Fix warning C4530 (#3393)

* Fix warning C4530

* Rename FMT_EXCEPTIONS to FMT_USE_EXCEPTIONS

.clang-tidy

@@ -27,7 +27,6 @@ clang-analyzer-*,
 
 WarningsAsErrors: ''
 HeaderFilterRegex: '*spdlog/[^f].*'
-AnalyzeTemporaryDtors: false
 FormatStyle:     none
 
 CheckOptions:    

.github/workflows/linux.yml

@@ -1,9 +1,15 @@
-name: ci
+name: linux
 
 on: [push, pull_request]
 
+permissions:
+  contents: read
+
 jobs:
-  build_linux:
+  # -----------------------------------------------------------------------
+  # Linux build matrix
+  # -----------------------------------------------------------------------
+  build:
     runs-on: ubuntu-latest
     defaults:
       run:
@@ -16,16 +22,18 @@ jobs:
           - { compiler: gcc, version: 9, build_type: Release, cppstd: 17 }
           - { compiler: gcc, version: 11, build_type: Debug, cppstd: 20 }
           - { compiler: gcc, version: 12, build_type: Release, cppstd: 20 }
-          - { compiler: clang, version: 12, build_type: Debug, cppstd: 17, asan: OFF }
-          - { compiler: clang, version: 15, build_type: Release, cppstd: 20, asan: OFF }
+          - { compiler: gcc, version: 12, build_type: Debug, cppstd: 20, asan: ON }
+          - { compiler: clang, version: 12, build_type: Debug, cppstd: 17 }
+          - { compiler: clang, version: 15, build_type: Release, cppstd: 20, tsan: ON }
     container:
       image: ${{ matrix.config.compiler == 'clang' && 'teeks99/clang-ubuntu' || matrix.config.compiler }}:${{ matrix.config.version }}
-    name: "${{ matrix.config.compiler}} ${{ matrix.config.version }} (C++${{ matrix.config.cppstd }}, ${{ matrix.config.build_type }})"
+    name: "${{ matrix.config.compiler}} ${{ matrix.config.version }} (C++${{ matrix.config.cppstd }} ${{ matrix.config.build_type }} ${{ matrix.config.asan == 'ON' && 'ASAN' || '' }}${{ matrix.config.tsan == 'ON' && 'TSAN' || '' }})"
     steps:
-      - uses: actions/checkout@main
+      - uses: actions/checkout@v4
       - name: Setup
         run: |
-          apt-get update && apt-get install -y curl git pkg-config libsystemd-dev
+          apt-get update
+          apt-get install -y curl git pkg-config libsystemd-dev
           CMAKE_VERSION="3.24.2"
           curl -sSL https://github.com/Kitware/CMake/releases/download/v${CMAKE_VERSION}/cmake-${CMAKE_VERSION}-linux-x86_64.sh -o install-cmake.sh
           chmod +x install-cmake.sh
@@ -33,10 +41,8 @@ jobs:
       - name: Setup Compiler
         if: matrix.config.compiler == 'clang'
         run: |
-          if [[ "${{ matrix.config.version }}" -ge 4 ]]; then
           scripts/ci_setup_clang.sh "${{ matrix.config.version }}"
           echo "CXXFLAGS=-stdlib=libc++" >> $GITHUB_ENV          
-          fi
           echo "CC=clang-${{ matrix.config.version }}" >> $GITHUB_ENV
           echo "CXX=clang++-${{ matrix.config.version }}" >> $GITHUB_ENV
       - name: Build
@@ -51,15 +57,19 @@ jobs:
             -DSPDLOG_BUILD_BENCH=OFF \
             -DSPDLOG_BUILD_TESTS=ON \
             -DSPDLOG_BUILD_TESTS_HO=OFF \
-            -DSPDLOG_SANITIZE_ADDRESS=${{ matrix.config.asan || 'ON' }}
-          make -j2
-          ctest -j2 --output-on-failure
+            -DSPDLOG_SANITIZE_ADDRESS=${{ matrix.config.asan || 'OFF' }} \
+            -DSPDLOG_SANITIZE_THREAD=${{ matrix.config.tsan || 'OFF' }}
+          make -j 4
+          ctest -j 4 --output-on-failure
 
+  # -----------------------------------------------------------------------
+  # OS X build matrix
+  # -----------------------------------------------------------------------
   build_osx:
     runs-on: macOS-latest
     name: "OS X Clang (C++11, Release)"
     steps:
-      - uses: actions/checkout@main
+      - uses: actions/checkout@v4
       - name: Build
         run: |
           mkdir -p build && cd build
@@ -73,6 +83,5 @@ jobs:
             -DSPDLOG_BUILD_TESTS=ON \
             -DSPDLOG_BUILD_TESTS_HO=OFF \
             -DSPDLOG_SANITIZE_ADDRESS=OFF
-          make -j2
-          ctest -j2 --output-on-failure
-
+          make -j 4
+          ctest -j 4 --output-on-failure

.github/workflows/macos.yml

@@ -0,0 +1,38 @@
+name: macos
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: macOS-latest
+    name: "macOS Clang (C++11, Release)"
+    strategy:
+      fail-fast: true
+      matrix:
+        config:
+            - USE_STD_FORMAT: 'ON'
+              BUILD_EXAMPLE: 'OFF'
+            - USE_STD_FORMAT: 'OFF'
+              BUILD_EXAMPLE: 'ON'
+              
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build
+        run: |
+          mkdir -p build && cd build
+          cmake .. \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_CXX_STANDARD=11 \
+            -DSPDLOG_BUILD_EXAMPLE=${{ matrix.config.BUILD_EXAMPLE }} \
+            -DSPDLOG_BUILD_EXAMPLE_HO=${{ matrix.config.BUILD_EXAMPLE }} \
+            -DSPDLOG_BUILD_WARNINGS=ON \
+            -DSPDLOG_BUILD_BENCH=OFF \
+            -DSPDLOG_BUILD_TESTS=ON \
+            -DSPDLOG_BUILD_TESTS_HO=OFF \
+            -DSPDLOG_USE_STD_FORMAT=${{ matrix.config.USE_STD_FORMAT }} \
+            -DSPDLOG_SANITIZE_ADDRESS=OFF
+          make -j 4
+          ctest -j 4 --output-on-failure

