranges.h
 #include <type_traits>
 

example/example.cpp

@@ -33,6 +33,7 @@ void mdc_example();
 #include "spdlog/fmt/ostr.h"  // support for user defined types
 
 int main(int, char *[]) {
+    try {
         // Log levels can be loaded from argv/env using "SPDLOG_LEVEL"
         load_levels_example();
 
@@ -58,8 +59,8 @@ int main(int, char *[]) {
         spdlog::set_level(spdlog::level::info);
 
         // Backtrace support
-    // Loggers can store in a ring buffer all messages (including debug/trace) for later inspection.
-    // When needed, call dump_backtrace() to see what happened:
+        // Loggers can store in a ring buffer all messages (including debug/trace) for later
+        // inspection. When needed, call dump_backtrace() to see what happened:
         spdlog::enable_backtrace(10);  // create ring buffer with capacity of 10  messages
         for (int i = 0; i < 100; i++) {
             spdlog::debug("Backtrace message {}", i);  // not logged..
@@ -67,7 +68,6 @@ int main(int, char *[]) {
         // e.g. if some error happened:
         spdlog::dump_backtrace();  // log them now!
 
-    try {
         stdout_logger_example();
         basic_example();
         rotating_example();
@@ -148,6 +148,9 @@ void load_levels_example() {
     // Set the log level to "info" and mylogger to "trace":
     // SPDLOG_LEVEL=info,mylogger=trace && ./example
     spdlog::cfg::load_env_levels();
+    // or specify the env variable name:
+    // MYAPP_LEVEL=info,mylogger=trace && ./example
+    // spdlog::cfg::load_env_levels("MYAPP_LEVEL");
     // or from command line:
     // ./example SPDLOG_LEVEL=info,mylogger=trace
     // #include "spdlog/cfg/argv.h" // for loading levels from argv
@@ -266,7 +269,7 @@ void multi_sink_example() {
 struct my_type {
     int i = 0;
     explicit my_type(int i)
-        : i(i){}
+        : i(i) {}
 };
 
 #ifndef SPDLOG_USE_STD_FORMAT  // when using fmtlib
@@ -281,7 +284,7 @@ struct fmt::formatter<my_type> : fmt::formatter<std::string> {
 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);
+        return std::format_to(ctx.out(), "[my_type i={}]", my.i);
     }
 };
 #endif
@@ -368,25 +371,23 @@ 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);
+    auto new_logger = spdlog::basic_logger_mt("new_default_logger", "logs/somelog.txt", true);
+    spdlog::set_default_logger(std::move(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);
+    spdlog::set_default_logger(std::move(old_logger));
 }
 
-// Mapped Diagnostic Context (MDC) is a map that stores key-value pairs (string values) in thread local storage.
-// Each thread maintains its own MDC, which loggers use to append diagnostic information to log outputs.
-// Note: it is not supported in asynchronous mode due to its reliance on thread-local storage.
+// Mapped Diagnostic Context (MDC) is a map that stores key-value pairs (string values) in thread
+// local storage. Each thread maintains its own MDC, which loggers use to append diagnostic
+// information to log outputs. Note: it is not supported in asynchronous mode due to its reliance on
+// thread-local storage.
 
 #ifndef SPDLOG_NO_TLS
     #include "spdlog/mdc.h"
-void mdc_example()
-{
+void mdc_example() {
     spdlog::mdc::put("key1", "value1");
     spdlog::mdc::put("key2", "value2");
     // if not using the default format, you can use the %& formatter to print mdc data as well

include/spdlog/async.h

@@ -89,8 +89,7 @@ inline void init_thread_pool(size_t q_size,
 }
 
 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

@@ -33,7 +33,7 @@ SPDLOG_INLINE spdlog::async_logger::async_logger(std::string logger_name,
 // send the log message to the thread pool
 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_);
+        pool_ptr -> post_log(shared_from_this(), msg, overflow_policy_);
 }
 else {
     throw_spdlog_ex("async log: thread pool doesn't exist anymore");
@@ -45,7 +45,7 @@ SPDLOG_LOGGER_CATCH(msg.source)
 // send flush request to the thread pool
 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_);
+        pool_ptr -> post_flush(shared_from_this(), overflow_policy_);
 }
 else {
     throw_spdlog_ex("async flush: thread pool doesn't exist anymore");

include/spdlog/cfg/env.h

@@ -25,8 +25,8 @@
 
 namespace spdlog {
 namespace cfg {
-inline void load_env_levels() {
-    auto env_val = details::os::getenv("SPDLOG_LEVEL");
+inline void load_env_levels(const char* var = "SPDLOG_LEVEL") {
+    auto env_val = details::os::getenv(var);
     if (!env_val.empty()) {
         helpers::load_levels(env_val);
     }

include/spdlog/cfg/helpers-inl.h

@@ -9,7 +9,6 @@
 
 #include <spdlog/details/os.h>
 #include <spdlog/details/registry.h>
-#include <spdlog/spdlog.h>
 
 #include <algorithm>
 #include <sstream>
@@ -36,7 +35,7 @@ inline std::string &trim_(std::string &str) {
     return str;
 }
 
-// return (name,value) trimmed pair from given "name=value" string.
+// return (name,value) trimmed pair from the given "name = value" string.
 // return empty string on missing parts
 // "key=val" => ("key", "val")
 // " key  =  val " => ("key", "val")
@@ -55,7 +54,7 @@ inline std::pair<std::string, std::string> extract_kv_(char sep, const std::stri
     return std::make_pair(trim_(k), trim_(v));
 }
 
-// return vector of key/value pairs from sequence of "K1=V1,K2=V2,.."
+// return vector of key/value pairs from a sequence of "K1=V1,K2=V2,.."
 // "a=AAA,b=BBB,c=CCC,.." => {("a","AAA"),("b","BBB"),("c", "CCC"),...}
 inline std::unordered_map<std::string, std::string> extract_key_vals_(const std::string &str) {
     std::string token;
@@ -82,14 +81,14 @@ SPDLOG_INLINE void load_levels(const std::string &input) {
     bool global_level_found = false;
 
     for (auto &name_level : key_vals) {
-        auto &logger_name = name_level.first;
-        auto level_name = to_lower_(name_level.second);
+        const auto &logger_name = name_level.first;
+        const auto &level_name = to_lower_(name_level.second);
         auto level = level::from_str(level_name);
         // ignore unrecognized level names
         if (level == level::off && level_name != "off") {
             continue;
         }
-        if (logger_name.empty())  // no logger name indicate global level
+        if (logger_name.empty())  // no logger name indicates global level
         {
             global_level_found = true;
             global_level = level;

include/spdlog/common.h

@@ -364,12 +364,7 @@ SPDLOG_CONSTEXPR_FUNC spdlog::wstring_view_t to_string_view(spdlog::wstring_view
 }
 #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
+#if defined(SPDLOG_USE_STD_FORMAT) && __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 {

include/spdlog/details/file_helper-inl.h

@@ -11,10 +11,8 @@
 #include <spdlog/details/os.h>
 
 #include <cerrno>
-#include <chrono>
 #include <cstdio>
 #include <string>
-#include <thread>
 #include <tuple>
 
 namespace spdlog {
@@ -101,7 +99,8 @@ SPDLOG_INLINE void file_helper::write(const memory_buf_t &buf) {
     if (fd_ == nullptr) return;
     size_t msg_size = buf.size();
     auto data = buf.data();
-    if (std::fwrite(data, 1, msg_size, fd_) != msg_size) {
+
+    if (!details::os::fwrite_bytes(data, msg_size, fd_)) {
         throw_spdlog_ex("Failed writing to file " + os::filename_to_str(filename_), errno);
     }
 }

include/spdlog/details/os-inl.h

@@ -267,7 +267,8 @@ SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm) {
 
     #if defined(sun) || defined(__sun) || defined(_AIX) ||                        \
         (defined(__NEWLIB__) && !defined(__TM_GMTOFF)) ||                         \
-        (!defined(_BSD_SOURCE) && !defined(_GNU_SOURCE))
+        (!defined(__APPLE__) && !defined(_BSD_SOURCE) && !defined(_GNU_SOURCE) && \
+         (!defined(_POSIX_VERSION) || (_POSIX_VERSION < 202405L)))
     // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
     struct helper {
         static long int calculate_gmt_offset(const std::tm &localtm = details::os::localtime(),
@@ -482,13 +483,12 @@ SPDLOG_INLINE void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target) {
     }
 
     // find the size to allocate for the result buffer
-    int result_size =
-        ::MultiByteToWideChar(CP_UTF8, 0, str.data(), str_size, NULL, 0);
+    int result_size = ::MultiByteToWideChar(CP_UTF8, 0, str.data(), str_size, NULL, 0);
 
     if (result_size > 0) {
         target.resize(result_size);
-        result_size = ::MultiByteToWideChar(CP_UTF8, 0, str.data(), str_size, target.data(),
-                                            result_size);
+        result_size =
+            ::MultiByteToWideChar(CP_UTF8, 0, str.data(), str_size, target.data(), result_size);
         if (result_size > 0) {
             assert(result_size == target.size());
             return;
@@ -589,6 +589,18 @@ SPDLOG_INLINE bool fsync(FILE *fp) {
 #endif
 }
 
+// Do non-locking fwrite if possible by the os or use the regular locking fwrite
+// Return true on success.
+SPDLOG_INLINE bool fwrite_bytes(const void *ptr, const size_t n_bytes, FILE *fp) {
+#if defined(_WIN32) && defined(SPDLOG_FWRITE_UNLOCKED)
+    return _fwrite_nolock(ptr, 1, n_bytes, fp) == n_bytes;
+#elif defined(SPDLOG_FWRITE_UNLOCKED)
+    return ::fwrite_unlocked(ptr, 1, n_bytes, fp) == n_bytes;
+#else
+    return std::fwrite(ptr, 1, n_bytes, fp) == n_bytes;
+#endif
+}
+
 }  // namespace os
 }  // namespace details
 }  // namespace spdlog

include/spdlog/details/os.h

@@ -114,6 +114,10 @@ SPDLOG_API std::string getenv(const char *field);
 // Return true on success.
 SPDLOG_API bool fsync(FILE *fp);
 
+// Do non-locking fwrite if possible by the os or use the regular locking fwrite
+// Return true on success.
+SPDLOG_API bool fwrite_bytes(const void *ptr, const size_t n_bytes, FILE *fp);
+
 }  // namespace os
 }  // namespace details
 }  // namespace spdlog

include/spdlog/details/registry-inl.h

@@ -54,6 +54,11 @@ SPDLOG_INLINE void registry::register_logger(std::shared_ptr<logger> new_logger)
     register_logger_(std::move(new_logger));
 }
 
+SPDLOG_INLINE void registry::register_or_replace(std::shared_ptr<logger> new_logger) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    register_or_replace_(std::move(new_logger));
+}
+
 SPDLOG_INLINE void registry::initialize_logger(std::shared_ptr<logger> new_logger) {
     std::lock_guard<std::mutex> lock(logger_map_mutex_);
     new_logger->set_formatter(formatter_->clone());
@@ -96,7 +101,7 @@ SPDLOG_INLINE std::shared_ptr<logger> registry::default_logger() {
 SPDLOG_INLINE logger *registry::get_default_raw() { return default_logger_.get(); }
 
 // set default logger.
-// default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
+// the default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
 SPDLOG_INLINE void registry::set_default_logger(std::shared_ptr<logger> new_default_logger) {
     std::lock_guard<std::mutex> lock(logger_map_mutex_);
     if (new_default_logger != nullptr) {
@@ -252,10 +257,14 @@ SPDLOG_INLINE void registry::throw_if_exists_(const std::string &logger_name) {
 }
 
 SPDLOG_INLINE void registry::register_logger_(std::shared_ptr<logger> new_logger) {
-    auto logger_name = new_logger->name();
+    auto &logger_name = new_logger->name();
     throw_if_exists_(logger_name);
     loggers_[logger_name] = std::move(new_logger);
 }
 
+SPDLOG_INLINE void registry::register_or_replace_(std::shared_ptr<logger> new_logger) {
+    loggers_[new_logger->name()] = std::move(new_logger);
+}
+
 }  // namespace details
 }  // namespace spdlog

include/spdlog/details/registry.h

@@ -31,6 +31,7 @@ public:
     registry &operator=(const registry &) = delete;
 
     void register_logger(std::shared_ptr<logger> new_logger);
+    void register_or_replace(std::shared_ptr<logger> new_logger);
     void initialize_logger(std::shared_ptr<logger> new_logger);
     std::shared_ptr<logger> get(const std::string &logger_name);
     std::shared_ptr<logger> default_logger();
@@ -105,6 +106,7 @@ private:
 
     void throw_if_exists_(const std::string &logger_name);
     void register_logger_(std::shared_ptr<logger> new_logger);
+    void register_or_replace_(std::shared_ptr<logger> new_logger);
     bool set_level_from_cfg_(logger *logger);
     std::mutex logger_map_mutex_, flusher_mutex_;
     std::recursive_mutex tp_mutex_;

include/spdlog/details/thread_pool-inl.h

@@ -35,11 +35,10 @@ SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items,
 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, [] {}) {}
+    : thread_pool(q_max_items, threads_n, std::move(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
 SPDLOG_INLINE thread_pool::~thread_pool() {
@@ -95,8 +94,7 @@ void SPDLOG_INLINE thread_pool::worker_loop_() {
 }
 
 // process next message in the queue
-// return true if this thread should still be active (while no terminate msg
-// was received)
+// returns true if this thread should still be active (while no terminated msg was received)
 bool SPDLOG_INLINE thread_pool::process_next_msg_() {
     async_msg incoming_async_msg;
     q_.dequeue(incoming_async_msg);

include/spdlog/fmt/bin_to_hex.h

@@ -102,7 +102,7 @@ namespace
 
 template <typename T>
 struct formatter<spdlog::details::dump_info<T>, char> {
-    const char delimiter = ' ';
+    char delimiter = ' ';
     bool put_newlines = true;
     bool put_delimiters = true;
     bool use_uppercase = false;
@@ -142,8 +142,8 @@ struct formatter<spdlog::details::dump_info<T>, char> {
 
     // format the given bytes range as hex
     template <typename FormatContext, typename Container>
-    auto format(const spdlog::details::dump_info<Container> &the_range, FormatContext &ctx) const
-        -> 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;

include/spdlog/fmt/bundled/args.h

@@ -17,7 +17,6 @@
 #include "format.h"  // std_string_view
 
 FMT_BEGIN_NAMESPACE
-
 namespace detail {
 
 template <typename T> struct is_reference_wrapper : std::false_type {};
@@ -72,19 +71,13 @@ class dynamic_arg_list {
  * It can be implicitly converted into `fmt::basic_format_args` for passing
  * into type-erased formatting functions such as `fmt::vformat`.
  */
-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
-{
+template <typename Context> class dynamic_format_arg_store {
  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;
+        detail::mapped_type_constant<T, char_type>::value;
 
     enum {
       value = !(detail::is_reference_wrapper<T>::value ||
@@ -97,7 +90,7 @@ class dynamic_format_arg_store
   };
 
   template <typename T>
-  using stored_type = conditional_t<
+  using stored_t = conditional_t<
       std::is_convertible<T, std::basic_string<char_type>>::value &&
           !detail::is_reference_wrapper<T>::value,
       std::basic_string<char_type>, T>;
@@ -112,41 +105,37 @@ class dynamic_format_arg_store
 
   friend class basic_format_args<Context>;
 
-  auto get_types() const -> unsigned long long {
-    return detail::is_unpacked_bit | data_.size() |
-           (named_info_.empty()
-                ? 0ULL
-                : static_cast<unsigned long long>(detail::has_named_args_bit));
-  }
-
   auto data() const -> const basic_format_arg<Context>* {
     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));
+    data_.emplace_back(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)));
+    if (named_info_.empty())
+      data_.insert(data_.begin(), basic_format_arg<Context>(nullptr, 0));
+    data_.emplace_back(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()};
+    data_[0] = {named_info_.data(), named_info_.size()};
     guard.release();
   }
 
  public:
   constexpr dynamic_format_arg_store() = default;
 
+  operator basic_format_args<Context>() const {
+    return basic_format_args<Context>(data(), static_cast<int>(data_.size()),
+                                      !named_info_.empty());
+  }
+
   /**
    * Adds an argument into the dynamic store for later passing to a formatting
    * function.
@@ -164,7 +153,7 @@ class dynamic_format_arg_store
    */
   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));
+      emplace_arg(dynamic_args_.push<stored_t<T>>(arg));
     else
       emplace_arg(detail::unwrap(arg));
   }
@@ -200,7 +189,7 @@ class dynamic_format_arg_store
         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)));
+          fmt::arg(arg_name, dynamic_args_.push<stored_t<T>>(arg.value)));
     } else {
       emplace_arg(fmt::arg(arg_name, arg.value));
     }
@@ -210,17 +199,20 @@ class dynamic_format_arg_store
   void clear() {
     data_.clear();
     named_info_.clear();
-    dynamic_args_ = detail::dynamic_arg_list();
+    dynamic_args_ = {};
   }
 
   /// Reserves space to store at least `new_cap` arguments including
   /// `new_cap_named` named arguments.
   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");
+               "set of arguments includes set of named arguments");
     data_.reserve(new_cap);
     named_info_.reserve(new_cap_named);
   }
+
+  /// Returns the number of elements in the store.
+  size_t size() const noexcept { return data_.size(); }
 };
 
 FMT_END_NAMESPACE

include/spdlog/fmt/bundled/color.h

@@ -190,11 +190,11 @@ enum class emphasis : uint8_t {
 // rgb is a struct for red, green and blue colors.
 // Using the name "rgb" makes some editors show the color in a tooltip.
 struct rgb {
-  FMT_CONSTEXPR rgb() : r(0), g(0), b(0) {}
-  FMT_CONSTEXPR rgb(uint8_t r_, uint8_t g_, uint8_t b_) : r(r_), g(g_), b(b_) {}
-  FMT_CONSTEXPR rgb(uint32_t hex)
+  constexpr rgb() : r(0), g(0), b(0) {}
+  constexpr rgb(uint8_t r_, uint8_t g_, uint8_t b_) : r(r_), g(g_), b(b_) {}
+  constexpr rgb(uint32_t hex)
       : r((hex >> 16) & 0xFF), g((hex >> 8) & 0xFF), b(hex & 0xFF) {}
-  FMT_CONSTEXPR rgb(color hex)
+  constexpr rgb(color hex)
       : r((uint32_t(hex) >> 16) & 0xFF),
         g((uint32_t(hex) >> 8) & 0xFF),
         b(uint32_t(hex) & 0xFF) {}
@@ -205,97 +205,135 @@ struct rgb {
 
 namespace detail {
 
-// color is a struct of either a rgb color or a terminal color.
+// A bit-packed variant of an RGB color, a terminal color, or unset color.
+// see text_style for the bit-packing scheme.
 struct color_type {
-  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);
+  constexpr color_type() noexcept = default;
+  constexpr color_type(color rgb_color) noexcept
+      : value_(static_cast<uint32_t>(rgb_color) | (1 << 24)) {}
+  constexpr color_type(rgb rgb_color) noexcept
+      : color_type(static_cast<color>(
+            (static_cast<uint32_t>(rgb_color.r) << 16) |
+            (static_cast<uint32_t>(rgb_color.g) << 8) | rgb_color.b)) {}
+  constexpr color_type(terminal_color term_color) noexcept
+      : value_(static_cast<uint32_t>(term_color) | (3 << 24)) {}
+
+  constexpr auto is_terminal_color() const noexcept -> bool {
+    return (value_ & (1 << 25)) != 0;
   }
-  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;
+
+  constexpr auto value() const noexcept -> uint32_t {
+    return value_ & 0xFFFFFF;
   }
-  FMT_CONSTEXPR color_type(terminal_color term_color) noexcept
-      : is_rgb(), value{} {
-    value.term_color = static_cast<uint8_t>(term_color);
-  }
-  bool is_rgb;
-  union color_union {
-    uint8_t term_color;
-    uint32_t rgb_color;
-  } value;
+
+  constexpr color_type(uint32_t value) noexcept : value_(value) {}
+
+  uint32_t value_ = 0;
 };
 }  // namespace detail
 
