Add full date to stdout tests

clang-format
2026-01-02 09:57:55 +08:00 · 2025-11-28 17:30:23 +02:00 · 2025-11-28 17:21:14 +02:00 · 2025-11-28 17:10:57 +02:00 · 2025-11-28 15:48:07 +02:00 · 2025-11-01 18:03:07 +02:00
41 changed files with 1527 additions and 1249 deletions
--- a/.github/workflows/coverity_scan.yml
+++ b/.github/workflows/coverity_scan.yml
@@ -0,0 +1,52 @@
+name: coverity-linux
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  coverity_scan:
+    runs-on: ubuntu-latest
+    name: Coverity Scan
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y curl build-essential cmake pkg-config libsystemd-dev
+
+      - name: Download Coverity Tool
+        run: |
+          curl -s -L --output coverity_tool.tgz "https://scan.coverity.com/download/linux64?token=${{ secrets.COVERITY_TOKEN }}&project=gabime%2Fspdlog"
+          mkdir coverity_tool
+          tar -C coverity_tool --strip-components=1 -xf coverity_tool.tgz
+          echo "$PWD/coverity_tool/bin" >> $GITHUB_PATH
+
+      - name: Build with Coverity
+        run: |
+          mkdir build && cd build
+          cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_STANDARD=17
+          cd ..
+          cov-build --dir cov-int make -C build -j4
+
+      - name: Submit results to Coverity
+        run: |
+          tar czf cov-int.tgz cov-int
+          response=$(curl --silent --show-error --fail \
+            --form email="${{ secrets.EMAIL }}" \
+            --form token="${{ secrets.COVERITY_TOKEN }}" \
+            --form file=@cov-int.tgz \
+            --form version="GitHub PR #${{ github.event.pull_request.number }}" \
+            --form description="CI run for PR" \
+            https://scan.coverity.com/builds?project=gabime%2Fspdlog)
+
+          echo "$response"
+
+          if echo "$response" | grep -qi "Build successfully submitted"; then
+            echo "Coverity upload succeeded"
+          else
+            echo "Coverity upload failed or was rejected"
+            exit 1
+          fi
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -18,9 +18,8 @@ jobs:
      fail-fast: false
      matrix:
        config:
-          - { compiler: gcc, version: 7, build_type: Release, cppstd: 11 }
-          - { compiler: gcc, version: 9, build_type: Release, cppstd: 17 }
-          - { compiler: gcc, version: 11, build_type: Debug, cppstd: 20 }
+          - { compiler: gcc, version: 9, build_type: Release, cppstd: 11 }
+          - { compiler: gcc, version: 11, build_type: Debug, cppstd: 17 }
          - { compiler: gcc, version: 12, build_type: Release, cppstd: 20 }
          - { compiler: gcc, version: 12, build_type: Debug, cppstd: 20, asan: ON }
          - { compiler: clang, version: 12, build_type: Debug, cppstd: 17 }
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -75,74 +75,5 @@ jobs:
        run: |
          build\tests\${{ matrix.config.BUILD_TYPE }}\spdlog-utests.exe

-  # -----------------------------------------------------------------------
-  # MSVC 2019 build matrix
-  # -----------------------------------------------------------------------
-  build_2019:
-    runs-on: windows-2019
-    strategy:
-      fail-fast: true
-      matrix:
-        config:
-          - GENERATOR: "Visual Studio 16 2019"
-            BUILD_TYPE: Release
-            BUILD_SHARED: 'ON'
-            FATAL_ERRORS: 'ON'
-            WCHAR: 'OFF'
-            WCHAR_FILES: 'OFF'
-            BUILD_EXAMPLE: 'ON'
-            USE_STD_FORMAT: 'OFF'
-            CXX_STANDARD: 17
-          - GENERATOR: "Visual Studio 16 2019"
-            BUILD_TYPE: Release
-            BUILD_SHARED: 'ON'
-            FATAL_ERRORS: 'ON'
-            WCHAR: 'OFF'
-            WCHAR_FILES: 'OFF'
-            BUILD_EXAMPLE: 'ON'
-            USE_STD_FORMAT: 'OFF'
-            CXX_STANDARD: 14
-          - GENERATOR: "Visual Studio 16 2019"
-            BUILD_TYPE: Release
-            BUILD_SHARED: 'ON'
-            FATAL_ERRORS: 'ON'
-            WCHAR: 'OFF'
-            WCHAR_FILES: 'OFF'
-            BUILD_EXAMPLE: 'ON'
-            USE_STD_FORMAT: 'OFF'
-            CXX_STANDARD: 11

-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-
-      - name: CMake ${{ matrix.config.GENERATOR }} CXX=${{matrix.config.CXX_STANDARD}} WCHAR=${{matrix.config.WCHAR_FILES}} STD_FORMAT=${{matrix.config.USE_STD_FORMAT}}
-        shell: pwsh
-        run: |
-          mkdir build
-          cd build
-          cmake -G "${{ matrix.config.GENERATOR }}"  -A x64 `
-            -D CMAKE_BUILD_TYPE=${{ matrix.config.BUILD_TYPE }} `
-            -D BUILD_SHARED_LIBS=${{ matrix.config.BUILD_SHARED }} `
-            -D SPDLOG_WCHAR_SUPPORT=${{ matrix.config.WCHAR }} `
-            -D SPDLOG_WCHAR_FILENAMES=${{ matrix.config.WCHAR_FILES }} `
-            -D SPDLOG_BUILD_EXAMPLE=${{ matrix.config.BUILD_EXAMPLE }} `
-            -D SPDLOG_BUILD_EXAMPLE_HO=${{ matrix.config.BUILD_EXAMPLE }} `
-            -D SPDLOG_BUILD_TESTS=ON `
-            -D SPDLOG_BUILD_TESTS_HO=OFF `
-            -D SPDLOG_BUILD_WARNINGS=${{ matrix.config.FATAL_ERRORS }} `
-            -D SPDLOG_USE_STD_FORMAT=${{ matrix.config.USE_STD_FORMAT }} `
-            -D CMAKE_CXX_STANDARD=${{ matrix.config.CXX_STANDARD }} ..
-
-      - name: Build
-        shell: pwsh
-        run: |
-          cd build
-          cmake --build  . --parallel --config ${{ matrix.config.BUILD_TYPE }}
-
-      - name: Run Tests
-        shell: pwsh
-        env:
-          PATH: ${{ env.PATH }};${{ github.workspace }}\build\_deps\catch2-build\src\${{ matrix.config.BUILD_TYPE }};${{ github.workspace }}\build\${{ matrix.config.BUILD_TYPE }}
-        run: |
-          build\tests\${{ matrix.config.BUILD_TYPE }}\spdlog-utests.exe
+  
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -19,7 +19,11 @@ include(GNUInstallDirs)
 # Set default build to release
 # ---------------------------------------------------------------------------------------
 if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
-    set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Choose Release or Debug" FORCE)
+    # Set CMAKE_BUILD_TYPE only if this project is top-level
+    if((DEFINED PROJECT_IS_TOP_LEVEL AND PROJECT_IS_TOP_LEVEL) OR (NOT DEFINED PROJECT_IS_TOP_LEVEL
+                                                                   AND CMAKE_SOURCE_DIR STREQUAL PROJECT_SOURCE_DIR))
+        set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Choose Release or Debug" FORCE)
+    endif()
 endif()

 # ---------------------------------------------------------------------------------------
@@ -62,6 +66,9 @@ option(SPDLOG_ENABLE_PCH "Build static or shared library using precompiled heade
 # build position independent code
 option(SPDLOG_BUILD_PIC "Build position independent code (-fPIC)" OFF)

+# debug build postfix
+set(SPDLOG_DEBUG_POSTFIX "d" CACHE STRING "Filename postfix for libraries in debug builds")
+
 # example options
 option(SPDLOG_BUILD_EXAMPLE "Build example" ${SPDLOG_MASTER_PROJECT})
 option(SPDLOG_BUILD_EXAMPLE_HO "Build header only example" OFF)
@@ -90,6 +97,7 @@ option(SPDLOG_USE_STD_FORMAT "Use std::format instead of fmt library." OFF)
 option(SPDLOG_FMT_EXTERNAL "Use external fmt library instead of bundled" OFF)
 option(SPDLOG_FMT_EXTERNAL_HO "Use external fmt header-only library instead of bundled" OFF)
 option(SPDLOG_NO_EXCEPTIONS "Compile with -fno-exceptions. Call abort() on any spdlog exceptions" OFF)
+option(SPDLOG_NO_TZ_OFFSET "Omit %z timezone offset (use on platforms without tm_gmtoff)" OFF)

 if(SPDLOG_FMT_EXTERNAL AND SPDLOG_FMT_EXTERNAL_HO)
    message(FATAL_ERROR "SPDLOG_FMT_EXTERNAL and SPDLOG_FMT_EXTERNAL_HO are mutually exclusive")
@@ -191,7 +199,7 @@ spdlog_enable_warnings(spdlog)

 set_target_properties(spdlog PROPERTIES VERSION ${SPDLOG_VERSION} SOVERSION
                                                                  ${SPDLOG_VERSION_MAJOR}.${SPDLOG_VERSION_MINOR})
-set_target_properties(spdlog PROPERTIES DEBUG_POSTFIX d)
+set_target_properties(spdlog PROPERTIES DEBUG_POSTFIX ${SPDLOG_DEBUG_POSTFIX})

 if(COMMAND target_precompile_headers AND SPDLOG_ENABLE_PCH)
    configure_file(${CMAKE_CURRENT_SOURCE_DIR}/cmake/pch.h.in ${PROJECT_BINARY_DIR}/spdlog_pch.h @ONLY)
@@ -279,7 +287,8 @@ foreach(
    SPDLOG_NO_TLS
    SPDLOG_NO_ATOMIC_LEVELS
    SPDLOG_DISABLE_DEFAULT_LOGGER
-    SPDLOG_USE_STD_FORMAT)
+    SPDLOG_USE_STD_FORMAT
+    SPDLOG_NO_TZ_OFFSET)
    if(${SPDLOG_OPTION})
        target_compile_definitions(spdlog PUBLIC ${SPDLOG_OPTION})
        target_compile_definitions(spdlog_header_only INTERFACE ${SPDLOG_OPTION})
--- a/README.md
+++ b/README.md
@@ -80,7 +80,7 @@ int main()
    spdlog::info("Positional args are {1} {0}..", "too", "supported");
    spdlog::info("{:<30}", "left aligned");
    
-    spdlog::set_level(spdlog::level::debug); // Set global log level to debug
+    spdlog::set_level(spdlog::level::debug); // Set *global* log level to debug
    spdlog::debug("This message should be displayed..");    
    
    // change log pattern
@@ -224,7 +224,7 @@ void binary_example()
 ```c++

 // create a logger with 2 targets, with different log levels and formats.
-// The console will show only warnings or errors, while the file will log all.
+// The console will show only warnings or errors, while the file will log all. 
 void multi_sink_example()
 {
    auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
@@ -241,6 +241,29 @@ void multi_sink_example()
 }
 ```

+---
+#### Register several loggers - change global level
+```c++
+
+// Creation of loggers. Set levels to all registered loggers. 
+void set_level_example()
+{
+    auto logger1 = spdlog::basic_logger_mt("logger1", "logs/logger1.txt");
+    auto logger2 = spdlog::basic_logger_mt("logger2", "logs/logger2.txt");
+
+    spdlog::set_default_logger(logger2);
+    spdlog::default_logger()->set_level(spdlog::level::trace); // set level for the default logger (logger2) to trace
+
+    spdlog::trace("trace message to the logger2 (specified as default)");
+
+    spdlog::set_level(spdlog::level::off) // (sic!) set level for *all* registered loggers to off (disable)
+  
+    logger1.warn("warn message will not appear because the level set to off");
+    logger2.warn("warn message will not appear because the level set to off");
+    spdlog::warn("warn message will not appear because the level set to off");
+}
+```
+
 ---
 #### User-defined callbacks about log events
 ```c++
@@ -524,6 +547,7 @@ Documentation can be found in the [wiki](https://github.com/gabime/spdlog/wiki)

 ---

-Thanks to [JetBrains](https://www.jetbrains.com/?from=spdlog) for donating product licenses to help develop **spdlog** <a href="https://www.jetbrains.com/?from=spdlog"><img src="logos/jetbrains-variant-4.svg" width="94" align="center" /></a>
-
-
+### Powered by
+<a href="https://jb.gg/OpenSource">
+  <img src="https://resources.jetbrains.com/storage/products/company/brand/logos/jetbrains.svg" alt="JetBrains logo" width="200">
+</a>
--- a/example/example.cpp
+++ b/example/example.cpp
@@ -33,41 +33,41 @@ void mdc_example();
 #include "spdlog/fmt/ostr.h"  // support for user defined types

 int main(int, char *[]) {
-    // Log levels can be loaded from argv/env using "SPDLOG_LEVEL"
-    load_levels_example();
-
-    spdlog::info("Welcome to spdlog version {}.{}.{}  !", SPDLOG_VER_MAJOR, SPDLOG_VER_MINOR,
-                 SPDLOG_VER_PATCH);
-
-    spdlog::warn("Easy padding in numbers like {:08d}", 12);
-    spdlog::critical("Support for int: {0:d};  hex: {0:x};  oct: {0:o}; bin: {0:b}", 42);
-    spdlog::info("Support for floats {:03.2f}", 1.23456);
-    spdlog::info("Positional args are {1} {0}..", "too", "supported");
-    spdlog::info("{:>8} aligned, {:<8} aligned", "right", "left");
-
-    // Runtime log levels
-    spdlog::set_level(spdlog::level::info);  // Set global log level to info
-    spdlog::debug("This message should not be displayed!");
-    spdlog::set_level(spdlog::level::trace);  // Set specific logger's log level
-    spdlog::debug("This message should be displayed..");
-
-    // Customize msg format for all loggers
-    spdlog::set_pattern("[%H:%M:%S %z] [%^%L%$] [thread %t] %v");
-    spdlog::info("This an info message with custom format");
-    spdlog::set_pattern("%+");  // back to default format
-    spdlog::set_level(spdlog::level::info);
-
-    // Backtrace support
-    // Loggers can store in a ring buffer all messages (including debug/trace) for later inspection.
-    // When needed, call dump_backtrace() to see what happened:
-    spdlog::enable_backtrace(10);  // create ring buffer with capacity of 10  messages
-    for (int i = 0; i < 100; i++) {
-        spdlog::debug("Backtrace message {}", i);  // not logged..
-    }
-    // e.g. if some error happened:
-    spdlog::dump_backtrace();  // log them now!
-
    try {
+        // Log levels can be loaded from argv/env using "SPDLOG_LEVEL"
+        load_levels_example();
+
+        spdlog::info("Welcome to spdlog version {}.{}.{}  !", SPDLOG_VER_MAJOR, SPDLOG_VER_MINOR,
+                     SPDLOG_VER_PATCH);
+
+        spdlog::warn("Easy padding in numbers like {:08d}", 12);
+        spdlog::critical("Support for int: {0:d};  hex: {0:x};  oct: {0:o}; bin: {0:b}", 42);
+        spdlog::info("Support for floats {:03.2f}", 1.23456);
+        spdlog::info("Positional args are {1} {0}..", "too", "supported");
+        spdlog::info("{:>8} aligned, {:<8} aligned", "right", "left");
+
+        // Runtime log levels
+        spdlog::set_level(spdlog::level::info);  // Set global log level to info
+        spdlog::debug("This message should not be displayed!");
+        spdlog::set_level(spdlog::level::trace);  // Set specific logger's log level
+        spdlog::debug("This message should be displayed..");
+
+        // Customize msg format for all loggers
+        spdlog::set_pattern("[%H:%M:%S %z] [%^%L%$] [thread %t] %v");
+        spdlog::info("This an info message with custom format");
+        spdlog::set_pattern("%+");  // back to default format
+        spdlog::set_level(spdlog::level::info);
+
+        // Backtrace support
+        // Loggers can store in a ring buffer all messages (including debug/trace) for later
+        // inspection. When needed, call dump_backtrace() to see what happened:
+        spdlog::enable_backtrace(10);  // create ring buffer with capacity of 10  messages
+        for (int i = 0; i < 100; i++) {
+            spdlog::debug("Backtrace message {}", i);  // not logged..
+        }
+        // e.g. if some error happened:
+        spdlog::dump_backtrace();  // log them now!
+
        stdout_logger_example();
        basic_example();
        rotating_example();
@@ -371,15 +371,13 @@ void replace_default_logger_example() {
    // store the old logger so we don't break other examples.
    auto old_logger = spdlog::default_logger();

-    auto new_logger =
-        spdlog::basic_logger_mt("new_default_logger", "logs/new-default-log.txt", true);
-    spdlog::set_default_logger(new_logger);
+    auto new_logger = spdlog::basic_logger_mt("new_default_logger", "logs/somelog.txt", true);
+    spdlog::set_default_logger(std::move(new_logger));
    spdlog::set_level(spdlog::level::info);
    spdlog::debug("This message should not be displayed!");
    spdlog::set_level(spdlog::level::trace);
    spdlog::debug("This message should be displayed..");
-
-    spdlog::set_default_logger(old_logger);
+    spdlog::set_default_logger(std::move(old_logger));
 }

 // Mapped Diagnostic Context (MDC) is a map that stores key-value pairs (string values) in thread
--- a/include/spdlog/cfg/helpers-inl.h
+++ b/include/spdlog/cfg/helpers-inl.h
@@ -9,7 +9,6 @@

 #include <spdlog/details/os.h>
 #include <spdlog/details/registry.h>
-#include <spdlog/spdlog.h>

 #include <algorithm>
 #include <sstream>
@@ -36,7 +35,7 @@ inline std::string &trim_(std::string &str) {
    return str;
 }

-// return (name,value) trimmed pair from given "name=value" string.
+// return (name,value) trimmed pair from the given "name = value" string.
 // return empty string on missing parts
 // "key=val" => ("key", "val")
 // " key  =  val " => ("key", "val")
@@ -55,7 +54,7 @@ inline std::pair<std::string, std::string> extract_kv_(char sep, const std::stri
    return std::make_pair(trim_(k), trim_(v));
 }

-// return vector of key/value pairs from sequence of "K1=V1,K2=V2,.."
+// return vector of key/value pairs from a sequence of "K1=V1,K2=V2,.."