.github/workflows/windows.yml

@@ -0,0 +1,148 @@
+name: windows
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: windows-latest
+    strategy:
+      fail-fast: true
+      matrix:
+        config:
+          - GENERATOR: "Visual Studio 17 2022"
+            BUILD_TYPE: Release
+            BUILD_SHARED: 'ON'
+            FATAL_ERRORS: 'ON'
+            WCHAR: 'OFF'
+            WCHAR_FILES: 'OFF'
+            BUILD_EXAMPLE: 'OFF'
+            USE_STD_FORMAT: 'ON'
+            CXX_STANDARD: 20
+          - GENERATOR: "Visual Studio 17 2022"
+            BUILD_TYPE: Release
+            BUILD_SHARED: 'ON'
+            FATAL_ERRORS: 'ON'
+            WCHAR: 'ON'
+            WCHAR_FILES: 'ON'
+            BUILD_EXAMPLE: 'OFF'
+            USE_STD_FORMAT: 'ON'
+            CXX_STANDARD: 20
+          - GENERATOR: "Visual Studio 17 2022"
+            BUILD_TYPE: Release
+            BUILD_SHARED: 'ON'
+            FATAL_ERRORS: 'ON'
+            WCHAR: 'OFF'
+            WCHAR_FILES: 'OFF'
+            BUILD_EXAMPLE: 'ON'
+            USE_STD_FORMAT: 'OFF'
+            CXX_STANDARD: 17
+
+    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
+
+  # -----------------------------------------------------------------------
+  # 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

.gitignore

@@ -93,3 +93,6 @@ cmake-build-*/
 # macos
 *.DS_store
 *.xcodeproj/
+/.vs
+/out/build
+/CMakeSettings.json

CMakeLists.txt

@@ -1,6 +1,6 @@
 # Copyright(c) 2019 spdlog authors Distributed under the MIT License (http://opensource.org/licenses/MIT)
 
-cmake_minimum_required(VERSION 3.11)
+cmake_minimum_required(VERSION 3.10...3.21)
 
 # ---------------------------------------------------------------------------------------
 # Start spdlog project
@@ -18,43 +18,39 @@ include(GNUInstallDirs)
 # ---------------------------------------------------------------------------------------
 # Set default build to release
 # ---------------------------------------------------------------------------------------
-if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+if (NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
     set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Choose Release or Debug" FORCE)
-endif()
+endif ()
 
 # ---------------------------------------------------------------------------------------
 # Compiler config
 # ---------------------------------------------------------------------------------------
-if(SPDLOG_USE_STD_FORMAT)
+if (SPDLOG_USE_STD_FORMAT)
     set(CMAKE_CXX_STANDARD 20)
     set(CMAKE_CXX_STANDARD_REQUIRED ON)
-elseif(NOT CMAKE_CXX_STANDARD)
+elseif (NOT CMAKE_CXX_STANDARD)
     set(CMAKE_CXX_STANDARD 11)
     set(CMAKE_CXX_STANDARD_REQUIRED ON)
-endif()
+endif ()
 
-# make sure __cplusplus is defined when using msvc and enable parallel build
-if(MSVC)
-    string(APPEND CMAKE_CXX_FLAGS " /Zc:__cplusplus /MP")
-endif()
 
 set(CMAKE_CXX_EXTENSIONS OFF)
 
-if(CMAKE_SYSTEM_NAME MATCHES "CYGWIN" OR CMAKE_SYSTEM_NAME MATCHES "MSYS")
+if (CMAKE_SYSTEM_NAME MATCHES "CYGWIN" OR CMAKE_SYSTEM_NAME MATCHES "MSYS" OR CMAKE_SYSTEM_NAME MATCHES "MINGW")
     set(CMAKE_CXX_EXTENSIONS ON)
-endif()
+endif ()
 
 # ---------------------------------------------------------------------------------------
 # Set SPDLOG_MASTER_PROJECT to ON if we are building spdlog
 # ---------------------------------------------------------------------------------------
 # Check if spdlog is being used directly or via add_subdirectory, but allow overriding
-if(NOT DEFINED SPDLOG_MASTER_PROJECT)
-    if(CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
+if (NOT DEFINED SPDLOG_MASTER_PROJECT)
+    if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
         set(SPDLOG_MASTER_PROJECT ON)
-    else()
+    else ()
         set(SPDLOG_MASTER_PROJECT OFF)
-    endif()
-endif()
+    endif ()
+endif ()
 
 option(SPDLOG_BUILD_ALL "Build all artifacts" OFF)
 
@@ -80,6 +76,10 @@ option(SPDLOG_BUILD_BENCH "Build benchmarks (Requires https://github.com/google/
 
 # sanitizer options
 option(SPDLOG_SANITIZE_ADDRESS "Enable address sanitizer in tests" OFF)
+option(SPDLOG_SANITIZE_THREAD "Enable thread sanitizer in tests" OFF)
+if (SPDLOG_SANITIZE_ADDRESS AND SPDLOG_SANITIZE_THREAD)
+    message(FATAL_ERROR "SPDLOG_SANITIZE_ADDRESS and SPDLOG_SANITIZE_THREAD are mutually exclusive")
+endif ()
 
 # warning options
 option(SPDLOG_BUILD_WARNINGS "Enable compiler warnings" OFF)
@@ -92,32 +92,38 @@ 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)
 
-if(SPDLOG_FMT_EXTERNAL AND SPDLOG_FMT_EXTERNAL_HO)
+if (SPDLOG_FMT_EXTERNAL AND SPDLOG_FMT_EXTERNAL_HO)
     message(FATAL_ERROR "SPDLOG_FMT_EXTERNAL and SPDLOG_FMT_EXTERNAL_HO are mutually exclusive")
-endif()
+endif ()
 
-if(SPDLOG_USE_STD_FORMAT AND SPDLOG_FMT_EXTERNAL_HO)
+if (SPDLOG_USE_STD_FORMAT AND SPDLOG_FMT_EXTERNAL_HO)
     message(FATAL_ERROR "SPDLOG_USE_STD_FORMAT and SPDLOG_FMT_EXTERNAL_HO are mutually exclusive")
-endif()
+endif ()
 
-if(SPDLOG_USE_STD_FORMAT AND SPDLOG_FMT_EXTERNAL)
+if (SPDLOG_USE_STD_FORMAT AND SPDLOG_FMT_EXTERNAL)
     message(FATAL_ERROR "SPDLOG_USE_STD_FORMAT and SPDLOG_FMT_EXTERNAL are mutually exclusive")
-endif()
+endif ()
 
