Updated fmt bundled files

update comments
Bump fmt to 11.2.0
2025-09-29 01:29:35 +08:00 · 2025-05-08 18:06:13 +03:00 · 2025-05-08 15:56:58 +03:00 · 2025-05-08 15:52:38 +03:00 · 2025-05-08 15:42:54 +03:00 · 2025-05-08 14:02:00 +03:00
43 changed files with 785 additions and 636 deletions
--- a/CMakeLists.txt
+++ b/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")
@@ -291,11 +290,12 @@ if (MSVC)
    target_compile_options(spdlog PRIVATE "/Zc:__cplusplus")
    target_compile_options(spdlog_header_only INTERFACE "/Zc:__cplusplus")
    if(SPDLOG_MSVC_UTF8)
-        # fmtlib requires the /utf-8 flag when building with msvc.
-        # see https://github.com/fmtlib/fmt/pull/4159 on the purpose of the additional
+        # 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>)
+        target_compile_options(spdlog_header_only
+                               INTERFACE $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>:/utf-8>)
    endif()
 endif()

@@ -304,12 +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()
 # ---------------------------------------------------------------------------------------
--- a/README.md
+++ b/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
@@ -48,7 +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.
@@ -58,7 +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.
@@ -467,7 +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
 ```
@@ -519,7 +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.

 ---

--- a/cmake/pch.h.in
+++ b/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>

--- a/example/example.cpp
+++ b/example/example.cpp
@@ -382,14 +382,14 @@ void replace_default_logger_example() {
    spdlog::set_default_logger(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
--- a/include/spdlog/async.h
+++ b/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.
--- a/include/spdlog/details/os-inl.h
+++ b/include/spdlog/details/os-inl.h
@@ -483,13 +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;
--- a/include/spdlog/details/registry-inl.h
+++ b/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());
@@ -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
--- a/include/spdlog/details/registry.h
+++ b/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_;
--- a/include/spdlog/details/thread_pool-inl.h
+++ b/include/spdlog/details/thread_pool-inl.h
@@ -38,8 +38,7 @@ SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items,
    : thread_pool(q_max_items, threads_n, on_thread_start, [] {}) {}

 SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items, size_t threads_n)
-    : thread_pool(
-          q_max_items, threads_n, [] {}, [] {}) {}
+    : thread_pool(q_max_items, threads_n, [] {}, [] {}) {}

 // message all threads to terminate gracefully join them
 SPDLOG_INLINE thread_pool::~thread_pool() {
--- a/include/spdlog/fmt/bin_to_hex.h
+++ b/include/spdlog/fmt/bin_to_hex.h
@@ -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;
--- a/include/spdlog/fmt/bundled/base.h
+++ b/include/spdlog/fmt/bundled/base.h
@@ -21,7 +21,7 @@
 #endif

 // The fmt library version in the form major * 10000 + minor * 100 + patch.
-#define FMT_VERSION 110104
+#define FMT_VERSION 110200

 // Detect compiler versions.
 #if defined(__clang__) && !defined(__ibmxl__)
@@ -209,20 +209,6 @@
 #  define FMT_DEPRECATED /* deprecated */
 #endif

-#ifdef FMT_ALWAYS_INLINE
-// Use the provided definition.
-#elif FMT_GCC_VERSION || FMT_CLANG_VERSION
-#  define FMT_ALWAYS_INLINE inline __attribute__((always_inline))
-#else
-#  define FMT_ALWAYS_INLINE inline
-#endif
-// A version of FMT_ALWAYS_INLINE to prevent code bloat in debug mode.
-#ifdef NDEBUG
-#  define FMT_INLINE FMT_ALWAYS_INLINE
-#else
-#  define FMT_INLINE inline
-#endif
-
 #if FMT_GCC_VERSION || FMT_CLANG_VERSION
 #  define FMT_VISIBILITY(value) __attribute__((visibility(value)))
 #else
@@ -249,6 +235,28 @@
 #  define FMT_MSC_WARNING(...)
 #endif

+// Enable minimal optimizations for more compact code in debug mode.
+FMT_PRAGMA_GCC(push_options)
+#if !defined(__OPTIMIZE__) && !defined(__CUDACC__) && !defined(FMT_MODULE)
+FMT_PRAGMA_GCC(optimize("Og"))
+#  define FMT_GCC_OPTIMIZED
+#endif
+FMT_PRAGMA_CLANG(diagnostic push)
+
+#ifdef FMT_ALWAYS_INLINE
+// Use the provided definition.
+#elif FMT_GCC_VERSION || FMT_CLANG_VERSION
+#  define FMT_ALWAYS_INLINE inline __attribute__((always_inline))
+#else
+#  define FMT_ALWAYS_INLINE inline
+#endif
+// A version of FMT_ALWAYS_INLINE to prevent code bloat in debug mode.
+#if defined(NDEBUG) || defined(FMT_GCC_OPTIMIZED)
+#  define FMT_INLINE FMT_ALWAYS_INLINE
+#else
+#  define FMT_INLINE inline
+#endif
+
 #ifndef FMT_BEGIN_NAMESPACE
 #  define FMT_BEGIN_NAMESPACE \
    namespace fmt {           \
@@ -297,13 +305,6 @@
  using unused = int[];          \
  (void)unused { 0, (expr, 0)... }

-// Enable minimal optimizations for more compact code in debug mode.
-FMT_PRAGMA_GCC(push_options)
-#if !defined(__OPTIMIZE__) && !defined(__CUDACC__) && !defined(FMT_MODULE)
-FMT_PRAGMA_GCC(optimize("Og"))
-#endif
-FMT_PRAGMA_CLANG(diagnostic push)
-
 FMT_BEGIN_NAMESPACE

 // Implementations of enable_if_t and other metafunctions for older systems.
@@ -325,8 +326,8 @@ using underlying_t = typename std::underlying_type<T>::type;
 template <typename T> using decay_t = typename std::decay<T>::type;
 using nullptr_t = decltype(nullptr);

-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 500
-// A workaround for gcc 4.9 to make void_t work in a SFINAE context.
+#if (FMT_GCC_VERSION && FMT_GCC_VERSION < 500) || FMT_MSC_VERSION
+// A workaround for gcc 4.9 & MSVC v141 to make void_t work in a SFINAE context.
 template <typename...> struct void_t_impl {
  using type = void;
 };
@@ -526,20 +527,20 @@ template <typename Char> class basic_string_view {

  constexpr basic_string_view() noexcept : data_(nullptr), size_(0) {}

-  /// Constructs a string reference object from a C string and a size.
+  /// Constructs a string view object from a C string and a size.
  constexpr basic_string_view(const Char* s, size_t count) noexcept
      : data_(s), size_(count) {}

  constexpr basic_string_view(nullptr_t) = delete;

-  /// Constructs a string reference object from a C string.
+  /// Constructs a string view object from a C string.