 // "a=AAA,b=BBB,c=CCC,.." => {("a","AAA"),("b","BBB"),("c", "CCC"),...}
 inline std::unordered_map<std::string, std::string> extract_key_vals_(const std::string &str) {
    std::string token;
@@ -72,7 +71,7 @@ inline std::unordered_map<std::string, std::string> extract_key_vals_(const std:
 }

 SPDLOG_INLINE void load_levels(const std::string &input) {
-    if (input.empty() || input.size() > 512) {
+    if (input.empty() || input.size() >= 32768) {
        return;
    }

@@ -82,14 +81,14 @@ SPDLOG_INLINE void load_levels(const std::string &input) {
    bool global_level_found = false;

    for (auto &name_level : key_vals) {
-        auto &logger_name = name_level.first;
-        auto level_name = to_lower_(name_level.second);
+        const auto &logger_name = name_level.first;
+        const auto &level_name = to_lower_(name_level.second);
        auto level = level::from_str(level_name);
        // ignore unrecognized level names
        if (level == level::off && level_name != "off") {
            continue;
        }
-        if (logger_name.empty())  // no logger name indicate global level
+        if (logger_name.empty())  // no logger name indicates global level
        {
            global_level_found = true;
            global_level = level;
--- a/include/spdlog/details/file_helper-inl.h
+++ b/include/spdlog/details/file_helper-inl.h
@@ -11,10 +11,8 @@
 #include <spdlog/details/os.h>

 #include <cerrno>
-#include <chrono>
 #include <cstdio>
 #include <string>
-#include <thread>
 #include <tuple>

 namespace spdlog {
--- a/include/spdlog/details/os-inl.h
+++ b/include/spdlog/details/os-inl.h
@@ -23,7 +23,6 @@

 #ifdef _WIN32
    #include <spdlog/details/windows_include.h>
-    #include <fileapi.h>  // for FlushFileBuffers
    #include <io.h>       // for _get_osfhandle, _isatty, _fileno
    #include <process.h>  // for _get_pid

@@ -245,15 +244,16 @@ SPDLOG_INLINE size_t filesize(FILE *f) {
 #endif

 // Return utc offset in minutes or throw spdlog_ex on failure
+#if !defined(SPDLOG_NO_TZ_OFFSET)
 SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm) {
-#ifdef _WIN32
-    #if _WIN32_WINNT < _WIN32_WINNT_WS08
+    #ifdef _WIN32
+        #if _WIN32_WINNT < _WIN32_WINNT_WS08
    TIME_ZONE_INFORMATION tzinfo;
    auto rv = ::GetTimeZoneInformation(&tzinfo);
-    #else
+        #else
    DYNAMIC_TIME_ZONE_INFORMATION tzinfo;
    auto rv = ::GetDynamicTimeZoneInformation(&tzinfo);
-    #endif
+        #endif
    if (rv == TIME_ZONE_ID_INVALID) throw_spdlog_ex("Failed getting timezone info. ", errno);

    int offset = -tzinfo.Bias;
@@ -263,47 +263,12 @@ SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm) {
        offset -= tzinfo.StandardBias;
    }
    return offset;
-#else
-
-    #if defined(sun) || defined(__sun) || defined(_AIX) ||                        \
-        (defined(__NEWLIB__) && !defined(__TM_GMTOFF)) ||                         \
-        (!defined(__APPLE__) && !defined(_BSD_SOURCE) && !defined(_GNU_SOURCE) && \
-         (!defined(_POSIX_VERSION) || (_POSIX_VERSION < 202405L)))
-    // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
-    struct helper {
-        static long int calculate_gmt_offset(const std::tm &localtm = details::os::localtime(),
-                                             const std::tm &gmtm = details::os::gmtime()) {
-            int local_year = localtm.tm_year + (1900 - 1);
-            int gmt_year = gmtm.tm_year + (1900 - 1);
-
-            long int days = (
-                // difference in day of year
-                localtm.tm_yday -
-                gmtm.tm_yday
-
-                // + intervening leap days
-                + ((local_year >> 2) - (gmt_year >> 2)) - (local_year / 100 - gmt_year / 100) +
-                ((local_year / 100 >> 2) - (gmt_year / 100 >> 2))
-
-                // + difference in years * 365 */
-                + static_cast<long int>(local_year - gmt_year) * 365);
-
-            long int hours = (24 * days) + (localtm.tm_hour - gmtm.tm_hour);
-            long int mins = (60 * hours) + (localtm.tm_min - gmtm.tm_min);
-            long int secs = (60 * mins) + (localtm.tm_sec - gmtm.tm_sec);
-
-            return secs;
-        }
-    };
-
-    auto offset_seconds = helper::calculate_gmt_offset(tm);
    #else
    auto offset_seconds = tm.tm_gmtoff;
-    #endif
-
    return static_cast<int>(offset_seconds / 60);
-#endif
+    #endif
 }
+#endif  // SPDLOG_NO_TZ_OFFSET

 // Return current thread id as size_t
 // It exists because the std::this_thread::get_id() is much slower(especially
@@ -490,7 +455,7 @@ SPDLOG_INLINE void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target) {
        result_size =
            ::MultiByteToWideChar(CP_UTF8, 0, str.data(), str_size, target.data(), result_size);
        if (result_size > 0) {
-            assert(result_size == target.size());
+            assert(result_size == static_cast<int>(target.size()));
            return;
        }
    }
@@ -563,21 +528,21 @@ SPDLOG_INLINE filename_t dir_name(const filename_t &path) {
    return pos != filename_t::npos ? path.substr(0, pos) : filename_t{};
 }

+#ifdef _MSC_VER
+    #pragma warning(push)
+    #pragma warning(disable : 4996)
+#endif  // _MSC_VER
 std::string SPDLOG_INLINE getenv(const char *field) {
-#if defined(_MSC_VER)
-    #if defined(__cplusplus_winrt)
+#if defined(_MSC_VER) && defined(__cplusplus_winrt)
    return std::string{};  // not supported under uwp
-    #else
-    size_t len = 0;
-    char buf[128];
-    bool ok = ::getenv_s(&len, buf, sizeof(buf), field) == 0;
-    return ok ? buf : std::string{};
-    #endif
-#else  // revert to getenv
-    char *buf = ::getenv(field);
+#else
+    char *buf = std::getenv(field);
    return buf ? buf : std::string{};
 #endif
 }
+#ifdef _MSC_VER
+    #pragma warning(pop)
+#endif  // _MSC_VER

 // Do fsync by FILE handlerpointer
 // Return true on success
--- a/include/spdlog/details/registry-inl.h
+++ b/include/spdlog/details/registry-inl.h
@@ -101,7 +101,7 @@ SPDLOG_INLINE std::shared_ptr<logger> registry::default_logger() {
 SPDLOG_INLINE logger *registry::get_default_raw() { return default_logger_.get(); }

 // set default logger.
-// default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
+// the default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
 SPDLOG_INLINE void registry::set_default_logger(std::shared_ptr<logger> new_default_logger) {
    std::lock_guard<std::mutex> lock(logger_map_mutex_);
    if (new_default_logger != nullptr) {
--- a/include/spdlog/details/tcp_client-windows.h
+++ b/include/spdlog/details/tcp_client-windows.h
@@ -58,8 +58,81 @@ public:

    SOCKET fd() const { return socket_; }

+    int connect_socket_with_timeout(SOCKET sockfd,
+                                    const struct sockaddr *addr,
+                                    int addrlen,
+                                    const timeval &tv) {
+        // If no timeout requested, do a normal blocking connect.
+        if (tv.tv_sec == 0 && tv.tv_usec == 0) {
+            int rv = ::connect(sockfd, addr, addrlen);
+            if (rv == SOCKET_ERROR && WSAGetLastError() == WSAEISCONN) {
+                return 0;
+            }
+            return rv;
+        }
+
+        // Switch to non‐blocking mode
+        u_long mode = 1UL;
+        if (::ioctlsocket(sockfd, FIONBIO, &mode) == SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+
+        int rv = ::connect(sockfd, addr, addrlen);
+        int last_error = WSAGetLastError();
+        if (rv == 0 || last_error == WSAEISCONN) {
+            mode = 0UL;
+            if (::ioctlsocket(sockfd, FIONBIO, &mode) == SOCKET_ERROR) {
+                return SOCKET_ERROR;
+            }
+            return 0;
+        }
+        if (last_error != WSAEWOULDBLOCK) {
+            // Real error
+            mode = 0UL;
+            if (::ioctlsocket(sockfd, FIONBIO, &mode)) {
+                return SOCKET_ERROR;
+            }
+            return SOCKET_ERROR;
+        }
+
+        // Wait until socket is writable or timeout expires
+        fd_set wfds;
+        FD_ZERO(&wfds);
+        FD_SET(sockfd, &wfds);
+
+        rv = ::select(0, nullptr, &wfds, nullptr, const_cast<timeval *>(&tv));
+
+        // Restore blocking mode regardless of select result
+        mode = 0UL;
+        if (::ioctlsocket(sockfd, FIONBIO, &mode) == SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+
+        if (rv == 0) {
+            WSASetLastError(WSAETIMEDOUT);
+            return SOCKET_ERROR;
+        }
+        if (rv == SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+
+        int so_error = 0;
+        int len = sizeof(so_error);
+        if (::getsockopt(sockfd, SOL_SOCKET, SO_ERROR, reinterpret_cast<char *>(&so_error), &len) ==
+            SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+        if (so_error != 0 && so_error != WSAEISCONN) {
+            // connection failed
+            WSASetLastError(so_error);
+            return SOCKET_ERROR;
+        }
+
+        return 0;  // success
+    }
+
    // try to connect or throw on failure
-    void connect(const std::string &host, int port) {
+    void connect(const std::string &host, int port, int timeout_ms = 0) {
        if (is_connected()) {
            close();
        }
@@ -71,6 +144,10 @@ public:
        hints.ai_flags = AI_NUMERICSERV;  // port passed as as numeric value
        hints.ai_protocol = 0;

+        timeval tv;
+        tv.tv_sec = timeout_ms / 1000;
+        tv.tv_usec = (timeout_ms % 1000) * 1000;
+
        auto port_str = std::to_string(port);
        struct addrinfo *addrinfo_result;
        auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
@@ -82,7 +159,6 @@ public:
        }

        // Try each address until we successfully connect(2).
-
        for (auto *rp = addrinfo_result; rp != nullptr; rp = rp->ai_next) {
            socket_ = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
            if (socket_ == INVALID_SOCKET) {
@@ -90,18 +166,24 @@ public:
                WSACleanup();
                continue;
            }
-            if (::connect(socket_, rp->ai_addr, (int)rp->ai_addrlen) == 0) {
+            if (connect_socket_with_timeout(socket_, rp->ai_addr, (int)rp->ai_addrlen, tv) == 0) {
+                last_error = 0;
                break;
-            } else {
-                last_error = ::WSAGetLastError();
-                close();
            }
+            last_error = WSAGetLastError();
+            ::closesocket(socket_);
+            socket_ = INVALID_SOCKET;
        }
        ::freeaddrinfo(addrinfo_result);
        if (socket_ == INVALID_SOCKET) {
            WSACleanup();
            throw_winsock_error_("connect failed", last_error);
        }
+        if (timeout_ms > 0) {
+            DWORD tv = static_cast<DWORD>(timeout_ms);
+            ::setsockopt(socket_, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof(tv));
+            ::setsockopt(socket_, SOL_SOCKET, SO_SNDTIMEO, (const char *)&tv, sizeof(tv));
+        }

        // set TCP_NODELAY
        int enable_flag = 1;
--- a/include/spdlog/details/tcp_client.h
+++ b/include/spdlog/details/tcp_client.h
@@ -39,8 +39,72 @@ public:

    ~tcp_client() { close(); }

+    int connect_socket_with_timeout(int sockfd,
+                                    const struct sockaddr *addr,
+                                    socklen_t addrlen,
+                                    const timeval &tv) {
+        // Blocking connect if timeout is zero
+        if (tv.tv_sec == 0 && tv.tv_usec == 0) {
+            int rv = ::connect(sockfd, addr, addrlen);
+            if (rv < 0 && errno == EISCONN) {
+                // already connected, treat as success
+                return 0;
+            }
+            return rv;
+        }
+
+        // Non-blocking path
+        int orig_flags = ::fcntl(sockfd, F_GETFL, 0);
+        if (orig_flags < 0) {
+            return -1;
+        }
+        if (::fcntl(sockfd, F_SETFL, orig_flags | O_NONBLOCK) < 0) {
+            return -1;
+        }
+
+        int rv = ::connect(sockfd, addr, addrlen);
+        if (rv == 0 || (rv < 0 && errno == EISCONN)) {
+            // immediate connect or already connected
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            return 0;
+        }
+        if (errno != EINPROGRESS) {
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            return -1;
+        }
+
+        // wait for writability
+        fd_set wfds;
+        FD_ZERO(&wfds);
+        FD_SET(sockfd, &wfds);
+
+        struct timeval tv_copy = tv;
+        rv = ::select(sockfd + 1, nullptr, &wfds, nullptr, &tv_copy);
+        if (rv <= 0) {
+            // timeout or error
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            if (rv == 0) errno = ETIMEDOUT;
+            return -1;
+        }
+
+        // check socket error
+        int so_error = 0;
+        socklen_t len = sizeof(so_error);
+        if (::getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &so_error, &len) < 0) {
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            return -1;
+        }
+        ::fcntl(sockfd, F_SETFL, orig_flags);
+        if (so_error != 0 && so_error != EISCONN) {
+            errno = so_error;
+            return -1;
+        }
+
+        return 0;
+    }
+
    // try to connect or throw on failure
-    void connect(const std::string &host, int port) {
+    void connect(const std::string &host, int port, int timeout_ms = 0) {
        close();
        struct addrinfo hints {};
        memset(&hints, 0, sizeof(struct addrinfo));
@@ -49,6 +113,10 @@ public:
        hints.ai_flags = AI_NUMERICSERV;  // port passed as as numeric value
        hints.ai_protocol = 0;

+        struct timeval tv;
+        tv.tv_sec = timeout_ms / 1000;
+        tv.tv_usec = (timeout_ms % 1000) * 1000;
+
        auto port_str = std::to_string(port);
        struct addrinfo *addrinfo_result;
        auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
@@ -69,8 +137,9 @@ public:
                last_errno = errno;
                continue;
            }
-            rv = ::connect(socket_, rp->ai_addr, rp->ai_addrlen);
-            if (rv == 0) {
+            ::fcntl(socket_, F_SETFD, FD_CLOEXEC);
+            if (connect_socket_with_timeout(socket_, rp->ai_addr, rp->ai_addrlen, tv) == 0) {
+                last_errno = 0;
                break;
            }
            last_errno = errno;
@@ -82,6 +151,12 @@ public:
            throw_spdlog_ex("::connect failed", last_errno);
        }

+        if (timeout_ms > 0) {
+            // Set timeouts for send and recv
+            ::setsockopt(socket_, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof(tv));
+            ::setsockopt(socket_, SOL_SOCKET, SO_SNDTIMEO, (const char *)&tv, sizeof(tv));
+        }
+
        // set TCP_NODELAY
        int enable_flag = 1;
        ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&enable_flag),
--- a/include/spdlog/details/thread_pool-inl.h
+++ b/include/spdlog/details/thread_pool-inl.h
@@ -35,7 +35,7 @@ SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items,
 SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items,
                                       size_t threads_n,
                                       std::function<void()> on_thread_start)
-    : thread_pool(q_max_items, threads_n, on_thread_start, [] {}) {}
+    : thread_pool(q_max_items, threads_n, std::move(on_thread_start), [] {}) {}

 SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items, size_t threads_n)
    : thread_pool(q_max_items, threads_n, [] {}, [] {}) {}
@@ -94,8 +94,7 @@ void SPDLOG_INLINE thread_pool::worker_loop_() {
 }

 // process next message in the queue
-// return true if this thread should still be active (while no terminate msg
-// was received)
+// returns true if this thread should still be active (while no terminated msg was received)
 bool SPDLOG_INLINE thread_pool::process_next_msg_() {
    async_msg incoming_async_msg;
    q_.dequeue(incoming_async_msg);
--- a/include/spdlog/fmt/bundled/args.h
+++ b/include/spdlog/fmt/bundled/args.h
@@ -71,7 +71,7 @@ class dynamic_arg_list {
 * It can be implicitly converted into `fmt::basic_format_args` for passing
 * into type-erased formatting functions such as `fmt::vformat`.
 */
-template <typename Context> class dynamic_format_arg_store {
+FMT_EXPORT template <typename Context> class dynamic_format_arg_store {
 private:
  using char_type = typename Context::char_type;

@@ -212,7 +212,7 @@ template <typename Context> class dynamic_format_arg_store {
  }

  /// Returns the number of elements in the store.
-  size_t size() const noexcept { return data_.size(); }
+  auto size() const noexcept -> size_t { return data_.size(); }
 };

 FMT_END_NAMESPACE
--- 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 110200
+#define FMT_VERSION 120000

 // Detect compiler versions.
 #if defined(__clang__) && !defined(__ibmxl__)
@@ -201,14 +201,6 @@
 #  define FMT_NODISCARD
 #endif

-#ifdef FMT_DEPRECATED
-// Use the provided definition.
-#elif FMT_HAS_CPP14_ATTRIBUTE(deprecated)
-#  define FMT_DEPRECATED [[deprecated]]
-#else
-#  define FMT_DEPRECATED /* deprecated */
-#endif
-
 #if FMT_GCC_VERSION || FMT_CLANG_VERSION
 #  define FMT_VISIBILITY(value) __attribute__((visibility(value)))
 #else
@@ -260,7 +252,7 @@ FMT_PRAGMA_CLANG(diagnostic push)
 #ifndef FMT_BEGIN_NAMESPACE
 #  define FMT_BEGIN_NAMESPACE \
    namespace fmt {           \
-    inline namespace v11 {
+    inline namespace v12 {
 #  define FMT_END_NAMESPACE \
    }                       \
    }
@@ -356,6 +348,9 @@ template <typename T> constexpr auto max_of(T a, T b) -> T {
  return a > b ? a : b;
 }

+FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
+                                      const char* message);
+
 namespace detail {
 // Suppresses "unused variable" warnings with the method described in
 // https://herbsutter.com/2009/10/18/mailbag-shutting-up-compiler-warnings/.
@@ -396,7 +391,7 @@ FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
 #  define FMT_ASSERT(condition, message)                                    \
    ((condition) /* void() fails with -Winvalid-constexpr on clang 4.0.1 */ \
         ? (void)0                                                          \
-         : fmt::detail::assert_fail(__FILE__, __LINE__, (message)))
+         : ::fmt::assert_fail(__FILE__, __LINE__, (message)))
 #endif

 #ifdef FMT_USE_INT128
@@ -463,12 +458,13 @@ enum { use_utf8 = !FMT_WIN32 || is_utf8_enabled };
 static_assert(!FMT_UNICODE || use_utf8,
              "Unicode support requires compiling with /utf-8");

-template <typename T> constexpr const char* narrow(const T*) { return nullptr; }
-constexpr FMT_ALWAYS_INLINE const char* narrow(const char* s) { return s; }
+template <typename T> constexpr auto narrow(T*) -> char* { return nullptr; }
+constexpr FMT_ALWAYS_INLINE auto narrow(const char* s) -> const char* {
+  return s;
+}

 template <typename Char>
-FMT_CONSTEXPR auto compare(const Char* s1, const Char* s2, std::size_t n)
-    -> int {
+FMT_CONSTEXPR auto compare(const Char* s1, const Char* s2, size_t n) -> int {
  if (!is_constant_evaluated() && sizeof(Char) == 1) return memcmp(s1, s2, n);
  for (; n != 0; ++s1, ++s2, --n) {
    if (*s1 < *s2) return -1;
@@ -540,7 +536,7 @@ template <typename Char> class basic_string_view {
  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 && !detail::is_constant_evaluated()) {
-      size_ = __builtin_strlen(detail::narrow(s));  // strlen is not costexpr.