 /// A text style consisting of foreground and background colors and emphasis.
 class text_style {
+  // The information is packed as follows:
+  // ┌──┐
+  // │ 0│─┐
+  // │..│ ├── foreground color value
+  // │23│─┘
+  // ├──┤
+  // │24│─┬── discriminator for the above value. 00 if unset, 01 if it's
+  // │25│─┘   an RGB color, or 11 if it's a terminal color (10 is unused)
+  // ├──┤
+  // │26│──── overflow bit, always zero (see below)
+  // ├──┤
+  // │27│─┐
+  // │..│ │
+  // │50│ │
+  // ├──┤ │
+  // │51│ ├── background color (same format as the foreground color)
+  // │52│ │
+  // ├──┤ │
+  // │53│─┘
+  // ├──┤
+  // │54│─┐
+  // │..│ ├── emphases
+  // │61│─┘
+  // ├──┤
+  // │62│─┬── unused
+  // │63│─┘
+  // └──┘
+  // The overflow bits are there to make operator|= efficient.
+  // When ORing, we must throw if, for either the foreground or background,
+  // one style specifies a terminal color and the other specifies any color
+  // (terminal or RGB); in other words, if one discriminator is 11 and the
+  // other is 11 or 01.
+  //
+  // We do that check by adding the styles. Consider what adding does to each
+  // possible pair of discriminators:
+  //    00 + 00 = 000
+  //    01 + 00 = 001
+  //    11 + 00 = 011
+  //    01 + 01 = 010
+  //    11 + 01 = 100 (!!)
+  //    11 + 11 = 110 (!!)
+  // In the last two cases, the ones we want to catch, the third bit——the
+  // overflow bit——is set. Bingo.
+  //
+  // We must take into account the possible carry bit from the bits
+  // before the discriminator. The only potentially problematic case is
+  // 11 + 00 = 011 (a carry bit would make it 100, not good!), but a carry
+  // bit is impossible in that case, because 00 (unset color) means the
+  // 24 bits that precede the discriminator are all zero.
+  //
+  // This test can be applied to both colors simultaneously.
+
  public:
   FMT_CONSTEXPR text_style(emphasis em = emphasis()) noexcept
-      : set_foreground_color(), set_background_color(), ems(em) {}
+      : style_(static_cast<uint64_t>(em) << 54) {}
 
-  FMT_CONSTEXPR auto operator|=(const text_style& rhs) -> text_style& {
-    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_CONSTEXPR auto operator|=(text_style rhs) -> text_style& {
+    if (((style_ + rhs.style_) & ((1ULL << 26) | (1ULL << 53))) != 0)
       report_error("can't OR 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)
-        report_error("can't OR 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));
+    style_ |= rhs.style_;
     return *this;
   }
 
-  friend FMT_CONSTEXPR auto operator|(text_style lhs, const text_style& rhs)
+  friend FMT_CONSTEXPR auto operator|(text_style lhs, text_style rhs)
       -> text_style {
     return lhs |= rhs;
   }
 
+  FMT_CONSTEXPR auto operator==(text_style rhs) const noexcept -> bool {
+    return style_ == rhs.style_;
+  }
+
+  FMT_CONSTEXPR auto operator!=(text_style rhs) const noexcept -> bool {
+    return !(*this == rhs);
+  }
+
   FMT_CONSTEXPR auto has_foreground() const noexcept -> bool {
-    return set_foreground_color;
+    return (style_ & (1 << 24)) != 0;
   }
   FMT_CONSTEXPR auto has_background() const noexcept -> bool {
-    return set_background_color;
+    return (style_ & (1ULL << 51)) != 0;
   }
   FMT_CONSTEXPR auto has_emphasis() const noexcept -> bool {
-    return static_cast<uint8_t>(ems) != 0;
+    return (style_ >> 54) != 0;
   }
   FMT_CONSTEXPR auto get_foreground() const noexcept -> detail::color_type {
     FMT_ASSERT(has_foreground(), "no foreground specified for this style");
-    return foreground_color;
+    return style_ & 0x3FFFFFF;
   }
   FMT_CONSTEXPR auto get_background() const noexcept -> detail::color_type {
     FMT_ASSERT(has_background(), "no background specified for this style");
-    return background_color;
+    return (style_ >> 27) & 0x3FFFFFF;
   }
   FMT_CONSTEXPR auto get_emphasis() const noexcept -> emphasis {
     FMT_ASSERT(has_emphasis(), "no emphasis specified for this style");
-    return ems;
+    return static_cast<emphasis>(style_ >> 54);
   }
 
  private:
-  FMT_CONSTEXPR text_style(bool is_foreground,
-                           detail::color_type text_color) noexcept
-      : set_foreground_color(), set_background_color(), ems() {
-    if (is_foreground) {
-      foreground_color = text_color;
-      set_foreground_color = true;
-    } else {
-      background_color = text_color;
-      set_background_color = true;
-    }
-  }
+  FMT_CONSTEXPR text_style(uint64_t style) noexcept : style_(style) {}
 
   friend FMT_CONSTEXPR auto fg(detail::color_type foreground) noexcept
       -> text_style;
@@ -303,23 +341,19 @@ class text_style {
   friend FMT_CONSTEXPR auto bg(detail::color_type background) noexcept
       -> text_style;
 
-  detail::color_type foreground_color;
-  detail::color_type background_color;
-  bool set_foreground_color;
-  bool set_background_color;
-  emphasis ems;
+  uint64_t style_ = 0;
 };
 
 /// Creates a text style from the foreground (text) color.
 FMT_CONSTEXPR inline auto fg(detail::color_type foreground) noexcept
     -> text_style {
-  return text_style(true, foreground);
+  return foreground.value_;
 }
 
 /// Creates a text style from the background color.
 FMT_CONSTEXPR inline auto bg(detail::color_type background) noexcept
     -> text_style {
-  return text_style(false, background);
+  return static_cast<uint64_t>(background.value_) << 27;
 }
 
 FMT_CONSTEXPR inline auto operator|(emphasis lhs, emphasis rhs) noexcept
@@ -330,13 +364,13 @@ FMT_CONSTEXPR inline auto operator|(emphasis lhs, emphasis rhs) noexcept
 namespace detail {
 
 template <typename Char> struct ansi_color_escape {
-  FMT_CONSTEXPR ansi_color_escape(detail::color_type text_color,
+  FMT_CONSTEXPR ansi_color_escape(color_type text_color,
                                   const char* esc) noexcept {
     // If we have a terminal color, we need to output another escape code
     // sequence.
-    if (!text_color.is_rgb) {
+    if (text_color.is_terminal_color()) {
       bool is_background = esc == string_view("\x1b[48;2;");
-      uint32_t value = text_color.value.term_color;
+      uint32_t value = text_color.value();
       // Background ASCII codes are the same as the foreground ones but with
       // 10 more.
       if (is_background) value += 10u;
@@ -360,7 +394,7 @@ template <typename Char> struct ansi_color_escape {
     for (int i = 0; i < 7; i++) {
       buffer[i] = static_cast<Char>(esc[i]);
     }
-    rgb color(text_color.value.rgb_color);
+    rgb color(text_color.value());
     to_esc(color.r, buffer + 7, ';');
     to_esc(color.g, buffer + 11, ';');
     to_esc(color.b, buffer + 15, 'm');
@@ -412,13 +446,13 @@ template <typename Char> struct ansi_color_escape {
 };
 
 template <typename Char>
-FMT_CONSTEXPR auto make_foreground_color(detail::color_type foreground) noexcept
+FMT_CONSTEXPR auto make_foreground_color(color_type foreground) noexcept
     -> ansi_color_escape<Char> {
   return ansi_color_escape<Char>(foreground, "\x1b[38;2;");
 }
 
 template <typename Char>
-FMT_CONSTEXPR auto make_background_color(detail::color_type background) noexcept
+FMT_CONSTEXPR auto make_background_color(color_type background) noexcept
     -> ansi_color_escape<Char> {
   return ansi_color_escape<Char>(background, "\x1b[48;2;");
 }
@@ -434,40 +468,33 @@ template <typename Char> inline void reset_color(buffer<Char>& buffer) {
   buffer.append(reset_color.begin(), reset_color.end());
 }
 
-template <typename T> struct styled_arg : detail::view {
+template <typename T> struct styled_arg : view {
   const T& value;
   text_style style;
   styled_arg(const T& v, text_style s) : value(v), style(s) {}
 };
 
 template <typename Char>
-void vformat_to(
-    buffer<Char>& buf, const text_style& ts, basic_string_view<Char> format_str,
-    basic_format_args<buffered_context<type_identity_t<Char>>> args) {
-  bool has_style = false;
+void vformat_to(buffer<Char>& buf, text_style ts, basic_string_view<Char> fmt,
+                basic_format_args<buffered_context<Char>> args) {
   if (ts.has_emphasis()) {
-    has_style = true;
-    auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
+    auto emphasis = make_emphasis<Char>(ts.get_emphasis());
     buf.append(emphasis.begin(), emphasis.end());
   }
   if (ts.has_foreground()) {
-    has_style = true;
-    auto foreground = detail::make_foreground_color<Char>(ts.get_foreground());
+    auto foreground = make_foreground_color<Char>(ts.get_foreground());
     buf.append(foreground.begin(), foreground.end());
   }
   if (ts.has_background()) {
-    has_style = true;
-    auto background = detail::make_background_color<Char>(ts.get_background());
+    auto background = make_background_color<Char>(ts.get_background());
     buf.append(background.begin(), background.end());
   }
-  detail::vformat_to(buf, format_str, args, {});
-  if (has_style) detail::reset_color<Char>(buf);
+  vformat_to(buf, fmt, args);
+  if (ts != text_style()) reset_color<Char>(buf);
 }
-
 }  // namespace detail
 
-inline void vprint(FILE* f, const text_style& ts, string_view fmt,
-                   format_args args) {
+inline void vprint(FILE* f, text_style ts, string_view fmt, format_args args) {
   auto buf = memory_buffer();
   detail::vformat_to(buf, ts, fmt, args);
   print(f, FMT_STRING("{}"), string_view(buf.begin(), buf.size()));
@@ -483,9 +510,8 @@ inline void vprint(FILE* f, const text_style& ts, string_view fmt,
  *                "Elapsed time: {0:.2f} seconds", 1.23);
  */
 template <typename... T>
-void print(FILE* f, const text_style& ts, format_string<T...> fmt,
-           T&&... args) {
-  vprint(f, ts, fmt, fmt::make_format_args(args...));
+void print(FILE* f, text_style ts, format_string<T...> fmt, T&&... args) {
+  vprint(f, ts, fmt.str, vargs<T...>{{args...}});
 }
 
 /**
@@ -498,11 +524,11 @@ void print(FILE* f, const text_style& ts, format_string<T...> fmt,
  *                "Elapsed time: {0:.2f} seconds", 1.23);
  */
 template <typename... T>
-void print(const text_style& ts, format_string<T...> fmt, T&&... args) {
+void print(text_style ts, format_string<T...> fmt, T&&... args) {
   return print(stdout, ts, fmt, std::forward<T>(args)...);
 }
 