 #if FMT_GCC_VERSION
  FMT_ALWAYS_INLINE
 #endif
  FMT_CONSTEXPR20 basic_string_view(const Char* s) : data_(s) {
 #if FMT_HAS_BUILTIN(__builtin_strlen) || FMT_GCC_VERSION || FMT_CLANG_VERSION
-    if (std::is_same<Char, char>::value) {
-      size_ = __builtin_strlen(detail::narrow(s));
+    if (std::is_same<Char, char>::value && !detail::is_constant_evaluated()) {
+      size_ = __builtin_strlen(detail::narrow(s));  // strlen is not costexpr.
      return;
    }
 #endif
@@ -548,7 +549,7 @@ template <typename Char> class basic_string_view {
    size_ = len;
  }

-  /// Constructs a string reference from a `std::basic_string` or a
+  /// Constructs a string view from a `std::basic_string` or a
  /// `std::basic_string_view` object.
  template <typename S,
            FMT_ENABLE_IF(detail::is_std_string_like<S>::value&& std::is_same<
@@ -585,7 +586,6 @@ template <typename Char> class basic_string_view {
    return starts_with(basic_string_view<Char>(s));
  }

-  // Lexicographically compare this string reference to other.
  FMT_CONSTEXPR auto compare(basic_string_view other) const -> int {
    int result =
        detail::compare(data_, other.data_, min_of(size_, other.size_));
@@ -616,7 +616,7 @@ template <typename Char> class basic_string_view {

 using string_view = basic_string_view<char>;

-/// Specifies if `T` is an extended character type. Can be specialized by users.
+// DEPRECATED! Will be merged with is_char and moved to detail.
 template <typename T> struct is_xchar : std::false_type {};
 template <> struct is_xchar<wchar_t> : std::true_type {};
 template <> struct is_xchar<char16_t> : std::true_type {};
@@ -625,7 +625,7 @@ template <> struct is_xchar<char32_t> : std::true_type {};
 template <> struct is_xchar<char8_t> : std::true_type {};
 #endif

-// DEPRECATED! Will be replaced with an alias to prevent specializations.
+// Specifies if `T` is a character (code unit) type.
 template <typename T> struct is_char : is_xchar<T> {};
 template <> struct is_char<char> : std::true_type {};

@@ -1032,6 +1032,11 @@ enum {

 struct view {};

+template <typename T, typename Enable = std::true_type>
+struct is_view : std::false_type {};
+template <typename T>
+struct is_view<T, bool_constant<sizeof(T) != 0>> : std::is_base_of<view, T> {};
+
 template <typename Char, typename T> struct named_arg;
 template <typename T> struct is_named_arg : std::false_type {};
 template <typename T> struct is_static_named_arg : std::false_type {};
@@ -1064,6 +1069,16 @@ template <typename Char> struct named_arg_info {
  int id;
 };

+// named_args is non-const to suppress a bogus -Wmaybe-uninitalized in gcc 13.
+template <typename Char>
+FMT_CONSTEXPR void check_for_duplicate(named_arg_info<Char>* named_args,
+                                       int named_arg_index,
+                                       basic_string_view<Char> arg_name) {
+  for (int i = 0; i < named_arg_index; ++i) {
+    if (named_args[i].name == arg_name) report_error("duplicate named arg");
+  }
+}
+
 template <typename Char, typename T, FMT_ENABLE_IF(!is_named_arg<T>::value)>
 void init_named_arg(named_arg_info<Char>*, int& arg_index, int&, const T&) {
  ++arg_index;
@@ -1071,6 +1086,7 @@ void init_named_arg(named_arg_info<Char>*, int& arg_index, int&, const T&) {
 template <typename Char, typename T, FMT_ENABLE_IF(is_named_arg<T>::value)>
 void init_named_arg(named_arg_info<Char>* named_args, int& arg_index,
                    int& named_arg_index, const T& arg) {
+  check_for_duplicate<Char>(named_args, named_arg_index, arg.name);
  named_args[named_arg_index++] = {arg.name, arg_index++};
 }

@@ -1084,12 +1100,13 @@ template <typename T, typename Char,
          FMT_ENABLE_IF(is_static_named_arg<T>::value)>
 FMT_CONSTEXPR void init_static_named_arg(named_arg_info<Char>* named_args,
                                         int& arg_index, int& named_arg_index) {
+  check_for_duplicate<Char>(named_args, named_arg_index, T::name);
  named_args[named_arg_index++] = {T::name, arg_index++};
 }

 // To minimize the number of types we need to deal with, long is translated
 // either to int or to long long depending on its size.
-enum { long_short = sizeof(long) == sizeof(int) };
+enum { long_short = sizeof(long) == sizeof(int) && FMT_BUILTIN_TYPES };
 using long_type = conditional_t<long_short, int, long long>;
 using ulong_type = conditional_t<long_short, unsigned, unsigned long long>;

@@ -1706,7 +1723,17 @@ class format_string_checker {
      -> const Char* {
    context_.advance_to(begin);
    if (id >= 0 && id < NUM_ARGS) return parse_funcs_[id](context_);
-    while (begin != end && *begin != '}') ++begin;
+
+    // If id is out of range, it means we do not know the type and cannot parse
+    // the format at compile time. Instead, skip over content until we finish
+    // the format spec, accounting for any nested replacements.
+    for (int bracket_count = 0;
+         begin != end && (bracket_count > 0 || *begin != '}'); ++begin) {
+      if (*begin == '{')
+        ++bracket_count;
+      else if (*begin == '}')
+        --bracket_count;
+    }
    return begin;
  }

@@ -2703,7 +2730,7 @@ template <typename... T> struct fstring {
  template <size_t N>
  FMT_CONSTEVAL FMT_ALWAYS_INLINE fstring(const char (&s)[N]) : str(s, N - 1) {
    using namespace detail;
-    static_assert(count<(std::is_base_of<view, remove_reference_t<T>>::value &&
+    static_assert(count<(is_view<remove_cvref_t<T>>::value &&
                         std::is_reference<T>::value)...>() == 0,
                  "passing views as lvalues is disallowed");
    if (FMT_USE_CONSTEVAL) parse_format_string<char>(s, checker(s, arg_pack()));
--- a/include/spdlog/fmt/bundled/chrono.h
+++ b/include/spdlog/fmt/bundled/chrono.h
@@ -22,21 +22,6 @@

 #include "format.h"

-namespace fmt_detail {
-struct time_zone {
-  template <typename Duration, typename T>
-  auto to_sys(T)
-      -> std::chrono::time_point<std::chrono::system_clock, Duration> {
-    return {};
-  }
-};
-template <typename... T> inline auto current_zone(T...) -> time_zone* {
-  return nullptr;
-}
-
-template <typename... T> inline void _tzset(T...) {}
-}  // namespace fmt_detail
-
 FMT_BEGIN_NAMESPACE

 // Enable safe chrono durations, unless explicitly disabled.
@@ -435,14 +420,11 @@ auto write(OutputIt out, const std::tm& time, const std::locale& loc,
  return write_encoded_tm_str(out, string_view(buf.data(), buf.size()), loc);
 }

-template <typename Rep1, typename Rep2>
-struct is_same_arithmetic_type
-    : public std::integral_constant<bool,
-                                    (std::is_integral<Rep1>::value &&
-                                     std::is_integral<Rep2>::value) ||
-                                        (std::is_floating_point<Rep1>::value &&
-                                         std::is_floating_point<Rep2>::value)> {
-};
+template <typename T, typename U>
+using is_similar_arithmetic_type =
+    bool_constant<(std::is_integral<T>::value && std::is_integral<U>::value) ||
+                  (std::is_floating_point<T>::value &&
+                   std::is_floating_point<U>::value)>;

 FMT_NORETURN inline void throw_duration_error() {
  FMT_THROW(format_error("cannot format duration"));
@@ -501,9 +483,9 @@ auto duration_cast(std::chrono::duration<FromRep, FromPeriod> from) -> To {
 #endif
 }

-template <
-    typename To, typename FromRep, typename FromPeriod,
-    FMT_ENABLE_IF(!is_same_arithmetic_type<FromRep, typename To::rep>::value)>
+template <typename To, typename FromRep, typename FromPeriod,
+          FMT_ENABLE_IF(
+              !is_similar_arithmetic_type<FromRep, typename To::rep>::value)>
 auto duration_cast(std::chrono::duration<FromRep, FromPeriod> from) -> To {
  // Mixed integer <-> float cast is not supported by safe_duration_cast.
  return std::chrono::duration_cast<To>(from);
@@ -519,12 +501,30 @@ auto to_time_t(sys_time<Duration> time_point) -> std::time_t {
      .count();
 }

-// Workaround a bug in libstdc++ which sets __cpp_lib_chrono to 201907 without
-// providing current_zone(): https://github.com/fmtlib/fmt/issues/4160.