+      size_ = __builtin_strlen(detail::narrow(s));  // strlen is not constexpr.
      return;
    }
 #endif
@@ -616,19 +612,6 @@ template <typename Char> class basic_string_view {

 using string_view = basic_string_view<char>;

-// 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 {};
-template <> struct is_xchar<char32_t> : std::true_type {};
-#ifdef __cpp_char8_t
-template <> struct is_xchar<char8_t> : std::true_type {};
-#endif
-
-// 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 {};
-
 template <typename T> class basic_appender;
 using appender = basic_appender<char>;

@@ -781,7 +764,7 @@ class basic_specs {
            (static_cast<unsigned>(p) << precision_shift);
  }

-  constexpr bool dynamic() const {
+  constexpr auto dynamic() const -> bool {
    return (data_ & (width_mask | precision_mask)) != 0;
  }

@@ -921,14 +904,47 @@ template <typename Char = char> class parse_context {
  FMT_CONSTEXPR void check_dynamic_spec(int arg_id);
 };

+#ifndef FMT_USE_LOCALE
+#  define FMT_USE_LOCALE (FMT_OPTIMIZE_SIZE <= 1)
+#endif
+
+// A type-erased reference to std::locale to avoid the heavy <locale> include.
+class locale_ref {
+#if FMT_USE_LOCALE
+ private:
+  const void* locale_;  // A type-erased pointer to std::locale.
+
+ public:
+  constexpr locale_ref() : locale_(nullptr) {}
+
+  template <typename Locale, FMT_ENABLE_IF(sizeof(Locale::collate) != 0)>
+  locale_ref(const Locale& loc);
+
+  inline explicit operator bool() const noexcept { return locale_ != nullptr; }
+#endif  // FMT_USE_LOCALE
+
+ public:
+  template <typename Locale> auto get() const -> Locale;
+};
+
 FMT_END_EXPORT

 namespace detail {

+// Specifies if `T` is a code unit type.
+template <typename T> struct is_code_unit : std::false_type {};
+template <> struct is_code_unit<char> : std::true_type {};
+template <> struct is_code_unit<wchar_t> : std::true_type {};
+template <> struct is_code_unit<char16_t> : std::true_type {};
+template <> struct is_code_unit<char32_t> : std::true_type {};
+#ifdef __cpp_char8_t
+template <> struct is_code_unit<char8_t> : bool_constant<is_utf8_enabled> {};
+#endif
+
 // Constructs fmt::basic_string_view<Char> from types implicitly convertible
 // to it, deducing Char. Explicitly convertible types such as the ones returned
 // from FMT_STRING are intentionally excluded.
-template <typename Char, FMT_ENABLE_IF(is_char<Char>::value)>
+template <typename Char, FMT_ENABLE_IF(is_code_unit<Char>::value)>
 constexpr auto to_string_view(const Char* s) -> basic_string_view<Char> {
  return s;
 }
@@ -1057,11 +1073,11 @@ template <bool B1, bool B2, bool... Tail> constexpr auto count() -> int {
  return (B1 ? 1 : 0) + count<B2, Tail...>();
 }

-template <typename... Args> constexpr auto count_named_args() -> int {
-  return count<is_named_arg<Args>::value...>();
+template <typename... T> constexpr auto count_named_args() -> int {
+  return count<is_named_arg<T>::value...>();
 }
-template <typename... Args> constexpr auto count_static_named_args() -> int {
-  return count<is_static_named_arg<Args>::value...>();
+template <typename... T> constexpr auto count_static_named_args() -> int {
+  return count<is_static_named_arg<T>::value...>();
 }

 template <typename Char> struct named_arg_info {
@@ -1069,7 +1085,7 @@ template <typename Char> struct named_arg_info {
  int id;
 };

-// named_args is non-const to suppress a bogus -Wmaybe-uninitalized in gcc 13.
+// named_args is non-const to suppress a bogus -Wmaybe-uninitialized in gcc 13.
 template <typename Char>
 FMT_CONSTEXPR void check_for_duplicate(named_arg_info<Char>* named_args,
                                       int named_arg_index,
@@ -1173,7 +1189,7 @@ template <typename Char> struct type_mapper {
  static auto map(ubitint<N>)
      -> conditional_t<N <= 64, unsigned long long, void>;

-  template <typename T, FMT_ENABLE_IF(is_char<T>::value)>
+  template <typename T, FMT_ENABLE_IF(is_code_unit<T>::value)>
  static auto map(T) -> conditional_t<
      std::is_same<T, char>::value || std::is_same<T, Char>::value, Char, void>;

@@ -1679,12 +1695,12 @@ template <typename... T> struct arg_pack {};
 template <typename Char, int NUM_ARGS, int NUM_NAMED_ARGS, bool DYNAMIC_NAMES>
 class format_string_checker {
 private:
-  type types_[max_of(1, NUM_ARGS)];
-  named_arg_info<Char> named_args_[max_of(1, NUM_NAMED_ARGS)];
+  type types_[max_of<size_t>(1, NUM_ARGS)];
+  named_arg_info<Char> named_args_[max_of<size_t>(1, NUM_NAMED_ARGS)];
  compile_parse_context<Char> context_;

  using parse_func = auto (*)(parse_context<Char>&) -> const Char*;
-  parse_func parse_funcs_[max_of(1, NUM_ARGS)];
+  parse_func parse_funcs_[max_of<size_t>(1, NUM_ARGS)];

 public:
  template <typename... T>
@@ -2033,6 +2049,17 @@ struct has_back_insert_iterator_container_append<
                        .append(std::declval<InputIt>(),
                                std::declval<InputIt>()))>> : std::true_type {};

+template <typename OutputIt, typename InputIt, typename = void>
+struct has_back_insert_iterator_container_insert_at_end : std::false_type {};
+
+template <typename OutputIt, typename InputIt>
+struct has_back_insert_iterator_container_insert_at_end<
+    OutputIt, InputIt,
+    void_t<decltype(get_container(std::declval<OutputIt>())
+                        .insert(get_container(std::declval<OutputIt>()).end(),
+                                std::declval<InputIt>(),
+                                std::declval<InputIt>()))>> : std::true_type {};
+
 // An optimized version of std::copy with the output value type (T).
 template <typename T, typename InputIt, typename OutputIt,
          FMT_ENABLE_IF(is_back_insert_iterator<OutputIt>::value&&
@@ -2047,6 +2074,8 @@ FMT_CONSTEXPR20 auto copy(InputIt begin, InputIt end, OutputIt out)
 template <typename T, typename InputIt, typename OutputIt,
          FMT_ENABLE_IF(is_back_insert_iterator<OutputIt>::value &&
                        !has_back_insert_iterator_container_append<
+                            OutputIt, InputIt>::value &&
+                        has_back_insert_iterator_container_insert_at_end<
                            OutputIt, InputIt>::value)>
 FMT_CONSTEXPR20 auto copy(InputIt begin, InputIt end, OutputIt out)
    -> OutputIt {
@@ -2056,7 +2085,11 @@ FMT_CONSTEXPR20 auto copy(InputIt begin, InputIt end, OutputIt out)
 }

 template <typename T, typename InputIt, typename OutputIt,
-          FMT_ENABLE_IF(!is_back_insert_iterator<OutputIt>::value)>
+          FMT_ENABLE_IF(!(is_back_insert_iterator<OutputIt>::value &&
+                          (has_back_insert_iterator_container_append<
+                               OutputIt, InputIt>::value ||
+                           has_back_insert_iterator_container_insert_at_end<
+                               OutputIt, InputIt>::value)))>
 FMT_CONSTEXPR auto copy(InputIt begin, InputIt end, OutputIt out) -> OutputIt {
  while (begin != end) *out++ = static_cast<T>(*begin++);
  return out;
@@ -2176,7 +2209,7 @@ template <typename Context> class value {
    static_assert(N <= 64, "unsupported _BitInt");
  }

-  template <typename T, FMT_ENABLE_IF(is_char<T>::value)>
+  template <typename T, FMT_ENABLE_IF(is_code_unit<T>::value)>
  constexpr FMT_INLINE value(T x FMT_BUILTIN) : char_value(x) {
    static_assert(
        std::is_same<T, char>::value || std::is_same<T, char_type>::value,
@@ -2252,7 +2285,7 @@ template <typename Context> class value {
        custom.value = const_cast<value_type*>(&x);
 #endif
    }
-    custom.format = format_custom<value_type, formatter<value_type, char_type>>;
+    custom.format = format_custom<value_type>;
  }

  template <typename T, FMT_ENABLE_IF(!has_formatter<T, char_type>())>
@@ -2263,10 +2296,10 @@ template <typename Context> class value {
  }

  // Formats an argument of a custom type, such as a user-defined class.
-  template <typename T, typename Formatter>
+  template <typename T>
  static void format_custom(void* arg, parse_context<char_type>& parse_ctx,
                            Context& ctx) {
-    auto f = Formatter();
+    auto f = formatter<T, char_type>();
    parse_ctx.advance_to(f.parse(parse_ctx));
    using qualified_type =
        conditional_t<has_formatter<const T, char_type>(), const T, T>;
@@ -2293,35 +2326,14 @@ struct is_output_iterator<
    enable_if_t<std::is_assignable<decltype(*std::declval<decay_t<It>&>()++),
                                   T>::value>> : std::true_type {};

-#ifndef FMT_USE_LOCALE
-#  define FMT_USE_LOCALE (FMT_OPTIMIZE_SIZE <= 1)
-#endif
-
-// A type-erased reference to an std::locale to avoid a heavy <locale> include.
-class locale_ref {
-#if FMT_USE_LOCALE
- private:
-  const void* locale_;  // A type-erased pointer to std::locale.
-
- public:
-  constexpr locale_ref() : locale_(nullptr) {}
-  template <typename Locale> locale_ref(const Locale& loc);
-
-  inline explicit operator bool() const noexcept { return locale_ != nullptr; }
-#endif  // FMT_USE_LOCALE
-
- public:
-  template <typename Locale> auto get() const -> Locale;
-};
-
 template <typename> constexpr auto encode_types() -> unsigned long long {
  return 0;
 }

-template <typename Context, typename Arg, typename... Args>
+template <typename Context, typename First, typename... T>
 constexpr auto encode_types() -> unsigned long long {
-  return static_cast<unsigned>(stored_type_constant<Arg, Context>::value) |
-         (encode_types<Context, Args...>() << packed_arg_bits);
+  return static_cast<unsigned>(stored_type_constant<First, Context>::value) |
+         (encode_types<Context, T...>() << packed_arg_bits);
 }

 template <typename Context, typename... T, size_t NUM_ARGS = sizeof...(T)>
@@ -2338,8 +2350,9 @@ template <typename Context, int NUM_ARGS, int NUM_NAMED_ARGS,
          unsigned long long DESC>
 struct named_arg_store {
  // args_[0].named_args points to named_args to avoid bloating format_args.
-  arg_t<Context, NUM_ARGS> args[1 + NUM_ARGS];
-  named_arg_info<typename Context::char_type> named_args[NUM_NAMED_ARGS];
+  arg_t<Context, NUM_ARGS> args[1u + NUM_ARGS];
+  named_arg_info<typename Context::char_type>
+      named_args[static_cast<size_t>(NUM_NAMED_ARGS)];

  template <typename... T>
  FMT_CONSTEXPR FMT_ALWAYS_INLINE named_arg_store(T&... values)
@@ -2358,8 +2371,8 @@ struct named_arg_store {
  }

  named_arg_store(const named_arg_store& rhs) = delete;
-  named_arg_store& operator=(const named_arg_store& rhs) = delete;
-  named_arg_store& operator=(named_arg_store&& rhs) = delete;
+  auto operator=(const named_arg_store& rhs) -> named_arg_store& = delete;
+  auto operator=(named_arg_store&& rhs) -> named_arg_store& = delete;
  operator const arg_t<Context, NUM_ARGS>*() const { return args + 1; }
 };

@@ -2372,7 +2385,7 @@ struct format_arg_store {
  // +1 to workaround a bug in gcc 7.5 that causes duplicated-branches warning.
  using type =
      conditional_t<NUM_NAMED_ARGS == 0,
-                    arg_t<Context, NUM_ARGS>[max_of(1, NUM_ARGS)],
+                    arg_t<Context, NUM_ARGS>[max_of<size_t>(1, NUM_ARGS)],
                    named_arg_store<Context, NUM_ARGS, NUM_NAMED_ARGS, DESC>>;
  type args;
 };
@@ -2656,22 +2669,17 @@ class context {
 private:
  appender out_;
  format_args args_;
-  FMT_NO_UNIQUE_ADDRESS detail::locale_ref loc_;
+  FMT_NO_UNIQUE_ADDRESS locale_ref loc_;

 public:
-  /// The character type for the output.
-  using char_type = char;
-
+  using char_type = char;  ///< The character type for the output.
  using iterator = appender;
  using format_arg = basic_format_arg<context>;
-  using parse_context_type FMT_DEPRECATED = parse_context<>;
-  template <typename T> using formatter_type FMT_DEPRECATED = formatter<T>;
  enum { builtin_types = FMT_BUILTIN_TYPES };

  /// Constructs a `context` object. References to the arguments are stored
  /// in the object so make sure they have appropriate lifetimes.
-  FMT_CONSTEXPR context(iterator out, format_args args,
-                        detail::locale_ref loc = {})
+  FMT_CONSTEXPR context(iterator out, format_args args, locale_ref loc = {})
      : out_(out), args_(args), loc_(loc) {}
  context(context&&) = default;
  context(const context&) = delete;
@@ -2692,7 +2700,7 @@ class context {
  // Advances the begin iterator to `it`.
  FMT_CONSTEXPR void advance_to(iterator) {}

-  FMT_CONSTEXPR auto locale() const -> detail::locale_ref { return loc_; }
+  FMT_CONSTEXPR auto locale() const -> locale_ref { return loc_; }
 };

 template <typename Char = char> struct runtime_format_string {
@@ -2779,9 +2787,6 @@ template <typename T, typename Char = char>
 concept formattable = is_formattable<remove_reference_t<T>, Char>::value;
 #endif

-template <typename T, typename Char>
-using has_formatter FMT_DEPRECATED = std::is_constructible<formatter<T, Char>>;
-
 // A formatter specialization for natively supported types.
 template <typename T, typename Char>
 struct formatter<T, Char,
@@ -2978,9 +2983,9 @@ FMT_INLINE void println(format_string<T...> fmt, T&&... args) {
  return fmt::println(stdout, fmt, static_cast<T&&>(args)...);
 }

-FMT_END_EXPORT
 FMT_PRAGMA_CLANG(diagnostic pop)
 FMT_PRAGMA_GCC(pop_options)
+FMT_END_EXPORT
 FMT_END_NAMESPACE

 #ifdef FMT_HEADER_ONLY
--- a/include/spdlog/fmt/bundled/chrono.h
+++ b/include/spdlog/fmt/bundled/chrono.h
@@ -38,6 +38,7 @@ FMT_BEGIN_NAMESPACE
 // Copyright Paul Dreik 2019
 namespace safe_duration_cast {

+// DEPRECATED!
 template <typename To, typename From,
          FMT_ENABLE_IF(!std::is_same<From, To>::value &&
                        std::numeric_limits<From>::is_signed ==
@@ -161,17 +162,6 @@ auto safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
                        int& ec) -> To {
  using From = std::chrono::duration<FromRep, FromPeriod>;
  ec = 0;
-  if (std::isnan(from.count())) {
-    // nan in, gives nan out. easy.
-    return To{std::numeric_limits<typename To::rep>::quiet_NaN()};
-  }
-  // maybe we should also check if from is denormal, and decide what to do about
-  // it.
-
-  // +-inf should be preserved.
-  if (std::isinf(from.count())) {
-    return To{from.count()};
-  }

  // the basic idea is that we need to convert from count() in the from type
  // to count() in the To type, by multiplying it with this:
@@ -282,8 +272,6 @@ namespace detail {
 #define FMT_NOMACRO

 template <typename T = void> struct null {};
-inline auto localtime_r FMT_NOMACRO(...) -> null<> { return null<>(); }
-inline auto localtime_s(...) -> null<> { return null<>(); }
 inline auto gmtime_r(...) -> null<> { return null<>(); }
 inline auto gmtime_s(...) -> null<> { return null<>(); }

@@ -326,7 +314,7 @@ inline auto get_classic_locale() -> const std::locale& {
 }

 template <typename CodeUnit> struct codecvt_result {
-  static constexpr const size_t max_size = 32;
+  static constexpr size_t max_size = 32;
  CodeUnit buf[max_size];
  CodeUnit* end;
 };
@@ -443,11 +431,7 @@ auto duration_cast(std::chrono::duration<FromRep, FromPeriod> from) -> To {

  using common_rep = typename std::common_type<FromRep, typename To::rep,
                                               decltype(factor::num)>::type;
-
-  int ec = 0;
-  auto count = safe_duration_cast::lossless_integral_conversion<common_rep>(
-      from.count(), ec);
-  if (ec) throw_duration_error();
+  common_rep count = from.count();  // This conversion is lossless.

  // Multiply from.count() by factor and check for overflow.
  if (const_check(factor::num != 1)) {
@@ -458,6 +442,7 @@ auto duration_cast(std::chrono::duration<FromRep, FromPeriod> from) -> To {
    count *= factor::num;
  }
  if (const_check(factor::den != 1)) count /= factor::den;
+  int ec = 0;
  auto to =
      To(safe_duration_cast::lossless_integral_conversion<typename To::rep>(
          count, ec));
@@ -471,6 +456,8 @@ template <typename To, typename FromRep, typename FromPeriod,
                            std::is_floating_point<typename To::rep>::value)>
 auto duration_cast(std::chrono::duration<FromRep, FromPeriod> from) -> To {
 #if FMT_SAFE_DURATION_CAST
+  // Preserve infinity and NaN.
+  if (!isfinite(from.count())) return static_cast<To>(from.count());
  // Throwing version of safe_duration_cast is only available for
  // integer to integer or float to float casts.
  int ec;
@@ -487,7 +474,7 @@ 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.
+  // Mixed integer <-> float cast is not supported by safe duration_cast.
  return std::chrono::duration_cast<To>(from);
 }

@@ -501,86 +488,10 @@ auto to_time_t(sys_time<Duration> time_point) -> std::time_t {
      .count();
 }

-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

 FMT_BEGIN_EXPORT

-/**
- * Converts given time since epoch as `std::time_t` value into calendar time,
- * expressed in local time. Unlike `std::localtime`, this function is
- * thread-safe on most platforms.