-inline auto vformat(const text_style& ts, string_view fmt, format_args args)
+inline auto vformat(text_style ts, string_view fmt, format_args args)
     -> std::string {
   auto buf = memory_buffer();
   detail::vformat_to(buf, ts, fmt, args);
@@ -522,16 +548,16 @@ inline auto vformat(const text_style& ts, string_view fmt, format_args args)
  * ```
  */
 template <typename... T>
-inline auto format(const text_style& ts, format_string<T...> fmt, T&&... args)
+inline auto format(text_style ts, format_string<T...> fmt, T&&... args)
     -> std::string {
-  return fmt::vformat(ts, fmt, fmt::make_format_args(args...));
+  return fmt::vformat(ts, fmt.str, vargs<T...>{{args...}});
 }
 
 /// Formats a string with the given text_style and writes the output to `out`.
 template <typename OutputIt,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
-auto vformat_to(OutputIt out, const text_style& ts, string_view fmt,
-                format_args args) -> OutputIt {
+auto vformat_to(OutputIt out, text_style ts, string_view fmt, format_args args)
+    -> OutputIt {
   auto&& buf = detail::get_buffer<char>(out);
   detail::vformat_to(buf, ts, fmt, args);
   return detail::get_iterator(buf, out);
@@ -549,9 +575,9 @@ auto vformat_to(OutputIt out, const text_style& ts, string_view fmt,
  */
 template <typename OutputIt, typename... T,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
-inline auto format_to(OutputIt out, const text_style& ts,
-                      format_string<T...> fmt, T&&... args) -> OutputIt {
-  return vformat_to(out, ts, fmt, fmt::make_format_args(args...));
+inline auto format_to(OutputIt out, text_style ts, format_string<T...> fmt,
+                      T&&... args) -> OutputIt {
+  return vformat_to(out, ts, fmt.str, vargs<T...>{{args...}});
 }
 
 template <typename T, typename Char>
@@ -560,31 +586,30 @@ struct formatter<detail::styled_arg<T>, Char> : formatter<T, Char> {
   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);
+      out = detail::copy<Char>(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);
+      out = detail::copy<Char>(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 = detail::copy<Char>(background.begin(), background.end(), out);
     }
-    out = formatter<T, Char>::format(value, ctx);
+    out = formatter<T, Char>::format(arg.value, ctx);
     if (has_style) {
       auto reset_color = string_view("\x1b[0m");
-      out = std::copy(reset_color.begin(), reset_color.end(), out);
+      out = detail::copy<Char>(reset_color.begin(), reset_color.end(), out);
     }
     return out;
   }

include/spdlog/fmt/bundled/compile.h

@@ -19,17 +19,11 @@ FMT_BEGIN_NAMESPACE
 // A compile-time string which is compiled into fast formatting code.
 FMT_EXPORT class compiled_string {};
 
-namespace detail {
-
-template <typename T, typename InputIt>
-FMT_CONSTEXPR inline auto copy(InputIt begin, InputIt end, counting_iterator it)
-    -> counting_iterator {
-  return it + (end - begin);
-}
-
 template <typename S>
 struct is_compiled_string : std::is_base_of<compiled_string, S> {};
 
+namespace detail {
+
 /**
  * Converts a string literal `s` into a format string that will be parsed at
  * compile time and converted into efficient formatting code. Requires C++17
@@ -42,22 +36,11 @@ struct is_compiled_string : std::is_base_of<compiled_string, S> {};
  *     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
  */
 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
-#  define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::compiled_string, explicit)
+#  define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::compiled_string)
 #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>
 auto first(const T& value, const Tail&...) -> const T& {
   return value;
@@ -77,6 +60,29 @@ constexpr const auto& get([[maybe_unused]] const T& first,
     return detail::get<N - 1>(rest...);
 }
 
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+template <int N, typename T, typename... Args, typename Char>
+constexpr auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
+  if constexpr (is_static_named_arg<T>()) {
+    if (name == T::name) return N;
+  }
+  if constexpr (sizeof...(Args) > 0)
+    return get_arg_index_by_name<N + 1, Args...>(name);
+  (void)name;  // Workaround an MSVC bug about "unused" parameter.
+  return -1;
+}
+#  endif
+
+template <typename... Args, typename Char>
+FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+  if constexpr (sizeof...(Args) > 0)
+    return get_arg_index_by_name<0, Args...>(name);
+#  endif
+  (void)name;
+  return -1;
+}
+
 template <typename Char, typename... Args>
 constexpr int get_arg_index_by_name(basic_string_view<Char> name,
                                     type_list<Args...>) {
@@ -149,9 +155,10 @@ template <typename Char, typename T, int N> struct field {
     if constexpr (std::is_convertible<T, basic_string_view<Char>>::value) {
       auto s = basic_string_view<Char>(arg);
       return copy<Char>(s.begin(), s.end(), out);
-    }
+    } else {
       return write<Char>(out, arg);
     }
+  }
 };
 
 template <typename Char, typename T, int N>
@@ -275,6 +282,7 @@ constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
 }
 
 template <typename Char> struct arg_id_handler {
+  arg_id_kind kind;
   arg_ref<Char> arg_id;
 
   constexpr int on_auto() {
@@ -282,25 +290,28 @@ template <typename Char> struct arg_id_handler {
     return 0;
   }
   constexpr int on_index(int id) {
+    kind = arg_id_kind::index;
     arg_id = arg_ref<Char>(id);
     return 0;
   }
   constexpr int on_name(basic_string_view<Char> id) {
+    kind = arg_id_kind::name;
     arg_id = arg_ref<Char>(id);
     return 0;
   }
 };
 
 template <typename Char> struct parse_arg_id_result {
+  arg_id_kind kind;
   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 handler = arg_id_handler<Char>{arg_id_kind::none, 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};
+  return parse_arg_id_result<Char>{handler.kind, handler.arg_id, arg_id_end};
 }
 
 template <typename T, typename Enable = void> struct field_type {
@@ -363,18 +374,18 @@ constexpr auto compile_format_string(S fmt) {
       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) {
+      if constexpr (arg_id_result.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;
+        constexpr auto arg_index = arg_id_result.arg_id.index;
         return parse_replacement_field_then_tail<get_type<arg_index, Args>,
                                                  Args, arg_id_end_pos,
                                                  arg_index, manual_indexing_id>(
             fmt);
-      } else if constexpr (arg_id_result.arg_id.kind == arg_id_kind::name) {
+      } else if constexpr (arg_id_result.kind == arg_id_kind::name) {
         constexpr auto arg_index =
-            get_arg_index_by_name(arg_id_result.arg_id.val.name, Args{});
+            get_arg_index_by_name(arg_id_result.arg_id.name, Args{});
         if constexpr (arg_index >= 0) {
           constexpr auto next_id =
               ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
@@ -383,8 +394,7 @@ constexpr auto compile_format_string(S fmt) {
               arg_index, next_id>(fmt);
         } 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},
-              fmt);
+              runtime_named_field<char_type>{arg_id_result.arg_id.name}, fmt);
         } else if constexpr (c == ':') {
           return unknown_format();  // no type info for specs parsing
         }
@@ -405,7 +415,7 @@ constexpr auto compile_format_string(S fmt) {
 }
 
 template <typename... Args, typename S,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 constexpr auto compile(S fmt) {
   constexpr auto str = basic_string_view<typename S::char_type>(fmt);
   if constexpr (str.size() == 0) {
@@ -441,7 +451,7 @@ constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
                                                            Args&&... args) {
   if constexpr (std::is_same<typename S::char_type, char>::value) {
@@ -468,7 +478,7 @@ FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
 }
 
 template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(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)>,
@@ -483,7 +493,7 @@ FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
 #endif
 
 template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 auto format_to_n(OutputIt out, size_t n, const S& fmt, Args&&... args)
     -> format_to_n_result<OutputIt> {
   using traits = detail::fixed_buffer_traits;
@@ -493,32 +503,32 @@ auto format_to_n(OutputIt out, size_t n, const S& fmt, Args&&... args)
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 FMT_CONSTEXPR20 auto formatted_size(const S& fmt, const Args&... args)
     -> size_t {
-  return fmt::format_to(detail::counting_iterator(), fmt, args...).count();
+  auto buf = detail::counting_buffer<>();
+  fmt::format_to(appender(buf), fmt, args...);
+  return buf.count();
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 void print(std::FILE* f, const S& fmt, const Args&... args) {
-  memory_buffer buffer;
-  fmt::format_to(std::back_inserter(buffer), fmt, args...);
-  detail::print(f, {buffer.data(), buffer.size()});
+  auto buf = memory_buffer();
+  fmt::format_to(appender(buf), fmt, args...);
+  detail::print(f, {buf.data(), buf.size()});
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 void print(const S& fmt, const Args&... args) {
   print(stdout, fmt, 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>();
+template <detail::fixed_string Str> constexpr auto operator""_cf() {
+  return FMT_COMPILE(Str.data);
 }
 }  // namespace literals
 #endif

include/spdlog/fmt/bundled/fmt.license.rst

@@ -1,4 +1,4 @@
-Copyright (c) 2012 - present, Victor Zverovich
+Copyright (c) 2012 - present, Victor Zverovich and {fmt} contributors
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the

include/spdlog/fmt/bundled/format-inl.h

@@ -14,10 +14,6 @@
 #  include <climits>
 #  include <cmath>
 #  include <exception>
-
-#  if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
-#    include <locale>
-#  endif
 #endif
 
 #if defined(_WIN32) && !defined(FMT_USE_WRITE_CONSOLE)
@@ -26,16 +22,22 @@
 
 #include "format.h"
 
+#if FMT_USE_LOCALE
+#  include <locale>
+#endif
+
+#ifndef FMT_FUNC
+#  define FMT_FUNC
+#endif
+
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
 FMT_FUNC void assert_fail(const char* file, int line, const char* message) {
   // Use unchecked std::fprintf to avoid triggering another assertion when
-  // writing to stderr fails
-  std::fprintf(stderr, "%s:%d: assertion failed: %s", file, line, message);
-  // Chosen instead of std::abort to satisfy Clang in CUDA mode during device
-  // code pass.
-  std::terminate();
+  // writing to stderr fails.
+  fprintf(stderr, "%s:%d: assertion failed: %s", file, line, message);
+  abort();
 }
 
 FMT_FUNC void format_error_code(detail::buffer<char>& out, int error_code,
@@ -61,86 +63,95 @@ FMT_FUNC void format_error_code(detail::buffer<char>& out, int error_code,
   FMT_ASSERT(out.size() <= inline_buffer_size, "");
 }
 
-FMT_FUNC void report_error(format_func func, int error_code,
+FMT_FUNC void do_report_error(format_func func, int error_code,
                               const char* message) noexcept {
   memory_buffer full_message;
   func(full_message, error_code, message);
-  // Don't use fwrite_fully because the latter may throw.
+  // Don't use fwrite_all because the latter may throw.
   if (std::fwrite(full_message.data(), full_message.size(), 1, stderr) > 0)
     std::fputc('\n', stderr);
 }
 
 // A wrapper around fwrite that throws on error.
-inline void fwrite_fully(const void* ptr, size_t count, FILE* stream) {
+inline void fwrite_all(const void* ptr, size_t count, FILE* stream) {
   size_t written = std::fwrite(ptr, 1, count, stream);
   if (written < count)
     FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
 }
 
-#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#if FMT_USE_LOCALE
+using std::locale;
+using std::numpunct;
+using std::use_facet;
+
 template <typename Locale>
 locale_ref::locale_ref(const Locale& loc) : locale_(&loc) {
-  static_assert(std::is_same<Locale, std::locale>::value, "");
+  static_assert(std::is_same<Locale, locale>::value, "");
 }
+#else
+struct locale {};
+template <typename Char> struct numpunct {
+  auto grouping() const -> std::string { return "\03"; }
+  auto thousands_sep() const -> Char { return ','; }
+  auto decimal_point() const -> Char { return '.'; }
+};
+template <typename Facet> Facet use_facet(locale) { return {}; }
+#endif  // FMT_USE_LOCALE
 
 template <typename Locale> auto locale_ref::get() const -> Locale {
-  static_assert(std::is_same<Locale, std::locale>::value, "");
-  return locale_ ? *static_cast<const std::locale*>(locale_) : std::locale();
+  static_assert(std::is_same<Locale, locale>::value, "");
+#if FMT_USE_LOCALE
+  if (locale_) return *static_cast<const locale*>(locale_);
+#endif
+  return locale();
 }
 
 template <typename Char>
 FMT_FUNC auto thousands_sep_impl(locale_ref loc) -> thousands_sep_result<Char> {
-  auto& facet = std::use_facet<std::numpunct<Char>>(loc.get<std::locale>());
+  auto&& facet = use_facet<numpunct<Char>>(loc.get<locale>());
   auto grouping = facet.grouping();
   auto thousands_sep = grouping.empty() ? Char() : facet.thousands_sep();
   return {std::move(grouping), thousands_sep};
 }
 template <typename Char>
 FMT_FUNC auto decimal_point_impl(locale_ref loc) -> Char {
-  return std::use_facet<std::numpunct<Char>>(loc.get<std::locale>())
-      .decimal_point();
+  return use_facet<numpunct<Char>>(loc.get<locale>()).decimal_point();
 }
-#else
-template <typename Char>
-FMT_FUNC auto thousands_sep_impl(locale_ref) -> thousands_sep_result<Char> {
-  return {"\03", FMT_STATIC_THOUSANDS_SEPARATOR};
-}
-template <typename Char> FMT_FUNC Char decimal_point_impl(locale_ref) {
-  return '.';
-}
-#endif
 
+#if FMT_USE_LOCALE
 FMT_FUNC auto write_loc(appender out, loc_value value,
                         const format_specs& specs, locale_ref loc) -> bool {
-#ifdef FMT_STATIC_THOUSANDS_SEPARATOR
-  value.visit(loc_writer<>{
-      out, specs, std::string(1, FMT_STATIC_THOUSANDS_SEPARATOR), "\3", "."});
-  return true;
-#else
   auto locale = loc.get<std::locale>();
   // We cannot use the num_put<char> facet because it may produce output in
   // a wrong encoding.
   using facet = format_facet<std::locale>;
   if (std::has_facet<facet>(locale))
-    return std::use_facet<facet>(locale).put(out, value, specs);
+    return use_facet<facet>(locale).put(out, value, specs);
   return facet(locale).put(out, value, specs);
-#endif
 }
+#endif
 }  // namespace detail
 
 FMT_FUNC void report_error(const char* message) {
+#if FMT_USE_EXCEPTIONS
+  // Use FMT_THROW instead of throw to avoid bogus unreachable code warnings
+  // from MSVC.
   FMT_THROW(format_error(message));
+#else
+  fputs(message, stderr);
+  abort();
+#endif
 }
 
 template <typename Locale> typename Locale::id format_facet<Locale>::id;
 
-#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
 template <typename Locale> format_facet<Locale>::format_facet(Locale& loc) {
-  auto& numpunct = std::use_facet<std::numpunct<char>>(loc);
-  grouping_ = numpunct.grouping();
-  if (!grouping_.empty()) separator_ = std::string(1, numpunct.thousands_sep());
+  auto& np = detail::use_facet<detail::numpunct<char>>(loc);
+  grouping_ = np.grouping();
+  if (!grouping_.empty()) separator_ = std::string(1, np.thousands_sep());
 }
 
+#if FMT_USE_LOCALE
 template <>
 FMT_API FMT_FUNC auto format_facet<std::locale>::do_put(
     appender out, loc_value val, const format_specs& specs) const -> bool {
@@ -201,7 +212,7 @@ inline auto floor_log10_pow2_minus_log10_4_over_3(int e) noexcept -> int {
   return (e * 631305 - 261663) >> 21;
 }
 
-FMT_INLINE_VARIABLE constexpr struct {
+FMT_INLINE_VARIABLE constexpr struct div_small_pow10_infos_struct {
   uint32_t divisor;
   int shift_amount;
 } div_small_pow10_infos[] = {{10, 16}, {100, 16}};
@@ -1086,7 +1097,7 @@ template <> struct cache_accessor<double> {
     return {r.high(), r.low() == 0};
   }
 
-  static auto compute_delta(cache_entry_type const& cache, int beta) noexcept
+  static auto compute_delta(const cache_entry_type& cache, int beta) noexcept
       -> uint32_t {
     return static_cast<uint32_t>(cache.high() >> (64 - 1 - beta));
   }
@@ -1425,7 +1436,7 @@ FMT_FUNC void format_system_error(detail::buffer<char>& out, int error_code,
 
 FMT_FUNC void report_system_error(int error_code,
                                   const char* message) noexcept {
-  report_error(format_system_error, error_code, message);
+  do_report_error(format_system_error, error_code, message);
 }
 
 FMT_FUNC auto vformat(string_view fmt, format_args args) -> std::string {
@@ -1438,6 +1449,15 @@ FMT_FUNC auto vformat(string_view fmt, format_args args) -> std::string {
 
 namespace detail {
 
+FMT_FUNC void vformat_to(buffer<char>& buf, string_view fmt, format_args args,
+                         locale_ref loc) {
+  auto out = appender(buf);
+  if (fmt.size() == 2 && equal2(fmt.data(), "{}"))
+    return args.get(0).visit(default_arg_formatter<char>{out});
+  parse_format_string(
+      fmt, format_handler<char>{parse_context<char>(fmt), {out, args, loc}});
+}
+
 template <typename T> struct span {
   T* data;
   size_t size;
@@ -1506,7 +1526,7 @@ template <typename F> class glibc_file : public file_base<F> {
   }
 
   void init_buffer() {
-    if (this->file_->_IO_write_ptr) return;
+    if (this->file_->_IO_write_ptr < this->file_->_IO_write_end) return;
     // Force buffer initialization by placing and removing a char in a buffer.
     putc_unlocked(0, this->file_);
     --this->file_->_IO_write_ptr;
@@ -1615,7 +1635,7 @@ template <typename F> class fallback_file : public file_base<F> {
 };
 
 #ifndef FMT_USE_FALLBACK_FILE
-#  define FMT_USE_FALLBACK_FILE 1
+#  define FMT_USE_FALLBACK_FILE 0
 #endif
 
 template <typename F,
@@ -1692,7 +1712,7 @@ FMT_FUNC void vprint_mojibake(std::FILE* f, string_view fmt, format_args args,
   auto buffer = memory_buffer();
   detail::vformat_to(buffer, fmt, args);
   if (newline) buffer.push_back('\n');
-  fwrite_fully(buffer.data(), buffer.size(), f);
+  fwrite_all(buffer.data(), buffer.size(), f);
 }
 #endif
 
@@ -1704,7 +1724,7 @@ FMT_FUNC void print(std::FILE* f, string_view text) {
     if (write_console(fd, text)) return;
   }
 #endif
-  fwrite_fully(text.data(), text.size(), f);
+  fwrite_all(text.data(), text.size(), f);
 }
 }  // namespace detail
 

include/spdlog/fmt/bundled/locale.h

@@ -1,2 +0,0 @@
-#include "xchar.h"
-#warning fmt/locale.h is deprecated, include fmt/format.h or fmt/xchar.h instead

include/spdlog/fmt/bundled/os.h

@@ -118,7 +118,7 @@ FMT_API void format_windows_error(buffer<char>& out, int error_code,
                                   const char* message) noexcept;
 }
 
-FMT_API std::system_error vwindows_error(int error_code, string_view format_str,
+FMT_API std::system_error vwindows_error(int error_code, string_view fmt,
                                          format_args args);
 
 /**
@@ -146,10 +146,10 @@ FMT_API std::system_error vwindows_error(int error_code, string_view format_str,
  *                                "cannot open file '{}'", filename);
  *     }
  */
-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...));
+template <typename... T>
+auto windows_error(int error_code, string_view message, const T&... args)
+    -> std::system_error {
+  return vwindows_error(error_code, message, vargs<T...>{{args...}});
 }
 
 // Reports a Windows error without throwing an exception.
@@ -164,8 +164,8 @@ inline auto system_category() noexcept -> const std::error_category& {
 // 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());
+void say(const S& fmt, Args&&... args) {
+  std::system(format("say \"{}\"", format(fmt, args...)).c_str());
 }
 #endif
 
@@ -176,24 +176,24 @@ class buffered_file {
 
   friend class file;
 
-  explicit buffered_file(FILE* f) : file_(f) {}
+  inline explicit buffered_file(FILE* f) : file_(f) {}
 
  public:
   buffered_file(const buffered_file&) = delete;
   void operator=(const buffered_file&) = delete;
 
   // Constructs a buffered_file object which doesn't represent any file.
-  buffered_file() noexcept : file_(nullptr) {}
+  inline buffered_file() noexcept : file_(nullptr) {}
 
   // Destroys the object closing the file it represents if any.
   FMT_API ~buffered_file() noexcept;
 