 # misc tweakme options
-if(WIN32)
+if (WIN32)
     option(SPDLOG_WCHAR_SUPPORT "Support wchar api" OFF)
     option(SPDLOG_WCHAR_FILENAMES "Support wchar filenames" OFF)
-else()
+    option(SPDLOG_WCHAR_CONSOLE "Support wchar output to console" OFF)
+else ()
     set(SPDLOG_WCHAR_SUPPORT OFF CACHE BOOL "non supported option" FORCE)
     set(SPDLOG_WCHAR_FILENAMES OFF CACHE BOOL "non supported option" FORCE)
-endif()
+    set(SPDLOG_WCHAR_CONSOLE OFF CACHE BOOL "non supported option" FORCE)
+endif ()
 
-if(${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
+if (MSVC)
+    option(SPDLOG_MSVC_UTF8 "Enable/disable msvc /utf-8 flag required by fmt lib" ON)
+endif ()
+
+if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
     option(SPDLOG_CLOCK_COARSE "Use CLOCK_REALTIME_COARSE instead of the regular clock," OFF)
-else()
+else ()
     set(SPDLOG_CLOCK_COARSE OFF CACHE BOOL "non supported option" FORCE)
-endif()
+endif ()
 
 option(SPDLOG_PREVENT_CHILD_FD "Prevent from child processes to inherit log file descriptors" OFF)
 option(SPDLOG_NO_THREAD_ID "prevent spdlog from querying the thread id on each log call if thread id is not needed" OFF)
@@ -127,19 +133,20 @@ option(
         "prevent spdlog from using of std::atomic log levels (use only if your code never modifies log levels concurrently"
         OFF)
 option(SPDLOG_DISABLE_DEFAULT_LOGGER "Disable default logger creation" OFF)
+option(SPDLOG_FWRITE_UNLOCKED "Use the unlocked variant of fwrite. Leave this on unless your libc doesn't have it" ON)
 
 # clang-tidy
 option(SPDLOG_TIDY "run clang-tidy" OFF)
 
-if(SPDLOG_TIDY)
+if (SPDLOG_TIDY)
     set(CMAKE_CXX_CLANG_TIDY "clang-tidy")
     set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
     message(STATUS "Enabled clang-tidy")
-endif()
+endif ()
 
-if(SPDLOG_BUILD_PIC)
+if (SPDLOG_BUILD_PIC)
     set(CMAKE_POSITION_INDEPENDENT_CODE ON)
-endif()
+endif ()
 
 find_package(Threads REQUIRED)
 message(STATUS "Build type: " ${CMAKE_BUILD_TYPE})
@@ -148,34 +155,34 @@ message(STATUS "Build type: " ${CMAKE_BUILD_TYPE})
 # ---------------------------------------------------------------------------------------
 set(SPDLOG_SRCS src/spdlog.cpp src/stdout_sinks.cpp src/color_sinks.cpp src/file_sinks.cpp src/async.cpp src/cfg.cpp)
 
-if(NOT SPDLOG_USE_STD_FORMAT AND NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
+if (NOT SPDLOG_USE_STD_FORMAT AND NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
     list(APPEND SPDLOG_SRCS src/bundled_fmtlib_format.cpp)
-endif()
+endif ()
 
-if(SPDLOG_BUILD_SHARED OR BUILD_SHARED_LIBS)
-    if(WIN32)
+if (SPDLOG_BUILD_SHARED OR BUILD_SHARED_LIBS)
+    if (WIN32)
         configure_file(${CMAKE_CURRENT_SOURCE_DIR}/cmake/version.rc.in ${CMAKE_CURRENT_BINARY_DIR}/version.rc @ONLY)
         list(APPEND SPDLOG_SRCS ${CMAKE_CURRENT_BINARY_DIR}/version.rc)
-    endif()
+    endif ()
     add_library(spdlog SHARED ${SPDLOG_SRCS} ${SPDLOG_ALL_HEADERS})
     target_compile_definitions(spdlog PUBLIC SPDLOG_SHARED_LIB)
-    if(MSVC)
+    if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
         target_compile_options(spdlog PUBLIC $<$<AND:$<CXX_COMPILER_ID:MSVC>,$<NOT:$<COMPILE_LANGUAGE:CUDA>>>:/wd4251
                 /wd4275>)
-    endif()
-    if(NOT SPDLOG_USE_STD_FORMAT AND NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
-        target_compile_definitions(spdlog PRIVATE FMT_EXPORT PUBLIC FMT_SHARED)
-    endif()
-else()
+    endif ()
+    if (NOT SPDLOG_USE_STD_FORMAT AND NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
+        target_compile_definitions(spdlog PRIVATE FMT_LIB_EXPORT PUBLIC FMT_SHARED)
+    endif ()
+else ()
     add_library(spdlog STATIC ${SPDLOG_SRCS} ${SPDLOG_ALL_HEADERS})
-endif()
+endif ()
 
 add_library(spdlog::spdlog ALIAS spdlog)
 
 set(SPDLOG_INCLUDES_LEVEL "")
-if(SPDLOG_SYSTEM_INCLUDES)
+if (SPDLOG_SYSTEM_INCLUDES)
     set(SPDLOG_INCLUDES_LEVEL "SYSTEM")
-endif()
+endif ()
 
 target_compile_definitions(spdlog PUBLIC SPDLOG_COMPILED_LIB)
 target_include_directories(spdlog ${SPDLOG_INCLUDES_LEVEL} PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>"
@@ -187,10 +194,17 @@ set_target_properties(spdlog PROPERTIES VERSION ${SPDLOG_VERSION} SOVERSION
         ${SPDLOG_VERSION_MAJOR}.${SPDLOG_VERSION_MINOR})
 set_target_properties(spdlog PROPERTIES DEBUG_POSTFIX d)
 
-if(COMMAND target_precompile_headers AND SPDLOG_ENABLE_PCH)
+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)
     target_precompile_headers(spdlog PRIVATE ${PROJECT_BINARY_DIR}/spdlog_pch.h)
-endif()
+endif ()
+
+# sanitizer support
+if (SPDLOG_SANITIZE_ADDRESS)
+    spdlog_enable_addr_sanitizer(spdlog)
+elseif (SPDLOG_SANITIZE_THREAD)
+    spdlog_enable_thread_sanitizer(spdlog)
+endif ()
 