-template <typename T> FMT_CONSTEXPR auto has_current_zone() -> bool {
-  using namespace std::chrono;
-  using namespace fmt_detail;
-  return !std::is_same<decltype(current_zone()), fmt_detail::time_zone*>::value;
+namespace tz {
+
+// DEPRECATED!
+struct time_zone {
+  template <typename Duration, typename LocalTime>
+  auto to_sys(LocalTime) -> sys_time<Duration> {
+    return {};
+  }
+};
+template <typename... T> auto current_zone(T...) -> time_zone* {
+  return nullptr;
+}
+
+template <typename... T> void _tzset(T...) {}
+}  // namespace tz
+
+// DEPRECATED!
+inline void tzset_once() {
+  static bool init = []() {
+    using namespace tz;
+    _tzset();
+    return false;
+  }();
+  ignore_unused(init);
 }
 }  // namespace detail

@@ -535,7 +535,7 @@ FMT_BEGIN_EXPORT
 * expressed in local time. Unlike `std::localtime`, this function is
 * thread-safe on most platforms.
 */
-inline auto localtime(std::time_t time) -> std::tm {
+FMT_DEPRECATED inline auto localtime(std::time_t time) -> std::tm {
  struct dispatcher {
    std::time_t time_;
    std::tm tm_;
@@ -572,11 +572,11 @@ inline auto localtime(std::time_t time) -> std::tm {
 }

 #if FMT_USE_LOCAL_TIME
-template <typename Duration,
-          FMT_ENABLE_IF(detail::has_current_zone<Duration>())>
-inline auto localtime(std::chrono::local_time<Duration> time) -> std::tm {
+template <typename Duration>
+FMT_DEPRECATED auto localtime(std::chrono::local_time<Duration> time)
+    -> std::tm {
  using namespace std::chrono;
-  using namespace fmt_detail;
+  using namespace detail::tz;
  return localtime(detail::to_time_t(current_zone()->to_sys<Duration>(time)));
 }
 #endif
@@ -911,7 +911,14 @@ template <typename Derived> struct null_chrono_spec_handler {
  FMT_CONSTEXPR void on_tz_name() { unsupported(); }
 };

-struct tm_format_checker : null_chrono_spec_handler<tm_format_checker> {
+class tm_format_checker : public null_chrono_spec_handler<tm_format_checker> {
+ private:
+  bool has_timezone_ = false;
+
+ public:
+  constexpr explicit tm_format_checker(bool has_timezone)
+      : has_timezone_(has_timezone) {}
+
  FMT_NORETURN inline void unsupported() {
    FMT_THROW(format_error("no format"));
  }
@@ -949,8 +956,12 @@ struct tm_format_checker : null_chrono_spec_handler<tm_format_checker> {
  FMT_CONSTEXPR void on_24_hour_time() {}
  FMT_CONSTEXPR void on_iso_time() {}
  FMT_CONSTEXPR void on_am_pm() {}
-  FMT_CONSTEXPR void on_utc_offset(numeric_system) {}
-  FMT_CONSTEXPR void on_tz_name() {}
+  FMT_CONSTEXPR void on_utc_offset(numeric_system) {
+    if (!has_timezone_) FMT_THROW(format_error("no timezone"));
+  }
+  FMT_CONSTEXPR void on_tz_name() {
+    if (!has_timezone_) FMT_THROW(format_error("no timezone"));
+  }
 };

 inline auto tm_wday_full_name(int wday) -> const char* {
@@ -980,24 +991,27 @@ inline auto tm_mon_short_name(int mon) -> const char* {
 }

 template <typename T, typename = void>
-struct has_member_data_tm_gmtoff : std::false_type {};
+struct has_tm_gmtoff : std::false_type {};
 template <typename T>
-struct has_member_data_tm_gmtoff<T, void_t<decltype(T::tm_gmtoff)>>
-    : std::true_type {};
+struct has_tm_gmtoff<T, void_t<decltype(T::tm_gmtoff)>> : std::true_type {};

-template <typename T, typename = void>
-struct has_member_data_tm_zone : std::false_type {};
+template <typename T, typename = void> struct has_tm_zone : std::false_type {};
 template <typename T>
-struct has_member_data_tm_zone<T, void_t<decltype(T::tm_zone)>>
-    : std::true_type {};
+struct has_tm_zone<T, void_t<decltype(T::tm_zone)>> : std::true_type {};

-inline void tzset_once() {
-  static bool init = []() {
-    using namespace fmt_detail;
-    _tzset();
+template <typename T, FMT_ENABLE_IF(has_tm_zone<T>::value)>
+bool set_tm_zone(T& time, char* tz) {
+  time.tm_zone = tz;
+  return true;
+}
+template <typename T, FMT_ENABLE_IF(!has_tm_zone<T>::value)>
+bool set_tm_zone(T&, char*) {
  return false;
-  }();
-  ignore_unused(init);
+}
+
+inline char* utc() {
+  static char tz[] = "UTC";
+  return tz;
 }

 // Converts value to Int and checks that it's in the range [0, upper).
@@ -1005,7 +1019,7 @@ template <typename T, typename Int, FMT_ENABLE_IF(std::is_integral<T>::value)>
 inline auto to_nonnegative_int(T value, Int upper) -> Int {
  if (!std::is_unsigned<Int>::value &&
      (value < 0 || to_unsigned(value) > to_unsigned(upper))) {
-    FMT_THROW(fmt::format_error("chrono value is out of range"));
+    FMT_THROW(format_error("chrono value is out of range"));
  }
  return static_cast<Int>(value);
 }
@@ -1090,7 +1104,7 @@ void write_fractional_seconds(OutputIt& out, Duration d, int precision = -1) {

 // Format subseconds which are given as a floating point type with an
 // appropriate number of digits. We cannot pass the Duration here, as we
-// explicitly need to pass the Rep value in the chrono_formatter.