  public:
-  buffered_file(buffered_file&& other) noexcept : file_(other.file_) {
+  inline buffered_file(buffered_file&& other) noexcept : file_(other.file_) {
     other.file_ = nullptr;
   }
 
-  auto operator=(buffered_file&& other) -> buffered_file& {
+  inline auto operator=(buffered_file&& other) -> buffered_file& {
     close();
     file_ = other.file_;
     other.file_ = nullptr;
@@ -207,13 +207,13 @@ class buffered_file {
   FMT_API void close();
 
   // Returns the pointer to a FILE object representing this file.
-  auto get() const noexcept -> FILE* { return file_; }
+  inline auto get() const noexcept -> FILE* { return file_; }
 
   FMT_API auto descriptor() const -> int;
 
   template <typename... T>
   inline void print(string_view fmt, const T&... args) {
-    const auto& vargs = fmt::make_format_args(args...);
+    fmt::vargs<T...> vargs = {{args...}};
     detail::is_locking<T...>() ? fmt::vprint_buffered(file_, fmt, vargs)
                                : fmt::vprint(file_, fmt, vargs);
   }
@@ -248,7 +248,7 @@ class FMT_API file {
   };
 
   // Constructs a file object which doesn't represent any file.
-  file() noexcept : fd_(-1) {}
+  inline file() noexcept : fd_(-1) {}
 
   // Opens a file and constructs a file object representing this file.
   file(cstring_view path, int oflag);
@@ -257,10 +257,10 @@ class FMT_API file {
   file(const file&) = delete;
   void operator=(const file&) = delete;
 
-  file(file&& other) noexcept : fd_(other.fd_) { other.fd_ = -1; }
+  inline file(file&& other) noexcept : fd_(other.fd_) { other.fd_ = -1; }
 
   // Move assignment is not noexcept because close may throw.
-  auto operator=(file&& other) -> file& {
+  inline auto operator=(file&& other) -> file& {
     close();
     fd_ = other.fd_;
     other.fd_ = -1;
@@ -271,7 +271,7 @@ class FMT_API file {
   ~file() noexcept;
 
   // Returns the file descriptor.
-  auto descriptor() const noexcept -> int { return fd_; }
+  inline auto descriptor() const noexcept -> int { return fd_; }
 
   // Closes the file.
   void close();
@@ -324,9 +324,9 @@ auto getpagesize() -> long;
 namespace detail {
 
 struct buffer_size {
-  buffer_size() = default;
+  constexpr buffer_size() = default;
   size_t value = 0;
-  auto operator=(size_t val) const -> buffer_size {
+  FMT_CONSTEXPR auto operator=(size_t val) const -> buffer_size {
     auto bs = buffer_size();
     bs.value = val;
     return bs;
@@ -337,7 +337,7 @@ struct ostream_params {
   int oflag = file::WRONLY | file::CREATE | file::TRUNC;
   size_t buffer_size = BUFSIZ > 32768 ? BUFSIZ : 32768;
 
-  ostream_params() {}
+  constexpr ostream_params() {}
 
   template <typename... T>
   ostream_params(T... params, int new_oflag) : ostream_params(params...) {
@@ -358,59 +358,47 @@ struct ostream_params {
 #  endif
 };
 
-class file_buffer final : public buffer<char> {
+}  // namespace detail
+
+FMT_INLINE_VARIABLE constexpr auto buffer_size = detail::buffer_size();
+
+/// A fast buffered output stream for writing from a single thread. Writing from
+/// multiple threads without external synchronization may result in a data race.
+class FMT_API ostream : private detail::buffer<char> {
  private:
   file file_;
 
-  FMT_API static void grow(buffer<char>& buf, size_t);
+  ostream(cstring_view path, const detail::ostream_params& params);
+
+  static void grow(buffer<char>& buf, size_t);
 
  public:
-  FMT_API file_buffer(cstring_view path, const ostream_params& params);
-  FMT_API file_buffer(file_buffer&& other) noexcept;
-  FMT_API ~file_buffer();
+  ostream(ostream&& other) noexcept;
+  ~ostream();
 
-  void flush() {
+  operator writer() {
+    detail::buffer<char>& buf = *this;
+    return buf;
+  }
+
+  inline void flush() {
     if (size() == 0) return;
     file_.write(data(), size() * sizeof(data()[0]));
     clear();
   }
 
-  void close() {
-    flush();
-    file_.close();
-  }
-};
-
-}  // namespace detail
-
-constexpr auto buffer_size = detail::buffer_size();
-
-/// A fast output stream for writing from a single thread. Writing from
-/// multiple threads without external synchronization may result in a data race.
-class FMT_API ostream {
- private:
-  FMT_MSC_WARNING(suppress : 4251)
-  detail::file_buffer buffer_;
-
-  ostream(cstring_view path, const detail::ostream_params& params)
-      : buffer_(path, params) {}
-
- public:
-  ostream(ostream&& other) : buffer_(std::move(other.buffer_)) {}
-
-  ~ostream();
-
-  void flush() { buffer_.flush(); }
-
   template <typename... T>
   friend auto output_file(cstring_view path, T... params) -> ostream;
 
-  void close() { buffer_.close(); }
+  inline void close() {
+    flush();
+    file_.close();
+  }
 
   /// 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(appender(buffer_), fmt, fmt::make_format_args(args...));
+    vformat_to(appender(*this), fmt.str, vargs<T...>{{args...}});
   }
 };
 

include/spdlog/fmt/bundled/ostream.h

@@ -22,6 +22,14 @@
 
 #include "chrono.h"  // formatbuf
 
+#ifdef _MSVC_STL_UPDATE
+#  define FMT_MSVC_STL_UPDATE _MSVC_STL_UPDATE
+#elif defined(_MSC_VER) && _MSC_VER < 1912  // VS 15.5
+#  define FMT_MSVC_STL_UPDATE _MSVC_LANG
+#else
+#  define FMT_MSVC_STL_UPDATE 0
+#endif
+
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
@@ -35,53 +43,18 @@ class file_access {
   friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
 };
 
-#if FMT_MSC_VERSION
+#if FMT_MSVC_STL_UPDATE
 template class file_access<file_access_tag, std::filebuf,
                            &std::filebuf::_Myfile>;
 auto get_file(std::filebuf&) -> FILE*;
 #endif
 
-inline auto write_ostream_unicode(std::ostream& os, fmt::string_view data)
-    -> bool {
-  FILE* f = nullptr;
-#if FMT_MSC_VERSION && FMT_USE_RTTI
-  if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
-    f = get_file(*buf);
-  else
-    return false;
-#elif defined(_WIN32) && defined(__GLIBCXX__) && FMT_USE_RTTI
-  auto* rdbuf = os.rdbuf();
-  if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
-    f = sfbuf->file();
-  else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
-    f = fbuf->file();
-  else
-    return false;
-#else
-  ignore_unused(os, data, f);
-#endif
-#ifdef _WIN32
-  if (f) {
-    int fd = _fileno(f);
-    if (_isatty(fd)) {
-      os.flush();
-      return write_console(fd, data);
-    }
-  }
-#endif
-  return false;
-}
-inline auto write_ostream_unicode(std::wostream&,
-                                  fmt::basic_string_view<wchar_t>) -> bool {
-  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();
-  using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
+  using unsigned_streamsize = make_unsigned_t<std::streamsize>;
   unsigned_streamsize size = buf.size();
   unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>());
   do {
@@ -92,21 +65,9 @@ void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
   } while (size != 0);
 }
 
-template <typename Char, typename T>
-void format_value(buffer<Char>& buf, const T& value) {
-  auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf);
-  auto&& output = std::basic_ostream<Char>(&format_buf);
-#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
-  output.imbue(std::locale::classic());  // The default is always unlocalized.
-#endif
-  output << value;
-  output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
-}
-
 template <typename T> struct streamed_view {
   const T& value;
 };
-
 }  // namespace detail
 
 // Formats an object of type T that has an overloaded ostream operator<<.
@@ -117,7 +78,11 @@ struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
   template <typename T, typename Context>
   auto format(const T& value, Context& ctx) const -> decltype(ctx.out()) {
     auto buffer = basic_memory_buffer<Char>();
-    detail::format_value(buffer, value);
+    auto&& formatbuf = detail::formatbuf<std::basic_streambuf<Char>>(buffer);
+    auto&& output = std::basic_ostream<Char>(&formatbuf);
+    output.imbue(std::locale::classic());  // The default is always unlocalized.
+    output << value;
+    output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
     return formatter<basic_string_view<Char>, Char>::format(
         {buffer.data(), buffer.size()}, ctx);
   }
@@ -148,24 +113,30 @@ constexpr auto streamed(const T& value) -> detail::streamed_view<T> {
   return {value};
 }
 
-namespace detail {
-
-inline void vprint_directly(std::ostream& os, string_view format_str,
-                            format_args args) {
+inline void vprint(std::ostream& os, string_view fmt, format_args args) {
   auto buffer = memory_buffer();
-  detail::vformat_to(buffer, format_str, args);
-  detail::write_buffer(os, buffer);
-}
-
-}  // namespace detail
-
-FMT_EXPORT template <typename Char>
-void vprint(std::basic_ostream<Char>& os,
-            basic_string_view<type_identity_t<Char>> format_str,
-            typename detail::vformat_args<Char>::type args) {
-  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::vformat_to(buffer, fmt, args);
+  FILE* f = nullptr;
+#if FMT_MSVC_STL_UPDATE && FMT_USE_RTTI
+  if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
+    f = detail::get_file(*buf);
+#elif defined(_WIN32) && defined(__GLIBCXX__) && FMT_USE_RTTI
+  auto* rdbuf = os.rdbuf();
+  if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
+    f = sfbuf->file();
+  else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
+    f = fbuf->file();
+#endif
+#ifdef _WIN32
+  if (f) {
+    int fd = _fileno(f);
+    if (_isatty(fd)) {
+      os.flush();
+      if (detail::write_console(fd, {buffer.data(), buffer.size()})) return;
+    }
+  }
+#endif
+  detail::ignore_unused(f);
   detail::write_buffer(os, buffer);
 }
 
@@ -178,32 +149,17 @@ void vprint(std::basic_ostream<Char>& os,
  */
 FMT_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::use_utf8())
-    vprint(os, fmt, vargs);
-  else
-    detail::vprint_directly(os, fmt, vargs);
-}
-
-FMT_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<buffered_context<wchar_t>>(args...));
+  fmt::vargs<T...> vargs = {{args...}};
+  if (detail::const_check(detail::use_utf8)) return vprint(os, fmt.str, vargs);
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, fmt.str, vargs);
+  detail::write_buffer(os, buffer);
 }
 
 FMT_EXPORT template <typename... T>
 void println(std::ostream& os, format_string<T...> fmt, T&&... args) {
-  fmt::print(os, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
-}
-
-FMT_EXPORT
-template <typename... Args>
-void println(std::wostream& os,
-             basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
-             Args&&... args) {
-  print(os, L"{}\n", fmt::format(fmt, std::forward<Args>(args)...));
+  fmt::print(os, FMT_STRING("{}\n"),
+             fmt::format(fmt, std::forward<T>(args)...));
 }
 
 FMT_END_NAMESPACE

include/spdlog/fmt/bundled/printf.h

@@ -33,8 +33,9 @@ template <typename Char> class basic_printf_context {
 
  public:
   using char_type = Char;
-  using parse_context_type = basic_format_parse_context<Char>;
+  using parse_context_type = parse_context<Char>;
   template <typename T> using formatter_type = printf_formatter<T>;
+  enum { builtin_types = 1 };
 
   /// Constructs a `printf_context` object. References to the arguments are
   /// stored in the context object so make sure they have appropriate lifetimes.
@@ -54,6 +55,23 @@ template <typename Char> class basic_printf_context {
 
 namespace detail {
 
+// Return the result via the out param to workaround gcc bug 77539.
+template <bool IS_CONSTEXPR, typename T, typename Ptr = const T*>
+FMT_CONSTEXPR auto find(Ptr first, Ptr last, T value, Ptr& out) -> bool {
+  for (out = first; out != last; ++out) {
+    if (*out == value) return true;
+  }
+  return false;
+}
+
+template <>
+inline auto find<false, char>(const char* first, const char* last, char value,
+                              const char*& out) -> bool {
+  out =
+      static_cast<const char*>(memchr(first, value, to_unsigned(last - first)));
+  return out != nullptr;
+}
+
 // Checks if a value fits in int - used to avoid warnings about comparing
 // signed and unsigned integers.
 template <bool IsSigned> struct int_checker {
@@ -61,7 +79,7 @@ template <bool IsSigned> struct int_checker {
     unsigned max = to_unsigned(max_value<int>());
     return value <= max;
   }
-  static auto fits_in_int(bool) -> bool { return true; }
+  inline static auto fits_in_int(bool) -> bool { return true; }
 };
 
 template <> struct int_checker<true> {
@@ -69,7 +87,7 @@ template <> struct int_checker<true> {
     return value >= (std::numeric_limits<int>::min)() &&
            value <= max_value<int>();
   }
-  static auto fits_in_int(int) -> bool { return true; }
+  inline static auto fits_in_int(int) -> bool { return true; }
 };
 
 struct printf_precision_handler {
@@ -127,25 +145,19 @@ template <typename T, typename Context> class arg_converter {
     using target_type = conditional_t<std::is_same<T, void>::value, U, T>;
     if (const_check(sizeof(target_type) <= sizeof(int))) {
       // Extra casts are used to silence warnings.
-      if (is_signed) {
-        auto n = static_cast<int>(static_cast<target_type>(value));
-        arg_ = detail::make_arg<Context>(n);
-      } else {
       using unsigned_type = typename make_unsigned_or_bool<target_type>::type;
-        auto n = static_cast<unsigned>(static_cast<unsigned_type>(value));
-        arg_ = detail::make_arg<Context>(n);
-      }
+      if (is_signed)
+        arg_ = static_cast<int>(static_cast<target_type>(value));
+      else
+        arg_ = static_cast<unsigned>(static_cast<unsigned_type>(value));
     } else {
-      if (is_signed) {
       // glibc's printf doesn't sign extend arguments of smaller types:
       //   std::printf("%lld", -42);  // prints "4294967254"
       // but we don't have to do the same because it's a UB.
-        auto n = static_cast<long long>(value);
-        arg_ = detail::make_arg<Context>(n);
-      } else {
-        auto n = static_cast<typename make_unsigned_or_bool<U>::type>(value);
-        arg_ = detail::make_arg<Context>(n);
-      }
+      if (is_signed)
+        arg_ = static_cast<long long>(value);
+      else
+        arg_ = static_cast<typename make_unsigned_or_bool<U>::type>(value);
     }
   }
 
@@ -172,8 +184,7 @@ template <typename Context> class char_converter {
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   void operator()(T value) {
-    auto c = static_cast<typename Context::char_type>(value);
-    arg_ = detail::make_arg<Context>(c);
+    arg_ = static_cast<typename Context::char_type>(value);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
@@ -194,13 +205,13 @@ class printf_width_handler {
   format_specs& specs_;
 
  public:
-  explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
+  inline explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   auto operator()(T value) -> unsigned {
     auto width = static_cast<uint32_or_64_or_128_t<T>>(value);
     if (detail::is_negative(value)) {
-      specs_.align = align::left;
+      specs_.set_align(align::left);
       width = 0 - width;
     }
     unsigned int_max = to_unsigned(max_value<int>());
@@ -234,69 +245,74 @@ class printf_arg_formatter : public arg_formatter<Char> {
 
   void write_null_pointer(bool is_string = false) {
     auto s = this->specs;
-    s.type = presentation_type::none;
+    s.set_type(presentation_type::none);
     write_bytes<Char>(this->out, is_string ? "(null)" : "(nil)", s);
   }
 
+  template <typename T> void write(T value) {
+    detail::write<Char>(this->out, value, this->specs, this->locale);
+  }
+
  public:
   printf_arg_formatter(basic_appender<Char> iter, format_specs& s,
                        context_type& ctx)
       : base(make_arg_formatter(iter, s)), context_(ctx) {}
 
-  void operator()(monostate value) { base::operator()(value); }
+  void operator()(monostate value) { write(value); }
 
   template <typename T, FMT_ENABLE_IF(detail::is_integral<T>::value)>
   void 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) {
-      base::operator()(value);
+      write(value);
       return;
     }
     format_specs s = this->specs;
-    if (s.type != presentation_type::none && s.type != presentation_type::chr) {
+    if (s.type() != presentation_type::none &&
+        s.type() != presentation_type::chr) {
       return (*this)(static_cast<int>(value));
     }
-    s.sign = sign::none;
-    s.alt = false;
-    s.fill = ' ';  // Ignore '0' flag for char types.
+    s.set_sign(sign::none);
+    s.clear_alt();
+    s.set_fill(' ');  // Ignore '0' flag for char types.
     // align::numeric needs to be overwritten here since the '0' flag is
     // ignored for non-numeric types
-    if (s.align == align::none || s.align == align::numeric)
-      s.align = align::right;
-    write<Char>(this->out, static_cast<Char>(value), s);
+    if (s.align() == align::none || s.align() == align::numeric)
+      s.set_align(align::right);
+    detail::write<Char>(this->out, static_cast<Char>(value), s);
   }
 
   template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
   void operator()(T value) {
-    base::operator()(value);
+    write(value);
   }
 
   void operator()(const char* value) {
     if (value)
-      base::operator()(value);
+      write(value);
     else
-      write_null_pointer(this->specs.type != presentation_type::pointer);
+      write_null_pointer(this->specs.type() != presentation_type::pointer);
   }
 
   void operator()(const wchar_t* value) {
     if (value)
-      base::operator()(value);
+      write(value);
     else
-      write_null_pointer(this->specs.type != presentation_type::pointer);
+      write_null_pointer(this->specs.type() != presentation_type::pointer);
   }
 
-  void operator()(basic_string_view<Char> value) { base::operator()(value); }
+  void operator()(basic_string_view<Char> value) { write(value); }
 
   void operator()(const void* value) {
     if (value)
-      base::operator()(value);
+      write(value);
     else
       write_null_pointer();
   }
 
   void operator()(typename basic_format_arg<context_type>::handle handle) {
-    auto parse_ctx = basic_format_parse_context<Char>({});
+    auto parse_ctx = parse_context<Char>({});
     handle.format(parse_ctx, context_);
   }
 };
@@ -305,23 +321,14 @@ template <typename Char>
 void parse_flags(format_specs& specs, const Char*& it, const Char* end) {
   for (; it != end; ++it) {
     switch (*it) {
-    case '-':
-      specs.align = align::left;
-      break;
-    case '+':
-      specs.sign = sign::plus;
-      break;
-    case '0':
-      specs.fill = '0';
-      break;
+    case '-': specs.set_align(align::left); break;
+    case '+': specs.set_sign(sign::plus); break;
+    case '0': specs.set_fill('0'); break;
     case ' ':
-      if (specs.sign != sign::plus) specs.sign = sign::space;
+      if (specs.sign() != sign::plus) specs.set_sign(sign::space);
       break;
-    case '#':
-      specs.alt = true;
-      break;
-    default:
-      return;
+    case '#': specs.set_alt(); break;
+    default:  return;
     }
   }
 }
@@ -339,7 +346,7 @@ auto parse_header(const Char*& it, const Char* end, format_specs& specs,
       ++it;
       arg_index = value != -1 ? value : max_value<int>();
     } else {
-      if (c == '0') specs.fill = '0';
+      if (c == '0') specs.set_fill('0');
       if (value != 0) {
         // Nonzero value means that we parsed width and don't need to
         // parse it or flags again, so return now.
@@ -369,43 +376,22 @@ inline auto parse_printf_presentation_type(char c, type t, bool& upper)
   using pt = presentation_type;
   constexpr auto integral_set = sint_set | uint_set | bool_set | char_set;
   switch (c) {
-  case 'd':
-    return in(t, integral_set) ? pt::dec : pt::none;
-  case 'o':
-    return in(t, integral_set) ? pt::oct : pt::none;
-  case 'X':
-    upper = true;
-    FMT_FALLTHROUGH;
-  case 'x':
-    return in(t, integral_set) ? pt::hex : pt::none;
-  case 'E':
-    upper = true;
-    FMT_FALLTHROUGH;
-  case 'e':
-    return in(t, float_set) ? pt::exp : pt::none;
-  case 'F':
-    upper = true;
-    FMT_FALLTHROUGH;
-  case 'f':
-    return in(t, float_set) ? pt::fixed : pt::none;
-  case 'G':
-    upper = true;
-    FMT_FALLTHROUGH;
-  case 'g':
-    return in(t, float_set) ? pt::general : pt::none;
-  case 'A':
-    upper = true;
-    FMT_FALLTHROUGH;
-  case 'a':
-    return in(t, float_set) ? pt::hexfloat : pt::none;
-  case 'c':
-    return in(t, integral_set) ? pt::chr : pt::none;
-  case 's':