 # ---------------------------------------------------------------------------------------
 # Header only version
@@ -206,40 +220,58 @@ target_link_libraries(spdlog_header_only INTERFACE Threads::Threads)
 # ---------------------------------------------------------------------------------------
 # Use fmt package if using external fmt
 # ---------------------------------------------------------------------------------------
-if(SPDLOG_FMT_EXTERNAL OR SPDLOG_FMT_EXTERNAL_HO)
-    if(NOT TARGET fmt::fmt)
+if (SPDLOG_FMT_EXTERNAL OR SPDLOG_FMT_EXTERNAL_HO)
+    if (NOT TARGET fmt::fmt)
         find_package(fmt CONFIG REQUIRED)
-    endif()
+    endif ()
     target_compile_definitions(spdlog PUBLIC SPDLOG_FMT_EXTERNAL)
     target_compile_definitions(spdlog_header_only INTERFACE SPDLOG_FMT_EXTERNAL)
 
-    # use external fmt-header-nly
-    if(SPDLOG_FMT_EXTERNAL_HO)
+    # use external fmt-header-only
+    if (SPDLOG_FMT_EXTERNAL_HO)
         target_link_libraries(spdlog PUBLIC fmt::fmt-header-only)
         target_link_libraries(spdlog_header_only INTERFACE fmt::fmt-header-only)
-    else() # use external compile fmt
+    else () # use external compile fmt
         target_link_libraries(spdlog PUBLIC fmt::fmt)
         target_link_libraries(spdlog_header_only INTERFACE fmt::fmt)
-    endif()
+    endif ()
 
     set(PKG_CONFIG_REQUIRES fmt) # add dependency to pkg-config
-endif()
+endif ()
+
+# ---------------------------------------------------------------------------------------
+# Check if fwrite_unlocked/_fwrite_nolock is available
+# ---------------------------------------------------------------------------------------
+if (SPDLOG_FWRITE_UNLOCKED)
+    include(CheckSymbolExists)
+    if (WIN32)
+        check_symbol_exists(_fwrite_nolock "stdio.h" HAVE_FWRITE_UNLOCKED)
+    else ()
+        check_symbol_exists(fwrite_unlocked "stdio.h" HAVE_FWRITE_UNLOCKED)
+    endif ()
+    if (HAVE_FWRITE_UNLOCKED)
+        target_compile_definitions(spdlog PRIVATE SPDLOG_FWRITE_UNLOCKED)
+        target_compile_definitions(spdlog_header_only INTERFACE SPDLOG_FWRITE_UNLOCKED)
+    endif ()
+endif ()
 
 # ---------------------------------------------------------------------------------------
 # Add required libraries for Android CMake build
 # ---------------------------------------------------------------------------------------
-if(ANDROID)
+if (ANDROID)
     target_link_libraries(spdlog PUBLIC log)
     target_link_libraries(spdlog_header_only INTERFACE log)
-endif()
+endif ()
 
 # ---------------------------------------------------------------------------------------
 # Misc definitions according to tweak options
 # ---------------------------------------------------------------------------------------
 set(SPDLOG_WCHAR_TO_UTF8_SUPPORT ${SPDLOG_WCHAR_SUPPORT})
-foreach(
+set(SPDLOG_UTF8_TO_WCHAR_CONSOLE ${SPDLOG_WCHAR_CONSOLE})
+foreach (
         SPDLOG_OPTION
         SPDLOG_WCHAR_TO_UTF8_SUPPORT
+        SPDLOG_UTF8_TO_WCHAR_CONSOLE
         SPDLOG_WCHAR_FILENAMES
         SPDLOG_NO_EXCEPTIONS
         SPDLOG_CLOCK_COARSE
@@ -249,52 +281,65 @@ foreach(
         SPDLOG_NO_ATOMIC_LEVELS
         SPDLOG_DISABLE_DEFAULT_LOGGER
         SPDLOG_USE_STD_FORMAT)
-    if(${SPDLOG_OPTION})
+    if (${SPDLOG_OPTION})
         target_compile_definitions(spdlog PUBLIC ${SPDLOG_OPTION})
         target_compile_definitions(spdlog_header_only INTERFACE ${SPDLOG_OPTION})
-    endif()
-endforeach()
+    endif ()
+endforeach ()
+
+if (MSVC)
+    target_compile_options(spdlog PRIVATE "/Zc:__cplusplus")
+    target_compile_options(spdlog_header_only INTERFACE "/Zc:__cplusplus")
+    if (SPDLOG_MSVC_UTF8)
+        # fmtlib requires the /utf-8 flag when building with msvc.
+        # see https://github.com/fmtlib/fmt/pull/4159 on the purpose of the additional
+        # "$<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>"
+        target_compile_options(spdlog PUBLIC $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>:/utf-8>)
+        target_compile_options(spdlog_header_only INTERFACE $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>:/utf-8>)
+    endif ()
+endif ()
 
 # ---------------------------------------------------------------------------------------
 # If exceptions are disabled, disable them in the bundled fmt as well
 # ---------------------------------------------------------------------------------------
-if(SPDLOG_NO_EXCEPTIONS)
-    if(NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
-        target_compile_definitions(spdlog PUBLIC FMT_EXCEPTIONS=0)
-    endif()
-    if(NOT MSVC)
+if (SPDLOG_NO_EXCEPTIONS)
+    if (NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
+        target_compile_definitions(spdlog PUBLIC FMT_USE_EXCEPTIONS=0)
+    endif ()
+    if (NOT MSVC)
         target_compile_options(spdlog PRIVATE -fno-exceptions)
-    else()
+    else ()
         target_compile_options(spdlog PRIVATE /EHs-c-)
-    endif()
-endif()
+        target_compile_definitions(spdlog PRIVATE _HAS_EXCEPTIONS=0)
+    endif ()
+endif ()
 # ---------------------------------------------------------------------------------------
 # Build binaries
 # ---------------------------------------------------------------------------------------
-if(SPDLOG_BUILD_EXAMPLE OR SPDLOG_BUILD_EXAMPLE_HO OR SPDLOG_BUILD_ALL)
+if (SPDLOG_BUILD_EXAMPLE OR SPDLOG_BUILD_EXAMPLE_HO OR SPDLOG_BUILD_ALL)
     message(STATUS "Generating example(s)")
     add_subdirectory(example)
     spdlog_enable_warnings(example)
-    if(SPDLOG_BUILD_EXAMPLE_HO)
+    if (SPDLOG_BUILD_EXAMPLE_HO)
         spdlog_enable_warnings(example_header_only)
-    endif()
-endif()
+    endif ()
+endif ()
 