- */
-FMT_DEPRECATED inline auto localtime(std::time_t time) -> std::tm {
-  struct dispatcher {
-    std::time_t time_;
-    std::tm tm_;
-
-    inline dispatcher(std::time_t t) : time_(t) {}
-
-    inline auto run() -> bool {
-      using namespace fmt::detail;
-      return handle(localtime_r(&time_, &tm_));
-    }
-
-    inline auto handle(std::tm* tm) -> bool { return tm != nullptr; }
-
-    inline auto handle(detail::null<>) -> bool {
-      using namespace fmt::detail;
-      return fallback(localtime_s(&tm_, &time_));
-    }
-
-    inline auto fallback(int res) -> bool { return res == 0; }
-
-#if !FMT_MSC_VERSION
-    inline auto fallback(detail::null<>) -> bool {
-      using namespace fmt::detail;
-      std::tm* tm = std::localtime(&time_);
-      if (tm) tm_ = *tm;
-      return tm != nullptr;
-    }
-#endif
-  };
-  dispatcher lt(time);
-  // Too big time values may be unsupported.
-  if (!lt.run()) FMT_THROW(format_error("time_t value out of range"));
-  return lt.tm_;
-}
-
-#if FMT_USE_LOCAL_TIME
-template <typename Duration>
-FMT_DEPRECATED auto localtime(std::chrono::local_time<Duration> time)
-    -> std::tm {
-  using namespace std::chrono;
-  using namespace detail::tz;
-  return localtime(detail::to_time_t(current_zone()->to_sys<Duration>(time)));
-}
-#endif
-
 /**
 * Converts given time since epoch as `std::time_t` value into calendar time,
 * expressed in Coordinated Universal Time (UTC). Unlike `std::gmtime`, this
@@ -652,7 +563,7 @@ inline void write_digit2_separated(char* buf, unsigned a, unsigned b,
  // Add ASCII '0' to each digit byte and insert separators.
  digits |= 0x3030003030003030 | (usep << 16) | (usep << 40);

-  constexpr const size_t len = 8;
+  constexpr size_t len = 8;
  if (const_check(is_big_endian())) {
    char tmp[len];
    std::memcpy(tmp, &digits, len);
@@ -1000,16 +911,16 @@ template <typename T>
 struct has_tm_zone<T, void_t<decltype(T::tm_zone)>> : std::true_type {};

 template <typename T, FMT_ENABLE_IF(has_tm_zone<T>::value)>
-bool set_tm_zone(T& time, char* tz) {
+auto set_tm_zone(T& time, char* tz) -> bool {
  time.tm_zone = tz;
  return true;
 }
 template <typename T, FMT_ENABLE_IF(!has_tm_zone<T>::value)>
-bool set_tm_zone(T&, char*) {
+auto set_tm_zone(T&, char*) -> bool {
  return false;
 }

-inline char* utc() {
+inline auto utc() -> char* {
  static char tz[] = "UTC";
  return tz;
 }
@@ -2230,7 +2141,7 @@ template <typename Char> struct formatter<std::tm, Char> {
    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
                                ctx);

-    auto loc_ref = specs.localized() ? ctx.locale() : detail::locale_ref();
+    auto loc_ref = specs.localized() ? ctx.locale() : 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);
--- a/include/spdlog/fmt/bundled/color.h
+++ b/include/spdlog/fmt/bundled/color.h
@@ -375,19 +375,17 @@ template <typename Char> struct ansi_color_escape {
      // 10 more.
      if (is_background) value += 10u;

-      size_t index = 0;
-      buffer[index++] = static_cast<Char>('\x1b');
-      buffer[index++] = static_cast<Char>('[');
+      buffer[size++] = static_cast<Char>('\x1b');
+      buffer[size++] = static_cast<Char>('[');

      if (value >= 100u) {
-        buffer[index++] = static_cast<Char>('1');
+        buffer[size++] = static_cast<Char>('1');
        value %= 100u;
      }
-      buffer[index++] = static_cast<Char>('0' + value / 10u);
-      buffer[index++] = static_cast<Char>('0' + value % 10u);
+      buffer[size++] = static_cast<Char>('0' + value / 10u);
+      buffer[size++] = static_cast<Char>('0' + value % 10u);

-      buffer[index++] = static_cast<Char>('m');
-      buffer[index++] = static_cast<Char>('\0');
+      buffer[size++] = static_cast<Char>('m');
      return;
    }

@@ -398,7 +396,7 @@ template <typename Char> struct ansi_color_escape {
    to_esc(color.r, buffer + 7, ';');
    to_esc(color.g, buffer + 11, ';');
    to_esc(color.b, buffer + 15, 'm');
-    buffer[19] = static_cast<Char>(0);
+    size = 19;
  }
  FMT_CONSTEXPR ansi_color_escape(emphasis em) noexcept {
    uint8_t em_codes[num_emphases] = {};
@@ -411,26 +409,28 @@ template <typename Char> struct ansi_color_escape {
    if (has_emphasis(em, emphasis::conceal)) em_codes[6] = 8;
    if (has_emphasis(em, emphasis::strikethrough)) em_codes[7] = 9;

-    size_t index = 0;
+    buffer[size++] = static_cast<Char>('\x1b');
+    buffer[size++] = static_cast<Char>('[');
+
    for (size_t i = 0; i < num_emphases; ++i) {
      if (!em_codes[i]) continue;
-      buffer[index++] = static_cast<Char>('\x1b');
-      buffer[index++] = static_cast<Char>('[');
-      buffer[index++] = static_cast<Char>('0' + em_codes[i]);
-      buffer[index++] = static_cast<Char>('m');
+      buffer[size++] = static_cast<Char>('0' + em_codes[i]);
+      buffer[size++] = static_cast<Char>(';');
    }
-    buffer[index++] = static_cast<Char>(0);
+
+    buffer[size - 1] = static_cast<Char>('m');
  }
  FMT_CONSTEXPR operator const Char*() const noexcept { return buffer; }

  FMT_CONSTEXPR auto begin() const noexcept -> const Char* { return buffer; }
-  FMT_CONSTEXPR20 auto end() const noexcept -> const Char* {
-    return buffer + basic_string_view<Char>(buffer).size();
+  FMT_CONSTEXPR auto end() const noexcept -> const Char* {
+    return buffer + size;
  }

 private:
  static constexpr size_t num_emphases = 8;
-  Char buffer[7u + 3u * num_emphases + 1u];
+  Char buffer[7u + 4u * num_emphases];
+  size_t size = 0;

  static FMT_CONSTEXPR void to_esc(uint8_t c, Char* out,
                                   char delimiter) noexcept {
--- a/include/spdlog/fmt/bundled/compile.h
+++ b/include/spdlog/fmt/bundled/compile.h
@@ -22,8 +22,6 @@ FMT_EXPORT class compiled_string {};
 template <typename S>
 struct is_compiled_string : std::is_base_of<compiled_string, S> {};

-namespace detail {
-
 /**
 * Converts a string literal `s` into a format string that will be parsed at
 * compile time and converted into efficient formatting code. Requires C++17
@@ -41,18 +39,40 @@ namespace detail {
 #  define FMT_COMPILE(s) FMT_STRING(s)
 #endif

+/**
+ * Converts a string literal into a format string that will be parsed at
+ * compile time and converted into efficient formatting code. Requires support
+ * for class types in constant template parameters (a C++20 feature).
+ *
+ *  **Example**:
+ *
+ *     // Converts 42 into std::string using the most efficient method and no
+ *     // runtime format string processing.
+ *     using namespace fmt::literals;
+ *     std::string s = fmt::format("{}"_cf, 42);
+ */
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+inline namespace literals {
+template <detail::fixed_string Str> constexpr auto operator""_cf() {
+  return FMT_COMPILE(Str.data);
+}
+}  // namespace literals
+#endif
+
+namespace detail {
+
 template <typename T, typename... Tail>
-auto first(const T& value, const Tail&...) -> const T& {
+constexpr auto first(const T& value, const Tail&...) -> const T& {
  return value;
 }

 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
-template <typename... Args> struct type_list {};
+template <typename... T> struct type_list {};

 // Returns a reference to the argument at index N from [first, rest...].
 template <int N, typename T, typename... Args>
-constexpr const auto& get([[maybe_unused]] const T& first,
-                          [[maybe_unused]] const Args&... rest) {
+constexpr auto get([[maybe_unused]] const T& first,
+                   [[maybe_unused]] const Args&... rest) -> const auto& {
  static_assert(N < 1 + sizeof...(Args), "index is out of bounds");
  if constexpr (N == 0)
    return first;
@@ -84,8 +104,8 @@ FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
 }

 template <typename Char, typename... Args>
-constexpr int get_arg_index_by_name(basic_string_view<Char> name,
-                                    type_list<Args...>) {
+constexpr auto get_arg_index_by_name(basic_string_view<Char> name,
+                                     type_list<Args...>) -> int {
  return get_arg_index_by_name<Args...>(name);
 }

@@ -105,8 +125,8 @@ template <typename Char> struct text {
  basic_string_view<Char> data;
  using char_type = Char;

-  template <typename OutputIt, typename... Args>
-  constexpr OutputIt format(OutputIt out, const Args&...) const {
+  template <typename OutputIt, typename... T>
+  constexpr auto format(OutputIt out, const T&...) const -> OutputIt {
    return write<Char>(out, data);
  }
 };
@@ -115,8 +135,8 @@ template <typename Char>
 struct is_compiled_format<text<Char>> : std::true_type {};

 template <typename Char>
-constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
-                               size_t size) {
+constexpr auto make_text(basic_string_view<Char> s, size_t pos, size_t size)
+    -> text<Char> {
  return {{&s[pos], size}};
 }

@@ -124,8 +144,8 @@ template <typename Char> struct code_unit {
  Char value;
  using char_type = Char;

-  template <typename OutputIt, typename... Args>
-  constexpr OutputIt format(OutputIt out, const Args&...) const {
+  template <typename OutputIt, typename... T>
+  constexpr auto format(OutputIt out, const T&...) const -> OutputIt {
    *out++ = value;
    return out;
  }
@@ -133,7 +153,7 @@ template <typename Char> struct code_unit {

 // This ensures that the argument type is convertible to `const T&`.
 template <typename T, int N, typename... Args>
-constexpr const T& get_arg_checked(const Args&... args) {
+constexpr auto get_arg_checked(const Args&... args) -> const T& {
  const auto& arg = detail::get<N>(args...);
  if constexpr (detail::is_named_arg<remove_cvref_t<decltype(arg)>>()) {
    return arg.value;
@@ -146,13 +166,13 @@ template <typename Char>
 struct is_compiled_format<code_unit<Char>> : std::true_type {};

 // A replacement field that refers to argument N.
-template <typename Char, typename T, int N> struct field {
+template <typename Char, typename V, int N> struct field {
  using char_type = Char;

-  template <typename OutputIt, typename... Args>
-  constexpr OutputIt format(OutputIt out, const Args&... args) const {
-    const T& arg = get_arg_checked<T, N>(args...);
-    if constexpr (std::is_convertible<T, basic_string_view<Char>>::value) {
+  template <typename OutputIt, typename... T>
+  constexpr auto format(OutputIt out, const T&... args) const -> OutputIt {
+    const V& arg = get_arg_checked<V, N>(args...);
+    if constexpr (std::is_convertible<V, basic_string_view<Char>>::value) {
      auto s = basic_string_view<Char>(arg);
      return copy<Char>(s.begin(), s.end(), out);
    } else {
@@ -170,10 +190,10 @@ template <typename Char> struct runtime_named_field {
  basic_string_view<Char> name;

  template <typename OutputIt, typename T>
-  constexpr static bool try_format_argument(
+  constexpr static auto try_format_argument(
      OutputIt& out,
      // [[maybe_unused]] due to unused-but-set-parameter warning in GCC 7,8,9
-      [[maybe_unused]] basic_string_view<Char> arg_name, const T& arg) {
+      [[maybe_unused]] basic_string_view<Char> arg_name, const T& arg) -> bool {
    if constexpr (is_named_arg<typename std::remove_cv<T>::type>::value) {
      if (arg_name == arg.name) {
        out = write<Char>(out, arg.value);
@@ -183,8 +203,8 @@ template <typename Char> struct runtime_named_field {
    return false;
  }

-  template <typename OutputIt, typename... Args>
-  constexpr OutputIt format(OutputIt out, const Args&... args) const {
+  template <typename OutputIt, typename... T>
+  constexpr auto format(OutputIt out, const T&... args) const -> OutputIt {
    bool found = (try_format_argument(out, name, args) || ...);
    if (!found) {
      FMT_THROW(format_error("argument with specified name is not found"));
@@ -197,17 +217,17 @@ template <typename Char>
 struct is_compiled_format<runtime_named_field<Char>> : std::true_type {};

 // A replacement field that refers to argument N and has format specifiers.
-template <typename Char, typename T, int N> struct spec_field {
+template <typename Char, typename V, int N> struct spec_field {
  using char_type = Char;
-  formatter<T, Char> fmt;
+  formatter<V, Char> fmt;

-  template <typename OutputIt, typename... Args>
-  constexpr FMT_INLINE OutputIt format(OutputIt out,
-                                       const Args&... args) const {
+  template <typename OutputIt, typename... T>
+  constexpr FMT_INLINE auto format(OutputIt out, const T&... args) const
+      -> OutputIt {
    const auto& vargs =
        fmt::make_format_args<basic_format_context<OutputIt, Char>>(args...);
    basic_format_context<OutputIt, Char> ctx(out, vargs);
-    return fmt.format(get_arg_checked<T, N>(args...), ctx);
+    return fmt.format(get_arg_checked<V, N>(args...), ctx);
  }
 };

@@ -219,8 +239,8 @@ template <typename L, typename R> struct concat {
  R rhs;
  using char_type = typename L::char_type;

-  template <typename OutputIt, typename... Args>
-  constexpr OutputIt format(OutputIt out, const Args&... args) const {
+  template <typename OutputIt, typename... T>
+  constexpr auto format(OutputIt out, const T&... args) const -> OutputIt {
    out = lhs.format(out, args...);
    return rhs.format(out, args...);
  }
@@ -230,14 +250,14 @@ template <typename L, typename R>
 struct is_compiled_format<concat<L, R>> : std::true_type {};

 template <typename L, typename R>
-constexpr concat<L, R> make_concat(L lhs, R rhs) {
+constexpr auto make_concat(L lhs, R rhs) -> concat<L, R> {
  return {lhs, rhs};
 }

 struct unknown_format {};

 template <typename Char>
-constexpr size_t parse_text(basic_string_view<Char> str, size_t pos) {
+constexpr auto parse_text(basic_string_view<Char> str, size_t pos) -> size_t {
  for (size_t size = str.size(); pos != size; ++pos) {
    if (str[pos] == '{' || str[pos] == '}') break;
  }
@@ -270,8 +290,8 @@ template <typename T, typename Char> struct parse_specs_result {
 enum { manual_indexing_id = -1 };

 template <typename T, typename Char>
-constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
-                                                  size_t pos, int next_arg_id) {
+constexpr auto parse_specs(basic_string_view<Char> str, size_t pos,
+                           int next_arg_id) -> parse_specs_result<T, Char> {
  str.remove_prefix(pos);
  auto ctx =
      compile_parse_context<Char>(str, max_value<int>(), nullptr, next_arg_id);
@@ -285,16 +305,16 @@ template <typename Char> struct arg_id_handler {
  arg_id_kind kind;
  arg_ref<Char> arg_id;

-  constexpr int on_auto() {
+  constexpr auto on_auto() -> int {
    FMT_ASSERT(false, "handler cannot be used with automatic indexing");
    return 0;
  }
-  constexpr int on_index(int id) {
+  constexpr auto on_index(int id) -> int {
    kind = arg_id_kind::index;
    arg_id = arg_ref<Char>(id);
    return 0;
  }
-  constexpr int on_name(basic_string_view<Char> id) {
+  constexpr auto on_name(basic_string_view<Char> id) -> int {
    kind = arg_id_kind::name;
    arg_id = arg_ref<Char>(id);
    return 0;
@@ -433,27 +453,28 @@ FMT_BEGIN_EXPORT

 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)

-template <typename CompiledFormat, typename... Args,
+template <typename CompiledFormat, typename... T,
          typename Char = typename CompiledFormat::char_type,
          FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
-FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
-                                          const Args&... args) {
+FMT_INLINE FMT_CONSTEXPR_STRING auto format(const CompiledFormat& cf,
+                                            const T&... args)
+    -> std::basic_string<Char> {
  auto s = std::basic_string<Char>();
  cf.format(std::back_inserter(s), args...);
  return s;
 }

-template <typename OutputIt, typename CompiledFormat, typename... Args,
+template <typename OutputIt, typename CompiledFormat, typename... T,
          FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
-constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
-                                        const Args&... args) {
+constexpr FMT_INLINE auto format_to(OutputIt out, const CompiledFormat& cf,
+                                    const T&... args) -> OutputIt {
  return cf.format(out, args...);
 }

-template <typename S, typename... Args,
+template <typename S, typename... T,
          FMT_ENABLE_IF(is_compiled_string<S>::value)>
-FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
-                                                           Args&&... args) {
+FMT_INLINE FMT_CONSTEXPR_STRING auto format(const S&, T&&... args)
+    -> std::basic_string<typename S::char_type> {
  if constexpr (std::is_same<typename S::char_type, char>::value) {
    constexpr auto str = basic_string_view<typename S::char_type>(S());
    if constexpr (str.size() == 2 && str[0] == '{' && str[1] == '}') {
@@ -466,72 +487,97 @@ FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
      }
    }
  }
-  constexpr auto compiled = detail::compile<Args...>(S());
+  constexpr auto compiled = detail::compile<T...>(S());
  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
                             detail::unknown_format>()) {
    return fmt::format(
        static_cast<basic_string_view<typename S::char_type>>(S()),
-        std::forward<Args>(args)...);
+        std::forward<T>(args)...);
  } else {
-    return fmt::format(compiled, std::forward<Args>(args)...);
+    return fmt::format(compiled, std::forward<T>(args)...);
  }
 }

-template <typename OutputIt, typename S, typename... Args,
+template <typename OutputIt, typename S, typename... T,
          FMT_ENABLE_IF(is_compiled_string<S>::value)>
-FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
-  constexpr auto compiled = detail::compile<Args...>(S());
+FMT_CONSTEXPR auto format_to(OutputIt out, const S&, T&&... args) -> OutputIt {
+  constexpr auto compiled = detail::compile<T...>(S());
  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
                             detail::unknown_format>()) {
    return fmt::format_to(
        out, static_cast<basic_string_view<typename S::char_type>>(S()),
-        std::forward<Args>(args)...);
+        std::forward<T>(args)...);
  } else {
-    return fmt::format_to(out, compiled, std::forward<Args>(args)...);
+    return fmt::format_to(out, compiled, std::forward<T>(args)...);
  }
 }
 #endif

-template <typename OutputIt, typename S, typename... Args,
+template <typename OutputIt, typename S, typename... T,
          FMT_ENABLE_IF(is_compiled_string<S>::value)>
-auto format_to_n(OutputIt out, size_t n, const S& fmt, Args&&... args)
+auto format_to_n(OutputIt out, size_t n, const S& fmt, T&&... args)
    -> format_to_n_result<OutputIt> {
  using traits = detail::fixed_buffer_traits;
  auto buf = detail::iterator_buffer<OutputIt, char, traits>(out, n);
-  fmt::format_to(std::back_inserter(buf), fmt, std::forward<Args>(args)...);
+  fmt::format_to(std::back_inserter(buf), fmt, std::forward<T>(args)...);
  return {buf.out(), buf.count()};
 }

-template <typename S, typename... Args,
+template <typename S, typename... T,
          FMT_ENABLE_IF(is_compiled_string<S>::value)>
-FMT_CONSTEXPR20 auto formatted_size(const S& fmt, const Args&... args)
-    -> size_t {
+FMT_CONSTEXPR20 auto formatted_size(const S& fmt, T&&... args) -> size_t {
  auto buf = detail::counting_buffer<>();
-  fmt::format_to(appender(buf), fmt, args...);
+  fmt::format_to(appender(buf), fmt, std::forward<T>(args)...);
  return buf.count();
 }

-template <typename S, typename... Args,
+template <typename S, typename... T,
          FMT_ENABLE_IF(is_compiled_string<S>::value)>
-void print(std::FILE* f, const S& fmt, const Args&... args) {
+void print(std::FILE* f, const S& fmt, T&&... args) {
  auto buf = memory_buffer();
-  fmt::format_to(appender(buf), fmt, args...);
+  fmt::format_to(appender(buf), fmt, std::forward<T>(args)...);
  detail::print(f, {buf.data(), buf.size()});
 }

-template <typename S, typename... Args,
+template <typename S, typename... T,
          FMT_ENABLE_IF(is_compiled_string<S>::value)>
-void print(const S& fmt, const Args&... args) {
-  print(stdout, fmt, args...);
+void print(const S& fmt, T&&... args) {
+  print(stdout, fmt, std::forward<T>(args)...);
 }

-#if FMT_USE_NONTYPE_TEMPLATE_ARGS
-inline namespace literals {
-template <detail::fixed_string Str> constexpr auto operator""_cf() {
-  return FMT_COMPILE(Str.data);
-}
-}  // namespace literals
-#endif
+template <size_t N> class static_format_result {
+ private:
+  char data[N];
+
+ public:
+  template <typename S, typename... T,
+            FMT_ENABLE_IF(is_compiled_string<S>::value)>
+  explicit FMT_CONSTEXPR static_format_result(const S& fmt, T&&... args) {
+    *fmt::format_to(data, fmt, std::forward<T>(args)...) = '\0';
+  }
+
+  auto str() const -> fmt::string_view { return {data, N - 1}; }
+  auto c_str() const -> const char* { return data; }
+};
+
+/**
+ * Formats arguments according to the format string `fmt_str` and produces
+ * a string of the exact required size at compile time. Both the format string
+ * and the arguments must be compile-time expressions.