-    return in(t, string_set | cstring_set) ? pt::string : pt::none;
-  case 'p':
-    return in(t, pointer_set | cstring_set) ? pt::pointer : pt::none;
-  default:
-    return pt::none;
+  case 'd': return in(t, integral_set) ? pt::dec : pt::none;
+  case 'o': return in(t, integral_set) ? pt::oct : pt::none;
+  case 'X': upper = true; FMT_FALLTHROUGH;
+  case 'x': return in(t, integral_set) ? pt::hex : pt::none;
+  case 'E': upper = true; FMT_FALLTHROUGH;
+  case 'e': return in(t, float_set) ? pt::exp : pt::none;
+  case 'F': upper = true; FMT_FALLTHROUGH;
+  case 'f': return in(t, float_set) ? pt::fixed : pt::none;
+  case 'G': upper = true; FMT_FALLTHROUGH;
+  case 'g': return in(t, float_set) ? pt::general : pt::none;
+  case 'A': upper = true; FMT_FALLTHROUGH;
+  case 'a': return in(t, float_set) ? pt::hexfloat : pt::none;
+  case 'c': return in(t, integral_set) ? pt::chr : pt::none;
+  case 's': return in(t, string_set | cstring_set) ? pt::string : pt::none;
+  case 'p': return in(t, pointer_set | cstring_set) ? pt::pointer : pt::none;
+  default:  return pt::none;
   }
 }
 
@@ -415,7 +401,7 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
   using iterator = basic_appender<Char>;
   auto out = iterator(buf);
   auto context = basic_printf_context<Char>(out, args);
-  auto parse_ctx = basic_format_parse_context<Char>(format);
+  auto parse_ctx = parse_context<Char>(format);
 
   // Returns the argument with specified index or, if arg_index is -1, the next
   // argument.
@@ -444,7 +430,7 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
     write(out, basic_string_view<Char>(start, to_unsigned(it - 1 - start)));
 
     auto specs = format_specs();
-    specs.align = align::right;
+    specs.set_align(align::right);
 
     // Parse argument index, flags and width.
     int arg_index = parse_header(it, end, specs, get_arg);
@@ -468,9 +454,9 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
     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()) {
+    if (specs.precision >= 0 && is_integral_type(arg.type())) {
       // Ignore '0' for non-numeric types or if '-' present.
-      specs.fill = ' ';
+      specs.set_fill(' ');
     }
     if (specs.precision >= 0 && arg.type() == type::cstring_type) {
       auto str = arg.visit(get_cstring<Char>());
@@ -478,15 +464,16 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
       auto nul = std::find(str, str_end, Char());
       auto sv = basic_string_view<Char>(
           str, to_unsigned(nul != str_end ? nul - str : specs.precision));
-      arg = make_arg<basic_printf_context<Char>>(sv);
+      arg = sv;
+    }
+    if (specs.alt() && arg.visit(is_zero_int())) specs.clear_alt();
+    if (specs.fill_unit<Char>() == '0') {
+      if (is_arithmetic_type(arg.type()) && specs.align() != align::left) {
+        specs.set_align(align::numeric);
+      } else {
+        // Ignore '0' flag for non-numeric types or if '-' flag is also present.
+        specs.set_fill(' ');
       }
-    if (specs.alt && arg.visit(is_zero_int())) specs.alt = false;
-    if (specs.fill.template get<Char>() == '0') {
-      if (arg.is_arithmetic() && specs.align != align::left)
-        specs.align = align::numeric;
-      else
-        specs.fill = ' ';  // Ignore '0' flag for non-numeric types or if '-'
-                           // flag is also present.
     }
 
     // Parse length and convert the argument to the required type.
@@ -511,44 +498,34 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
         convert_arg<long>(arg, t);
       }
       break;
-    case 'j':
-      convert_arg<intmax_t>(arg, t);
-      break;
-    case 'z':
-      convert_arg<size_t>(arg, t);
-      break;
-    case 't':
-      convert_arg<std::ptrdiff_t>(arg, t);
-      break;
+    case 'j': convert_arg<intmax_t>(arg, t); break;
+    case 'z': convert_arg<size_t>(arg, t); break;
+    case 't': convert_arg<std::ptrdiff_t>(arg, t); break;
     case 'L':
       // printf produces garbage when 'L' is omitted for long double, no
       // need to do the same.
       break;
-    default:
-      --it;
-      convert_arg<void>(arg, c);
+    default: --it; convert_arg<void>(arg, c);
     }
 
     // Parse type.
     if (it == end) report_error("invalid format string");
     char type = static_cast<char>(*it++);
-    if (arg.is_integral()) {
+    if (is_integral_type(arg.type())) {
       // Normalize type.
       switch (type) {
       case 'i':
-      case 'u':
-        type = 'd';
-        break;
+      case 'u': type = 'd'; break;
       case 'c':
         arg.visit(char_converter<basic_printf_context<Char>>(arg));
         break;
       }
     }
     bool upper = false;
-    specs.type = parse_printf_presentation_type(type, arg.type(), upper);
-    if (specs.type == presentation_type::none)
+    specs.set_type(parse_printf_presentation_type(type, arg.type(), upper));
+    if (specs.type() == presentation_type::none)
       report_error("invalid format specifier");
-    specs.upper = upper;
+    if (upper) specs.set_upper();
 
     start = it;
 
@@ -583,7 +560,7 @@ inline auto vsprintf(basic_string_view<Char> fmt,
     -> std::basic_string<Char> {
   auto buf = basic_memory_buffer<Char>();
   detail::vprintf(buf, fmt, args);
-  return to_string(buf);
+  return {buf.data(), buf.size()};
 }
 
 /**
@@ -594,7 +571,7 @@ inline auto vsprintf(basic_string_view<Char> fmt,
  *
  *     std::string message = fmt::sprintf("The answer is %d", 42);
  */
-template <typename S, typename... T, typename Char = char_t<S>>
+template <typename S, typename... T, typename Char = detail::char_t<S>>
 inline auto sprintf(const S& fmt, const T&... args) -> std::basic_string<Char> {
   return vsprintf(detail::to_string_view(fmt),
                   fmt::make_format_args<basic_printf_context<Char>>(args...));
@@ -619,7 +596,7 @@ inline auto vfprintf(std::FILE* f, basic_string_view<Char> fmt,
  *
  *     fmt::fprintf(stderr, "Don't %s!", "panic");
  */
-template <typename S, typename... T, typename Char = char_t<S>>
+template <typename S, typename... T, typename Char = detail::char_t<S>>
 inline auto fprintf(std::FILE* f, const S& fmt, const T&... args) -> int {
   return vfprintf(f, detail::to_string_view(fmt),
                   make_printf_args<Char>(args...));

include/spdlog/fmt/bundled/ranges.h

@@ -44,18 +44,6 @@ template <typename T> class is_set {
       !std::is_void<decltype(check<T>(nullptr))>::value && !is_map<T>::value;
 };
 
-template <typename... Ts> struct conditional_helper {};
-
-template <typename T, typename _ = void> struct is_range_ : std::false_type {};
-
-#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* {
@@ -76,9 +64,13 @@ struct has_member_fn_begin_end_t<T, void_t<decltype(*std::declval<T>().begin()),
 
 // Member function overloads.
 template <typename T>
-auto range_begin(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).begin());
+auto range_begin(T&& rng) -> decltype(static_cast<T&&>(rng).begin()) {
+  return static_cast<T&&>(rng).begin();
+}
 template <typename T>
-auto range_end(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).end());
+auto range_end(T&& rng) -> decltype(static_cast<T&&>(rng).end()) {
+  return static_cast<T&&>(rng).end();
+}
 
 // ADL overloads. Only participate in overload resolution if member functions
 // are not found.
@@ -115,17 +107,16 @@ struct has_mutable_begin_end<
               // SFINAE properly unless there are distinct types
               int>> : std::true_type {};
 
+template <typename T, typename _ = void> struct is_range_ : std::false_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.
 template <typename T> class is_tuple_like_ {
-  template <typename U>
-  static auto check(U* p) -> decltype(std::tuple_size<U>::value, int());
+  template <typename U, typename V = typename std::remove_cv<U>::type>
+  static auto check(U* p) -> decltype(std::tuple_size<V>::value, 0);
   template <typename> static void check(...);
 
  public:
@@ -266,12 +257,12 @@ template <range_format K>
 using range_format_constant = std::integral_constant<range_format, K>;
 
 // These are not generic lambdas for compatibility with C++11.
-template <typename ParseContext> struct parse_empty_specs {
+template <typename Char> struct parse_empty_specs {
   template <typename Formatter> FMT_CONSTEXPR void operator()(Formatter& f) {
     f.parse(ctx);
     detail::maybe_set_debug_format(f, true);
   }
-  ParseContext& ctx;
+  parse_context<Char>& ctx;
 };
 template <typename FormatContext> struct format_tuple_element {
   using char_type = typename FormatContext::char_type;
@@ -327,11 +318,17 @@ struct formatter<Tuple, Char,
     closing_bracket_ = close;
   }
 
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     auto it = ctx.begin();
-    if (it != ctx.end() && *it != '}') report_error("invalid format specifier");
-    detail::for_each(formatters_, detail::parse_empty_specs<ParseContext>{ctx});
+    auto end = ctx.end();
+    if (it != end && detail::to_ascii(*it) == 'n') {
+      ++it;
+      set_brackets({}, {});
+      set_separator({});
+    }
+    if (it != end && *it != '}') report_error("invalid format specifier");
+    ctx.advance_to(it);
+    detail::for_each(formatters_, detail::parse_empty_specs<Char>{ctx});
     return it;
   }
 
@@ -352,38 +349,17 @@ template <typename T, typename Char> struct is_range {
 };
 
 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 =
-    formatter<remove_cvref_t<decltype(range_mapper<buffered_context<Char>>{}
-                                          .map(std::declval<Element>()))>,
-              Char>;
+using range_formatter_type = formatter<remove_cvref_t<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
     : is_formattable<uncvref_type<maybe_const_range<R>>, Char> {};
-#endif
 }  // namespace detail
 
 template <typename...> struct conjunction : std::true_type {};
@@ -415,7 +391,7 @@ struct range_formatter<
     auto buf = basic_memory_buffer<Char>();
     for (; it != end; ++it) buf.push_back(*it);
     auto specs = format_specs();
-    specs.type = presentation_type::debug;
+    specs.set_type(presentation_type::debug);
     return detail::write<Char>(
         out, basic_string_view<Char>(buf.data(), buf.size()), specs);
   }
@@ -443,8 +419,7 @@ struct range_formatter<
     closing_bracket_ = close;
   }
 
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     auto it = ctx.begin();
     auto end = ctx.end();
     detail::maybe_set_debug_format(underlying_, true);
@@ -486,7 +461,6 @@ struct range_formatter<
 
   template <typename R, typename FormatContext>
   auto format(R&& range, FormatContext& ctx) const -> decltype(ctx.out()) {
-    auto mapper = detail::range_mapper<buffered_context<Char>>();
     auto out = ctx.out();
     auto it = detail::range_begin(range);
     auto end = detail::range_end(range);
@@ -498,7 +472,7 @@ struct range_formatter<
       if (i > 0) out = detail::copy<Char>(separator_, out);
       ctx.advance_to(out);
       auto&& item = *it;  // Need an lvalue
-      out = underlying_.format(mapper.map(item), ctx);
+      out = underlying_.format(item, ctx);
       ++i;
     }
     out = detail::copy<Char>(closing_bracket_, out);
@@ -521,13 +495,8 @@ struct formatter<
             range_format_kind<R, Char>::value != range_format::disabled &&
             range_format_kind<R, Char>::value != range_format::map &&
             range_format_kind<R, Char>::value != range_format::string &&
-            range_format_kind<R, Char>::value != range_format::debug_string>
-// Workaround a bug in MSVC 2015 and earlier.
-#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
-        ,
-        detail::is_formattable_delayed<R, Char>
-#endif
-        >::value>> {
+            range_format_kind<R, Char>::value != range_format::debug_string>,
+        detail::is_formattable_delayed<R, Char>>::value>> {
  private:
   using range_type = detail::maybe_const_range<R>;
   range_formatter<detail::uncvref_type<range_type>, Char> range_formatter_;
@@ -543,8 +512,7 @@ struct formatter<
                                   detail::string_literal<Char, '}'>{});
   }
 
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     return range_formatter_.parse(ctx);
   }
 
@@ -559,7 +527,9 @@ struct formatter<
 template <typename R, typename Char>
 struct formatter<
     R, Char,
-    enable_if_t<range_format_kind<R, Char>::value == range_format::map>> {
+    enable_if_t<conjunction<
+        bool_constant<range_format_kind<R, Char>::value == range_format::map>,
+        detail::is_formattable_delayed<R, Char>>::value>> {
  private:
   using map_type = detail::maybe_const_range<R>;
   using element_type = detail::uncvref_type<map_type>;
@@ -571,8 +541,7 @@ struct formatter<
  public:
   FMT_CONSTEXPR formatter() {}
 
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     auto it = ctx.begin();
     auto end = ctx.end();
     if (it != end) {
@@ -586,7 +555,7 @@ struct formatter<
       }
       ctx.advance_to(it);
     }
-    detail::for_each(formatters_, detail::parse_empty_specs<ParseContext>{ctx});
+    detail::for_each(formatters_, detail::parse_empty_specs<Char>{ctx});
     return it;
   }
 
@@ -596,12 +565,11 @@ struct formatter<
     basic_string_view<Char> open = detail::string_literal<Char, '{'>{};
     if (!no_delimiters_) out = detail::copy<Char>(open, out);
     int i = 0;
-    auto mapper = detail::range_mapper<buffered_context<Char>>();
     basic_string_view<Char> sep = detail::string_literal<Char, ',', ' '>{};
     for (auto&& value : map) {
       if (i > 0) out = detail::copy<Char>(sep, out);
       ctx.advance_to(out);
-      detail::for_each2(formatters_, mapper.map(value),
+      detail::for_each2(formatters_, value,
                         detail::format_tuple_element<FormatContext>{
                             0, ctx, detail::string_literal<Char, ':', ' '>{}});
       ++i;
@@ -631,8 +599,7 @@ struct formatter<
   formatter<string_type, Char> underlying_;
 
  public:
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     return underlying_.parse(ctx);
   }
 
@@ -673,22 +640,22 @@ struct formatter<join_view<It, Sentinel, Char>, Char> {
 #endif
   formatter<remove_cvref_t<value_type>, Char> value_formatter_;
 
-  using view_ref = conditional_t<std::is_copy_constructible<It>::value,
-                                 const join_view<It, Sentinel, Char>&,
-                                 join_view<It, Sentinel, Char>&&>;
+  using view = conditional_t<std::is_copy_constructible<It>::value,
+                             const join_view<It, Sentinel, Char>,
+                             join_view<It, Sentinel, Char>>;
 
  public:
   using nonlocking = void;
 
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> const Char* {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     return value_formatter_.parse(ctx);
   }
 
   template <typename FormatContext>
-  auto format(view_ref& value, FormatContext& ctx) const
-      -> decltype(ctx.out()) {
-    auto it = std::forward<view_ref>(value).begin;
+  auto format(view& value, FormatContext& ctx) const -> decltype(ctx.out()) {
+    using iter =
+        conditional_t<std::is_copy_constructible<view>::value, It, It&>;
+    iter it = value.begin;
     auto out = ctx.out();
     if (it == value.end) return out;
     out = value_formatter_.format(*it, ctx);
@@ -703,39 +670,11 @@ struct formatter<join_view<It, Sentinel, Char>, Char> {
   }
 };
 
-/// Returns a view that formats the iterator range `[begin, end)` with elements
-/// separated by `sep`.
-template <typename It, typename Sentinel>
-auto join(It begin, Sentinel end, string_view sep) -> join_view<It, Sentinel> {
-  return {std::move(begin), end, sep};
-}
-
-/**
- * Returns a view that formats `range` with elements separated by `sep`.
- *
- * **Example**:
- *
- *     auto v = std::vector<int>{1, 2, 3};
- *     fmt::print("{}", fmt::join(v, ", "));
- *     // Output: 1, 2, 3
- *
- * `fmt::join` applies passed format specifiers to the range elements:
- *
- *     fmt::print("{:02}", fmt::join(v, ", "));
- *     // Output: 01, 02, 03
- */
-template <typename Range>
-auto join(Range&& r, string_view sep)
-    -> join_view<decltype(detail::range_begin(r)),
-                 decltype(detail::range_end(r))> {
-  return {detail::range_begin(r), detail::range_end(r), sep};
-}
-
-template <typename Char, typename... T> struct tuple_join_view : detail::view {
-  const std::tuple<T...>& tuple;
+template <typename Char, typename Tuple> struct tuple_join_view : detail::view {
+  const Tuple& tuple;
   basic_string_view<Char> sep;
 
-  tuple_join_view(const std::tuple<T...>& t, basic_string_view<Char> s)
+  tuple_join_view(const Tuple& t, basic_string_view<Char> s)
       : tuple(t), sep{s} {}
 };
 
@@ -746,37 +685,36 @@ template <typename Char, typename... T> struct tuple_join_view : detail::view {
 #  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 Char, typename Tuple>
+struct formatter<tuple_join_view<Char, Tuple>, Char,
+                 enable_if_t<is_tuple_like<Tuple>::value>> {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return do_parse(ctx, std::tuple_size<Tuple>());
   }
 
   template <typename FormatContext>
-  auto format(const tuple_join_view<Char, T...>& value,
+  auto format(const tuple_join_view<Char, Tuple>& value,
               FormatContext& ctx) const -> typename FormatContext::iterator {
-    return do_format(value, ctx,
-                     std::integral_constant<size_t, sizeof...(T)>());
+    return do_format(value, ctx, std::tuple_size<Tuple>());
   }
 
  private:
-  std::tuple<formatter<typename std::decay<T>::type, Char>...> formatters_;
+  decltype(detail::tuple::get_formatters<Tuple, Char>(
+      detail::tuple_index_sequence<Tuple>())) formatters_;
 
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto do_parse(ParseContext& ctx,
+  FMT_CONSTEXPR auto do_parse(parse_context<Char>& ctx,
                               std::integral_constant<size_t, 0>)
-      -> decltype(ctx.begin()) {
+      -> const Char* {
     return ctx.begin();
   }
 
-  template <typename ParseContext, size_t N>
-  FMT_CONSTEXPR auto do_parse(ParseContext& ctx,
+  template <size_t N>
+  FMT_CONSTEXPR auto do_parse(parse_context<Char>& ctx,
                               std::integral_constant<size_t, N>)
-      -> decltype(ctx.begin()) {
+      -> const Char* {
     auto end = ctx.begin();
 #if FMT_TUPLE_JOIN_SPECIFIERS
-    end = std::get<sizeof...(T) - N>(formatters_).parse(ctx);
+    end = std::get<std::tuple_size<Tuple>::value - N>(formatters_).parse(ctx);
     if (N > 1) {
       auto end1 = do_parse(ctx, std::integral_constant<size_t, N - 1>());
       if (end != end1)
@@ -787,18 +725,20 @@ struct formatter<tuple_join_view<Char, T...>, Char> {
   }
 
   template <typename FormatContext>
-  auto do_format(const tuple_join_view<Char, T...>&, FormatContext& ctx,
+  auto do_format(const tuple_join_view<Char, Tuple>&, FormatContext& ctx,
                  std::integral_constant<size_t, 0>) const ->
       typename FormatContext::iterator {
     return ctx.out();
   }
 
   template <typename FormatContext, size_t N>
-  auto do_format(const tuple_join_view<Char, T...>& value, FormatContext& ctx,
+  auto do_format(const tuple_join_view<Char, Tuple>& 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);
+    using std::get;
+    auto out =
+        std::get<std::tuple_size<Tuple>::value - N>(formatters_)
+            .format(get<std::tuple_size<Tuple>::value - N>(value.tuple), ctx);
     if (N <= 1) return out;
     out = detail::copy<Char>(value.sep, out);
     ctx.advance_to(out);
@@ -834,18 +774,46 @@ struct formatter<
     : formatter<detail::all<typename T::container_type>, Char> {
   using all = detail::all<typename T::container_type>;
   template <typename FormatContext>
-  auto format(const T& t, FormatContext& ctx) const -> decltype(ctx.out()) {
+  auto format(const T& value, FormatContext& ctx) const -> decltype(ctx.out()) {
     struct getter : T {
-      static auto get(const T& t) -> all {
-        return {t.*(&getter::c)};  // Access c through the derived class.
+      static auto get(const T& v) -> all {
+        return {v.*(&getter::c)};  // Access c through the derived class.
       }
     };
-    return formatter<all>::format(getter::get(t), ctx);
+    return formatter<all>::format(getter::get(value), ctx);
   }
 };
 
 FMT_BEGIN_EXPORT
 
+/// Returns a view that formats the iterator range `[begin, end)` with elements
+/// separated by `sep`.
+template <typename It, typename Sentinel>