-if(SPDLOG_BUILD_TESTS OR SPDLOG_BUILD_TESTS_HO OR SPDLOG_BUILD_ALL)
+if (SPDLOG_BUILD_TESTS OR SPDLOG_BUILD_TESTS_HO OR SPDLOG_BUILD_ALL)
     message(STATUS "Generating tests")
     enable_testing()
     add_subdirectory(tests)
-endif()
+endif ()
 
-if(SPDLOG_BUILD_BENCH OR SPDLOG_BUILD_ALL)
+if (SPDLOG_BUILD_BENCH OR SPDLOG_BUILD_ALL)
     message(STATUS "Generating benchmarks")
     add_subdirectory(bench)
-endif()
+endif ()
 
 # ---------------------------------------------------------------------------------------
 # Install
 # ---------------------------------------------------------------------------------------
-if(SPDLOG_INSTALL)
+if (SPDLOG_INSTALL)
     message(STATUS "Generating install")
     set(project_config_in "${CMAKE_CURRENT_LIST_DIR}/cmake/spdlogConfig.cmake.in")
     set(project_config_out "${CMAKE_CURRENT_BINARY_DIR}/spdlogConfig.cmake")
@@ -315,24 +360,24 @@ if(SPDLOG_INSTALL)
             ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
             RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 
-    if(NOT SPDLOG_USE_STD_FORMAT AND NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
+    if (NOT SPDLOG_USE_STD_FORMAT AND NOT SPDLOG_FMT_EXTERNAL AND NOT SPDLOG_FMT_EXTERNAL_HO)
         install(DIRECTORY include/${PROJECT_NAME}/fmt/bundled/
                 DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME}/fmt/bundled/")
-    endif()
+    endif ()
 
     # ---------------------------------------------------------------------------------------
     # Install pkg-config file
     # ---------------------------------------------------------------------------------------
-    if(IS_ABSOLUTE "${CMAKE_INSTALL_INCLUDEDIR}")
+    if (IS_ABSOLUTE "${CMAKE_INSTALL_INCLUDEDIR}")
         set(PKG_CONFIG_INCLUDEDIR "${CMAKE_INSTALL_INCLUDEDIR}")
-    else()
+    else ()
         set(PKG_CONFIG_INCLUDEDIR "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
-    endif()
-    if(IS_ABSOLUTE "${CMAKE_INSTALL_LIBDIR}")
+    endif ()
+    if (IS_ABSOLUTE "${CMAKE_INSTALL_LIBDIR}")
         set(PKG_CONFIG_LIBDIR "${CMAKE_INSTALL_LIBDIR}")
-    else()
+    else ()
         set(PKG_CONFIG_LIBDIR "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
-    endif()
+    endif ()
     get_target_property(PKG_CONFIG_DEFINES spdlog INTERFACE_COMPILE_DEFINITIONS)
     string(REPLACE ";" " -D" PKG_CONFIG_DEFINES "${PKG_CONFIG_DEFINES}")
     string(CONCAT PKG_CONFIG_DEFINES "-D" "${PKG_CONFIG_DEFINES}")
@@ -356,4 +401,4 @@ if(SPDLOG_INSTALL)
     # Support creation of installable packages
     # ---------------------------------------------------------------------------------------
     include(cmake/spdlogCPack.cmake)
-endif()
+endif ()

INSTALL

@@ -1,24 +1,27 @@
-Header only version:
+Header Only Version
 ==================================================================
 Just copy the files to your build tree and use a C++11 compiler.  
 Or use CMake:
+``` 
   add_executable(example_header_only example.cpp)
   target_link_libraries(example_header_only spdlog::spdlog_header_only)
+```
 
-
-Compiled library version:
+Compiled Library Version
 ==================================================================
 CMake:
+```  
   add_executable(example example.cpp)
   target_link_libraries(example spdlog::spdlog)
+```
 
 Or copy files src/*.cpp to your build tree and pass the -DSPDLOG_COMPILED_LIB to the compiler.
 
+Important Information for Compilation:
+==================================================================
+* If you encounter compilation errors with gcc 4.8.x, please note that gcc 4.8.x does not fully support C++11. In such cases, consider upgrading your compiler or using a different version that fully supports C++11 standards
+
 Tested on:  
 gcc 4.8.1 and above
 clang 3.5
 Visual Studio 2013
-
-
-
-

README.md

@@ -1,18 +1,25 @@
 # spdlog
 
-Very fast, header-only/compiled, C++ logging library. [![ci](https://github.com/gabime/spdlog/actions/workflows/ci.yml/badge.svg)](https://github.com/gabime/spdlog/actions/workflows/ci.yml)  [![Build status](https://ci.appveyor.com/api/projects/status/d2jnxclg20vd0o50?svg=true&branch=v1.x)](https://ci.appveyor.com/project/gabime/spdlog) [![Release](https://img.shields.io/github/release/gabime/spdlog.svg)](https://github.com/gabime/spdlog/releases/latest)
+ 
+[![ci](https://github.com/gabime/spdlog/actions/workflows/linux.yml/badge.svg)](https://github.com/gabime/spdlog/actions/workflows/linux.yml) 
+[![ci](https://github.com/gabime/spdlog/actions/workflows/windows.yml/badge.svg)](https://github.com/gabime/spdlog/actions/workflows/windows.yml) 
+[![ci](https://github.com/gabime/spdlog/actions/workflows/macos.yml/badge.svg)](https://github.com/gabime/spdlog/actions/workflows/macos.yml) 
+[![Build status](https://ci.appveyor.com/api/projects/status/d2jnxclg20vd0o50?svg=true&branch=v1.x)](https://ci.appveyor.com/project/gabime/spdlog) [![Release](https://img.shields.io/github/release/gabime/spdlog.svg)](https://github.com/gabime/spdlog/releases/latest)
+
+Fast C++ logging library
+
 
 ## Install
 #### Header-only version
-Copy the include [folder](https://github.com/gabime/spdlog/tree/v1.x/include/spdlog) to your build tree and use a C++11 compiler.
+Copy the include [folder](include/spdlog) to your build tree and use a C++11 compiler.
 
 #### Compiled version (recommended - much faster compile times)
 ```console
 $ git clone https://github.com/gabime/spdlog.git
 $ cd spdlog && mkdir build && cd build
-$ cmake .. && make -j
+$ cmake .. && cmake --build .
 ```
-see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/CMakeLists.txt) on how to use.
+see example [CMakeLists.txt](example/CMakeLists.txt) on how to use.
 