+ *
+ * The resulting string can be accessed as a C string via `c_str()` or as
+ * a `fmt::string_view` via `str()`.
+ *
+ * **Example**:
+ *
+ *     // Produces the static string "42" at compile time.
+ *     static constexpr auto result = FMT_STATIC_FORMAT("{}", 42);
+ *     const char* s = result.c_str();
+ */
+#define FMT_STATIC_FORMAT(fmt_str, ...)                            \
+  fmt::static_format_result<                                       \
+      fmt::formatted_size(FMT_COMPILE(fmt_str), __VA_ARGS__) + 1>( \
+      FMT_COMPILE(fmt_str), __VA_ARGS__)

 FMT_END_EXPORT
 FMT_END_NAMESPACE
--- a/include/spdlog/fmt/bundled/format-inl.h
+++ b/include/spdlog/fmt/bundled/format-inl.h
@@ -22,7 +22,7 @@

 #include "format.h"

-#if FMT_USE_LOCALE
+#if FMT_USE_LOCALE && !defined(FMT_MODULE)
 #  include <locale>
 #endif

@@ -31,14 +31,49 @@
 #endif

 FMT_BEGIN_NAMESPACE
-namespace detail {

+#ifndef FMT_CUSTOM_ASSERT_FAIL
 FMT_FUNC void assert_fail(const char* file, int line, const char* message) {
  // Use unchecked std::fprintf to avoid triggering another assertion when
  // writing to stderr fails.
  fprintf(stderr, "%s:%d: assertion failed: %s", file, line, message);
  abort();
 }
+#endif
+
+#if FMT_USE_LOCALE
+namespace detail {
+using std::locale;
+using std::numpunct;
+using std::use_facet;
+}  // namespace detail
+
+template <typename Locale, enable_if_t<(sizeof(Locale::collate) != 0), int>>
+locale_ref::locale_ref(const Locale& loc) : locale_(&loc) {
+  static_assert(std::is_same<Locale, std::locale>::value, "");
+}
+#else
+namespace detail {
+struct locale {};
+template <typename Char> struct numpunct {
+  auto grouping() const -> std::string { return "\03"; }
+  auto thousands_sep() const -> Char { return ','; }
+  auto decimal_point() const -> Char { return '.'; }
+};
+template <typename Facet> Facet use_facet(locale) { return {}; }
+}  // namespace detail
+#endif  // FMT_USE_LOCALE
+
+template <typename Locale> auto locale_ref::get() const -> Locale {
+  using namespace detail;
+  static_assert(std::is_same<Locale, locale>::value, "");
+#if FMT_USE_LOCALE
+  if (locale_) return *static_cast<const locale*>(locale_);
+#endif
+  return locale();
+}
+
+namespace detail {

 FMT_FUNC void format_error_code(detail::buffer<char>& out, int error_code,
                                string_view message) noexcept {
@@ -79,33 +114,6 @@ inline void fwrite_all(const void* ptr, size_t count, FILE* stream) {
    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
 }

-#if FMT_USE_LOCALE
-using std::locale;
-using std::numpunct;
-using std::use_facet;
-
-template <typename Locale>
-locale_ref::locale_ref(const Locale& loc) : locale_(&loc) {
-  static_assert(std::is_same<Locale, locale>::value, "");
-}
-#else
-struct locale {};
-template <typename Char> struct numpunct {
-  auto grouping() const -> std::string { return "\03"; }
-  auto thousands_sep() const -> Char { return ','; }
-  auto decimal_point() const -> Char { return '.'; }
-};
-template <typename Facet> Facet use_facet(locale) { return {}; }
-#endif  // FMT_USE_LOCALE
-
-template <typename Locale> auto locale_ref::get() const -> Locale {
-  static_assert(std::is_same<Locale, locale>::value, "");
-#if FMT_USE_LOCALE
-  if (locale_) return *static_cast<const locale*>(locale_);
-#endif
-  return locale();
-}
-
 template <typename Char>
 FMT_FUNC auto thousands_sep_impl(locale_ref loc) -> thousands_sep_result<Char> {
  auto&& facet = use_facet<numpunct<Char>>(loc.get<locale>());
@@ -133,14 +141,13 @@ FMT_FUNC auto write_loc(appender out, loc_value value,
 }  // namespace detail

 FMT_FUNC void report_error(const char* message) {
-#if FMT_USE_EXCEPTIONS
-  // Use FMT_THROW instead of throw to avoid bogus unreachable code warnings
-  // from MSVC.
-  FMT_THROW(format_error(message));
-#else
-  fputs(message, stderr);
-  abort();
+#if FMT_MSC_VERSION || defined(__NVCC__)
+  // Silence unreachable code warnings in MSVC and NVCC because these
+  // are nearly impossible to fix in a generic code.
+  volatile bool b = true;
+  if (!b) return;
 #endif
+  FMT_THROW(format_error(message));
 }

 template <typename Locale> typename Locale::id format_facet<Locale>::id;
@@ -174,11 +181,11 @@ inline auto operator==(basic_fp<F> x, basic_fp<F> y) -> bool {
 }

 // Compilers should be able to optimize this into the ror instruction.
-FMT_CONSTEXPR inline auto rotr(uint32_t n, uint32_t r) noexcept -> uint32_t {
+FMT_INLINE auto rotr(uint32_t n, uint32_t r) noexcept -> uint32_t {
  r &= 31;
  return (n >> r) | (n << (32 - r));
 }
-FMT_CONSTEXPR inline auto rotr(uint64_t n, uint32_t r) noexcept -> uint64_t {
+FMT_INLINE auto rotr(uint64_t n, uint32_t r) noexcept -> uint64_t {
  r &= 63;
  return (n >> r) | (n << (64 - r));
 }
@@ -275,7 +282,7 @@ template <> struct cache_accessor<float> {
  static auto get_cached_power(int k) noexcept -> uint64_t {
    FMT_ASSERT(k >= float_info<float>::min_k && k <= float_info<float>::max_k,
               "k is out of range");
-    static constexpr const uint64_t pow10_significands[] = {
+    static constexpr uint64_t pow10_significands[] = {
        0x81ceb32c4b43fcf5, 0xa2425ff75e14fc32, 0xcad2f7f5359a3b3f,
        0xfd87b5f28300ca0e, 0x9e74d1b791e07e49, 0xc612062576589ddb,
        0xf79687aed3eec552, 0x9abe14cd44753b53, 0xc16d9a0095928a28,
@@ -370,7 +377,7 @@ template <> struct cache_accessor<double> {
    FMT_ASSERT(k >= float_info<double>::min_k && k <= float_info<double>::max_k,
               "k is out of range");

-    static constexpr const uint128_fallback pow10_significands[] = {
+    static constexpr uint128_fallback pow10_significands[] = {
 #if FMT_USE_FULL_CACHE_DRAGONBOX
      {0xff77b1fcbebcdc4f, 0x25e8e89c13bb0f7b},
      {0x9faacf3df73609b1, 0x77b191618c54e9ad},
@@ -1037,7 +1044,7 @@ template <> struct cache_accessor<double> {
 #if FMT_USE_FULL_CACHE_DRAGONBOX
    return pow10_significands[k - float_info<double>::min_k];
 #else
-    static constexpr const uint64_t powers_of_5_64[] = {
+    static constexpr uint64_t powers_of_5_64[] = {
        0x0000000000000001, 0x0000000000000005, 0x0000000000000019,
        0x000000000000007d, 0x0000000000000271, 0x0000000000000c35,
        0x0000000000003d09, 0x000000000001312d, 0x000000000005f5e1,
@@ -1149,8 +1156,8 @@ auto is_left_endpoint_integer_shorter_interval(int exponent) noexcept -> bool {
         exponent <= case_shorter_interval_left_endpoint_upper_threshold;
 }

-// Remove trailing zeros from n and return the number of zeros removed (float)
-FMT_INLINE int remove_trailing_zeros(uint32_t& n, int s = 0) noexcept {
+// Remove trailing zeros from n and return the number of zeros removed (float).
+FMT_INLINE auto remove_trailing_zeros(uint32_t& n, int s = 0) noexcept -> int {
  FMT_ASSERT(n != 0, "");
  // Modular inverse of 5 (mod 2^32): (mod_inv_5 * 5) mod 2^32 = 1.
  constexpr uint32_t mod_inv_5 = 0xcccccccd;
@@ -1170,22 +1177,19 @@ FMT_INLINE int remove_trailing_zeros(uint32_t& n, int s = 0) noexcept {
  return s;
 }

-// Removes trailing zeros and returns the number of zeros removed (double)
-FMT_INLINE int remove_trailing_zeros(uint64_t& n) noexcept {
+// Removes trailing zeros and returns the number of zeros removed (double).
+FMT_INLINE auto remove_trailing_zeros(uint64_t& n) noexcept -> int {
  FMT_ASSERT(n != 0, "");

-  // This magic number is ceil(2^90 / 10^8).
-  constexpr uint64_t magic_number = 12379400392853802749ull;
-  auto nm = umul128(n, magic_number);
-
  // Is n is divisible by 10^8?
-  if ((nm.high() & ((1ull << (90 - 64)) - 1)) == 0 && nm.low() < magic_number) {
+  constexpr uint32_t ten_pow_8 = 100000000u;
+  if ((n % ten_pow_8) == 0) {
    // If yes, work with the quotient...
-    auto n32 = static_cast<uint32_t>(nm.high() >> (90 - 64));
+    auto n32 = static_cast<uint32_t>(n / ten_pow_8);
    // ... and use the 32 bit variant of the function
-    int s = remove_trailing_zeros(n32, 8);
+    int num_zeros = remove_trailing_zeros(n32, 8);
    n = n32;
-    return s;
+    return num_zeros;
  }

  // If n is not divisible by 10^8, work with n itself.
@@ -1210,7 +1214,7 @@ FMT_INLINE int remove_trailing_zeros(uint64_t& n) noexcept {

 // The main algorithm for shorter interval case
 template <typename T>
-FMT_INLINE decimal_fp<T> shorter_interval_case(int exponent) noexcept {
+FMT_INLINE auto shorter_interval_case(int exponent) noexcept -> decimal_fp<T> {
  decimal_fp<T> ret_value;
  // Compute k and beta
  const int minus_k = floor_log10_pow2_minus_log10_4_over_3(exponent);
@@ -1454,8 +1458,8 @@ FMT_FUNC void vformat_to(buffer<char>& buf, string_view fmt, format_args args,
  auto out = appender(buf);
  if (fmt.size() == 2 && equal2(fmt.data(), "{}"))
    return args.get(0).visit(default_arg_formatter<char>{out});
-  parse_format_string(
-      fmt, format_handler<char>{parse_context<char>(fmt), {out, args, loc}});
+  parse_format_string(fmt,
+                      format_handler<>{parse_context<>(fmt), {out, args, loc}});
 }

 template <typename T> struct span {
@@ -1546,10 +1550,11 @@ template <typename F> class glibc_file : public file_base<F> {

  void advance_write_buffer(size_t size) { this->file_->_IO_write_ptr += size; }

-  bool needs_flush() const {
+  auto needs_flush() const -> bool {
    if ((this->file_->_flags & line_buffered) == 0) return false;
    char* end = this->file_->_IO_write_end;
-    return memchr(end, '\n', to_unsigned(this->file_->_IO_write_ptr - end));
+    auto size = max_of<ptrdiff_t>(this->file_->_IO_write_ptr - end, 0);
+    return memchr(end, '\n', static_cast<size_t>(size));
  }

  void flush() { fflush_unlocked(this->file_); }
@@ -1573,7 +1578,7 @@ template <typename F> class apple_file : public file_base<F> {
  void init_buffer() {
    if (this->file_->_p) return;
    // Force buffer initialization by placing and removing a char in a buffer.
-    putc_unlocked(0, this->file_);
+    if (!FMT_CLANG_ANALYZER) putc_unlocked(0, this->file_);
    --this->file_->_p;
    ++this->file_->_w;
  }
@@ -1594,7 +1599,7 @@ template <typename F> class apple_file : public file_base<F> {
    this->file_->_w -= size;
  }

-  bool needs_flush() const {
+  auto needs_flush() const -> bool {
    if ((this->file_->_flags & line_buffered) == 0) return false;
    return memchr(this->file_->_p + this->file_->_w, '\n',
                  to_unsigned(-this->file_->_w));
--- a/include/spdlog/fmt/bundled/format.h
+++ b/include/spdlog/fmt/bundled/format.h
--- a/include/spdlog/fmt/bundled/os.h
+++ b/include/spdlog/fmt/bundled/os.h
@@ -29,7 +29,8 @@
 #  if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
       defined(__linux__)) &&                              \
      (!defined(WINAPI_FAMILY) ||                          \
-       (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
+       (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP)) &&    \
+      !defined(__wasm__)
 #    include <fcntl.h>  // for O_RDONLY
 #    define FMT_USE_FCNTL 1
 #  else
--- a/include/spdlog/fmt/bundled/ostream.h
+++ b/include/spdlog/fmt/bundled/ostream.h
@@ -33,8 +33,8 @@
 FMT_BEGIN_NAMESPACE
 namespace detail {

-// Generate a unique explicit instantion in every translation unit using a tag
-// type in an anonymous namespace.
+// Generate a unique explicit instantiation in every translation unit using a
+// tag type in an anonymous namespace.
 namespace {
 struct file_access_tag {};
 }  // namespace
--- a/include/spdlog/fmt/bundled/printf.h
+++ b/include/spdlog/fmt/bundled/printf.h
@@ -9,7 +9,7 @@
 #define FMT_PRINTF_H_

 #ifndef FMT_MODULE
-#  include <algorithm>  // std::max
+#  include <algorithm>  // std::find
 #  include <limits>     // std::numeric_limits
 #endif

@@ -18,10 +18,6 @@
 FMT_BEGIN_NAMESPACE
 FMT_BEGIN_EXPORT

-template <typename T> struct printf_formatter {
-  printf_formatter() = delete;
-};
-
 template <typename Char> class basic_printf_context {
 private:
  basic_appender<Char> out_;
@@ -33,8 +29,6 @@ template <typename Char> class basic_printf_context {

 public:
  using char_type = Char;
-  using parse_context_type = parse_context<Char>;
-  template <typename T> using formatter_type = printf_formatter<T>;
  enum { builtin_types = 1 };

  /// Constructs a `printf_context` object. References to the arguments are
@@ -46,7 +40,7 @@ template <typename Char> class basic_printf_context {
  auto out() -> basic_appender<Char> { return out_; }
  void advance_to(basic_appender<Char>) {}

-  auto locale() -> detail::locale_ref { return {}; }
+  auto locale() -> locale_ref { return {}; }

  auto arg(int id) const -> basic_format_arg<basic_printf_context> {
    return args_.get(id);
@@ -74,10 +68,9 @@ inline auto find<false, char>(const char* first, const char* last, char value,

 // Checks if a value fits in int - used to avoid warnings about comparing
 // signed and unsigned integers.