+auto join(It begin, Sentinel end, string_view sep) -> join_view<It, Sentinel> {
+  return {std::move(begin), end, sep};
+}
+
+/**
+ * Returns a view that formats `range` with elements separated by `sep`.
+ *
+ * **Example**:
+ *
+ *     auto v = std::vector<int>{1, 2, 3};
+ *     fmt::print("{}", fmt::join(v, ", "));
+ *     // Output: 1, 2, 3
+ *
+ * `fmt::join` applies passed format specifiers to the range elements:
+ *
+ *     fmt::print("{:02}", fmt::join(v, ", "));
+ *     // Output: 01, 02, 03
+ */
+template <typename Range, FMT_ENABLE_IF(!is_tuple_like<Range>::value)>
+auto join(Range&& r, string_view sep)
+    -> join_view<decltype(detail::range_begin(r)),
+                 decltype(detail::range_end(r))> {
+  return {detail::range_begin(r), detail::range_end(r), sep};
+}
+
 /**
  * Returns an object that formats `std::tuple` with elements separated by `sep`.
  *
@@ -855,9 +823,9 @@ FMT_BEGIN_EXPORT
  *     fmt::print("{}", fmt::join(t, ", "));
  *     // Output: 1, a
  */
-template <typename... T>
-FMT_CONSTEXPR auto join(const std::tuple<T...>& tuple, string_view sep)
-    -> tuple_join_view<char, T...> {
+template <typename Tuple, FMT_ENABLE_IF(is_tuple_like<Tuple>::value)>
+FMT_CONSTEXPR auto join(const Tuple& tuple, string_view sep)
+    -> tuple_join_view<char, Tuple> {
   return {tuple, sep};
 }
 

include/spdlog/fmt/bundled/std.h

@@ -17,6 +17,7 @@
 #  include <complex>
 #  include <cstdlib>
 #  include <exception>
+#  include <functional>
 #  include <memory>
 #  include <thread>
 #  include <type_traits>
@@ -26,7 +27,8 @@
 
 // Check FMT_CPLUSPLUS to suppress a bogus warning in MSVC.
 #  if FMT_CPLUSPLUS >= 201703L
-#    if FMT_HAS_INCLUDE(<filesystem>)
+#    if FMT_HAS_INCLUDE(<filesystem>) && \
+        (!defined(FMT_CPP_LIB_FILESYSTEM) || FMT_CPP_LIB_FILESYSTEM != 0)
 #      include <filesystem>
 #    endif
 #    if FMT_HAS_INCLUDE(<variant>)
@@ -111,7 +113,6 @@ void write_escaped_path(basic_memory_buffer<Char>& quoted,
 
 }  // namespace detail
 
-FMT_EXPORT
 template <typename Char> struct formatter<std::filesystem::path, Char> {
  private:
   format_specs specs_;
@@ -122,14 +123,16 @@ template <typename Char> struct formatter<std::filesystem::path, Char> {
  public:
   FMT_CONSTEXPR void set_debug_format(bool set = true) { debug_ = set; }
 
-  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) {
     auto it = ctx.begin(), end = ctx.end();
     if (it == end) return it;
 
     it = detail::parse_align(it, end, specs_);
     if (it == end) return it;
 
-    it = detail::parse_dynamic_spec(it, end, specs_.width, width_ref_, ctx);
+    Char c = *it;
+    if ((c >= '0' && c <= '9') || c == '{')
+      it = detail::parse_width(it, end, specs_, width_ref_, ctx);
     if (it != end && *it == '?') {
       debug_ = true;
       ++it;
@@ -145,7 +148,7 @@ template <typename Char> struct formatter<std::filesystem::path, Char> {
         !path_type_ ? p.native()
                     : p.generic_string<std::filesystem::path::value_type>();
 
-    detail::handle_dynamic_spec<detail::width_checker>(specs.width, width_ref_,
+    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
                                 ctx);
     if (!debug_) {
       auto s = detail::get_path_string<Char>(p, path_string);
@@ -178,9 +181,9 @@ FMT_END_NAMESPACE
 #endif  // FMT_CPP_LIB_FILESYSTEM
 
 FMT_BEGIN_NAMESPACE
-FMT_EXPORT
 template <std::size_t N, typename Char>
-struct formatter<std::bitset<N>, Char> : nested_formatter<string_view> {
+struct formatter<std::bitset<N>, Char>
+    : nested_formatter<basic_string_view<Char>, Char> {
  private:
   // Functor because C++11 doesn't support generic lambdas.
   struct writer {
@@ -200,18 +203,16 @@ struct formatter<std::bitset<N>, Char> : nested_formatter<string_view> {
   template <typename FormatContext>
   auto format(const std::bitset<N>& bs, FormatContext& ctx) const
       -> decltype(ctx.out()) {
-    return write_padded(ctx, writer{bs});
+    return this->write_padded(ctx, writer{bs});
   }
 };
 
-FMT_EXPORT
 template <typename Char>
 struct formatter<std::thread::id, Char> : basic_ostream_formatter<Char> {};
 FMT_END_NAMESPACE
 
 #ifdef __cpp_lib_optional
 FMT_BEGIN_NAMESPACE
-FMT_EXPORT
 template <typename T, typename Char>
 struct formatter<std::optional<T>, Char,
                  std::enable_if_t<is_formattable<T, Char>::value>> {
@@ -233,7 +234,7 @@ struct formatter<std::optional<T>, Char,
   FMT_CONSTEXPR static void maybe_set_debug_format(U&, ...) {}
 
  public:
-  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) {
     maybe_set_debug_format(underlying_, true);
     return underlying_.parse(ctx);
   }
@@ -274,13 +275,12 @@ FMT_END_NAMESPACE
 #ifdef __cpp_lib_expected
 FMT_BEGIN_NAMESPACE
 
-FMT_EXPORT
 template <typename T, typename E, typename Char>
 struct formatter<std::expected<T, E>, Char,
-                 std::enable_if_t<is_formattable<T, Char>::value &&
+                 std::enable_if_t<(std::is_void<T>::value ||
+                                   is_formattable<T, Char>::value) &&
                                   is_formattable<E, Char>::value>> {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     return ctx.begin();
   }
 
@@ -291,6 +291,7 @@ struct formatter<std::expected<T, E>, Char,
 
     if (value.has_value()) {
       out = detail::write<Char>(out, "expected(");
+      if constexpr (!std::is_void<T>::value)
         out = detail::write_escaped_alternative<Char>(out, *value);
     } else {
       out = detail::write<Char>(out, "unexpected(");
@@ -305,11 +306,8 @@ FMT_END_NAMESPACE
 
 #ifdef __cpp_lib_source_location
 FMT_BEGIN_NAMESPACE
-FMT_EXPORT
 template <> struct formatter<std::source_location> {
-  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
-    return ctx.begin();
-  }
+  FMT_CONSTEXPR auto parse(parse_context<>& ctx) { return ctx.begin(); }
 
   template <typename FormatContext>
   auto format(const std::source_location& loc, FormatContext& ctx) const
@@ -363,10 +361,8 @@ template <typename T, typename C> struct is_variant_formattable {
       detail::is_variant_formattable_<T, C>::value;
 };
 
-FMT_EXPORT
 template <typename Char> struct formatter<std::monostate, Char> {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     return ctx.begin();
   }
 
@@ -377,14 +373,12 @@ template <typename Char> struct formatter<std::monostate, Char> {
   }
 };
 
-FMT_EXPORT
 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()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     return ctx.begin();
   }
 
@@ -412,21 +406,55 @@ FMT_END_NAMESPACE
 #endif  // FMT_CPP_LIB_VARIANT
 
 FMT_BEGIN_NAMESPACE
-FMT_EXPORT
-template <typename Char> struct formatter<std::error_code, Char> {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
+template <> struct formatter<std::error_code> {
+ private:
+  format_specs specs_;
+  detail::arg_ref<char> width_ref_;
+  bool debug_ = false;
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<>& ctx) -> const char* {
+    auto it = ctx.begin(), end = ctx.end();
+    if (it == end) return it;
+
+    it = detail::parse_align(it, end, specs_);
+
+    char c = *it;
+    if (it != end && ((c >= '0' && c <= '9') || c == '{'))
+      it = detail::parse_width(it, end, specs_, width_ref_, ctx);
+
+    if (it != end && *it == '?') {
+      debug_ = true;
+      ++it;
+    }
+    if (it != end && *it == 's') {
+      specs_.set_type(presentation_type::string);
+      ++it;
+    }
+    return it;
   }
 
   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<Char>(out, ec.category().name(), format_specs());
-    out = detail::write<Char>(out, Char(':'));
-    out = detail::write<Char>(out, ec.value());
-    return out;
+  FMT_CONSTEXPR20 auto format(const std::error_code& ec,
+                              FormatContext& ctx) const -> decltype(ctx.out()) {
+    auto specs = specs_;
+    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
+                                ctx);
+    auto buf = memory_buffer();
+    if (specs_.type() == presentation_type::string) {
+      buf.append(ec.message());
+    } else {
+      buf.append(string_view(ec.category().name()));
+      buf.push_back(':');
+      detail::write<char>(appender(buf), ec.value());
+    }
+    auto quoted = memory_buffer();
+    auto str = string_view(buf.data(), buf.size());
+    if (debug_) {
+      detail::write_escaped_string<char>(std::back_inserter(quoted), str);
+      str = string_view(quoted.data(), quoted.size());
+    }
+    return detail::write<char>(ctx.out(), str, specs);
   }
 };
 
@@ -501,13 +529,11 @@ auto write_demangled_name(OutputIt out, const std::type_info& ti) -> OutputIt {
 
 }  // namespace detail
 
-FMT_EXPORT
 template <typename Char>
 struct formatter<std::type_info, Char  // DEPRECATED! Mixing code unit types.
                  > {
  public:
-  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
-      -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     return ctx.begin();
   }
 
@@ -519,7 +545,6 @@ struct formatter<std::type_info, Char  // DEPRECATED! Mixing code unit types.
 };
 #endif
 
-FMT_EXPORT
 template <typename T, typename Char>
 struct formatter<
     T, Char,  // DEPRECATED! Mixing code unit types.
@@ -528,8 +553,7 @@ struct formatter<
   bool with_typename_ = false;
 
  public:
-  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
-      -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     auto it = ctx.begin();
     auto end = ctx.end();
     if (it == end || *it == '}') return it;
@@ -586,7 +610,6 @@ struct is_bit_reference_like<std::__bit_const_reference<C>> {
 // We can't use std::vector<bool, Allocator>::reference and
 // std::bitset<N>::reference because the compiler can't deduce Allocator and N
 // in partial specialization.
-FMT_EXPORT
 template <typename BitRef, typename Char>
 struct formatter<BitRef, Char,
                  enable_if_t<detail::is_bit_reference_like<BitRef>::value>>
@@ -606,7 +629,6 @@ template <typename T> auto ptr(const std::shared_ptr<T>& p) -> const void* {
   return p.get();
 }
 
-FMT_EXPORT
 template <typename T, typename Char>
 struct formatter<std::atomic<T>, Char,
                  enable_if_t<is_formattable<T, Char>::value>>
@@ -619,7 +641,6 @@ struct formatter<std::atomic<T>, Char,
 };
 
 #ifdef __cpp_lib_atomic_flag_test
-FMT_EXPORT
 template <typename Char>
 struct formatter<std::atomic_flag, Char> : formatter<bool, Char> {
   template <typename FormatContext>
@@ -630,7 +651,6 @@ struct formatter<std::atomic_flag, Char> : formatter<bool, Char> {
 };
 #endif  // __cpp_lib_atomic_flag_test
 
-FMT_EXPORT
 template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
  private:
   detail::dynamic_format_specs<Char> specs_;
@@ -643,7 +663,7 @@ template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
     if (c.real() != 0) {
       *out++ = Char('(');
       out = detail::write<Char>(out, c.real(), specs, ctx.locale());
-      specs.sign = sign::plus;
+      specs.set_sign(sign::plus);
       out = detail::write<Char>(out, c.imag(), specs, ctx.locale());
       if (!detail::isfinite(c.imag())) *out++ = Char(' ');
       *out++ = Char('i');
@@ -657,8 +677,7 @@ template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
   }
 
  public:
-  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
-      -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     if (ctx.begin() == ctx.end() || *ctx.begin() == '}') return ctx.begin();
     return parse_format_specs(ctx.begin(), ctx.end(), specs_, ctx,
                               detail::type_constant<T, Char>::value);
@@ -668,12 +687,11 @@ template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
   auto format(const std::complex<T>& c, FormatContext& ctx) const
       -> decltype(ctx.out()) {
     auto specs = specs_;
-    if (specs.width_ref.kind != detail::arg_id_kind::none ||
-        specs.precision_ref.kind != detail::arg_id_kind::none) {
-      detail::handle_dynamic_spec<detail::width_checker>(specs.width,
+    if (specs.dynamic()) {
+      detail::handle_dynamic_spec(specs.dynamic_width(), specs.width,
                                   specs.width_ref, ctx);
-      detail::handle_dynamic_spec<detail::precision_checker>(
-          specs.precision, specs.precision_ref, ctx);
+      detail::handle_dynamic_spec(specs.dynamic_precision(), specs.precision,
+                                  specs.precision_ref, ctx);
     }
 
     if (specs.width == 0) return do_format(c, specs, ctx, ctx.out());
@@ -681,12 +699,12 @@ template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
 
     auto outer_specs = format_specs();
     outer_specs.width = specs.width;
-    outer_specs.fill = specs.fill;
-    outer_specs.align = specs.align;
+    outer_specs.copy_fill_from(specs);
+    outer_specs.set_align(specs.align());
 
     specs.width = 0;
-    specs.fill = {};
-    specs.align = align::none;
+    specs.set_fill({});
+    specs.set_align(align::none);
 
     do_format(c, specs, ctx, basic_appender<Char>(buf));
     return detail::write<Char>(ctx.out(),
@@ -695,5 +713,16 @@ template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
   }
 };
 
+template <typename T, typename Char>
+struct formatter<std::reference_wrapper<T>, Char,
+                 enable_if_t<is_formattable<remove_cvref_t<T>, Char>::value>>
+    : formatter<remove_cvref_t<T>, Char> {
+  template <typename FormatContext>
+  auto format(std::reference_wrapper<T> ref, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<remove_cvref_t<T>, Char>::format(ref.get(), ctx);
+  }
+};
+
 FMT_END_NAMESPACE
 #endif  // FMT_STD_H_

include/spdlog/fmt/bundled/xchar.h

@@ -10,11 +10,12 @@
 
 #include "color.h"
 #include "format.h"
+#include "ostream.h"
 #include "ranges.h"
 
 #ifndef FMT_MODULE
 #  include <cwchar>
-#  if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
+#  if FMT_USE_LOCALE
 #    include <locale>
 #  endif
 #endif
@@ -34,7 +35,8 @@ struct format_string_char<
 };
 
 template <typename S>
-struct format_string_char<S, enable_if_t<is_compile_string<S>::value>> {
+struct format_string_char<
+    S, enable_if_t<std::is_base_of<detail::compile_string, S>::value>> {
   using type = typename S::char_type;
 };
 
@@ -43,7 +45,7 @@ using format_string_char_t = typename format_string_char<S>::type;
 
 inline auto write_loc(basic_appender<wchar_t> out, loc_value value,
                       const format_specs& specs, locale_ref loc) -> bool {
-#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#if FMT_USE_LOCALE
   auto& numpunct =
       std::use_facet<std::numpunct<wchar_t>>(loc.get<std::locale>());
   auto separator = std::wstring();
@@ -58,30 +60,60 @@ inline auto write_loc(basic_appender<wchar_t> out, loc_value value,
 FMT_BEGIN_EXPORT
 
 using wstring_view = basic_string_view<wchar_t>;
-using wformat_parse_context = basic_format_parse_context<wchar_t>;
+using wformat_parse_context = parse_context<wchar_t>;
 using wformat_context = buffered_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>...>;
+template <typename Char, typename... T> struct basic_fstring {
+ private:
+  basic_string_view<Char> str_;
+
+  static constexpr int num_static_named_args =
+      detail::count_static_named_args<T...>();
+
+  using checker = detail::format_string_checker<
+      Char, static_cast<int>(sizeof...(T)), num_static_named_args,
+      num_static_named_args != detail::count_named_args<T...>()>;
+
+  using arg_pack = detail::arg_pack<T...>;
+
+ public:
+  using t = basic_fstring;
+
+  template <typename S,
+            FMT_ENABLE_IF(
+                std::is_convertible<const S&, basic_string_view<Char>>::value)>
+  FMT_CONSTEVAL FMT_ALWAYS_INLINE basic_fstring(const S& s) : str_(s) {
+    if (FMT_USE_CONSTEVAL)
+      detail::parse_format_string<Char>(s, checker(s, arg_pack()));
+  }
+  template <typename S,
+            FMT_ENABLE_IF(std::is_base_of<detail::compile_string, S>::value&&
+                              std::is_same<typename S::char_type, Char>::value)>
+  FMT_ALWAYS_INLINE basic_fstring(const S&) : str_(S()) {
+    FMT_CONSTEXPR auto sv = basic_string_view<Char>(S());
+    FMT_CONSTEXPR int ignore =
+        (parse_format_string(sv, checker(sv, arg_pack())), 0);
+    detail::ignore_unused(ignore);
+  }
+  basic_fstring(runtime_format_string<Char> fmt) : str_(fmt.str) {}
+
+  operator basic_string_view<Char>() const { return str_; }
+  auto get() const -> basic_string_view<Char> { return str_; }
+};
+
+template <typename Char, typename... T>
+using basic_format_string = basic_fstring<Char, T...>;
+
+template <typename... T>
+using wformat_string = typename basic_format_string<wchar_t, T...>::t;
 inline auto runtime(wstring_view s) -> runtime_format_string<wchar_t> {
   return {{s}};
 }
-#endif
-
-template <> struct is_char<wchar_t> : std::true_type {};
-template <> struct is_char<char16_t> : std::true_type {};
-template <> struct is_char<char32_t> : std::true_type {};
 
 #ifdef __cpp_char8_t
-template <>
-struct is_char<char8_t> : bool_constant<detail::is_utf8_enabled()> {};
+template <> struct is_char<char8_t> : bool_constant<detail::is_utf8_enabled> {};
 #endif
 
 template <typename... T>
@@ -90,14 +122,13 @@ constexpr auto make_wformat_args(T&... args)
   return fmt::make_format_args<wformat_context>(args...);
 }
 
+#if !FMT_USE_NONTYPE_TEMPLATE_ARGS
 inline namespace literals {
-#if FMT_USE_USER_DEFINED_LITERALS && !FMT_USE_NONTYPE_TEMPLATE_ARGS
-constexpr auto operator""_a(const wchar_t* s, size_t)
-    -> detail::udl_arg<wchar_t> {
+inline auto operator""_a(const wchar_t* s, size_t) -> detail::udl_arg<wchar_t> {
   return {s};
 }
-#endif
 }  // namespace literals
+#endif
 
 template <typename It, typename Sentinel>
 auto join(It begin, Sentinel end, wstring_view sep)
@@ -105,9 +136,9 @@ auto join(It begin, Sentinel end, wstring_view sep)
   return {begin, end, sep};
 }
 
-template <typename Range>
+template <typename Range, FMT_ENABLE_IF(!is_tuple_like<Range>::value)>
 auto join(Range&& range, wstring_view sep)
-    -> join_view<detail::iterator_t<Range>, detail::sentinel_t<Range>,
+    -> join_view<decltype(std::begin(range)), decltype(std::end(range)),
                  wchar_t> {
   return join(std::begin(range), std::end(range), sep);
 }
@@ -118,19 +149,19 @@ auto join(std::initializer_list<T> list, wstring_view sep)
   return join(std::begin(list), std::end(list), sep);
 }
 
-template <typename... T>
-auto join(const std::tuple<T...>& tuple, basic_string_view<wchar_t> sep)
-    -> tuple_join_view<wchar_t, T...> {
+template <typename Tuple, FMT_ENABLE_IF(is_tuple_like<Tuple>::value)>
+auto join(const Tuple& tuple, basic_string_view<wchar_t> sep)
+    -> tuple_join_view<wchar_t, Tuple> {
   return {tuple, sep};
 }
 
 template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
-auto vformat(basic_string_view<Char> format_str,
+auto vformat(basic_string_view<Char> fmt,
              typename detail::vformat_args<Char>::type args)
     -> std::basic_string<Char> {
   auto buf = basic_memory_buffer<Char>();
-  detail::vformat_to(buf, format_str, args);
-  return to_string(buf);
+  detail::vformat_to(buf, fmt, args);
+  return {buf.data(), buf.size()};
 }
 
 template <typename... T>
@@ -151,8 +182,8 @@ template <typename S, typename... T,
           typename Char = detail::format_string_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, T&&... args) -> std::basic_string<Char> {
-  return vformat(detail::to_string_view(format_str),
+auto format(const S& fmt, T&&... args) -> std::basic_string<Char> {
+  return vformat(detail::to_string_view(fmt),
                  fmt::make_format_args<buffered_context<Char>>(args...));
 }
 
@@ -160,20 +191,22 @@ template <typename Locale, typename S,
           typename Char = detail::format_string_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,
+inline auto vformat(const Locale& loc, const S& fmt,
                     typename detail::vformat_args<Char>::type args)
     -> std::basic_string<Char> {
-  return detail::vformat(loc, detail::to_string_view(format_str), args);
+  auto buf = basic_memory_buffer<Char>();
+  detail::vformat_to(buf, detail::to_string_view(fmt), args,
+                     detail::locale_ref(loc));
+  return {buf.data(), buf.size()};
 }
 
 template <typename Locale, typename S, typename... T,
           typename Char = detail::format_string_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, T&&... args)
+inline auto format(const Locale& loc, const S& fmt, T&&... args)
     -> std::basic_string<Char> {
-  return detail::vformat(
-      loc, detail::to_string_view(format_str),
+  return vformat(loc, detail::to_string_view(fmt),