+// explicitly need to pass the Rep value in the duration_formatter.
 template <typename Duration>
 void write_floating_seconds(memory_buffer& buf, Duration duration,
                            int num_fractional_digits = -1) {
@@ -1124,7 +1138,7 @@ class tm_writer {
  static constexpr int days_per_week = 7;

  const std::locale& loc_;
-  const bool is_classic_;
+  bool is_classic_;
  OutputIt out_;
  const Duration* subsecs_;
  const std::tm& tm_;
@@ -1160,8 +1174,8 @@ class tm_writer {
  }

  auto tm_hour12() const noexcept -> int {
-    const auto h = tm_hour();
-    const auto z = h < 12 ? h : h - 12;
+    auto h = tm_hour();
+    auto z = h < 12 ? h : h - 12;
    return z == 0 ? 12 : z;
  }

@@ -1177,11 +1191,11 @@ class tm_writer {

  // Algorithm: https://en.wikipedia.org/wiki/ISO_week_date.
  auto iso_year_weeks(long long curr_year) const noexcept -> int {
-    const auto prev_year = curr_year - 1;
-    const auto curr_p =
+    auto prev_year = curr_year - 1;
+    auto curr_p =
        (curr_year + curr_year / 4 - curr_year / 100 + curr_year / 400) %
        days_per_week;
-    const auto prev_p =
+    auto prev_p =
        (prev_year + prev_year / 4 - prev_year / 100 + prev_year / 400) %
        days_per_week;
    return 52 + ((curr_p == 4 || prev_p == 3) ? 1 : 0);
@@ -1191,15 +1205,15 @@ class tm_writer {
           days_per_week;
  }
  auto tm_iso_week_year() const noexcept -> long long {
-    const auto year = tm_year();
-    const auto w = iso_week_num(tm_yday(), tm_wday());
+    auto year = tm_year();
+    auto w = iso_week_num(tm_yday(), tm_wday());
    if (w < 1) return year - 1;
    if (w > iso_year_weeks(year)) return year + 1;
    return year;
  }
  auto tm_iso_week_of_year() const noexcept -> int {
-    const auto year = tm_year();
-    const auto w = iso_week_num(tm_yday(), tm_wday());
+    auto year = tm_year();
+    auto w = iso_week_num(tm_yday(), tm_wday());
    if (w < 1) return iso_year_weeks(year - 1);
    if (w > iso_year_weeks(year)) return 1;
    return w;
@@ -1236,9 +1250,8 @@ class tm_writer {
    uint32_or_64_or_128_t<long long> n = to_unsigned(year);
    const int num_digits = count_digits(n);
    if (negative && pad == pad_type::zero) *out_++ = '-';
-    if (width > num_digits) {
+    if (width > num_digits)
      out_ = detail::write_padding(out_, pad, width - num_digits);
-    }
    if (negative && pad != pad_type::zero) *out_++ = '-';
    out_ = format_decimal<Char>(out_, n, num_digits);
  }
@@ -1259,45 +1272,22 @@ class tm_writer {
    write2(static_cast<int>(offset % 60));
  }

-  template <typename T, FMT_ENABLE_IF(has_member_data_tm_gmtoff<T>::value)>
-  void format_utc_offset_impl(const T& tm, numeric_system ns) {
+  template <typename T, FMT_ENABLE_IF(has_tm_gmtoff<T>::value)>
+  void format_utc_offset(const T& tm, numeric_system ns) {
    write_utc_offset(tm.tm_gmtoff, ns);
  }
-  template <typename T, FMT_ENABLE_IF(!has_member_data_tm_gmtoff<T>::value)>
-  void format_utc_offset_impl(const T& tm, numeric_system ns) {
-#if defined(_WIN32) && defined(_UCRT)
-    tzset_once();
-    long offset = 0;
-    _get_timezone(&offset);
-    if (tm.tm_isdst) {
-      long dstbias = 0;
-      _get_dstbias(&dstbias);
-      offset += dstbias;
-    }
-    write_utc_offset(-offset, ns);
-#else
-    if (ns == numeric_system::standard) return format_localized('z');
-
-    // Extract timezone offset from timezone conversion functions.
-    std::tm gtm = tm;
-    std::time_t gt = std::mktime(&gtm);
-    std::tm ltm = gmtime(gt);
-    std::time_t lt = std::mktime(&ltm);
-    long long offset = gt - lt;
-    write_utc_offset(offset, ns);
-#endif
+  template <typename T, FMT_ENABLE_IF(!has_tm_gmtoff<T>::value)>
+  void format_utc_offset(const T&, numeric_system ns) {
+    write_utc_offset(0, ns);
  }

-  template <typename T, FMT_ENABLE_IF(has_member_data_tm_zone<T>::value)>
-  void format_tz_name_impl(const T& tm) {
-    if (is_classic_)
+  template <typename T, FMT_ENABLE_IF(has_tm_zone<T>::value)>
+  void format_tz_name(const T& tm) {
    out_ = write_tm_str<Char>(out_, tm.tm_zone, loc_);
-    else
-      format_localized('Z');
  }
-  template <typename T, FMT_ENABLE_IF(!has_member_data_tm_zone<T>::value)>
-  void format_tz_name_impl(const T&) {
-    format_localized('Z');
+  template <typename T, FMT_ENABLE_IF(!has_tm_zone<T>::value)>
+  void format_tz_name(const T&) {
+    out_ = std::copy_n(utc(), 3, out_);
  }

  void format_localized(char format, char modifier = 0) {
@@ -1408,8 +1398,8 @@ class tm_writer {
    out_ = copy<Char>(std::begin(buf) + offset, std::end(buf), out_);
  }

-  void on_utc_offset(numeric_system ns) { format_utc_offset_impl(tm_, ns); }
-  void on_tz_name() { format_tz_name_impl(tm_); }
+  void on_utc_offset(numeric_system ns) { format_utc_offset(tm_, ns); }
+  void on_tz_name() { format_tz_name(tm_); }

  void on_year(numeric_system ns, pad_type pad) {
    if (is_classic_ || ns == numeric_system::standard)
@@ -1483,11 +1473,10 @@ class tm_writer {
  void on_day_of_year(pad_type pad) {
    auto yday = tm_yday() + 1;
    auto digit1 = yday / 100;
-    if (digit1 != 0) {
+    if (digit1 != 0)
      write1(digit1);
-    } else {
+    else
      out_ = detail::write_padding(out_, pad);
-    }
    write2(yday % 100, pad);
  }

@@ -1624,18 +1613,16 @@ template <typename Rep, typename Period,
          FMT_ENABLE_IF(std::is_integral<Rep>::value)>
 inline auto get_milliseconds(std::chrono::duration<Rep, Period> d)
    -> std::chrono::duration<Rep, std::milli> {
-  // this may overflow and/or the result may not fit in the
-  // target type.
+  // This may overflow and/or the result may not fit in the target type.
 #if FMT_SAFE_DURATION_CAST
-  using CommonSecondsType =
+  using common_seconds_type =
      typename std::common_type<decltype(d), std::chrono::seconds>::type;
-  const auto d_as_common = detail::duration_cast<CommonSecondsType>(d);
-  const auto d_as_whole_seconds =
+  auto d_as_common = detail::duration_cast<common_seconds_type>(d);
+  auto d_as_whole_seconds =
      detail::duration_cast<std::chrono::seconds>(d_as_common);
-  // this conversion should be nonproblematic
-  const auto diff = d_as_common - d_as_whole_seconds;
-  const auto ms =
-      detail::duration_cast<std::chrono::duration<Rep, std::milli>>(diff);
+  // This conversion should be nonproblematic.