-template <bool IsSigned> struct int_checker {
+template <bool IS_SIGNED> struct int_checker {
  template <typename T> static auto fits_in_int(T value) -> bool {
-    unsigned max = to_unsigned(max_value<int>());
-    return value <= max;
+    return value <= to_unsigned(max_value<int>());
  }
  inline static auto fits_in_int(bool) -> bool { return true; }
 };
@@ -95,7 +88,7 @@ struct printf_precision_handler {
  auto operator()(T value) -> int {
    if (!int_checker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
      report_error("number is too big");
-    return (std::max)(static_cast<int>(value), 0);
+    return max_of(static_cast<int>(value), 0);
  }

  template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
@@ -410,7 +403,9 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
      arg_index = parse_ctx.next_arg_id();
    else
      parse_ctx.check_arg_id(--arg_index);
-    return detail::get_arg(context, arg_index);
+    auto arg = context.arg(arg_index);
+    if (!arg) report_error("argument not found");
+    return arg;
  };

  const Char* start = parse_ctx.begin();
@@ -571,15 +566,19 @@ inline auto vsprintf(basic_string_view<Char> fmt,
 *
 *     std::string message = fmt::sprintf("The answer is %d", 42);
 */
-template <typename S, typename... T, typename Char = detail::char_t<S>>
-inline auto sprintf(const S& fmt, const T&... args) -> std::basic_string<Char> {
-  return vsprintf(detail::to_string_view(fmt),
-                  fmt::make_format_args<basic_printf_context<Char>>(args...));
+template <typename... T>
+inline auto sprintf(string_view fmt, const T&... args) -> std::string {
+  return vsprintf(fmt, make_printf_args(args...));
+}
+template <typename... T>
+FMT_DEPRECATED auto sprintf(basic_string_view<wchar_t> fmt, const T&... args)
+    -> std::wstring {
+  return vsprintf(fmt, make_printf_args<wchar_t>(args...));
 }

 template <typename Char>
-inline auto vfprintf(std::FILE* f, basic_string_view<Char> fmt,
-                     typename vprintf_args<Char>::type args) -> int {
+auto vfprintf(std::FILE* f, basic_string_view<Char> fmt,
+              typename vprintf_args<Char>::type args) -> int {
  auto buf = basic_memory_buffer<Char>();
  detail::vprintf(buf, fmt, args);
  size_t size = buf.size();
@@ -596,17 +595,14 @@ inline auto vfprintf(std::FILE* f, basic_string_view<Char> fmt,
 *
 *     fmt::fprintf(stderr, "Don't %s!", "panic");
 */
-template <typename S, typename... T, typename Char = detail::char_t<S>>
-inline auto fprintf(std::FILE* f, const S& fmt, const T&... args) -> int {
-  return vfprintf(f, detail::to_string_view(fmt),
-                  make_printf_args<Char>(args...));
+template <typename... T>
+inline auto fprintf(std::FILE* f, string_view fmt, const T&... args) -> int {
+  return vfprintf(f, fmt, make_printf_args(args...));
 }
-
-template <typename Char>
-FMT_DEPRECATED inline auto vprintf(basic_string_view<Char> fmt,
-                                   typename vprintf_args<Char>::type args)
-    -> int {
-  return vfprintf(stdout, fmt, args);
+template <typename... T>
+FMT_DEPRECATED auto fprintf(std::FILE* f, basic_string_view<wchar_t> fmt,
+                            const T&... args) -> int {
+  return vfprintf(f, fmt, make_printf_args<wchar_t>(args...));
 }

 /**
@@ -621,11 +617,6 @@ template <typename... T>
 inline auto printf(string_view fmt, const T&... args) -> int {
  return vfprintf(stdout, fmt, make_printf_args(args...));
 }
-template <typename... T>
-FMT_DEPRECATED inline auto printf(basic_string_view<wchar_t> fmt,
-                                  const T&... args) -> int {
-  return vfprintf(stdout, fmt, make_printf_args<wchar_t>(args...));
-}

 FMT_END_EXPORT
 FMT_END_NAMESPACE
--- a/include/spdlog/fmt/bundled/ranges.h
+++ b/include/spdlog/fmt/bundled/ranges.h
@@ -11,7 +11,6 @@
 #ifndef FMT_MODULE
 #  include <initializer_list>
 #  include <iterator>
-#  include <string>
 #  include <tuple>
 #  include <type_traits>
 #  include <utility>
@@ -31,7 +30,7 @@ template <typename T> class is_map {
  template <typename> static void check(...);

 public:
-  static constexpr const bool value =
+  static constexpr bool value =
      !std::is_void<decltype(check<T>(nullptr))>::value;
 };

@@ -40,17 +39,16 @@ template <typename T> class is_set {
  template <typename> static void check(...);

 public:
-  static constexpr const bool value =
+  static constexpr bool value =
      !std::is_void<decltype(check<T>(nullptr))>::value && !is_map<T>::value;
 };

 // C array overload
-template <typename T, std::size_t N>
+template <typename T, size_t N>
 auto range_begin(const T (&arr)[N]) -> const T* {
  return arr;
 }
-template <typename T, std::size_t N>
-auto range_end(const T (&arr)[N]) -> const T* {
+template <typename T, size_t N> auto range_end(const T (&arr)[N]) -> const T* {
  return arr + N;
 }

@@ -120,7 +118,7 @@ template <typename T> class is_tuple_like_ {
  template <typename> static void check(...);

 public:
-  static constexpr const bool value =
+  static constexpr bool value =
      !std::is_void<decltype(check<T>(nullptr))>::value;
 };

@@ -154,7 +152,7 @@ using tuple_index_sequence = make_index_sequence<std::tuple_size<T>::value>;
 template <typename T, typename C, bool = is_tuple_like_<T>::value>
 class is_tuple_formattable_ {
 public:
-  static constexpr const bool value = false;
+  static constexpr bool value = false;
 };
 template <typename T, typename C> class is_tuple_formattable_<T, C, true> {
  template <size_t... Is>
@@ -170,7 +168,7 @@ template <typename T, typename C> class is_tuple_formattable_<T, C, true> {
                                       C>::value)...>{}));

 public:
-  static constexpr const bool value =
+  static constexpr bool value =
      decltype(check(tuple_index_sequence<T>{}))::value;
 };

@@ -208,7 +206,7 @@ template <typename Char, typename... T>
 using result_t = std::tuple<formatter<remove_cvref_t<T>, Char>...>;

 using std::get;
-template <typename Tuple, typename Char, std::size_t... Is>
+template <typename Tuple, typename Char, size_t... Is>
 auto get_formatters(index_sequence<Is...>)
    -> result_t<Char, decltype(get<Is>(std::declval<Tuple>()))...>;
 }  // namespace tuple
@@ -219,7 +217,7 @@ template <typename R> struct range_reference_type_impl {
  using type = decltype(*detail::range_begin(std::declval<R&>()));
 };

-template <typename T, std::size_t N> struct range_reference_type_impl<T[N]> {
+template <typename T, size_t N> struct range_reference_type_impl<T[N]> {
  using type = T&;
 };

@@ -281,14 +279,15 @@ template <typename FormatContext> struct format_tuple_element {

 }  // namespace detail

+FMT_EXPORT
 template <typename T> struct is_tuple_like {
-  static constexpr const bool value =
+  static constexpr bool value =
      detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value;
 };

+FMT_EXPORT
 template <typename T, typename C> struct is_tuple_formattable {
-  static constexpr const bool value =
-      detail::is_tuple_formattable_<T, C>::value;
+  static constexpr bool value = detail::is_tuple_formattable_<T, C>::value;
 };

 template <typename Tuple, typename Char>
@@ -343,8 +342,9 @@ struct formatter<Tuple, Char,
  }
 };

+FMT_EXPORT
 template <typename T, typename Char> struct is_range {
-  static constexpr const bool value =
+  static constexpr bool value =
      detail::is_range_<T>::value && !detail::has_to_string_view<T>::value;
 };

@@ -368,6 +368,7 @@ template <typename P1, typename... Pn>
 struct conjunction<P1, Pn...>
    : conditional_t<bool(P1::value), conjunction<Pn...>, P1> {};

+FMT_EXPORT
 template <typename T, typename Char, typename Enable = void>
 struct range_formatter;

@@ -670,7 +671,8 @@ struct formatter<join_view<It, Sentinel, Char>, Char> {
  }
 };

-template <typename Char, typename Tuple> struct tuple_join_view : detail::view {
+FMT_EXPORT
+template <typename Tuple, typename Char> struct tuple_join_view : detail::view {
  const Tuple& tuple;
  basic_string_view<Char> sep;

@@ -685,15 +687,15 @@ template <typename Char, typename Tuple> struct tuple_join_view : detail::view {
 #  define FMT_TUPLE_JOIN_SPECIFIERS 0
 #endif

-template <typename Char, typename Tuple>
-struct formatter<tuple_join_view<Char, Tuple>, Char,
+template <typename Tuple, typename Char>
+struct formatter<tuple_join_view<Tuple, Char>, Char,
                 enable_if_t<is_tuple_like<Tuple>::value>> {
  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
    return do_parse(ctx, std::tuple_size<Tuple>());
  }

  template <typename FormatContext>
-  auto format(const tuple_join_view<Char, Tuple>& value,
+  auto format(const tuple_join_view<Tuple, Char>& value,
              FormatContext& ctx) const -> typename FormatContext::iterator {
    return do_format(value, ctx, std::tuple_size<Tuple>());
  }
@@ -725,14 +727,14 @@ struct formatter<tuple_join_view<Char, Tuple>, Char,
  }

  template <typename FormatContext>
-  auto do_format(const tuple_join_view<Char, Tuple>&, FormatContext& ctx,
+  auto do_format(const tuple_join_view<Tuple, Char>&, FormatContext& ctx,
                 std::integral_constant<size_t, 0>) const ->
      typename FormatContext::iterator {
    return ctx.out();
  }

  template <typename FormatContext, size_t N>
-  auto do_format(const tuple_join_view<Char, Tuple>& value, FormatContext& ctx,
+  auto do_format(const tuple_join_view<Tuple, Char>& value, FormatContext& ctx,
                 std::integral_constant<size_t, N>) const ->
      typename FormatContext::iterator {
    using std::get;
@@ -754,7 +756,7 @@ template <typename T> class is_container_adaptor_like {
  template <typename> static void check(...);

 public:
-  static constexpr const bool value =
+  static constexpr bool value =
      !std::is_void<decltype(check<T>(nullptr))>::value;
 };

@@ -825,7 +827,7 @@ auto join(Range&& r, string_view sep)
 */
 template <typename Tuple, FMT_ENABLE_IF(is_tuple_like<Tuple>::value)>
 FMT_CONSTEXPR auto join(const Tuple& tuple, string_view sep)
-    -> tuple_join_view<char, Tuple> {
+    -> tuple_join_view<Tuple, char> {
  return {tuple, sep};
 }

--- a/include/spdlog/fmt/bundled/std.h
+++ b/include/spdlog/fmt/bundled/std.h
@@ -15,15 +15,13 @@
 #  include <atomic>
 #  include <bitset>
 #  include <complex>
-#  include <cstdlib>
 #  include <exception>
-#  include <functional>
+#  include <functional>  // std::reference_wrapper
 #  include <memory>
 #  include <thread>
 #  include <type_traits>
-#  include <typeinfo>
-#  include <utility>
-#  include <vector>
+#  include <typeinfo>  // std::type_info
+#  include <utility>   // std::make_index_sequence

 // Check FMT_CPLUSPLUS to suppress a bogus warning in MSVC.
 #  if FMT_CPLUSPLUS >= 201703L
@@ -62,27 +60,26 @@
 #  endif
 #endif

-// For older Xcode versions, __cpp_lib_xxx flags are inaccurately defined.
-#ifndef FMT_CPP_LIB_FILESYSTEM
-#  ifdef __cpp_lib_filesystem
-#    define FMT_CPP_LIB_FILESYSTEM __cpp_lib_filesystem
-#  else
-#    define FMT_CPP_LIB_FILESYSTEM 0
-#  endif
+#ifdef FMT_CPP_LIB_FILESYSTEM
+// Use the provided definition.
+#elif defined(__cpp_lib_filesystem)
+#  define FMT_CPP_LIB_FILESYSTEM __cpp_lib_filesystem
+#else
+#  define FMT_CPP_LIB_FILESYSTEM 0
 #endif

-#ifndef FMT_CPP_LIB_VARIANT
-#  ifdef __cpp_lib_variant
-#    define FMT_CPP_LIB_VARIANT __cpp_lib_variant
-#  else
-#    define FMT_CPP_LIB_VARIANT 0
-#  endif
+#ifdef FMT_CPP_LIB_VARIANT
+// Use the provided definition.
+#elif defined(__cpp_lib_variant)
+#  define FMT_CPP_LIB_VARIANT __cpp_lib_variant
+#else
+#  define FMT_CPP_LIB_VARIANT 0
 #endif

+FMT_BEGIN_NAMESPACE
+namespace detail {
+
 #if FMT_CPP_LIB_FILESYSTEM
-FMT_BEGIN_NAMESPACE
-
-namespace detail {

 template <typename Char, typename PathChar>
 auto get_path_string(const std::filesystem::path& p,
@@ -111,8 +108,168 @@ void write_escaped_path(basic_memory_buffer<Char>& quoted,
  }
 }

+#endif  // FMT_CPP_LIB_FILESYSTEM
+
+#if defined(__cpp_lib_expected) || FMT_CPP_LIB_VARIANT
+template <typename Char, typename OutputIt, typename T>
+auto write_escaped_alternative(OutputIt out, const T& v) -> OutputIt {
+  if constexpr (has_to_string_view<T>::value)
+    return write_escaped_string<Char>(out, detail::to_string_view(v));
+  if constexpr (std::is_same_v<T, Char>) return write_escaped_char(out, v);
+  return write<Char>(out, v);
+}
+#endif
+
+#if FMT_CPP_LIB_VARIANT
+
+template <typename> struct is_variant_like_ : std::false_type {};
+template <typename... Types>
+struct is_variant_like_<std::variant<Types...>> : std::true_type {};
+
+template <typename Variant, typename Char> class is_variant_formattable {
+  template <size_t... Is>
+  static auto check(std::index_sequence<Is...>) -> std::conjunction<
+      is_formattable<std::variant_alternative_t<Is, Variant>, Char>...>;
+
+ public:
+  static constexpr bool value = decltype(check(
+      std::make_index_sequence<std::variant_size<Variant>::value>()))::value;
+};
+
+#endif  // FMT_CPP_LIB_VARIANT
+
+#if FMT_USE_RTTI
+
+template <typename OutputIt>
+auto write_demangled_name(OutputIt out, const std::type_info& ti) -> OutputIt {
+#  ifdef FMT_HAS_ABI_CXA_DEMANGLE
+  int status = 0;
+  size_t size = 0;
+  std::unique_ptr<char, void (*)(void*)> demangled_name_ptr(
+      abi::__cxa_demangle(ti.name(), nullptr, &size, &status), &std::free);
+
+  string_view demangled_name_view;
+  if (demangled_name_ptr) {
+    demangled_name_view = demangled_name_ptr.get();
+
+    // Normalization of stdlib inline namespace names.
+    // libc++ inline namespaces.
+    //  std::__1::*       -> std::*
+    //  std::__1::__fs::* -> std::*
+    // libstdc++ inline namespaces.
+    //  std::__cxx11::*             -> std::*
+    //  std::filesystem::__cxx11::* -> std::filesystem::*
+    if (demangled_name_view.starts_with("std::")) {
+      char* begin = demangled_name_ptr.get();
+      char* to = begin + 5;  // std::
+      for (char *from = to, *end = begin + demangled_name_view.size();
+           from < end;) {
+        // This is safe, because demangled_name is NUL-terminated.
+        if (from[0] == '_' && from[1] == '_') {
+          char* next = from + 1;
+          while (next < end && *next != ':') next++;
+          if (next[0] == ':' && next[1] == ':') {
+            from = next + 2;
+            continue;
+          }
+        }
+        *to++ = *from++;
+      }
+      demangled_name_view = {begin, detail::to_unsigned(to - begin)};
+    }
+  } else {
+    demangled_name_view = string_view(ti.name());
+  }
+  return detail::write_bytes<char>(out, demangled_name_view);
+#  elif FMT_MSC_VERSION
+  const string_view demangled_name(ti.name());
+  for (size_t i = 0; i < demangled_name.size(); ++i) {
+    auto sub = demangled_name;
+    sub.remove_prefix(i);
+    if (sub.starts_with("enum ")) {
+      i += 4;
+      continue;
+    }
+    if (sub.starts_with("class ") || sub.starts_with("union ")) {
+      i += 5;
+      continue;
+    }
+    if (sub.starts_with("struct ")) {
+      i += 6;
+      continue;
+    }
+    if (*sub.begin() != ' ') *out++ = *sub.begin();
+  }
+  return out;
+#  else
+  return detail::write_bytes<char>(out, string_view(ti.name()));
+#  endif
+}
+
+#endif  // FMT_USE_RTTI
+
+template <typename T, typename Enable = void>
+struct has_flip : std::false_type {};
+
+template <typename T>
+struct has_flip<T, void_t<decltype(std::declval<T>().flip())>>
+    : std::true_type {};
+
+template <typename T> struct is_bit_reference_like {
+  static constexpr bool value = std::is_convertible<T, bool>::value &&
+                                std::is_nothrow_assignable<T, bool>::value &&
+                                has_flip<T>::value;
+};
+
+// Workaround for libc++ incompatibility with C++ standard.
+// According to the Standard, `bitset::operator[] const` returns bool.
+#if defined(_LIBCPP_VERSION) && !defined(FMT_IMPORT_STD)
+template <typename C>
+struct is_bit_reference_like<std::__bit_const_reference<C>> {
+  static constexpr bool value = true;
+};
+#endif
+
+template <typename T, typename Enable = void>
+struct has_format_as : std::false_type {};
+template <typename T>
+struct has_format_as<T, void_t<decltype(format_as(std::declval<const T&>()))>>
+    : std::true_type {};
+
+template <typename T, typename Enable = void>
+struct has_format_as_member : std::false_type {};
+template <typename T>
+struct has_format_as_member<
+    T, void_t<decltype(formatter<T>::format_as(std::declval<const T&>()))>>
+    : std::true_type {};
+
 }  // namespace detail

+template <typename T, typename Deleter>
+auto ptr(const std::unique_ptr<T, Deleter>& p) -> const void* {
+  return p.get();
+}
+template <typename T> auto ptr(const std::shared_ptr<T>& p) -> const void* {
+  return p.get();
+}
+
+#if FMT_CPP_LIB_FILESYSTEM
+
+class path : public std::filesystem::path {
+ public:
+  auto display_string() const -> std::string {
+    const std::filesystem::path& base = *this;
+    return fmt::format(FMT_STRING("{}"), base);
+  }
+  auto system_string() const -> std::string { return string(); }
+
+  auto generic_display_string() const -> std::string {
+    const std::filesystem::path& base = *this;
+    return fmt::format(FMT_STRING("{:g}"), base);
+  }
+  auto generic_system_string() const -> std::string { return generic_string(); }
+};
+
 template <typename Char> struct formatter<std::filesystem::path, Char> {
 private:
  format_specs specs_;
@@ -162,39 +319,20 @@ template <typename Char> struct formatter<std::filesystem::path, Char> {
  }
 };

-class path : public std::filesystem::path {
- public:
-  auto display_string() const -> std::string {
-    const std::filesystem::path& base = *this;
-    return fmt::format(FMT_STRING("{}"), base);
-  }
-  auto system_string() const -> std::string { return string(); }
-
-  auto generic_display_string() const -> std::string {
-    const std::filesystem::path& base = *this;
-    return fmt::format(FMT_STRING("{:g}"), base);
-  }
-  auto generic_system_string() const -> std::string { return generic_string(); }
-};
-
-FMT_END_NAMESPACE
 #endif  // FMT_CPP_LIB_FILESYSTEM

-FMT_BEGIN_NAMESPACE
-template <std::size_t N, typename Char>
+template <size_t N, typename Char>
 struct formatter<std::bitset<N>, Char>
    : nested_formatter<basic_string_view<Char>, Char> {
 private:
-  // Functor because C++11 doesn't support generic lambdas.