 ## Platforms
 * Linux, FreeBSD, OpenBSD, Solaris, AIX
@@ -29,8 +36,9 @@ see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/
 * Gentoo: `emerge dev-libs/spdlog`
 * Arch Linux: `pacman -S spdlog`
 * openSUSE: `sudo zypper in spdlog-devel`
+* ALT Linux: `apt-get install libspdlog-devel`
 * vcpkg: `vcpkg install spdlog`
-* conan: `spdlog/[>=1.4.1]`
+* conan: `conan install --requires=spdlog/[*]`
 * conda: `conda install -c conda-forge spdlog`
 * build2: ```depends: spdlog ^1.8.2```
 
@@ -40,7 +48,7 @@ see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/
 * Headers only or compiled
 * Feature-rich formatting, using the excellent [fmt](https://github.com/fmtlib/fmt) library.
 * Asynchronous mode (optional)
-* [Custom](https://github.com/gabime/spdlog/wiki/3.-Custom-formatting) formatting.
+* [Custom](https://github.com/gabime/spdlog/wiki/Custom-formatting) formatting.
 * Multi/Single threaded loggers.
 * Various log targets:
   * Rotating log files.
@@ -50,7 +58,7 @@ see example [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/
   * Windows event log.
   * Windows debugger (```OutputDebugString(..)```).
   * Log to Qt widgets ([example](#log-to-qt-with-nice-colors)).
-  * Easily [extendable](https://github.com/gabime/spdlog/wiki/4.-Sinks#implementing-your-own-sink) with custom log targets.
+  * Easily [extendable](https://github.com/gabime/spdlog/wiki/Sinks#implementing-your-own-sink) with custom log targets.
 * Log filtering - log levels can be modified at runtime as well as compile time.
 * Support for loading log levels from argv or environment var.
 * [Backtrace](#backtrace-support) support - store debug messages in a ring buffer and display them later on demand.
@@ -79,7 +87,8 @@ int main()
     spdlog::set_pattern("[%H:%M:%S %z] [%n] [%^---%L---%$] [thread %t] %v");
     
     // Compile time log levels
-    // define SPDLOG_ACTIVE_LEVEL to desired level
+    // Note that this does not change the current log level, it will only
+    // remove (depending on SPDLOG_ACTIVE_LEVEL) the call on the release code.
     SPDLOG_TRACE("Some trace message with param {}", 42);
     SPDLOG_DEBUG("Some debug message");
 }
@@ -272,6 +281,7 @@ void async_example()
 ---
 #### Asynchronous logger with multi sinks
 ```c++
+#include "spdlog/async.h"
 #include "spdlog/sinks/stdout_color_sinks.h"
 #include "spdlog/sinks/rotating_file_sink.h"
 
@@ -294,7 +304,7 @@ struct fmt::formatter<my_type> : fmt::formatter<std::string>
 {
     auto format(my_type my, format_context &ctx) const -> decltype(ctx.out())
     {
-        return format_to(ctx.out(), "[my_type i={}]", my.i);
+        return fmt::format_to(ctx.out(), "[my_type i={}]", my.i);
     }
 };
 
@@ -378,6 +388,9 @@ void android_example()
 int main (int argc, char *argv[])
 {
     spdlog::cfg::load_env_levels();
+    // or specify the env variable name:
+    // MYAPP_LEVEL=info,mylogger=trace && ./example
+    // spdlog::cfg::load_env_levels("MYAPP_LEVEL");
     // or from the command line:
     // ./example SPDLOG_LEVEL=info,mylogger=trace
     // #include "spdlog/cfg/argv.h" // for loading levels from argv
@@ -435,11 +448,26 @@ MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
     logger->info("Some info message");
 }
 ```
+---
 
+#### Mapped Diagnostic Context
+```c++
+// Mapped Diagnostic Context (MDC) is a map that stores key-value pairs (string values) in thread local storage.
+// Each thread maintains its own MDC, which loggers use to append diagnostic information to log outputs.
+// Note: it is not supported in asynchronous mode due to its reliance on thread-local storage.
+#include "spdlog/mdc.h"
+void mdc_example()
+{
+    spdlog::mdc::put("key1", "value1");
+    spdlog::mdc::put("key2", "value2");
+    // if not using the default format, use the %& formatter to print mdc data
+    // spdlog::set_pattern("[%H:%M:%S %z] [%^%L%$] [%&] %v");
+}
+```
 ---
 ## Benchmarks
 
-Below are some [benchmarks](https://github.com/gabime/spdlog/blob/v1.x/bench/bench.cpp) done in Ubuntu 64 bit, Intel i7-4770 CPU @ 3.40GHz
+Below are some [benchmarks](bench/bench.cpp) done in Ubuntu 64 bit, Intel i7-4770 CPU @ 3.40GHz
 
 #### Synchronous mode
 ```
@@ -491,7 +519,8 @@ Below are some [benchmarks](https://github.com/gabime/spdlog/blob/v1.x/bench/ben
 ```
 
 ## Documentation
-Documentation can be found in the [wiki](https://github.com/gabime/spdlog/wiki/1.-QuickStart) pages.
+
+Documentation can be found in the [wiki](https://github.com/gabime/spdlog/wiki) pages.
 
 ---
 

bench/async_bench.cpp

@@ -160,7 +160,7 @@ void bench_mt(int howmany, std::shared_ptr<spdlog::logger> logger, int thread_co
 
     for (auto &t : threads) {
         t.join();
-    };
+    }
 
     auto delta = high_resolution_clock::now() - start;
     auto delta_d = duration_cast<duration<double>>(delta).count();

bench/bench.cpp

@@ -181,7 +181,7 @@ void bench_mt(int howmany, std::shared_ptr<spdlog::logger> log, size_t thread_co
 
     for (auto &t : threads) {
         t.join();
-    };
+    }
 
     auto delta = high_resolution_clock::now() - start;
     auto delta_d = duration_cast<duration<double>>(delta).count();

bench/latency.cpp

@@ -121,7 +121,7 @@ int main(int argc, char *argv[]) {
     tracing_null_logger_st->enable_backtrace(64);
     benchmark::RegisterBenchmark("null_sink_st/backtrace", bench_logger, tracing_null_logger_st);
 
-#ifdef __linux
+#ifdef __linux__
     bench_dev_null();
 #endif  // __linux__
 

cmake/utils.cmake

@@ -49,7 +49,7 @@ function(spdlog_enable_warnings target_name)
 endfunction()
 