                  fmt::make_format_args<buffered_context<Char>>(args...));
 }
 
@@ -181,10 +214,10 @@ template <typename OutputIt, typename S,
           typename Char = detail::format_string_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,
+auto vformat_to(OutputIt out, const S& fmt,
                 typename detail::vformat_args<Char>::type args) -> OutputIt {
   auto&& buf = detail::get_buffer<Char>(out);
-  detail::vformat_to(buf, detail::to_string_view(format_str), args);
+  detail::vformat_to(buf, detail::to_string_view(fmt), args);
   return detail::get_iterator(buf, out);
 }
 
@@ -203,37 +236,35 @@ template <typename Locale, typename S, typename OutputIt, typename... Args,
           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,
+inline auto vformat_to(OutputIt out, const Locale& loc, const S& fmt,
                        typename detail::vformat_args<Char>::type args)
     -> OutputIt {
   auto&& buf = detail::get_buffer<Char>(out);
-  vformat_to(buf, detail::to_string_view(format_str), args,
-             detail::locale_ref(loc));
+  vformat_to(buf, detail::to_string_view(fmt), args, detail::locale_ref(loc));
   return detail::get_iterator(buf, out);
 }
 
-template <typename OutputIt, typename Locale, typename S, typename... T,
+template <typename Locale, typename OutputIt, typename S, typename... T,
           typename Char = detail::format_string_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,
+inline auto format_to(OutputIt out, const Locale& loc, const S& fmt,
                       T&&... args) ->
     typename std::enable_if<enable, OutputIt>::type {
-  return vformat_to(out, loc, detail::to_string_view(format_str),
+  return vformat_to(out, loc, detail::to_string_view(fmt),
                     fmt::make_format_args<buffered_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,
+inline auto vformat_to_n(OutputIt out, size_t n, basic_string_view<Char> fmt,
                          typename detail::vformat_args<Char>::type args)
     -> format_to_n_result<OutputIt> {
   using traits = detail::fixed_buffer_traits;
   auto buf = detail::iterator_buffer<OutputIt, Char, traits>(out, n);
-  detail::vformat_to(buf, format_str, args);
+  detail::vformat_to(buf, fmt, args);
   return {buf.out(), buf.count()};
 }
 
@@ -287,31 +318,47 @@ template <typename... T> void println(wformat_string<T...> fmt, T&&... args) {
   return print(L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
 }
 
-inline auto vformat(const text_style& ts, wstring_view fmt, wformat_args args)
+inline auto vformat(text_style ts, wstring_view fmt, wformat_args args)
     -> std::wstring {
   auto buf = wmemory_buffer();
   detail::vformat_to(buf, ts, fmt, args);
-  return fmt::to_string(buf);
+  return {buf.data(), buf.size()};
 }
 
 template <typename... T>
-inline auto format(const text_style& ts, wformat_string<T...> fmt, T&&... args)
+inline auto format(text_style ts, wformat_string<T...> fmt, T&&... args)
     -> std::wstring {
   return fmt::vformat(ts, fmt, fmt::make_wformat_args(args...));
 }
 
 template <typename... T>
-FMT_DEPRECATED void print(std::FILE* f, const text_style& ts,
-                          wformat_string<T...> fmt, const T&... args) {
+FMT_DEPRECATED void print(std::FILE* f, text_style ts, wformat_string<T...> fmt,
+                          const T&... args) {
   vprint(f, ts, fmt, fmt::make_wformat_args(args...));
 }
 
 template <typename... T>
-FMT_DEPRECATED void print(const text_style& ts, wformat_string<T...> fmt,
+FMT_DEPRECATED void print(text_style ts, wformat_string<T...> fmt,
                           const T&... args) {
   return print(stdout, ts, fmt, args...);
 }
 
+inline void vprint(std::wostream& os, wstring_view fmt, wformat_args args) {
+  auto buffer = basic_memory_buffer<wchar_t>();
+  detail::vformat_to(buffer, fmt, args);
+  detail::write_buffer(os, buffer);
+}
+
+template <typename... T>
+void print(std::wostream& os, wformat_string<T...> fmt, T&&... args) {
+  vprint(os, fmt, fmt::make_format_args<buffered_context<wchar_t>>(args...));
+}
+
+template <typename... T>
+void println(std::wostream& os, wformat_string<T...> fmt, T&&... args) {
+  print(os, L"{}\n", fmt::format(fmt, std::forward<T>(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);

include/spdlog/fmt/fmt.h

@@ -21,10 +21,10 @@
         #define FMT_USE_WINDOWS_H 0
     #endif
 
-    #include <spdlog/fmt/bundled/core.h>
+    #include <spdlog/fmt/bundled/base.h>
     #include <spdlog/fmt/bundled/format.h>
 
 #else  // SPDLOG_FMT_EXTERNAL is defined - use external fmtlib
-    #include <fmt/core.h>
+    #include <fmt/base.h>
     #include <fmt/format.h>
 #endif

include/spdlog/logger-inl.h

@@ -57,7 +57,7 @@ SPDLOG_INLINE void logger::swap(spdlog::logger &other) SPDLOG_NOEXCEPT {
     std::swap(tracer_, other.tracer_);
 }
 
-SPDLOG_INLINE void swap(logger &a, logger &b) { a.swap(b); }
+SPDLOG_INLINE void swap(logger &a, logger &b) noexcept { a.swap(b); }
 
 SPDLOG_INLINE void logger::set_level(level::level_enum log_level) { level_.store(log_level); }
 
@@ -163,12 +163,12 @@ SPDLOG_INLINE void logger::dump_backtrace_() {
     }
 }
 
-SPDLOG_INLINE bool logger::should_flush_(const details::log_msg &msg) {
+SPDLOG_INLINE bool logger::should_flush_(const details::log_msg &msg) const {
     auto flush_level = flush_level_.load(std::memory_order_relaxed);
     return (msg.level >= flush_level) && (msg.level != level::off);
 }
 
-SPDLOG_INLINE void logger::err_handler_(const std::string &msg) {
+SPDLOG_INLINE void logger::err_handler_(const std::string &msg) const {
     if (custom_err_handler_) {
         custom_err_handler_(msg);
     } else {

include/spdlog/logger.h

@@ -363,14 +363,14 @@ protected:
     virtual void sink_it_(const details::log_msg &msg);
     virtual void flush_();
     void dump_backtrace_();
-    bool should_flush_(const details::log_msg &msg);
+    bool should_flush_(const details::log_msg &msg) const;
 
     // handle errors during logging.
     // default handler prints the error to stderr at max rate of 1 message/sec.
-    void err_handler_(const std::string &msg);
+    void err_handler_(const std::string &msg) const;
 };
 
-void swap(logger &a, logger &b);
+void swap(logger &a, logger &b) noexcept;
 
 }  // namespace spdlog
 

include/spdlog/mdc.h

@@ -12,12 +12,14 @@
 
 #include <spdlog/common.h>
 
-// MDC is a simple map of key->string values stored in thread local storage whose content will be printed by the loggers.
-// Note: Not supported in async mode (thread local storage - so the async thread pool have different copy).
+// MDC is a simple map of key->string values stored in thread local storage whose content will be
+// printed by the loggers. Note: Not supported in async mode (thread local storage - so the async
+// thread pool have different copy).
 //
 // Usage example:
 // spdlog::mdc::put("mdc_key_1", "mdc_value_1");
-// spdlog::info("Hello, {}", "World!");  // => [2024-04-26 02:08:05.040] [info] [mdc_key_1:mdc_value_1] Hello, World!
+// spdlog::info("Hello, {}", "World!");  // => [2024-04-26 02:08:05.040] [info]
+// [mdc_key_1:mdc_value_1] Hello, World!
 
 namespace spdlog {
 class SPDLOG_API mdc {

include/spdlog/pattern_formatter-inl.h

@@ -70,6 +70,9 @@ public:
             pad_it(remaining_pad_);
         } else if (padinfo_.truncate_) {
             long new_size = static_cast<long>(dest_.size()) + remaining_pad_;
+            if (new_size < 0) {
+                new_size = 0;
+            }
             dest_.resize(static_cast<size_t>(new_size));
         }
     }
@@ -264,7 +267,7 @@ public:
         : flag_formatter(padinfo) {}
 
     void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override {
-        const size_t field_size = 10;
+        const size_t field_size = 8;
         ScopedPadder p(field_size, padinfo_, dest);
 
         fmt_helper::pad2(tm_time.tm_mon + 1, dest);
@@ -926,9 +929,8 @@ private:
     memory_buf_t cached_datetime_;
 
 #ifndef SPDLOG_NO_TLS
-    mdc_formatter<null_scoped_padder> mdc_formatter_{padding_info{}};
+    mdc_formatter<null_scoped_padder> mdc_formatter_{padding_info {}};
 #endif
-
 };
 
 }  // namespace details

include/spdlog/sinks/ansicolor_sink-inl.h

@@ -20,7 +20,7 @@ SPDLOG_INLINE ansicolor_sink<ConsoleMutex>::ansicolor_sink(FILE *target_file, co
       formatter_(details::make_unique<spdlog::pattern_formatter>())
 
 {
-    set_color_mode(mode);
+    set_color_mode_(mode);
     colors_.at(level::trace) = to_string_(white);
     colors_.at(level::debug) = to_string_(cyan);
     colors_.at(level::info) = to_string_(green);
@@ -82,12 +82,18 @@ SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_formatter(
 }
 
 template <typename ConsoleMutex>
-SPDLOG_INLINE bool ansicolor_sink<ConsoleMutex>::should_color() {
+SPDLOG_INLINE bool ansicolor_sink<ConsoleMutex>::should_color() const {
     return should_do_colors_;
 }
 
 template <typename ConsoleMutex>
 SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_color_mode(color_mode mode) {
+    std::lock_guard<mutex_t> lock(mutex_);
+    set_color_mode_(mode);
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_color_mode_(color_mode mode) {
     switch (mode) {
         case color_mode::always:
             should_do_colors_ = true;
@@ -105,15 +111,16 @@ SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_color_mode(color_mode mode)
 }
 
 template <typename ConsoleMutex>
-SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::print_ccode_(const string_view_t &color_code) {
-    fwrite(color_code.data(), sizeof(char), color_code.size(), target_file_);
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::print_ccode_(
+    const string_view_t &color_code) const {
+    details::os::fwrite_bytes(color_code.data(), color_code.size(), target_file_);
 }
 
 template <typename ConsoleMutex>
 SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::print_range_(const memory_buf_t &formatted,
                                                               size_t start,
-                                                              size_t end) {
-    fwrite(formatted.data() + start, sizeof(char), end - start, target_file_);
+                                                              size_t end) const {
+    details::os::fwrite_bytes(formatted.data() + start, end - start, target_file_);
 }
 
 template <typename ConsoleMutex>

include/spdlog/sinks/ansicolor_sink.h

@@ -36,7 +36,7 @@ public:
 
     void set_color(level::level_enum color_level, string_view_t color);
     void set_color_mode(color_mode mode);
-    bool should_color();
+    bool should_color() const;
 
     void log(const details::log_msg &msg) override;
     void flush() override;
@@ -84,8 +84,9 @@ private:
     bool should_do_colors_;
     std::unique_ptr<spdlog::formatter> formatter_;
     std::array<std::string, level::n_levels> colors_;
-    void print_ccode_(const string_view_t &color_code);
-    void print_range_(const memory_buf_t &formatted, size_t start, size_t end);
+    void set_color_mode_(color_mode mode);
+    void print_ccode_(const string_view_t &color_code) const;
+    void print_range_(const memory_buf_t &formatted, size_t start, size_t end) const;
     static std::string to_string_(const string_view_t &sv);
 };
 

include/spdlog/sinks/basic_file_sink-inl.h

@@ -26,6 +26,12 @@ SPDLOG_INLINE const filename_t &basic_file_sink<Mutex>::filename() const {
     return file_helper_.filename();
 }
 
+template <typename Mutex>
+SPDLOG_INLINE void basic_file_sink<Mutex>::truncate() {
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    file_helper_.reopen(true);
+}
+
 template <typename Mutex>
 SPDLOG_INLINE void basic_file_sink<Mutex>::sink_it_(const details::log_msg &msg) {
     memory_buf_t formatted;

include/spdlog/sinks/basic_file_sink.h

@@ -23,6 +23,7 @@ public:
                              bool truncate = false,
                              const file_event_handlers &event_handlers = {});
     const filename_t &filename() const;
+    void truncate();
 
 protected:
     void sink_it_(const details::log_msg &msg) override;

include/spdlog/sinks/callback_sink.h

@@ -27,7 +27,7 @@ public:
 
 protected:
     void sink_it_(const details::log_msg &msg) override { callback_(msg); }
-    void flush_() override{}
+    void flush_() override {}
 
 private:
     custom_log_callback callback_;

include/spdlog/sinks/daily_file_sink.h

@@ -62,7 +62,6 @@ struct daily_filename_format_calculator {
  * Rotating file sink based on date.
  * If truncate != false , the created file will be truncated.
  * If max_files > 0, retain only the last max_files and delete previous.
- * If max_files > 0, retain only the last max_files and delete previous.
  * Note that old log files from previous executions will not be deleted by this class,
  * rotation and deletion is only applied while the program is running.
  */

include/spdlog/sinks/dup_filter_sink.h

@@ -40,22 +40,21 @@ template <typename Mutex>
 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,
-                             level::level_enum notification_level = level::info)
-        : max_skip_duration_{max_skip_duration},
-          log_level_{notification_level} {}
+    explicit dup_filter_sink(std::chrono::duration<Rep, Period> max_skip_duration)
+        : max_skip_duration_{max_skip_duration} {}
 
 protected:
     std::chrono::microseconds max_skip_duration_;
     log_clock::time_point last_msg_time_;
     std::string last_msg_payload_;
     size_t skip_counter_ = 0;
-    level::level_enum log_level_;
+    level::level_enum skipped_msg_log_level_ = spdlog::level::level_enum::off;
 
     void sink_it_(const details::log_msg &msg) override {
         bool filtered = filter_(msg);
         if (!filtered) {
             skip_counter_ += 1;
+            skipped_msg_log_level_ = msg.level;
             return;
         }
 
@@ -65,7 +64,7 @@ protected:
             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_,
+                details::log_msg skipped_msg{msg.source, msg.logger_name, skipped_msg_log_level_,
                                              string_view_t{buf, static_cast<size_t>(msg_size)}};
                 dist_sink<Mutex>::sink_it_(skipped_msg);
             }

include/spdlog/sinks/null_sink.h

@@ -13,7 +13,7 @@ namespace spdlog {
 namespace sinks {
 
 template <typename Mutex>
-class null_sink : public base_sink<Mutex> {
+class null_sink final : public base_sink<Mutex> {
 protected:
     void sink_it_(const details::log_msg &) override {}
     void flush_() override {}

include/spdlog/sinks/rotating_file_sink-inl.h

@@ -14,7 +14,6 @@
 #include <spdlog/fmt/fmt.h>
 
 #include <cerrno>
-#include <chrono>
 #include <ctime>
 #include <mutex>
 #include <string>
@@ -38,8 +37,8 @@ SPDLOG_INLINE rotating_file_sink<Mutex>::rotating_file_sink(
         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");
+    if (max_files > MaxFiles) {
+        throw_spdlog_ex("rotating sink constructor: max_files arg cannot exceed MaxFiles");
     }
     file_helper_.open(calc_filename(base_filename_, 0));
     current_size_ = file_helper_.size();  // expensive. called only once
@@ -54,11 +53,12 @@ SPDLOG_INLINE rotating_file_sink<Mutex>::rotating_file_sink(
 template <typename Mutex>
 SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::calc_filename(const filename_t &filename,
                                                                   std::size_t index) {
-    if (index == 0u) {
+    if (index == 0U) {
         return filename;
     }
 
-    filename_t basename, ext;
+    filename_t basename;
+    filename_t ext;
     std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
     return fmt_lib::format(SPDLOG_FMT_STRING(SPDLOG_FILENAME_T("{}.{}{}")), basename, index, ext);
 }
@@ -69,6 +69,41 @@ SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::filename() {
     return file_helper_.filename();
 }
 
+template <typename Mutex>
+SPDLOG_INLINE void rotating_file_sink<Mutex>::rotate_now() {
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    rotate_();
+}
+template <typename Mutex>
+SPDLOG_INLINE void rotating_file_sink<Mutex>::set_max_size(std::size_t max_size) {
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    if (max_size == 0) {
+        throw_spdlog_ex("rotating sink set_max_size: max_size arg cannot be zero");
+    }
+    max_size_ = max_size;
+}
+
+template <typename Mutex>
+SPDLOG_INLINE std::size_t rotating_file_sink<Mutex>::get_max_size() {
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    return max_size_;
+}
+
+template <typename Mutex>
+SPDLOG_INLINE void rotating_file_sink<Mutex>::set_max_files(std::size_t max_files) {
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    if (max_files > MaxFiles) {
+        throw_spdlog_ex("rotating sink set_max_files: max_files arg cannot exceed 200000");
+    }
+    max_files_ = max_files;
+}
+
+template <typename Mutex>
+std::size_t rotating_file_sink<Mutex>::get_max_files() {
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    return max_files_;
+}
+
 template <typename Mutex>
 SPDLOG_INLINE void rotating_file_sink<Mutex>::sink_it_(const details::log_msg &msg) {
     memory_buf_t formatted;

include/spdlog/sinks/rotating_file_sink.h

@@ -8,7 +8,6 @@
 #include <spdlog/details/synchronous_factory.h>
 #include <spdlog/sinks/base_sink.h>
 
-#include <chrono>
 #include <mutex>
 #include <string>
 
@@ -21,6 +20,7 @@ namespace sinks {
 template <typename Mutex>
 class rotating_file_sink final : public base_sink<Mutex> {
 public:
+    static constexpr size_t MaxFiles = 200000;
     rotating_file_sink(filename_t base_filename,
                        std::size_t max_size,
                        std::size_t max_files,
@@ -28,6 +28,11 @@ public:
                        const file_event_handlers &event_handlers = {});
     static filename_t calc_filename(const filename_t &filename, std::size_t index);
     filename_t filename();
+    void rotate_now();
+    void set_max_size(std::size_t max_size);
+    std::size_t get_max_size();
+    void set_max_files(std::size_t max_files);
+    std::size_t get_max_files();
 
 protected:
     void sink_it_(const details::log_msg &msg) override;
@@ -60,9 +65,8 @@ using rotating_file_sink_st = rotating_file_sink<details::null_mutex>;
 //
 // factory functions
 //
-
 template <typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> rotating_logger_mt(const std::string &logger_name,
+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,
@@ -73,7 +77,7 @@ inline std::shared_ptr<logger> rotating_logger_mt(const std::string &logger_name
 }
 
 template <typename Factory = spdlog::synchronous_factory>
-inline std::shared_ptr<logger> rotating_logger_st(const std::string &logger_name,
+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,

include/spdlog/sinks/stdout_sinks-inl.h

@@ -10,6 +10,7 @@
 #include <memory>
 #include <spdlog/details/console_globals.h>
 #include <spdlog/pattern_formatter.h>
+#include <spdlog/details/os.h>
 
 #ifdef _WIN32
     // under windows using fwrite to non-binary stream results in \r\r\n (see issue #1675)
@@ -22,7 +23,7 @@
 
     #include <io.h>     // _get_osfhandle(..)
     #include <stdio.h>  // _fileno(..)
-#endif                  // WIN32
+#endif                  // _WIN32
 
 namespace spdlog {
 
@@ -44,7 +45,7 @@ SPDLOG_INLINE stdout_sink_base<ConsoleMutex>::stdout_sink_base(FILE *file)
     if (handle_ == INVALID_HANDLE_VALUE && file != stdout && file != stderr) {
         throw_spdlog_ex("spdlog::stdout_sink_base: _get_osfhandle() failed", errno);
     }
-#endif  // WIN32
+#endif  // _WIN32
 }
 
 template <typename ConsoleMutex>
@@ -67,8 +68,8 @@ SPDLOG_INLINE void stdout_sink_base<ConsoleMutex>::log(const details::log_msg &m
     std::lock_guard<mutex_t> lock(mutex_);
     memory_buf_t formatted;
     formatter_->format(msg, formatted);
-    ::fwrite(formatted.data(), sizeof(char), formatted.size(), file_);
-#endif                // WIN32
+    details::os::fwrite_bytes(formatted.data(), formatted.size(), file_);
+#endif                // _WIN32
     ::fflush(file_);  // flush every line to terminal
 }
 

include/spdlog/spdlog-inl.h

@@ -59,6 +59,10 @@ SPDLOG_INLINE void register_logger(std::shared_ptr<logger> logger) {
     details::registry::instance().register_logger(std::move(logger));
 }
 
+SPDLOG_INLINE void register_or_replace(std::shared_ptr<logger> logger) {
+    details::registry::instance().register_or_replace(std::move(logger));
+}
+
 SPDLOG_INLINE void apply_all(const std::function<void(std::shared_ptr<logger>)> &fun) {