+  auto diff = d_as_common - d_as_whole_seconds;
+  auto ms = detail::duration_cast<std::chrono::duration<Rep, std::milli>>(diff);
  return ms;
 #else
  auto s = detail::duration_cast<std::chrono::seconds>(d);
@@ -1707,32 +1694,28 @@ class get_locale {
  }
 };

-template <typename FormatContext, typename OutputIt, typename Rep,
-          typename Period>
-struct chrono_formatter {
-  FormatContext& context;
-  OutputIt out;
-  int precision;
-  bool localized = false;
+template <typename Char, typename Rep, typename Period>
+struct duration_formatter {
+  using iterator = basic_appender<Char>;
+  iterator out;
  // rep is unsigned to avoid overflow.
  using rep =
      conditional_t<std::is_integral<Rep>::value && sizeof(Rep) < sizeof(int),
                    unsigned, typename make_unsigned_or_unchanged<Rep>::type>;
  rep val;
+  int precision;
+  locale_ref locale;
+  bool localized = false;
  using seconds = std::chrono::duration<rep>;
  seconds s;
  using milliseconds = std::chrono::duration<rep, std::milli>;
  bool negative;

-  using char_type = typename FormatContext::char_type;
-  using tm_writer_type = tm_writer<OutputIt, char_type>;
+  using tm_writer_type = tm_writer<iterator, Char>;

-  chrono_formatter(FormatContext& ctx, OutputIt o,
-                   std::chrono::duration<Rep, Period> d)
-      : context(ctx),
-        out(o),
-        val(static_cast<rep>(d.count())),
-        negative(false) {
+  duration_formatter(iterator o, std::chrono::duration<Rep, Period> d,
+                     locale_ref loc)
+      : out(o), val(static_cast<rep>(d.count())), locale(loc), negative(false) {
    if (d.count() < 0) {
      val = 0 - val;
      negative = true;
@@ -1746,19 +1729,16 @@ struct chrono_formatter {

  // returns true if nan or inf, writes to out.
  auto handle_nan_inf() -> bool {
-    if (isfinite(val)) {
-      return false;
-    }
+    if (isfinite(val)) return false;
    if (isnan(val)) {
      write_nan();
      return true;
    }
    // must be +-inf
-    if (val > 0) {
-      write_pinf();
-    } else {
-      write_ninf();
-    }
+    if (val > 0)
+      std::copy_n("inf", 3, out);
+    else
+      std::copy_n("-inf", 4, out);
    return true;
  }

@@ -1786,11 +1766,10 @@ struct chrono_formatter {
  }

  void write_sign() {
-    if (negative) {
+    if (!negative) return;
    *out++ = '-';
    negative = false;
  }
-  }

  void write(Rep value, int width, pad_type pad = pad_type::zero) {
    write_sign();
@@ -1801,24 +1780,22 @@ struct chrono_formatter {
    if (width > num_digits) {
      out = detail::write_padding(out, pad, width - num_digits);
    }
-    out = format_decimal<char_type>(out, n, num_digits);
+    out = format_decimal<Char>(out, n, num_digits);
  }

  void write_nan() { std::copy_n("nan", 3, out); }
-  void write_pinf() { std::copy_n("inf", 3, out); }
-  void write_ninf() { std::copy_n("-inf", 4, out); }

  template <typename Callback, typename... Args>
  void format_tm(const tm& time, Callback cb, Args... args) {
    if (isnan(val)) return write_nan();
-    get_locale loc(localized, context.locale());
+    get_locale loc(localized, locale);
    auto w = tm_writer_type(loc, out, time);
    (w.*cb)(args...);
    out = w.out();
  }

-  void on_text(const char_type* begin, const char_type* end) {
-    copy<char_type>(begin, end, out);
+  void on_text(const Char* begin, const Char* end) {
+    copy<Char>(begin, end, out);
  }

  // These are not implemented because durations don't have date information.
@@ -1888,13 +1865,12 @@ struct chrono_formatter {
        write_floating_seconds(buf, std::chrono::duration<rep, Period>(val),
                               precision);
        if (negative) *out++ = '-';
-        if (buf.size() < 2 || buf[1] == '.') {
+        if (buf.size() < 2 || buf[1] == '.')
          out = detail::write_padding(out, pad);
-        }
-        out = copy<char_type>(buf.begin(), buf.end(), out);
+        out = copy<Char>(buf.begin(), buf.end(), out);
      } else {
        write(second(), 2, pad);
-        write_fractional_seconds<char_type>(
+        write_fractional_seconds<Char>(
            out, std::chrono::duration<rep, Period>(val), precision);
      }
      return;
@@ -1936,12 +1912,10 @@ struct chrono_formatter {
  void on_duration_value() {
    if (handle_nan_inf()) return;
    write_sign();
-    out = format_duration_value<char_type>(out, val, precision);
+    out = format_duration_value<Char>(out, val, precision);
  }

-  void on_duration_unit() {
-    out = format_duration_unit<char_type, Period>(out);
-  }
+  void on_duration_unit() { out = format_duration_unit<Char, Period>(out); }
 };

 }  // namespace detail
@@ -2011,12 +1985,11 @@ class year_month_day {
  constexpr auto month() const noexcept -> fmt::month { return month_; }
  constexpr auto day() const noexcept -> fmt::day { return day_; }
 };
-#endif
+#endif  // __cpp_lib_chrono >= 201907

 template <typename Char>
 struct formatter<weekday, Char> : private formatter<std::tm, Char> {
 private:
-  bool localized_ = false;
  bool use_tm_formatter_ = false;

 public:
@@ -2024,8 +1997,7 @@ struct formatter<weekday, Char> : private formatter<std::tm, Char> {
    auto it = ctx.begin(), end = ctx.end();
    if (it != end && *it == 'L') {
      ++it;
-      localized_ = true;
-      return it;
+      this->set_localized();
    }
    use_tm_formatter_ = it != end && *it != '}';
    return use_tm_formatter_ ? formatter<std::tm, Char>::parse(ctx) : it;
@@ -2036,7 +2008,7 @@ struct formatter<weekday, Char> : private formatter<std::tm, Char> {
    auto time = std::tm();
    time.tm_wday = static_cast<int>(wd.c_encoding());
    if (use_tm_formatter_) return formatter<std::tm, Char>::format(time, ctx);
-    detail::get_locale loc(localized_, ctx.locale());
+    detail::get_locale loc(this->localized(), ctx.locale());
    auto w = detail::tm_writer<decltype(ctx.out()), Char>(loc, ctx.out(), time);
    w.on_abbr_weekday();
    return w.out();
@@ -2070,7 +2042,6 @@ struct formatter<day, Char> : private formatter<std::tm, Char> {
 template <typename Char>
 struct formatter<month, Char> : private formatter<std::tm, Char> {
 private:
-  bool localized_ = false;
  bool use_tm_formatter_ = false;

 public:
@@ -2078,8 +2049,7 @@ struct formatter<month, Char> : private formatter<std::tm, Char> {
    auto it = ctx.begin(), end = ctx.end();
    if (it != end && *it == 'L') {
      ++it;
-      localized_ = true;
-      return it;
+      this->set_localized();
    }
    use_tm_formatter_ = it != end && *it != '}';
    return use_tm_formatter_ ? formatter<std::tm, Char>::parse(ctx) : it;
@@ -2090,7 +2060,7 @@ struct formatter<month, Char> : private formatter<std::tm, Char> {
    auto time = std::tm();
    time.tm_mon = static_cast<int>(static_cast<unsigned>(m)) - 1;
    if (use_tm_formatter_) return formatter<std::tm, Char>::format(time, ctx);
-    detail::get_locale loc(localized_, ctx.locale());
+    detail::get_locale loc(this->localized(), ctx.locale());