+  // This is a functor because C++11 doesn't support generic lambdas.
  struct writer {
    const std::bitset<N>& bs;

    template <typename OutputIt>
    FMT_CONSTEXPR auto operator()(OutputIt out) -> OutputIt {
-      for (auto pos = N; pos > 0; --pos) {
+      for (auto pos = N; pos > 0; --pos)
        out = detail::write<Char>(out, bs[pos - 1] ? Char('1') : Char('0'));
-      }
-
      return out;
    }
  };
@@ -209,10 +347,8 @@ struct formatter<std::bitset<N>, Char>

 template <typename Char>
 struct formatter<std::thread::id, Char> : basic_ostream_formatter<Char> {};
-FMT_END_NAMESPACE

 #ifdef __cpp_lib_optional
-FMT_BEGIN_NAMESPACE
 template <typename T, typename Char>
 struct formatter<std::optional<T>, Char,
                 std::enable_if_t<is_formattable<T, Char>::value>> {
@@ -251,30 +387,9 @@ struct formatter<std::optional<T>, Char,
    return detail::write(out, ')');
  }
 };
-FMT_END_NAMESPACE
 #endif  // __cpp_lib_optional

-#if defined(__cpp_lib_expected) || FMT_CPP_LIB_VARIANT
-
-FMT_BEGIN_NAMESPACE
-namespace detail {
-
-template <typename Char, typename OutputIt, typename T>
-auto write_escaped_alternative(OutputIt out, const T& v) -> OutputIt {
-  if constexpr (has_to_string_view<T>::value)
-    return write_escaped_string<Char>(out, detail::to_string_view(v));
-  if constexpr (std::is_same_v<T, Char>) return write_escaped_char(out, v);
-  return write<Char>(out, v);
-}
-
-}  // namespace detail
-
-FMT_END_NAMESPACE
-#endif
-
 #ifdef __cpp_lib_expected
-FMT_BEGIN_NAMESPACE
-
 template <typename T, typename E, typename Char>
 struct formatter<std::expected<T, E>, Char,
                 std::enable_if_t<(std::is_void<T>::value ||
@@ -301,11 +416,9 @@ struct formatter<std::expected<T, E>, Char,
    return out;
  }
 };
-FMT_END_NAMESPACE
 #endif  // __cpp_lib_expected

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

@@ -323,42 +436,12 @@ template <> struct formatter<std::source_location> {
    return out;
  }
 };
-FMT_END_NAMESPACE
 #endif

 #if FMT_CPP_LIB_VARIANT
-FMT_BEGIN_NAMESPACE
-namespace detail {
-
-template <typename T>
-using variant_index_sequence =
-    std::make_index_sequence<std::variant_size<T>::value>;
-
-template <typename> struct is_variant_like_ : std::false_type {};
-template <typename... Types>
-struct is_variant_like_<std::variant<Types...>> : std::true_type {};
-
-// formattable element check.
-template <typename T, typename C> class is_variant_formattable_ {
-  template <std::size_t... Is>
-  static std::conjunction<
-      is_formattable<std::variant_alternative_t<Is, T>, C>...>
-      check(std::index_sequence<Is...>);
-
- public:
-  static constexpr const bool value =
-      decltype(check(variant_index_sequence<T>{}))::value;
-};
-
-}  // namespace detail

 template <typename T> struct is_variant_like {
-  static constexpr const bool value = detail::is_variant_like_<T>::value;
-};
-
-template <typename T, typename C> struct is_variant_formattable {
-  static constexpr const bool value =
-      detail::is_variant_formattable_<T, C>::value;
+  static constexpr bool value = detail::is_variant_like_<T>::value;
 };

 template <typename Char> struct formatter<std::monostate, Char> {
@@ -374,10 +457,10 @@ template <typename Char> struct formatter<std::monostate, Char> {
 };

 template <typename Variant, typename Char>
-struct formatter<
-    Variant, Char,
-    std::enable_if_t<std::conjunction_v<
-        is_variant_like<Variant>, is_variant_formattable<Variant, Char>>>> {
+struct formatter<Variant, Char,
+                 std::enable_if_t<std::conjunction_v<
+                     is_variant_like<Variant>,
+                     detail::is_variant_formattable<Variant, Char>>>> {
  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
    return ctx.begin();
  }
@@ -402,10 +485,9 @@ struct formatter<
    return out;
  }
 };
-FMT_END_NAMESPACE
+
 #endif  // FMT_CPP_LIB_VARIANT

-FMT_BEGIN_NAMESPACE
 template <> struct formatter<std::error_code> {
 private:
  format_specs specs_;
@@ -459,101 +541,29 @@ template <> struct formatter<std::error_code> {
 };

 #if FMT_USE_RTTI
-namespace detail {
-
-template <typename Char, typename OutputIt>
-auto write_demangled_name(OutputIt out, const std::type_info& ti) -> OutputIt {
-#  ifdef FMT_HAS_ABI_CXA_DEMANGLE
-  int status = 0;
-  std::size_t size = 0;
-  std::unique_ptr<char, void (*)(void*)> demangled_name_ptr(
-      abi::__cxa_demangle(ti.name(), nullptr, &size, &status), &std::free);
-
-  string_view demangled_name_view;
-  if (demangled_name_ptr) {
-    demangled_name_view = demangled_name_ptr.get();
-
-    // Normalization of stdlib inline namespace names.
-    // libc++ inline namespaces.
-    //  std::__1::*       -> std::*
-    //  std::__1::__fs::* -> std::*
-    // libstdc++ inline namespaces.
-    //  std::__cxx11::*             -> std::*
-    //  std::filesystem::__cxx11::* -> std::filesystem::*
-    if (demangled_name_view.starts_with("std::")) {
-      char* begin = demangled_name_ptr.get();
-      char* to = begin + 5;  // std::
-      for (char *from = to, *end = begin + demangled_name_view.size();
-           from < end;) {
-        // This is safe, because demangled_name is NUL-terminated.
-        if (from[0] == '_' && from[1] == '_') {
-          char* next = from + 1;
-          while (next < end && *next != ':') next++;
-          if (next[0] == ':' && next[1] == ':') {
-            from = next + 2;
-            continue;
-          }
-        }
-        *to++ = *from++;
-      }
-      demangled_name_view = {begin, detail::to_unsigned(to - begin)};
-    }
-  } else {
-    demangled_name_view = string_view(ti.name());
-  }
-  return detail::write_bytes<Char>(out, demangled_name_view);
-#  elif FMT_MSC_VERSION
-  const string_view demangled_name(ti.name());
-  for (std::size_t i = 0; i < demangled_name.size(); ++i) {
-    auto sub = demangled_name;
-    sub.remove_prefix(i);
-    if (sub.starts_with("enum ")) {
-      i += 4;
-      continue;
-    }
-    if (sub.starts_with("class ") || sub.starts_with("union ")) {
-      i += 5;
-      continue;
-    }
-    if (sub.starts_with("struct ")) {
-      i += 6;
-      continue;
-    }
-    if (*sub.begin() != ' ') *out++ = *sub.begin();
-  }
-  return out;
-#  else
-  return detail::write_bytes<Char>(out, string_view(ti.name()));
-#  endif
-}
-
-}  // namespace detail
-
-template <typename Char>
-struct formatter<std::type_info, Char  // DEPRECATED! Mixing code unit types.
-                 > {
+template <> struct formatter<std::type_info> {
 public:
-  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+  FMT_CONSTEXPR auto parse(parse_context<>& ctx) -> const char* {
    return ctx.begin();
  }

  template <typename Context>
  auto format(const std::type_info& ti, Context& ctx) const
      -> decltype(ctx.out()) {
-    return detail::write_demangled_name<Char>(ctx.out(), ti);
+    return detail::write_demangled_name(ctx.out(), ti);
  }
 };
-#endif
+#endif  // FMT_USE_RTTI

-template <typename T, typename Char>
+template <typename T>
 struct formatter<
-    T, Char,  // DEPRECATED! Mixing code unit types.
+    T, char,
    typename std::enable_if<std::is_base_of<std::exception, T>::value>::type> {
 private:
  bool with_typename_ = false;

 public:
-  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+  FMT_CONSTEXPR auto parse(parse_context<>& ctx) -> const char* {
    auto it = ctx.begin();
    auto end = ctx.end();
    if (it == end || *it == '}') return it;
@@ -570,43 +580,15 @@ struct formatter<
    auto out = ctx.out();
 #if FMT_USE_RTTI
    if (with_typename_) {
-      out = detail::write_demangled_name<Char>(out, typeid(ex));
+      out = detail::write_demangled_name(out, typeid(ex));
      *out++ = ':';
      *out++ = ' ';
    }
 #endif
-    return detail::write_bytes<Char>(out, string_view(ex.what()));
+    return detail::write_bytes<char>(out, string_view(ex.what()));
  }
 };

-namespace detail {
-
-template <typename T, typename Enable = void>
-struct has_flip : std::false_type {};
-
-template <typename T>
-struct has_flip<T, void_t<decltype(std::declval<T>().flip())>>
-    : std::true_type {};
-
-template <typename T> struct is_bit_reference_like {
-  static constexpr const bool value =
-      std::is_convertible<T, bool>::value &&
-      std::is_nothrow_assignable<T, bool>::value && has_flip<T>::value;
-};
-
-#ifdef _LIBCPP_VERSION
-
-// Workaround for libc++ incompatibility with C++ standard.
-// According to the Standard, `bitset::operator[] const` returns bool.
-template <typename C>
-struct is_bit_reference_like<std::__bit_const_reference<C>> {
-  static constexpr const bool value = true;
-};
-
-#endif
-
-}  // namespace detail
-
 // 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.
@@ -621,14 +603,6 @@ struct formatter<BitRef, Char,
  }
 };

-template <typename T, typename Deleter>
-auto ptr(const std::unique_ptr<T, Deleter>& p) -> const void* {
-  return p.get();
-}
-template <typename T> auto ptr(const std::shared_ptr<T>& p) -> const void* {
-  return p.get();
-}
-
 template <typename T, typename Char>
 struct formatter<std::atomic<T>, Char,
                 enable_if_t<is_formattable<T, Char>::value>>
@@ -715,7 +689,11 @@ template <typename T, typename Char> struct formatter<std::complex<T>, Char> {

 template <typename T, typename Char>
 struct formatter<std::reference_wrapper<T>, Char,
-                 enable_if_t<is_formattable<remove_cvref_t<T>, Char>::value>>
+                 // Guard against format_as because reference_wrapper is
+                 // implicitly convertible to T&.
+                 enable_if_t<is_formattable<remove_cvref_t<T>, Char>::value &&
+                             !detail::has_format_as<T>::value &&
+                             !detail::has_format_as_member<T>::value>>
    : formatter<remove_cvref_t<T>, Char> {
  template <typename FormatContext>
  auto format(std::reference_wrapper<T> ref, FormatContext& ctx) const
@@ -725,4 +703,5 @@ struct formatter<std::reference_wrapper<T>, Char,
 };

 FMT_END_NAMESPACE
+
 #endif  // FMT_STD_H_
--- a/include/spdlog/fmt/bundled/xchar.h
+++ b/include/spdlog/fmt/bundled/xchar.h
@@ -55,6 +55,16 @@ inline auto write_loc(basic_appender<wchar_t> out, loc_value value,
 #endif
  return false;
 }
+
+template <typename Char>
+void vformat_to(buffer<Char>& buf, basic_string_view<Char> fmt,
+                basic_format_args<buffered_context<Char>> args,
+                locale_ref loc = {}) {
+  static_assert(!std::is_same<Char, char>::value, "");
+  auto out = basic_appender<Char>(buf);
+  parse_format_string(
+      fmt, format_handler<Char>{parse_context<Char>(fmt), {out, args, loc}});
+}
 }  // namespace detail

 FMT_BEGIN_EXPORT
@@ -112,10 +122,6 @@ inline auto runtime(wstring_view s) -> runtime_format_string<wchar_t> {
  return {{s}};
 }

-#ifdef __cpp_char8_t
-template <> struct is_char<char8_t> : bool_constant<detail::is_utf8_enabled> {};
-#endif
-
 template <typename... T>
 constexpr auto make_wformat_args(T&... args)
    -> decltype(fmt::make_format_args<wformat_context>(args...)) {
@@ -151,13 +157,13 @@ auto join(std::initializer_list<T> list, wstring_view sep)

 template <typename Tuple, FMT_ENABLE_IF(is_tuple_like<Tuple>::value)>
 auto join(const Tuple& tuple, basic_string_view<wchar_t> sep)
-    -> tuple_join_view<wchar_t, Tuple> {
+    -> tuple_join_view<Tuple, wchar_t> {
  return {tuple, sep};
 }

 template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
 auto vformat(basic_string_view<Char> fmt,
-             typename detail::vformat_args<Char>::type args)
+             basic_format_args<buffered_context<Char>> args)
    -> std::basic_string<Char> {
  auto buf = basic_memory_buffer<Char>();
  detail::vformat_to(buf, fmt, args);
@@ -187,24 +193,20 @@ auto format(const S& fmt, T&&... args) -> std::basic_string<Char> {
                 fmt::make_format_args<buffered_context<Char>>(args...));
 }

-template <typename Locale, typename S,
-          typename Char = detail::format_string_char_t<S>,
-          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
-                            detail::is_exotic_char<Char>::value)>
-inline auto vformat(const Locale& loc, const S& fmt,
-                    typename detail::vformat_args<Char>::type args)
+template <typename S, typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)>
+inline auto vformat(locale_ref loc, const S& fmt,
+                    basic_format_args<buffered_context<Char>> args)
    -> std::basic_string<Char> {
  auto buf = basic_memory_buffer<Char>();
-  detail::vformat_to(buf, detail::to_string_view(fmt), args,
-                     detail::locale_ref(loc));
+  detail::vformat_to(buf, detail::to_string_view(fmt), args, loc);
  return {buf.data(), buf.size()};
 }

-template <typename Locale, typename S, typename... T,
+template <typename S, typename... T,
          typename Char = detail::format_string_char_t<S>,
-          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
-                            detail::is_exotic_char<Char>::value)>
-inline auto format(const Locale& loc, const S& fmt, T&&... args)
+          FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)>
+inline auto format(locale_ref loc, const S& fmt, T&&... args)
    -> std::basic_string<Char> {
  return vformat(loc, detail::to_string_view(fmt),
                 fmt::make_format_args<buffered_context<Char>>(args...));
@@ -215,7 +217,7 @@ template <typename OutputIt, typename S,
          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
                            detail::is_exotic_char<Char>::value)>
 auto vformat_to(OutputIt out, const S& fmt,
-                typename detail::vformat_args<Char>::type args) -> OutputIt {
+                basic_format_args<buffered_context<Char>> args) -> OutputIt {
  auto&& buf = detail::get_buffer<Char>(out);
  detail::vformat_to(buf, detail::to_string_view(fmt), args);
  return detail::get_iterator(buf, out);
@@ -231,27 +233,24 @@ inline auto format_to(OutputIt out, const S& fmt, T&&... args) -> OutputIt {
                    fmt::make_format_args<buffered_context<Char>>(args...));
 }

-template <typename Locale, typename S, typename OutputIt, typename... Args,
+template <typename S, typename OutputIt, typename... Args,
          typename Char = detail::format_string_char_t<S>,
          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
-                            detail::is_locale<Locale>::value&&
-                                detail::is_exotic_char<Char>::value)>
-inline auto vformat_to(OutputIt out, const Locale& loc, const S& fmt,
-                       typename detail::vformat_args<Char>::type args)
+                            detail::is_exotic_char<Char>::value)>
+inline auto vformat_to(OutputIt out, locale_ref loc, const S& fmt,
+                       basic_format_args<buffered_context<Char>> args)
    -> OutputIt {
  auto&& buf = detail::get_buffer<Char>(out);
-  vformat_to(buf, detail::to_string_view(fmt), args, detail::locale_ref(loc));
+  vformat_to(buf, detail::to_string_view(fmt), args, loc);
  return detail::get_iterator(buf, out);
 }

-template <typename Locale, typename OutputIt, typename S, typename... T,
+template <typename OutputIt, typename S, typename... T,
          typename Char = detail::format_string_char_t<S>,
          bool enable = detail::is_output_iterator<OutputIt, Char>::value &&
-                        detail::is_locale<Locale>::value &&
                        detail::is_exotic_char<Char>::value>
-inline auto format_to(OutputIt out, const Locale& loc, const S& fmt,
-                      T&&... args) ->
-    typename std::enable_if<enable, OutputIt>::type {
+inline auto format_to(OutputIt out, locale_ref loc, const S& fmt, T&&... args)
+    -> typename std::enable_if<enable, OutputIt>::type {
  return vformat_to(out, loc, detail::to_string_view(fmt),
                    fmt::make_format_args<buffered_context<Char>>(args...));
 }
@@ -260,7 +259,7 @@ template <typename OutputIt, typename Char, typename... Args,
          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
                            detail::is_exotic_char<Char>::value)>
 inline auto vformat_to_n(OutputIt out, size_t n, basic_string_view<Char> fmt,
-                         typename detail::vformat_args<Char>::type args)
+                         basic_format_args<buffered_context<Char>> args)
    -> format_to_n_result<OutputIt> {
  using traits = detail::fixed_buffer_traits;
  auto buf = detail::iterator_buffer<OutputIt, Char, traits>(out, n);
@@ -331,18 +330,6 @@ inline auto format(text_style ts, wformat_string<T...> fmt, T&&... args)
  return fmt::vformat(ts, fmt, fmt::make_wformat_args(args...));
 }

-template <typename... T>
-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(text_style ts, wformat_string<T...> fmt,
-                          const T&... args) {
-  return print(stdout, ts, fmt, args...);
-}
-
 inline void vprint(std::wostream& os, wstring_view fmt, wformat_args args) {
  auto buffer = basic_memory_buffer<wchar_t>();
  detail::vformat_to(buffer, fmt, args);
--- a/include/spdlog/fmt/fmt.h
+++ b/include/spdlog/fmt/fmt.h
@@ -20,11 +20,7 @@
    #ifndef FMT_USE_WINDOWS_H
        #define FMT_USE_WINDOWS_H 0
    #endif
-
-    #include <spdlog/fmt/bundled/base.h>
    #include <spdlog/fmt/bundled/format.h>
-
 #else  // SPDLOG_FMT_EXTERNAL is defined - use external fmtlib
-    #include <fmt/base.h>
    #include <fmt/format.h>
 #endif
--- a/include/spdlog/logger-inl.h
+++ b/include/spdlog/logger-inl.h
@@ -57,7 +57,7 @@ SPDLOG_INLINE void logger::swap(spdlog::logger &other) SPDLOG_NOEXCEPT {
    std::swap(tracer_, other.tracer_);
 }

-SPDLOG_INLINE void swap(logger &a, logger &b) { a.swap(b); }
+SPDLOG_INLINE void swap(logger &a, logger &b) noexcept { a.swap(b); }

 SPDLOG_INLINE void logger::set_level(level::level_enum log_level) { level_.store(log_level); }

@@ -163,12 +163,12 @@ SPDLOG_INLINE void logger::dump_backtrace_() {
    }
 }

-SPDLOG_INLINE bool logger::should_flush_(const details::log_msg &msg) {
+SPDLOG_INLINE bool logger::should_flush_(const details::log_msg &msg) const {
    auto flush_level = flush_level_.load(std::memory_order_relaxed);
    return (msg.level >= flush_level) && (msg.level != level::off);
 }

-SPDLOG_INLINE void logger::err_handler_(const std::string &msg) {
+SPDLOG_INLINE void logger::err_handler_(const std::string &msg) const {
    if (custom_err_handler_) {
        custom_err_handler_(msg);
    } else {
--- a/include/spdlog/logger.h
+++ b/include/spdlog/logger.h
@@ -363,14 +363,14 @@ protected:
    virtual void sink_it_(const details::log_msg &msg);
    virtual void flush_();
    void dump_backtrace_();
-    bool should_flush_(const details::log_msg &msg);
+    bool should_flush_(const details::log_msg &msg) const;

    // handle errors during logging.