     details::registry::instance().apply_all(fun);
 }

include/spdlog/spdlog.h

@@ -25,7 +25,7 @@ namespace spdlog {
 using default_factory = synchronous_factory;
 
 // Create and register a logger with a templated sink type
-// The logger's level, formatter and flush level will be set according the
+// The logger's level, formatter and flush level will be set according to the
 // global settings.
 //
 // Example:
@@ -46,7 +46,7 @@ inline std::shared_ptr<spdlog::logger> create(std::string logger_name, SinkArgs
 //   spdlog::initialize_logger(mylogger);
 SPDLOG_API void initialize_logger(std::shared_ptr<logger> logger);
 
-// Return an existing logger or nullptr if a logger with such name doesn't
+// Return an existing logger or nullptr if a logger with such a name doesn't
 // exist.
 // example: spdlog::get("my_logger")->info("hello {}", "world");
 SPDLOG_API std::shared_ptr<logger> get(const std::string &name);
@@ -71,13 +71,13 @@ SPDLOG_API void dump_backtrace();
 // Get global logging level
 SPDLOG_API level::level_enum get_level();
 
-// Set global logging level
+// Set the global logging level
 SPDLOG_API void set_level(level::level_enum log_level);
 
 // Determine whether the default logger should log messages with a certain level
 SPDLOG_API bool should_log(level::level_enum lvl);
 
-// Set global flush level
+// Set a global flush level
 SPDLOG_API void flush_on(level::level_enum log_level);
 
 // Start/Restart a periodic flusher thread
@@ -91,9 +91,14 @@ inline void flush_every(std::chrono::duration<Rep, Period> interval) {
 SPDLOG_API void set_error_handler(void (*handler)(const std::string &msg));
 
 // Register the given logger with the given name
+// Will throw if a logger with the same name already exists.
 SPDLOG_API void register_logger(std::shared_ptr<logger> logger);
 
-// Apply a user defined function on all registered loggers
+// Register the given logger with the given name
+// Will replace any existing logger with the same name.
+SPDLOG_API void register_or_replace(std::shared_ptr<logger> logger);
+
+// Apply a user-defined function on all registered loggers
 // Example:
 // spdlog::apply_all([&](std::shared_ptr<spdlog::logger> l) {l->flush();});
 SPDLOG_API void apply_all(const std::function<void(std::shared_ptr<logger>)> &fun);
@@ -111,19 +116,19 @@ SPDLOG_API void shutdown();
 SPDLOG_API void set_automatic_registration(bool automatic_registration);
 
 // API for using default logger (stdout_color_mt),
-// e.g: spdlog::info("Message {}", 1);
+// e.g.: spdlog::info("Message {}", 1);
 //
 // The default logger object can be accessed using the spdlog::default_logger():
 // For example, to add another sink to it:
 // spdlog::default_logger()->sinks().push_back(some_sink);
 //
-// The default logger can replaced using spdlog::set_default_logger(new_logger).
+// The default logger can be replaced using spdlog::set_default_logger(new_logger).
 // For example, to replace it with a file logger.
 //
 // IMPORTANT:
 // The default API is thread safe (for _mt loggers), but:
 // set_default_logger() *should not* be used concurrently with the default API.
-// e.g do not call set_default_logger() from one thread while calling spdlog::info() from another.
+// e.g., do not call set_default_logger() from one thread while calling spdlog::info() from another.
 
 SPDLOG_API std::shared_ptr<spdlog::logger> default_logger();
 

include/spdlog/tweakme.h

@@ -104,6 +104,13 @@
 //
 // #define SPDLOG_LEVEL_NAMES { "MY TRACE", "MY DEBUG", "MY INFO", "MY WARNING", "MY ERROR", "MY
 // CRITICAL", "OFF" }
+//
+// For C++17 use string_view_literals:
+//
+// #include <string_view>
+// using namespace std::string_view_literals;
+// #define SPDLOG_LEVEL_NAMES { "MY TRACE"sv, "MY DEBUG"sv, "MY INFO"sv, "MY WARNING"sv, "MY
+// ERROR"sv, "MY CRITICAL"sv, "OFF"sv }
 ///////////////////////////////////////////////////////////////////////////////
 
 ///////////////////////////////////////////////////////////////////////////////

include/spdlog/version.h

@@ -5,7 +5,7 @@
 
 #define SPDLOG_VER_MAJOR 1
 #define SPDLOG_VER_MINOR 15
-#define SPDLOG_VER_PATCH 0
+#define SPDLOG_VER_PATCH 3
 
 #define SPDLOG_TO_VERSION(major, minor, patch) (major * 10000 + minor * 100 + patch)
 #define SPDLOG_VERSION SPDLOG_TO_VERSION(SPDLOG_VER_MAJOR, SPDLOG_VER_MINOR, SPDLOG_VER_PATCH)

src/bundled_fmtlib_format.cpp

@@ -13,31 +13,32 @@
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
-template FMT_API auto dragonbox::to_decimal(float x) noexcept
-    -> dragonbox::decimal_fp<float>;
-template FMT_API auto dragonbox::to_decimal(double x) noexcept
-    -> dragonbox::decimal_fp<double>;
+template FMT_API auto dragonbox::to_decimal(float x) noexcept -> dragonbox::decimal_fp<float>;
+template FMT_API auto dragonbox::to_decimal(double x) noexcept -> dragonbox::decimal_fp<double>;
 
-#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+    #if FMT_USE_LOCALE
+// DEPRECATED! locale_ref in the detail namespace
 template FMT_API locale_ref::locale_ref(const std::locale& loc);
 template FMT_API auto locale_ref::get<std::locale>() const -> std::locale;
-#endif
+    #endif
 
 // Explicit instantiations for char.
 
-template FMT_API auto thousands_sep_impl(locale_ref)
-    -> thousands_sep_result<char>;
+template FMT_API auto thousands_sep_impl(locale_ref) -> thousands_sep_result<char>;
 template FMT_API auto decimal_point_impl(locale_ref) -> char;
 
+// DEPRECATED!
 template FMT_API void buffer<char>::append(const char*, const char*);
 
-template FMT_API void vformat_to(buffer<char>&, string_view,
-                                 typename vformat_args<>::type, locale_ref);
+// DEPRECATED!
+template FMT_API void vformat_to(buffer<char>&,
+                                 string_view,
+                                 typename vformat_args<>::type,
+                                 locale_ref);
 
 // Explicit instantiations for wchar_t.
 
-template FMT_API auto thousands_sep_impl(locale_ref)
-    -> thousands_sep_result<wchar_t>;
+template FMT_API auto thousands_sep_impl(locale_ref) -> thousands_sep_result<wchar_t>;
 template FMT_API auto decimal_point_impl(locale_ref) -> wchar_t;
 
 template FMT_API void buffer<wchar_t>::append(const wchar_t*, const wchar_t*);

tests/CMakeLists.txt

@@ -19,8 +19,8 @@ if(Catch2_FOUND)
 else()
     message(STATUS "Bundled version of Catch will be downloaded and used.")
     include(FetchContent)
-    FetchContent_Declare(Catch2
-            GIT_REPOSITORY https://github.com/catchorg/Catch2.git
+    FetchContent_Declare(
+        Catch2 GIT_REPOSITORY https://github.com/catchorg/Catch2.git
         GIT_TAG 53d0d913a422d356b23dd927547febdf69ee9081 # v3.5.0
     )
     FetchContent_MakeAvailable(Catch2)
@@ -48,7 +48,8 @@ set(SPDLOG_UTESTS_SOURCES
     test_cfg.cpp
     test_time_point.cpp
     test_stopwatch.cpp
-    test_circular_q.cpp)
+    test_circular_q.cpp
+    test_bin_to_hex.cpp)
 
 if(NOT SPDLOG_NO_EXCEPTIONS)
     list(APPEND SPDLOG_UTESTS_SOURCES test_errors.cpp)
@@ -58,10 +59,6 @@ if(systemd_FOUND)
     list(APPEND SPDLOG_UTESTS_SOURCES test_systemd.cpp)
 endif()
 
-if(NOT SPDLOG_USE_STD_FORMAT)
-    list(APPEND SPDLOG_UTESTS_SOURCES test_bin_to_hex.cpp)
-endif()
-
 enable_testing()
 
 function(spdlog_prepare_test test_target spdlog_lib)
@@ -74,9 +71,9 @@ function(spdlog_prepare_test test_target spdlog_lib)
     target_link_libraries(${test_target} PRIVATE Catch2::Catch2WithMain)
     if(SPDLOG_SANITIZE_ADDRESS)
         spdlog_enable_addr_sanitizer(${test_target})
-    elseif (SPDLOG_SANITIZE_THREAD)
+    elseif(SPDLOG_SANITIZE_THREAD)
         spdlog_enable_thread_sanitizer(${test_target})
-    endif ()
+    endif()
     add_test(NAME ${test_target} COMMAND ${test_target})
     set_tests_properties(${test_target} PROPERTIES RUN_SERIAL ON)
 endfunction()

tests/test_cfg.cpp

@@ -19,6 +19,15 @@ TEST_CASE("env", "[cfg]") {
 #endif
     load_env_levels();
     REQUIRE(l1->level() == spdlog::level::warn);
+
+#ifdef CATCH_PLATFORM_WINDOWS
+    _putenv_s("MYAPP_LEVEL", "l1=trace");
+#else
+    setenv("MYAPP_LEVEL", "l1=trace", 1);
+#endif
+    load_env_levels("MYAPP_LEVEL");
+    REQUIRE(l1->level() == spdlog::level::trace);
+
     spdlog::set_default_logger(spdlog::create<test_sink_st>("cfg-default"));
     REQUIRE(spdlog::default_logger()->level() == spdlog::level::info);
 }

tests/test_custom_callbacks.cpp

@@ -16,7 +16,9 @@ TEST_CASE("custom_callback_logger", "[custom_callback_logger]") {
             spdlog::memory_buf_t formatted;
             formatter.format(msg, formatted);
             auto eol_len = strlen(spdlog::details::os::default_eol);
-            lines.emplace_back(formatted.begin(), formatted.end() - eol_len);
+            using diff_t =
+                typename std::iterator_traits<decltype(formatted.end())>::difference_type;
+            lines.emplace_back(formatted.begin(), formatted.end() - static_cast<diff_t>(eol_len));
         });
     std::shared_ptr<spdlog::sinks::test_sink_st> test_sink(new spdlog::sinks::test_sink_st);
 

tests/test_daily_logger.cpp

@@ -46,12 +46,8 @@ TEST_CASE("daily_logger with dateonly calculator", "[daily_logger]") {
 
 struct custom_daily_file_name_calculator {
     static spdlog::filename_t calc_filename(const spdlog::filename_t &basename, const tm &now_tm) {
-        filename_memory_buf_t w;
-        spdlog::fmt_lib::format_to(std::back_inserter(w), SPDLOG_FILENAME_T("{}{:04d}{:02d}{:02d}"),
-                                   basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1,
-                                   now_tm.tm_mday);
-
-        return SPDLOG_BUF_TO_STRING(w);
+        return spdlog::fmt_lib::format(SPDLOG_FILENAME_T("{}{:04d}{:02d}{:02d}"), basename,
+                                       now_tm.tm_year + 1900, now_tm.tm_mon + 1, now_tm.tm_mday);
     }
 };
 

tests/test_file_logging.cpp

@@ -45,6 +45,26 @@ TEST_CASE("flush_on", "[flush_on]") {
                                     default_eol, default_eol, default_eol));
 }
 
+TEST_CASE("simple_file_logger", "[truncate]") {
+    prepare_logdir();
+    const spdlog::filename_t filename = SPDLOG_FILENAME_T(SIMPLE_LOG);
+    const bool truncate = true;
+    const auto sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>(filename, truncate);
+    const auto logger = std::make_shared<spdlog::logger>("simple_file_logger", sink);
+
+    logger->info("Test message {}", 3.14);
+    logger->info("Test message {}", 2.71);
+    logger->flush();
+    REQUIRE(count_lines(SIMPLE_LOG) == 2);
+
+    sink->truncate();
+    REQUIRE(count_lines(SIMPLE_LOG) == 0);
+
+    logger->info("Test message {}", 6.28);
+    logger->flush();
+    REQUIRE(count_lines(SIMPLE_LOG) == 1);
+}
+
 TEST_CASE("rotating_file_logger1", "[rotating_logger]") {
     prepare_logdir();
     size_t max_size = 1024 * 10;
@@ -74,14 +94,11 @@ TEST_CASE("rotating_file_logger2", "[rotating_logger]") {
         // next logger can rename the first output file.
         spdlog::drop(logger->name());
     }
-
     auto logger = spdlog::rotating_logger_mt("logger", basename, max_size, 2, true);
     for (int i = 0; i < 10; ++i) {
         logger->info("Test message {}", i);
     }
-
     logger->flush();
-
     require_message_count(ROTATING_LOG, 10);
 
     for (int i = 0; i < 1000; i++) {
@@ -101,3 +118,70 @@ TEST_CASE("rotating_file_logger3", "[rotating_logger]") {
     REQUIRE_THROWS_AS(spdlog::rotating_logger_mt("logger", basename, max_size, 0),
                       spdlog::spdlog_ex);
 }
+
+// test on-demand rotation of logs
+TEST_CASE("rotating_file_logger4", "[rotating_logger]") {
+    prepare_logdir();
+    size_t max_size = 1024 * 10;
+    spdlog::filename_t basename = SPDLOG_FILENAME_T(ROTATING_LOG);
+    auto sink = std::make_shared<spdlog::sinks::rotating_file_sink_st>(basename, max_size, 2);
+    auto logger = std::make_shared<spdlog::logger>("rotating_sink_logger", sink);
+
+    logger->info("Test message - pre-rotation");
+    logger->flush();
+
+    sink->rotate_now();
+
+    logger->info("Test message - post-rotation");
+    logger->flush();
+
+    REQUIRE(get_filesize(ROTATING_LOG) > 0);
+    REQUIRE(get_filesize(ROTATING_LOG ".1") > 0);
+}
+
+// test changing the max size of the rotating file sink
+TEST_CASE("rotating_file_logger5", "[rotating_logger]") {
+    prepare_logdir();
+    size_t max_size = 5 * 1024;
+    size_t max_files = 2;
+    spdlog::filename_t basename = SPDLOG_FILENAME_T(ROTATING_LOG);
+    auto sink =
+        std::make_shared<spdlog::sinks::rotating_file_sink_st>(basename, max_size, max_files);
+    auto logger = std::make_shared<spdlog::logger>("rotating_sink_logger", sink);
+    logger->set_pattern("%v");
+
+    REQUIRE(sink->get_max_size() == max_size);
+    REQUIRE(sink->get_max_files() == max_files);
+    max_size = 7 * 1024;
+    max_files = 3;
+
+    sink->set_max_size(max_size);
+    sink->set_max_files(max_files);
+    REQUIRE(sink->get_max_size() == max_size);
+    REQUIRE(sink->get_max_files() == max_files);
+
+    const auto message = std::string(200, 'x');
+    assert(message.size() < max_size);
+    const auto n_messages = max_files * max_size / message.size();
+    for (size_t i = 0; i < n_messages; ++i) {
+        logger->info(message);
+    }
+    logger.reset();  // force flush and close the file
+
+    // validate that the files were rotated correctly with the new max size and max files
+    for (size_t i = 0; i <= max_files; i++) {
+        // calc filenames
+        // e.g. rotating_log, rotating_log.0 rotating_log.1, rotating_log.2, etc.
+        std::ostringstream oss;
+        oss << ROTATING_LOG;
+        if (i > 0) {
+            oss << '.' << i;
+        }
+        const auto filename = oss.str();
+        const auto filesize = get_filesize(filename);
+        REQUIRE(filesize <= max_size);
+        if (i > 0) {
+            REQUIRE(filesize >= max_size - message.size() - 2);
+        }
+    }
+}

tests/test_misc.cpp

@@ -1,8 +1,12 @@
+#ifdef _WIN32  // to prevent fopen warning on windows
+    #define _CRT_SECURE_NO_WARNINGS
+#endif
+
 #include "includes.h"
 #include "test_sink.h"
 
 template <class T>
-std::string log_info(const T &what, spdlog::level::level_enum logger_level = spdlog::level::info) {
+std::string log_info(const T& what, spdlog::level::level_enum logger_level = spdlog::level::info) {
     std::ostringstream oss;
     auto oss_sink = std::make_shared<spdlog::sinks::ostream_sink_mt>(oss);
 
@@ -181,7 +185,40 @@ TEST_CASE("utf8 to utf16 conversion using windows api", "[windows utf]") {
     spdlog::details::os::utf8_to_wstrbuf("\xc3\x28", buffer);  // Invalid UTF-8 sequence.
     REQUIRE(std::wstring(buffer.data(), buffer.size()) == std::wstring(L"\xfffd("));
 
-    spdlog::details::os::utf8_to_wstrbuf("\xe3\x81\xad\xe3\x81\x93", buffer); // "Neko" in hiragana.
+    spdlog::details::os::utf8_to_wstrbuf("\xe3\x81\xad\xe3\x81\x93",
+                                         buffer);  // "Neko" in hiragana.
     REQUIRE(std::wstring(buffer.data(), buffer.size()) == std::wstring(L"\x306d\x3053"));
 }
 #endif
+
+struct auto_closer {
+    FILE* fp = nullptr;
+    explicit auto_closer(FILE* f)
+        : fp(f) {}
+    auto_closer(const auto_closer&) = delete;
+    auto_closer& operator=(const auto_closer&) = delete;
+    ~auto_closer() {
+        if (fp != nullptr) (void)std::fclose(fp);
+    }
+};
+
+TEST_CASE("os::fwrite_bytes", "[os]") {
+    using spdlog::details::os::create_dir;
+    using spdlog::details::os::fwrite_bytes;
+    const char* filename = "log_tests/test_fwrite_bytes.txt";
+    const char* msg = "hello";
+    prepare_logdir();
+    REQUIRE(create_dir(SPDLOG_FILENAME_T("log_tests")) == true);
+    {
+        auto_closer closer(std::fopen(filename, "wb"));
+        REQUIRE(closer.fp != nullptr);
+        REQUIRE(fwrite_bytes(msg, std::strlen(msg), closer.fp) == true);
+        REQUIRE(fwrite_bytes(msg, 0, closer.fp) == true);
+        std::fflush(closer.fp);
+        REQUIRE(spdlog::details::os::filesize(closer.fp) == 5);
+    }
+    // fwrite_bytes should return false on write failure
+    auto_closer closer(std::fopen(filename, "r"));
+    REQUIRE(closer.fp != nullptr);
+    REQUIRE_FALSE(fwrite_bytes("Hello", 5, closer.fp));
+}

tests/test_pattern_formatter.cpp

@@ -1,6 +1,8 @@
 #include "includes.h"
 #include "test_sink.h"
 
+#include <chrono>
+
 using spdlog::memory_buf_t;
 using spdlog::details::to_string_view;
 
@@ -19,6 +21,23 @@ static std::string log_to_str(const std::string &msg, const Args &...args) {
     return oss.str();
 }
 
+// log to str and return it with time
+template <typename... Args>
+static std::string log_to_str_with_time(spdlog::log_clock::time_point log_time,
+                                        const std::string &msg,
+                                        const Args &...args) {
+    std::ostringstream oss;
+    auto oss_sink = std::make_shared<spdlog::sinks::ostream_sink_mt>(oss);
+    spdlog::logger oss_logger("pattern_tester", oss_sink);
+    oss_logger.set_level(spdlog::level::info);
+
+    oss_logger.set_formatter(
+        std::unique_ptr<spdlog::formatter>(new spdlog::pattern_formatter(args...)));
+
+    oss_logger.log(log_time, {}, spdlog::level::info, msg);
+    return oss.str();
+}
+
 TEST_CASE("custom eol", "[pattern_formatter]") {
     std::string msg = "Hello custom eol test";
     std::string eol = ";)";
@@ -58,6 +77,15 @@ TEST_CASE("date MM/DD/YY ", "[pattern_formatter]") {
             oss.str());
 }
 
+TEST_CASE("GMT offset ", "[pattern_formatter]") {
+    using namespace std::chrono_literals;
+    const auto now = std::chrono::system_clock::now();
+    const auto yesterday = now - 24h;
+
+    REQUIRE(log_to_str_with_time(yesterday, "Some message", "%z", spdlog::pattern_time_type::utc,
+                                 "\n") == "+00:00\n");
+}
+
 TEST_CASE("color range test1", "[pattern_formatter]") {
     auto formatter = std::make_shared<spdlog::pattern_formatter>(
         "%^%v%$", spdlog::pattern_time_type::local, "\n");

tests/test_registry.cpp

@@ -25,6 +25,19 @@ TEST_CASE("explicit register", "[registry]") {
 }
 #endif
 
+TEST_CASE("register_or_replace", "[registry]") {
+    spdlog::drop_all();
+    auto logger1 = std::make_shared<spdlog::logger>(
+        tested_logger_name, std::make_shared<spdlog::sinks::null_sink_st>());
+    spdlog::register_logger(logger1);
+    REQUIRE(spdlog::get(tested_logger_name) == logger1);
+
+    auto logger2 = std::make_shared<spdlog::logger>(
+        tested_logger_name, std::make_shared<spdlog::sinks::null_sink_st>());
+    spdlog::register_or_replace(logger2);
+    REQUIRE(spdlog::get(tested_logger_name) == logger2);
+}
+
 TEST_CASE("apply_all", "[registry]") {
     spdlog::drop_all();
     auto logger = std::make_shared<spdlog::logger>(tested_logger_name,

tests/test_sink.h

@@ -47,8 +47,9 @@ protected:
         base_sink<Mutex>::formatter_->format(msg, formatted);
         // save the line without the eol
         auto eol_len = strlen(details::os::default_eol);
+        using diff_t = typename std::iterator_traits<decltype(formatted.end())>::difference_type;
         if (lines_.size() < lines_to_save) {
-            lines_.emplace_back(formatted.begin(), formatted.end() - eol_len);
+            lines_.emplace_back(formatted.begin(), formatted.end() - static_cast<diff_t>(eol_len));
         }
         msg_counter_++;
         std::this_thread::sleep_for(delay_);

tests/test_stopwatch.cpp

@@ -5,7 +5,7 @@
 TEST_CASE("stopwatch1", "[stopwatch]") {
     using std::chrono::milliseconds;
     using clock = std::chrono::steady_clock;
-    milliseconds wait_ms(200);
+    milliseconds wait_ms(500);
     milliseconds tolerance_ms(250);
     auto start = clock::now();
     spdlog::stopwatch sw;
@@ -22,7 +22,7 @@ TEST_CASE("stopwatch2", "[stopwatch]") {
     using std::chrono::milliseconds;
     using clock = std::chrono::steady_clock;
 
-    clock::duration wait_duration(milliseconds(200));
+    clock::duration wait_duration(milliseconds(500));
     clock::duration tolerance_duration(milliseconds(250));
 
     auto test_sink = std::make_shared<test_sink_st>();

tests/utils.cpp

@@ -50,9 +50,8 @@ void require_message_count(const std::string &filename, const std::size_t messag
 std::size_t get_filesize(const std::string &filename) {
     std::ifstream ifs(filename, std::ifstream::ate | std::ifstream::binary);
     if (!ifs) {
-        throw std::runtime_error("Failed open file ");
+        throw std::runtime_error("Failed open file " + filename);
     }
-
     return static_cast<std::size_t>(ifs.tellg());
 }