    auto w = detail::tm_writer<decltype(ctx.out()), Char>(loc, ctx.out(), time);
    w.on_abbr_month();
    return w.out();
@@ -2154,7 +2124,6 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
  format_specs specs_;
  detail::arg_ref<Char> width_ref_;
  detail::arg_ref<Char> precision_ref_;
-  bool localized_ = false;
  basic_string_view<Char> fmt_;

 public:
@@ -2177,7 +2146,7 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
      it = detail::parse_precision(it, end, specs_, precision_ref_, ctx);
    }
    if (it != end && *it == 'L') {
-      localized_ = true;
+      specs_.set_localized();
      ++it;
    }
    end = detail::parse_chrono_format(it, end, checker);
@@ -2204,11 +2173,10 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
      out = detail::format_duration_value<Char>(out, d.count(), precision);
      detail::format_duration_unit<Char, Period>(out);
    } else {
-      using chrono_formatter =
-          detail::chrono_formatter<FormatContext, decltype(out), Rep, Period>;
-      auto f = chrono_formatter(ctx, out, d);
+      auto f =
+          detail::duration_formatter<Char, Rep, Period>(out, d, ctx.locale());
      f.precision = precision;
-      f.localized = localized_;
+      f.localized = specs_.localized();
      detail::parse_chrono_format(begin, end, f);
    }
    return detail::write(
@@ -2220,30 +2188,15 @@ template <typename Char> struct formatter<std::tm, Char> {
 private:
  format_specs specs_;
  detail::arg_ref<Char> width_ref_;
+  basic_string_view<Char> fmt_ =
+      detail::string_literal<Char, '%', 'F', ' ', '%', 'T'>();

 protected:
-  basic_string_view<Char> fmt_;
+  auto localized() const -> bool { return specs_.localized(); }
+  FMT_CONSTEXPR void set_localized() { specs_.set_localized(); }

-  template <typename Duration, typename FormatContext>
-  auto do_format(const std::tm& tm, FormatContext& ctx,
-                 const Duration* subsecs) const -> decltype(ctx.out()) {
-    auto specs = specs_;
-    auto buf = basic_memory_buffer<Char>();
-    auto out = basic_appender<Char>(buf);
-    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
-                                ctx);
-
-    auto loc_ref = ctx.locale();
-    detail::get_locale loc(static_cast<bool>(loc_ref), loc_ref);
-    auto w =
-        detail::tm_writer<decltype(out), Char, Duration>(loc, out, tm, subsecs);
-    detail::parse_chrono_format(fmt_.begin(), fmt_.end(), w);
-    return detail::write(
-        ctx.out(), basic_string_view<Char>(buf.data(), buf.size()), specs);
-  }
-
- public:
-  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+  FMT_CONSTEXPR auto do_parse(parse_context<Char>& ctx, bool has_timezone)
+      -> const Char* {
    auto it = ctx.begin(), end = ctx.end();
    if (it == end || *it == '}') return it;

@@ -2256,12 +2209,41 @@ template <typename Char> struct formatter<std::tm, Char> {
      if (it == end) return it;
    }

-    end = detail::parse_chrono_format(it, end, detail::tm_format_checker());
+    if (*it == 'L') {
+      specs_.set_localized();
+      ++it;
+    }
+
+    end = detail::parse_chrono_format(it, end,
+                                      detail::tm_format_checker(has_timezone));
    // Replace the default format string only if the new spec is not empty.
    if (end != it) fmt_ = {it, detail::to_unsigned(end - it)};
    return end;
  }

+  template <typename Duration, typename FormatContext>
+  auto do_format(const std::tm& tm, FormatContext& ctx,
+                 const Duration* subsecs) const -> decltype(ctx.out()) {
+    auto specs = specs_;
+    auto buf = basic_memory_buffer<Char>();
+    auto out = basic_appender<Char>(buf);
+    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
+                                ctx);
+
+    auto loc_ref = specs.localized() ? ctx.locale() : detail::locale_ref();
+    detail::get_locale loc(static_cast<bool>(loc_ref), loc_ref);
+    auto w = detail::tm_writer<basic_appender<Char>, Char, Duration>(
+        loc, out, tm, subsecs);
+    detail::parse_chrono_format(fmt_.begin(), fmt_.end(), w);
+    return detail::write(
+        ctx.out(), basic_string_view<Char>(buf.data(), buf.size()), specs);
+  }
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return do_parse(ctx, detail::has_tm_gmtoff<std::tm>::value);
+  }
+
  template <typename FormatContext>
  auto format(const std::tm& tm, FormatContext& ctx) const
      -> decltype(ctx.out()) {
@@ -2269,10 +2251,11 @@ template <typename Char> struct formatter<std::tm, Char> {
  }
 };

+// DEPRECATED! Reversed order of template parameters.
 template <typename Char, typename Duration>
-struct formatter<sys_time<Duration>, Char> : formatter<std::tm, Char> {
-  FMT_CONSTEXPR formatter() {
-    this->fmt_ = detail::string_literal<Char, '%', 'F', ' ', '%', 'T'>();
+struct formatter<sys_time<Duration>, Char> : private formatter<std::tm, Char> {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return this->do_parse(ctx, true);
  }

  template <typename FormatContext>
@@ -2283,6 +2266,7 @@ struct formatter<sys_time<Duration>, Char> : formatter<std::tm, Char> {
    if (detail::const_check(
            period::num == 1 && period::den == 1 &&
            !std::is_floating_point<typename Duration::rep>::value)) {
+      detail::set_tm_zone(tm, detail::utc());
      return formatter<std::tm, Char>::format(tm, ctx);
    }
    Duration epoch = val.time_since_epoch();
@@ -2290,11 +2274,13 @@ struct formatter<sys_time<Duration>, Char> : formatter<std::tm, Char> {
        epoch - detail::duration_cast<std::chrono::seconds>(epoch));
    if (subsecs.count() < 0) {
      auto second = detail::duration_cast<Duration>(std::chrono::seconds(1));
-      if (tm.tm_sec != 0)
+      if (tm.tm_sec != 0) {
        --tm.tm_sec;
-      else
+      } else {
        tm = gmtime(val - second);
-      subsecs += detail::duration_cast<Duration>(std::chrono::seconds(1));
+        detail::set_tm_zone(tm, detail::utc());
+      }
+      subsecs += second;
    }
    return formatter<std::tm, Char>::do_format(tm, ctx, &subsecs);
  }
@@ -2312,23 +2298,29 @@ struct formatter<utc_time<Duration>, Char>
 };

 template <typename Duration, typename Char>
-struct formatter<local_time<Duration>, Char> : formatter<std::tm, Char> {
-  FMT_CONSTEXPR formatter() {
-    this->fmt_ = detail::string_literal<Char, '%', 'F', ' ', '%', 'T'>();
+struct formatter<local_time<Duration>, Char>
+    : private formatter<std::tm, Char> {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return this->do_parse(ctx, false);
  }

  template <typename FormatContext>
  auto format(local_time<Duration> val, FormatContext& ctx) const
      -> decltype(ctx.out()) {
+    auto time_since_epoch = val.time_since_epoch();
+    auto seconds_since_epoch =
+        detail::duration_cast<std::chrono::seconds>(time_since_epoch);
+    // Use gmtime to prevent time zone conversion since local_time has an
+    // unspecified time zone.