 # Enable address sanitizer (gcc/clang only)
-function(spdlog_enable_sanitizer target_name)
+function(spdlog_enable_addr_sanitizer target_name)
     if(NOT CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
         message(FATAL_ERROR "Sanitizer supported only for gcc/clang")
     endif()
@@ -58,5 +58,16 @@ function(spdlog_enable_sanitizer target_name)
     target_compile_options(${target_name} PRIVATE -fno-sanitize=signed-integer-overflow)
     target_compile_options(${target_name} PRIVATE -fno-sanitize-recover=all)
     target_compile_options(${target_name} PRIVATE -fno-omit-frame-pointer)
-    target_link_libraries(${target_name} PRIVATE -fsanitize=address,undefined -fuse-ld=gold)
+    target_link_libraries(${target_name} PRIVATE -fsanitize=address,undefined)
+endfunction()
+
+# Enable thread sanitizer (gcc/clang only)
+function(spdlog_enable_thread_sanitizer target_name)
+    if(NOT CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
+        message(FATAL_ERROR "Sanitizer supported only for gcc/clang")
+    endif()
+    message(STATUS "Thread sanitizer enabled")
+    target_compile_options(${target_name} PRIVATE -fsanitize=thread)
+    target_compile_options(${target_name} PRIVATE -fno-omit-frame-pointer)
+    target_link_libraries(${target_name} PRIVATE -fsanitize=thread)
 endfunction()

example/example.cpp

@@ -26,6 +26,7 @@ void udp_example();
 void custom_flags_example();
 void file_events_example();
 void replace_default_logger_example();
+void mdc_example();
 
 #include "spdlog/spdlog.h"
 #include "spdlog/cfg/env.h"   // support for loading levels from the environment variable
@@ -84,6 +85,7 @@ int main(int, char *[]) {
         custom_flags_example();
         file_events_example();
         replace_default_logger_example();
+        mdc_example();
 
         // Flush all *registered* loggers using a worker thread every 3 seconds.
         // note: registered loggers *must* be thread safe for this to work correctly!
@@ -146,6 +148,9 @@ void load_levels_example() {
     // Set the log level to "info" and mylogger to "trace":
     // SPDLOG_LEVEL=info,mylogger=trace && ./example
     spdlog::cfg::load_env_levels();
+    // or specify the env variable name:
+    // MYAPP_LEVEL=info,mylogger=trace && ./example
+    // spdlog::cfg::load_env_levels("MYAPP_LEVEL");
     // or from command line:
     // ./example SPDLOG_LEVEL=info,mylogger=trace
     // #include "spdlog/cfg/argv.h" // for loading levels from argv
@@ -264,13 +269,13 @@ void multi_sink_example() {
 struct my_type {
     int i = 0;
     explicit my_type(int i)
-        : i(i){};
+        : i(i){}
 };
 
 #ifndef SPDLOG_USE_STD_FORMAT  // when using fmtlib
 template <>
 struct fmt::formatter<my_type> : fmt::formatter<std::string> {
-    auto format(my_type my, format_context &ctx) -> decltype(ctx.out()) {
+    auto format(my_type my, format_context &ctx) const -> decltype(ctx.out()) {
         return fmt::format_to(ctx.out(), "[my_type i={}]", my.i);
     }
 };
@@ -279,7 +284,7 @@ struct fmt::formatter<my_type> : fmt::formatter<std::string> {
 template <>
 struct std::formatter<my_type> : std::formatter<std::string> {
     auto format(my_type my, format_context &ctx) const -> decltype(ctx.out()) {
-        return format_to(ctx.out(), "[my_type i={}]", my.i);
+        return std::format_to(ctx.out(), "[my_type i={}]", my.i);
     }
 };
 #endif
@@ -376,3 +381,23 @@ void replace_default_logger_example() {
 
     spdlog::set_default_logger(old_logger);
 }
+
+// Mapped Diagnostic Context (MDC) is a map that stores key-value pairs (string values) in thread local storage.
+// Each thread maintains its own MDC, which loggers use to append diagnostic information to log outputs.
+// Note: it is not supported in asynchronous mode due to its reliance on thread-local storage.
+
+#ifndef SPDLOG_NO_TLS
+    #include "spdlog/mdc.h"
+void mdc_example()
+{
+    spdlog::mdc::put("key1", "value1");
+    spdlog::mdc::put("key2", "value2");
+    // if not using the default format, you can use the %& formatter to print mdc data as well
+    spdlog::set_pattern("[%H:%M:%S %z] [%^%L%$] [%&] %v");
+    spdlog::info("Some log message with context");
+}
+#else
+void mdc_example() {
+    // if TLS feature is disabled
+}
+#endif

include/spdlog/cfg/env.h

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

include/spdlog/common.h

@@ -319,7 +319,7 @@ struct source_loc {
           line{line_in},
           funcname{funcname_in} {}
 
-    SPDLOG_CONSTEXPR bool empty() const SPDLOG_NOEXCEPT { return line == 0; }
+    SPDLOG_CONSTEXPR bool empty() const SPDLOG_NOEXCEPT { return line <= 0; }
     const char *filename{nullptr};
     int line{0};
     const char *funcname{nullptr};
@@ -364,12 +364,7 @@ SPDLOG_CONSTEXPR_FUNC spdlog::wstring_view_t to_string_view(spdlog::wstring_view
 }
 #endif
 
-#ifndef SPDLOG_USE_STD_FORMAT
-template <typename T, typename... Args>
-inline fmt::basic_string_view<T> to_string_view(fmt::basic_format_string<T, Args...> fmt) {
-    return fmt;
-}
-#elif __cpp_lib_format >= 202207L
+#if defined(SPDLOG_USE_STD_FORMAT) &&  __cpp_lib_format >= 202207L
 template <typename T, typename... Args>
 SPDLOG_CONSTEXPR_FUNC std::basic_string_view<T> to_string_view(
     std::basic_format_string<T, Args...> fmt) SPDLOG_NOEXCEPT {

include/spdlog/details/circular_q.h

@@ -7,6 +7,8 @@
 #include <cassert>
 #include <vector>
 
+#include "spdlog/common.h"
+
 namespace spdlog {
 namespace details {
 template <typename T>