    // default handler prints the error to stderr at max rate of 1 message/sec.
-    void err_handler_(const std::string &msg);
+    void err_handler_(const std::string &msg) const;
 };

-void swap(logger &a, logger &b);
+void swap(logger &a, logger &b) noexcept;

 }  // namespace spdlog

--- a/include/spdlog/pattern_formatter-inl.h
+++ b/include/spdlog/pattern_formatter-inl.h
@@ -510,6 +510,7 @@ public:
 };

 // ISO 8601 offset from UTC in timezone (+-HH:MM)
+// If SPDLOG_NO_TZ_OFFSET is defined, print "+??.??" instead.
 template <typename ScopedPadder>
 class z_formatter final : public flag_formatter {
 public:
@@ -524,6 +525,10 @@ public:
        const size_t field_size = 6;
        ScopedPadder p(field_size, padinfo_, dest);

+#ifdef SPDLOG_NO_TZ_OFFSET
+        const char *str = "+??:??";
+        dest.append(str, str + 6);
+#else
        auto total_minutes = get_cached_offset(msg, tm_time);
        bool is_negative = total_minutes < 0;
        if (is_negative) {
@@ -536,6 +541,7 @@ public:
        fmt_helper::pad2(total_minutes / 60, dest);  // hours
        dest.push_back(':');
        fmt_helper::pad2(total_minutes % 60, dest);  // minutes
+#endif  // SPDLOG_NO_TZ_OFFSET
    }

 private:
@@ -1154,12 +1160,10 @@ SPDLOG_INLINE void pattern_formatter::handle_flag_(char flag, details::padding_i
            formatters_.push_back(details::make_unique<details::T_formatter<Padder>>(padding));
            need_localtime_ = true;
            break;
-
        case ('z'):  // timezone
            formatters_.push_back(details::make_unique<details::z_formatter<Padder>>(padding));
            need_localtime_ = true;
            break;
-
        case ('P'):  // pid
            formatters_.push_back(details::make_unique<details::pid_formatter<Padder>>(padding));
            break;
--- a/include/spdlog/sinks/ansicolor_sink.h
+++ b/include/spdlog/sinks/ansicolor_sink.h
@@ -40,7 +40,7 @@ public:

    void log(const details::log_msg &msg) override;
    void flush() override;
-    void set_pattern(const std::string &pattern) final override;
+    void set_pattern(const std::string &pattern) override;
    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override;

    // Formatting codes
--- a/include/spdlog/sinks/ringbuffer_sink.h
+++ b/include/spdlog/sinks/ringbuffer_sink.h
@@ -21,7 +21,11 @@ template <typename Mutex>
 class ringbuffer_sink final : public base_sink<Mutex> {
 public:
    explicit ringbuffer_sink(size_t n_items)
-        : q_{n_items} {}
+        : q_{n_items} {
+        if (n_items == 0) {
+            throw_spdlog_ex("ringbuffer_sink: n_items cannot be zero");
+        }
+    }

    std::vector<details::log_msg_buffer> last_raw(size_t lim = 0) {
        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
--- a/include/spdlog/sinks/tcp_sink.h
+++ b/include/spdlog/sinks/tcp_sink.h
@@ -31,6 +31,8 @@ namespace sinks {
 struct tcp_sink_config {
    std::string server_host;
    int server_port;
+    int timeout_ms =
+        0;  // The timeout for all 3 major socket operations that is connect, send, and recv
    bool lazy_connect = false;  // if true connect on first log call instead of on construction

    tcp_sink_config(std::string host, int port)
@@ -44,10 +46,22 @@ public:
    // connect to tcp host/port or throw if failed
    // host can be hostname or ip address

+    explicit tcp_sink(const std::string &host,
+                      int port,
+                      int timeout_ms = 0,
+                      bool lazy_connect = false)
+        : config_{host, port} {
+        config_.timeout_ms = timeout_ms;
+        config_.lazy_connect = lazy_connect;
+        if (!config_.lazy_connect) {
+            client_.connect(config_.server_host, config_.server_port, config_.timeout_ms);
+        }
+    }
+
    explicit tcp_sink(tcp_sink_config sink_config)
        : config_{std::move(sink_config)} {
        if (!config_.lazy_connect) {
-            this->client_.connect(config_.server_host, config_.server_port);
+            client_.connect(config_.server_host, config_.server_port, config_.timeout_ms);
        }
    }

@@ -58,7 +72,7 @@ protected:
        spdlog::memory_buf_t formatted;
        spdlog::sinks::base_sink<Mutex>::formatter_->format(msg, formatted);
        if (!client_.is_connected()) {
-            client_.connect(config_.server_host, config_.server_port);
+            client_.connect(config_.server_host, config_.server_port, config_.timeout_ms);
        }
        client_.send(formatted.data(), formatted.size());
    }
--- a/include/spdlog/sinks/wincolor_sink.h
+++ b/include/spdlog/sinks/wincolor_sink.h
@@ -31,10 +31,10 @@ public:

    // change the color for the given level
    void set_color(level::level_enum level, std::uint16_t color);
-    void log(const details::log_msg &msg) final override;
-    void flush() final override;
-    void set_pattern(const std::string &pattern) override final;
-    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override final;
+    void log(const details::log_msg &msg) override;
+    void flush() override;
+    void set_pattern(const std::string &pattern) override;
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override;
    void set_color_mode(color_mode mode);

 protected:
--- a/include/spdlog/version.h
+++ b/include/spdlog/version.h
@@ -4,8 +4,8 @@
 #pragma once

 #define SPDLOG_VER_MAJOR 1
-#define SPDLOG_VER_MINOR 15
-#define SPDLOG_VER_PATCH 3
+#define SPDLOG_VER_MINOR 16
+#define SPDLOG_VER_PATCH 0

 #define SPDLOG_TO_VERSION(major, minor, patch) (major * 10000 + minor * 100 + patch)
 #define SPDLOG_VERSION SPDLOG_TO_VERSION(SPDLOG_VER_MAJOR, SPDLOG_VER_MINOR, SPDLOG_VER_PATCH)
--- a/src/bundled_fmtlib_format.cpp
+++ b/src/bundled_fmtlib_format.cpp
@@ -11,36 +11,35 @@
    #include <spdlog/fmt/bundled/format-inl.h>

 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>;
-
-    #if FMT_USE_LOCALE
-// DEPRECATED! locale_ref in the detail namespace
+#if FMT_USE_LOCALE
 template FMT_API locale_ref::locale_ref(const std::locale& loc);
 template FMT_API auto locale_ref::get<std::locale>() const -> std::locale;
-    #endif
+#endif
+
+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>;

 // 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);
-
 // 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;

+// DEPRECATED!
 template FMT_API void buffer<wchar_t>::append(const wchar_t*, const wchar_t*);

 }  // namespace detail
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -49,7 +49,8 @@ set(SPDLOG_UTESTS_SOURCES
    test_time_point.cpp
    test_stopwatch.cpp
    test_circular_q.cpp
-    test_bin_to_hex.cpp)
+    test_bin_to_hex.cpp
+    test_ringbuffer.cpp)

 if(NOT SPDLOG_NO_EXCEPTIONS)
    list(APPEND SPDLOG_UTESTS_SOURCES test_errors.cpp)
@@ -74,7 +75,7 @@ function(spdlog_prepare_test test_target spdlog_lib)
    elseif(SPDLOG_SANITIZE_THREAD)
        spdlog_enable_thread_sanitizer(${test_target})
    endif()
-    add_test(NAME ${test_target} COMMAND ${test_target})
+    add_test(NAME ${test_target} COMMAND ${test_target} --order decl)
    set_tests_properties(${test_target} PROPERTIES RUN_SERIAL ON)
 endfunction()

--- a/tests/test_pattern_formatter.cpp
+++ b/tests/test_pattern_formatter.cpp
@@ -82,8 +82,13 @@ TEST_CASE("GMT offset ", "[pattern_formatter]") {
    const auto now = std::chrono::system_clock::now();
    const auto yesterday = now - 24h;

+#ifndef SPDLOG_NO_TZ_OFFSET
+    const std::string expected_result = "+00:00\n";
+#else
+    const std::string expected_result = "+??:??\n";
+#endif
    REQUIRE(log_to_str_with_time(yesterday, "Some message", "%z", spdlog::pattern_time_type::utc,
-                                 "\n") == "+00:00\n");
+                                 "\n") == expected_result);
 }

 TEST_CASE("color range test1", "[pattern_formatter]") {
--- a/tests/test_ringbuffer.cpp
+++ b/tests/test_ringbuffer.cpp
@@ -0,0 +1,52 @@
+#include "includes.h"
+#include "spdlog/sinks/ringbuffer_sink.h"
+
+TEST_CASE("ringbuffer invalid size", "[ringbuffer]") {
+    REQUIRE_THROWS_AS(spdlog::sinks::ringbuffer_sink_mt(0), spdlog::spdlog_ex);
+}
+
+TEST_CASE("ringbuffer stores formatted messages", "[ringbuffer]") {
+    spdlog::sinks::ringbuffer_sink_st sink(3);
+    sink.set_pattern("%v");
+
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "msg1"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "msg2"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "msg3"});
+
+    auto formatted = sink.last_formatted();
+    REQUIRE(formatted.size() == 3);
+    using spdlog::details::os::default_eol;
+    REQUIRE(formatted[0] == spdlog::fmt_lib::format("msg1{}", default_eol));
+    REQUIRE(formatted[1] == spdlog::fmt_lib::format("msg2{}", default_eol));
+    REQUIRE(formatted[2] == spdlog::fmt_lib::format("msg3{}", default_eol));
+}
+
+TEST_CASE("ringbuffer overrun keeps last items", "[ringbuffer]") {
+    spdlog::sinks::ringbuffer_sink_st sink(2);
+    sink.set_pattern("%v");
+
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "first"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "second"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "third"});
+
+    auto formatted = sink.last_formatted();
+    REQUIRE(formatted.size() == 2);
+    using spdlog::details::os::default_eol;
+    REQUIRE(formatted[0] == spdlog::fmt_lib::format("second{}", default_eol));
+    REQUIRE(formatted[1] == spdlog::fmt_lib::format("third{}", default_eol));
+}
+
+TEST_CASE("ringbuffer retrieval limit", "[ringbuffer]") {
+    spdlog::sinks::ringbuffer_sink_st sink(3);
+    sink.set_pattern("%v");
+
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "A"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "B"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "C"});
+
+    auto formatted = sink.last_formatted(2);
+    REQUIRE(formatted.size() == 2);
+    using spdlog::details::os::default_eol;
+    REQUIRE(formatted[0] == spdlog::fmt_lib::format("B{}", default_eol));
+    REQUIRE(formatted[1] == spdlog::fmt_lib::format("C{}", default_eol));
+}
--- a/tests/test_stdout_api.cpp
+++ b/tests/test_stdout_api.cpp
@@ -5,6 +5,7 @@
 #include "includes.h"
 #include "spdlog/sinks/stdout_sinks.h"
 #include "spdlog/sinks/stdout_color_sinks.h"
+
 TEST_CASE("stdout_st", "[stdout]") {
    auto l = spdlog::stdout_logger_st("test");
    l->set_pattern("%+");
@@ -72,8 +73,14 @@ TEST_CASE("stderr_color_mt", "[stderr]") {
    spdlog::drop_all();
 }

-#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+TEST_CASE("show_utc_offset", "[stdout]") {
+    auto l = spdlog::stdout_color_mt("test");
+    l->set_pattern("[%c %z] [%n] [%^%l%$] %v");
+    l->info("Full date");
+    spdlog::drop_all();
+}

+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
 TEST_CASE("wchar_api", "[stdout]") {
    auto l = spdlog::stdout_logger_st("wchar_logger");
    l->set_pattern("%+");
@@ -86,5 +93,4 @@ TEST_CASE("wchar_api", "[stdout]") {
    SPDLOG_LOGGER_DEBUG(l, L"Test SPDLOG_LOGGER_DEBUG {}", L"param");
    spdlog::drop_all();
 }
-
 #endif
--- a/tests/test_stopwatch.cpp
+++ b/tests/test_stopwatch.cpp
@@ -5,7 +5,7 @@
 TEST_CASE("stopwatch1", "[stopwatch]") {
    using std::chrono::milliseconds;
    using clock = std::chrono::steady_clock;
-    milliseconds wait_ms(200);
+    milliseconds wait_ms(500);
    milliseconds tolerance_ms(250);
    auto start = clock::now();
    spdlog::stopwatch sw;
@@ -22,7 +22,7 @@ TEST_CASE("stopwatch2", "[stopwatch]") {
    using std::chrono::milliseconds;
    using clock = std::chrono::steady_clock;

-    clock::duration wait_duration(milliseconds(200));
+    clock::duration wait_duration(milliseconds(500));
    clock::duration tolerance_duration(milliseconds(250));

    auto test_sink = std::make_shared<test_sink_st>();
Author	SHA1	Message	Date
gabime	2f10538576	Add full date to stdout tests	2025-11-28 17:30:23 +02:00
gabime	a2339c5463	Add full date to stdout tests	2025-11-28 17:21:14 +02:00
gabime	2a528b9068	clang-format	2025-11-28 17:10:57 +02:00
gabime	6af5c48d83	Fix issue #3483	2025-11-28 15:48:07 +02:00
Aleksandr	3f7e502859	fix sign-compare warning (#3479 )	2025-11-01 18:03:07 +02:00
Ashish Ahuja	dd3ca04a7a	set CMAKE_BUILD_TYPE only in top-level project (#3480 )	2025-11-01 17:55:59 +02:00
gabime	486b55554f	Version 1.16.0	2025-10-11 15:53:05 +03:00
gabime	1bea38edcc	clang-format	2025-10-11 15:50:16 +03:00
gabime	4418909af2	Bump fmt to 12.0.0	2025-10-11 15:18:15 +03:00
Angelio Mason	f1d748e5e3	Remove the fileapi.h include in os-inl.h (#3444 ) * Replaced fileapi.h include with windows.h, as instructed in https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-flushfilebuffers Otherwise this causes compilation error on older sdks. * Removed the fileapi.h include entirely, since windows.h is already included before --------- Co-authored-by: MasonAngelio <MasonAngelio>	2025-08-07 23:47:11 +03:00
Vitaly	3edc8036db	Run tests in the order they are declared in the source file. (#3451 ) Fixes an issue with running tests in random order in Catch2 3.9.0+.	2025-08-07 23:38:29 +03:00
Mihir Patel	9ecdf5c8a1	Added timeout for TCP calls such as connect, send, recv (#3432 ) * Now lets test on windows * I guess testing on windows passes. * Update tcp_client-windows.h Added default value to argument * Final edit * Update tcp_client-windows.h Changed improper misplaced includes.	2025-07-17 23:47:35 +03:00
Gabi Melman	737347d2df	Update linux.yml	2025-07-16 09:55:57 +03:00
Alexander	4f2b3d52f9	Update README.md (#3437 ) * Update README.md add example showcasing 2 loggers and `spdlog::set_level()` which set level not only to default logger, but to all registed loggers * Update README.md * simplify * simplify	2025-07-16 08:59:51 +03:00
Joshua Chapman	4397dac510	chore(cmake): add option to override CMAKE_DEBUG_POSTFIX (#3433 ) This will make it possible to use the pkg-config with CMake debug build.	2025-07-08 22:52:42 +03:00
Gabi Melman	6fd67ce169	Update windows.yml remove msvc 2019 build	2025-07-06 10:08:55 +03:00
Gabi Melman	4619e18a16	Update windows.yml	2025-07-06 09:53:42 +03:00
Gabi Melman	a6215527f4	Fix ringbuffer tests for newline (#3436 )	2025-07-06 08:38:48 +03:00
VZ	287333ee00	Remove unnecessary and inconsistent "final" from color sinks (#3430 ) The use of "final" differed between ansicolor_sink and wincolor_sink, resulting in the code inheriting from std{err,out}_color_sink classes, which are defined as one or the other on different platforms, being able to override most of the functions under non-Windows platforms, but not under Windows. This seems gratuitously inconsistent, so just remove all "final" keywords from both classes, especially because there doesn't seem any good reason to use it and the other sink classes don't use it (with the exception of base_sink, which is special). This also incidentally fixes using "final override" in most places but "override final" in wincolor_sink.h. Fixes #3429.	2025-06-30 07:39:32 +03:00
电线杆	ad725d34cc	Use std::getenv #3414 (#3415 )	2025-06-08 23:16:34 +03:00
Gabi Melman	e655dbb685	Fix issue #3408 Remove including core.h or base.h	2025-06-07 13:44:09 +03:00
gabime	b18a234ed6	Fix coverity ci	2025-05-12 17:44:17 +03:00
Gabi Melman	5d89b5b91c	Update jetbrains logo (#3401 ) * Update jetbrains logo	2025-05-12 16:04:04 +03:00
Gabi Melman	37ff466454	Add coverity scan to CI and fix warnings (#3400 ) * Move callback function in thread_pool ctor * Added const qualifiers to logger.h * Remove unused includes from file_helper-inl.h * Fix comments and remove unused include from helpers-inl.h * Fix typo in comment for set_default_logger method. * Use `std::move` for `old_logger` in `set_default_logger`. * Use std::move in example * Wrap `main` content in try block for exception safety. * Added coverity to ci	2025-05-12 15:36:07 +03:00
Gabi Melman	677a2d93e6	Update test_stopwatch.cpp	2025-05-09 13:22:39 +03:00