+    std::tm t = gmtime(seconds_since_epoch.count());
    using period = typename Duration::period;
    if (period::num == 1 && period::den == 1 &&
        !std::is_floating_point<typename Duration::rep>::value) {
-      return formatter<std::tm, Char>::format(localtime(val), ctx);
+      return formatter<std::tm, Char>::format(t, ctx);
    }
-    auto epoch = val.time_since_epoch();
-    auto subsecs = detail::duration_cast<Duration>(
-        epoch - detail::duration_cast<std::chrono::seconds>(epoch));
-    return formatter<std::tm, Char>::do_format(localtime(val), ctx, &subsecs);
+    auto subsecs =
+        detail::duration_cast<Duration>(time_since_epoch - seconds_since_epoch);
+    return formatter<std::tm, Char>::do_format(t, ctx, &subsecs);
  }
 };

--- a/include/spdlog/fmt/bundled/color.h
+++ b/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
@@ -334,9 +368,9 @@ template <typename Char> struct ansi_color_escape {
                                  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');
@@ -441,32 +475,26 @@ template <typename T> struct styled_arg : view {
 };

 template <typename Char>
-void vformat_to(buffer<Char>& buf, const text_style& ts,
-                basic_string_view<Char> fmt,
+void vformat_to(buffer<Char>& buf, text_style ts, basic_string_view<Char> fmt,
                basic_format_args<buffered_context<Char>> args) {
-  bool has_style = false;
  if (ts.has_emphasis()) {
-    has_style = true;
    auto emphasis = make_emphasis<Char>(ts.get_emphasis());
    buf.append(emphasis.begin(), emphasis.end());
  }
  if (ts.has_foreground()) {
-    has_style = true;
    auto foreground = make_foreground_color<Char>(ts.get_foreground());
    buf.append(foreground.begin(), foreground.end());
  }
  if (ts.has_background()) {
-    has_style = true;
    auto background = make_background_color<Char>(ts.get_background());
    buf.append(background.begin(), background.end());
  }
  vformat_to(buf, fmt, args);
-  if (has_style) reset_color<Char>(buf);
+  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()));
@@ -482,8 +510,7 @@ 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) {
+void print(FILE* f, text_style ts, format_string<T...> fmt, T&&... args) {
  vprint(f, ts, fmt.str, vargs<T...>{{args...}});
 }

@@ -497,11 +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);
@@ -521,7 +548,7 @@ 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.str, vargs<T...>{{args...}});
 }
@@ -529,8 +556,8 @@ inline auto format(const text_style& ts, format_string<T...> fmt, 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);
@@ -548,8 +575,8 @@ 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 {
+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...}});
 }

--- a/include/spdlog/fmt/bundled/fmt.license.rst
+++ b/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
--- a/include/spdlog/fmt/bundled/format-inl.h
+++ b/include/spdlog/fmt/bundled/format-inl.h
@@ -212,7 +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}};
@@ -1097,7 +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));
  }
@@ -1526,9 +1526,8 @@ 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.
-    assume(this->file_->_IO_write_ptr >= this->file_->_IO_write_end);
    putc_unlocked(0, this->file_);
    --this->file_->_IO_write_ptr;
  }
--- a/include/spdlog/fmt/bundled/format.h
+++ b/include/spdlog/fmt/bundled/format.h
@@ -117,6 +117,7 @@
 #  define FMT_NOINLINE
 #endif

+// GCC 4.9 doesn't support qualified names in specializations.
 namespace std {
 template <typename T> struct iterator_traits<fmt::basic_appender<T>> {
  using iterator_category = output_iterator_tag;
@@ -705,7 +706,7 @@ using is_integer =

 #if defined(FMT_USE_FLOAT128)
 // Use the provided definition.
-#elif FMT_CLANG_VERSION && FMT_HAS_INCLUDE(<quadmath.h>)
+#elif FMT_CLANG_VERSION >= 309 && FMT_HAS_INCLUDE(<quadmath.h>)
 #  define FMT_USE_FLOAT128 1
 #elif FMT_GCC_VERSION && defined(_GLIBCXX_USE_FLOAT128) && \
    !defined(__STRICT_ANSI__)
@@ -721,11 +722,10 @@ struct float128 {};

 template <typename T> using is_float128 = std::is_same<T, float128>;

-template <typename T>
-using is_floating_point =
-    bool_constant<std::is_floating_point<T>::value || is_float128<T>::value>;
+template <typename T> struct is_floating_point : std::is_floating_point<T> {};
+template <> struct is_floating_point<float128> : std::true_type {};

-template <typename T, bool = std::is_floating_point<T>::value>
+template <typename T, bool = is_floating_point<T>::value>
 struct is_fast_float : bool_constant<std::numeric_limits<T>::is_iec559 &&
                                     sizeof(T) <= sizeof(double)> {};
 template <typename T> struct is_fast_float<T, false> : std::false_type {};
@@ -1613,7 +1613,7 @@ constexpr auto convert_float(T value) -> convert_float_result<T> {
 }

 template <typename Char, typename OutputIt>
-FMT_NOINLINE FMT_CONSTEXPR auto fill(OutputIt it, size_t n,
+FMT_CONSTEXPR FMT_NOINLINE auto fill(OutputIt it, size_t n,
                                     const basic_specs& specs) -> OutputIt {
  auto fill_size = specs.fill_size();
  if (fill_size == 1) return detail::fill_n(it, n, specs.fill_unit<Char>());
@@ -2472,8 +2472,8 @@ template <typename T>
 struct has_isfinite<T, enable_if_t<sizeof(std::isfinite(T())) != 0>>
    : std::true_type {};

-template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value&&
-                                        has_isfinite<T>::value)>
+template <typename T,
+          FMT_ENABLE_IF(is_floating_point<T>::value&& has_isfinite<T>::value)>
 FMT_CONSTEXPR20 auto isfinite(T value) -> bool {
  constexpr T inf = T(std::numeric_limits<double>::infinity());
  if (is_constant_evaluated())
--- a/include/spdlog/fmt/bundled/ostream.h
+++ b/include/spdlog/fmt/bundled/ostream.h
@@ -158,7 +158,8 @@ void print(std::ostream& os, format_string<T...> fmt, T&&... args) {

 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::print(os, FMT_STRING("{}\n"),
+             fmt::format(fmt, std::forward<T>(args)...));
 }

 FMT_END_NAMESPACE
--- a/include/spdlog/fmt/bundled/ranges.h
+++ b/include/spdlog/fmt/bundled/ranges.h
@@ -774,13 +774,13 @@ 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);
  }
 };

--- a/include/spdlog/fmt/bundled/std.h
+++ b/include/spdlog/fmt/bundled/std.h
@@ -113,7 +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_;
@@ -182,7 +181,6 @@ 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<basic_string_view<Char>, Char> {
@@ -209,14 +207,12 @@ struct formatter<std::bitset<N>, Char>
  }
 };

-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>> {
@@ -279,7 +275,6 @@ 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<(std::is_void<T>::value ||
@@ -311,7 +306,6 @@ FMT_END_NAMESPACE

 #ifdef __cpp_lib_source_location
 FMT_BEGIN_NAMESPACE
-FMT_EXPORT
 template <> struct formatter<std::source_location> {
  FMT_CONSTEXPR auto parse(parse_context<>& ctx) { return ctx.begin(); }

@@ -367,7 +361,6 @@ 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> {
  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
    return ctx.begin();
@@ -380,7 +373,6 @@ template <typename Char> struct formatter<std::monostate, Char> {
  }
 };

-FMT_EXPORT
 template <typename Variant, typename Char>
 struct formatter<
    Variant, Char,
@@ -414,11 +406,11 @@ FMT_END_NAMESPACE
 #endif  // FMT_CPP_LIB_VARIANT

 FMT_BEGIN_NAMESPACE
-FMT_EXPORT
 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* {
@@ -426,11 +418,19 @@ template <> struct formatter<std::error_code> {
    if (it == end) return it;

    it = detail::parse_align(it, end, specs_);
-    if (it == end) return it;

    char c = *it;
-    if ((c >= '0' && c <= '9') || c == '{')
+    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;
  }

@@ -440,12 +440,21 @@ template <> struct formatter<std::error_code> {
    auto specs = specs_;
    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
                                ctx);
-    memory_buffer buf;
+    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());
-    return detail::write<char>(ctx.out(), string_view(buf.data(), buf.size()),
-                               specs);
+    }
+    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);
  }
 };

@@ -520,7 +529,6 @@ 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.
                 > {
@@ -537,7 +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.
@@ -603,7 +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>>
@@ -623,7 +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>>
@@ -636,7 +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>
@@ -647,7 +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_;
@@ -710,7 +713,6 @@ template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
  }
 };

-FMT_EXPORT
 template <typename T, typename Char>
 struct formatter<std::reference_wrapper<T>, Char,
                 enable_if_t<is_formattable<remove_cvref_t<T>, Char>::value>>
--- a/include/spdlog/fmt/bundled/xchar.h
+++ b/include/spdlog/fmt/bundled/xchar.h
@@ -112,10 +112,6 @@ inline auto runtime(wstring_view s) -> runtime_format_string<wchar_t> {
  return {{s}};
 }

-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> {};
 #endif
@@ -322,7 +318,7 @@ 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);
@@ -330,19 +326,19 @@ inline auto vformat(const text_style& ts, wstring_view fmt, wformat_args args)
 }

 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...);
 }
--- a/include/spdlog/fmt/fmt.h
+++ b/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
--- a/include/spdlog/mdc.h
+++ b/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 {
--- a/include/spdlog/sinks/ansicolor_sink-inl.h
+++ b/include/spdlog/sinks/ansicolor_sink-inl.h
@@ -111,7 +111,8 @@ 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) const {
+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_);
 }

--- a/include/spdlog/sinks/dup_filter_sink.h
+++ b/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);
            }
--- a/include/spdlog/sinks/rotating_file_sink-inl.h
+++ b/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);
 }
@@ -74,6 +74,35 @@ 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) {
--- a/include/spdlog/sinks/rotating_file_sink.h
+++ b/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,
@@ -29,6 +29,10 @@ public:
    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;
@@ -61,9 +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,
@@ -74,7 +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,
--- a/include/spdlog/spdlog-inl.h
+++ b/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);
 }
--- a/include/spdlog/spdlog.h
+++ b/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 the existing logger with the same name if exists.
+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();

--- a/include/spdlog/tweakme.h
+++ b/include/spdlog/tweakme.h
@@ -109,8 +109,8 @@
 //
 // #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 }
+// #define SPDLOG_LEVEL_NAMES { "MY TRACE"sv, "MY DEBUG"sv, "MY INFO"sv, "MY WARNING"sv, "MY
+// ERROR"sv, "MY CRITICAL"sv, "OFF"sv }
 ///////////////////////////////////////////////////////////////////////////////

 ///////////////////////////////////////////////////////////////////////////////
--- a/src/bundled_fmtlib_format.cpp
+++ b/src/bundled_fmtlib_format.cpp
@@ -13,10 +13,8 @@
 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>;

    #if FMT_USE_LOCALE
 // DEPRECATED! locale_ref in the detail namespace
@@ -26,21 +24,21 @@ template FMT_API auto locale_ref::get<std::locale>() const -> std::locale;

 // 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*);

 // DEPRECATED!
-template FMT_API void vformat_to(buffer<char>&, string_view,
-                                 typename vformat_args<>::type, locale_ref);
+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*);
@@ -48,5 +46,4 @@ template FMT_API void buffer<wchar_t>::append(const wchar_t*, const wchar_t*);
 }  // namespace detail
 FMT_END_NAMESPACE

-
 #endif  // !SPDLOG_FMT_EXTERNAL
--- a/tests/CMakeLists.txt
+++ b/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)
--- a/tests/test_custom_callbacks.cpp
+++ b/tests/test_custom_callbacks.cpp
@@ -16,7 +16,8 @@ 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);
-            using diff_t = typename std::iterator_traits<decltype(formatted.end())>::difference_type; 
+            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);
--- a/tests/test_daily_logger.cpp
+++ b/tests/test_daily_logger.cpp
@@ -46,10 +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) {
-        
-        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);        
+        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);
    }
 };

--- a/tests/test_file_logging.cpp
+++ b/tests/test_file_logging.cpp
@@ -94,14 +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++) {
@@ -141,3 +138,50 @@ TEST_CASE("rotating_file_logger4", "[rotating_logger]") {
    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);
+        }
+    }
+}
--- a/tests/test_misc.cpp
+++ b/tests/test_misc.cpp
@@ -185,14 +185,16 @@ 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) {}
+    explicit auto_closer(FILE* f)
+        : fp(f) {}
    auto_closer(const auto_closer&) = delete;
    auto_closer& operator=(const auto_closer&) = delete;
    ~auto_closer() {
@@ -201,8 +203,8 @@ struct auto_closer {
 };

 TEST_CASE("os::fwrite_bytes", "[os]") {
-    using spdlog::details::os::fwrite_bytes;
    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();
--- a/tests/test_pattern_formatter.cpp
+++ b/tests/test_pattern_formatter.cpp
@@ -23,7 +23,9 @@ static std::string log_to_str(const std::string &msg, const Args &...args) {

 // 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) {
+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);
@@ -80,8 +82,8 @@ TEST_CASE("GMT offset ", "[pattern_formatter]") {
    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");
+    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]") {
--- a/tests/test_registry.cpp
+++ b/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,
--- a/tests/utils.cpp
+++ b/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());
 }
Author	SHA1	Message	Date
gabime	14ab43ec0b	Updated fmt bundled files	2025-05-08 18:06:13 +03:00
gabime	ebf72d7d3e	update comments	2025-05-08 15:56:58 +03:00
gabime	829deec2ee	Bump fmt to 11.2.0	2025-05-08 15:52:38 +03:00
Gabi Melman	943fcbd761	Register replace logger (#3398 ) * Add register_or_replace(logger) to atomically replace logger in registry * fix some comments	2025-05-08 15:42:54 +03:00
Gabi Melman	7e022c4300	Feature 3379 (#3397 ) * Fix #3379 * clang format	2025-05-08 14:02:00 +03:00
Hinageshi	548b264254	Fix warning C4530 (#3393 ) * Fix warning C4530 * Rename FMT_EXCEPTIONS to FMT_USE_EXCEPTIONS	2025-04-23 19:46:25 +03:00
Tihran Katolikian	847db3375f	dup_filter_sink: remove notification_level argument; use last message log level for notification instead (#3390 )	2025-04-18 20:45:56 +03:00
Dmitry Kozlovtsev	bb8694b50f	Fix links for #3380 (#3381 )	2025-04-14 19:22:47 +03:00
Christoph Gringmuth	cec28bf839	Fix links to local reference. (#3378 ) Enables local navigation in IDE and removes links to branch.	2025-04-10 17:58:19 +03:00
Gabi Melman	bd0609d7a0	Update README.md	2025-04-10 17:06:12 +03:00
Christoph Gringmuth	1f4959c832	Fix link to wiki. (#3377 )	2025-04-10 17:04:23 +03:00