include/spdlog/details/file_helper-inl.h

@@ -98,10 +98,11 @@ SPDLOG_INLINE void file_helper::close() {
 }
 
 SPDLOG_INLINE void file_helper::write(const memory_buf_t &buf) {
-    if(fd_ == nullptr) return;
+    if (fd_ == nullptr) return;
     size_t msg_size = buf.size();
     auto data = buf.data();
-    if (std::fwrite(data, 1, msg_size, fd_) != msg_size) {
+
+    if (!details::os::fwrite_bytes(data, msg_size, fd_)) {
         throw_spdlog_ex("Failed writing to file " + os::filename_to_str(filename_), errno);
     }
 }

include/spdlog/details/mpmc_blocking_q.h

@@ -148,19 +148,19 @@ public:
 #endif
 
     size_t overrun_counter() {
-        std::unique_lock<std::mutex> lock(queue_mutex_);
+        std::lock_guard<std::mutex> lock(queue_mutex_);
         return q_.overrun_counter();
     }
 
     size_t discard_counter() { return discard_counter_.load(std::memory_order_relaxed); }
 
     size_t size() {
-        std::unique_lock<std::mutex> lock(queue_mutex_);
+        std::lock_guard<std::mutex> lock(queue_mutex_);
         return q_.size();
     }
 
     void reset_overrun_counter() {
-        std::unique_lock<std::mutex> lock(queue_mutex_);
+        std::lock_guard<std::mutex> lock(queue_mutex_);
         q_.reset_overrun_counter();
     }
 

include/spdlog/details/os-inl.h

@@ -177,12 +177,12 @@ SPDLOG_INLINE int rename(const filename_t &filename1, const filename_t &filename
 // Return true if path exists (file or directory)
 SPDLOG_INLINE bool path_exists(const filename_t &filename) SPDLOG_NOEXCEPT {
 #ifdef _WIN32
+    struct _stat buffer;
     #ifdef SPDLOG_WCHAR_FILENAMES
-    auto attribs = ::GetFileAttributesW(filename.c_str());
+    return (::_wstat(filename.c_str(), &buffer) == 0);
     #else
-    auto attribs = ::GetFileAttributesA(filename.c_str());
+    return (::_stat(filename.c_str(), &buffer) == 0);
     #endif
-    return attribs != INVALID_FILE_ATTRIBUTES;
 #else  // common linux/unix all have the stat system call
     struct stat buffer;
     return (::stat(filename.c_str(), &buffer) == 0);
@@ -267,7 +267,8 @@ SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm) {
 
     #if defined(sun) || defined(__sun) || defined(_AIX) || \
         (defined(__NEWLIB__) && !defined(__TM_GMTOFF)) ||  \
-        (!defined(_BSD_SOURCE) && !defined(_GNU_SOURCE))
+        (!defined(__APPLE__) && !defined(_BSD_SOURCE) && !defined(_GNU_SOURCE) && \
+            (!defined(_POSIX_VERSION) || (_POSIX_VERSION < 202405L)))
     // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
     struct helper {
         static long int calculate_gmt_offset(const std::tm &localtm = details::os::localtime(),
@@ -439,7 +440,7 @@ SPDLOG_INLINE bool in_terminal(FILE *file) SPDLOG_NOEXCEPT {
 
 #if (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
 SPDLOG_INLINE void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target) {
-    if (wstr.size() > static_cast<size_t>((std::numeric_limits<int>::max)()) / 2 - 1) {
+    if (wstr.size() > static_cast<size_t>((std::numeric_limits<int>::max)()) / 4 - 1) {
         throw_spdlog_ex("UTF-16 string is too big to be converted to UTF-8");
     }
 
@@ -450,7 +451,7 @@ SPDLOG_INLINE void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target) {
     }
 
     int result_size = static_cast<int>(target.capacity());
-    if ((wstr_size + 1) * 2 > result_size) {
+    if ((wstr_size + 1) * 4 > result_size) {
         result_size =
             ::WideCharToMultiByte(CP_UTF8, 0, wstr.data(), wstr_size, NULL, 0, NULL, NULL);
     }
@@ -483,12 +484,12 @@ SPDLOG_INLINE void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target) {
 
     // find the size to allocate for the result buffer
     int result_size =
-        ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str.data(), str_size, NULL, 0);
+        ::MultiByteToWideChar(CP_UTF8, 0, str.data(), str_size, NULL, 0);
 
     if (result_size > 0) {
         target.resize(result_size);
-        result_size = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str.data(), str_size,
-                                            target.data(), result_size);
+        result_size = ::MultiByteToWideChar(CP_UTF8, 0, str.data(), str_size, target.data(),
+                                            result_size);
         if (result_size > 0) {
             assert(result_size == target.size());
             return;
@@ -534,6 +535,15 @@ SPDLOG_INLINE bool create_dir(const filename_t &path) {
         }
 
         auto subdir = path.substr(0, token_pos);
+#ifdef _WIN32
+        // if subdir is just a drive letter, add a slash e.g. "c:"=>"c:\",
+        // otherwise path_exists(subdir) returns false (issue #3079)
+        const bool is_drive = subdir.length() == 2 && subdir[1] == ':';
+        if (is_drive) {
+            subdir += '\\';
+            token_pos++;
+        }
+#endif
 
         if (!subdir.empty() && !path_exists(subdir) && !mkdir_(subdir)) {
             return false;  // return error if failed creating dir
@@ -580,6 +590,18 @@ SPDLOG_INLINE bool fsync(FILE *fp) {
 #endif
 }
 
+// Do non-locking fwrite if possible by the os or use the regular locking fwrite
+// Return true on success.
+SPDLOG_INLINE bool fwrite_bytes(const void *ptr, const size_t n_bytes, FILE *fp) {
+    #if defined(_WIN32) && defined(SPDLOG_FWRITE_UNLOCKED)
+    return _fwrite_nolock(ptr, 1, n_bytes, fp) == n_bytes;
+    #elif defined(SPDLOG_FWRITE_UNLOCKED)
+    return ::fwrite_unlocked(ptr, 1, n_bytes, fp) == n_bytes;
+    #else
+    return std::fwrite(ptr, 1, n_bytes, fp) == n_bytes;
+    #endif
+}
+
 }  // namespace os
 }  // namespace details
 }  // namespace spdlog

include/spdlog/details/os.h

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

include/spdlog/details/periodic_worker.h

@@ -38,6 +38,7 @@ public:
             }
         });
     }
+    std::thread &get_thread() { return worker_thread_; }
     periodic_worker(const periodic_worker &) = delete;
     periodic_worker &operator=(const periodic_worker &) = delete;
     // stop the worker thread and join it

include/spdlog/details/registry-inl.h

@@ -99,10 +99,6 @@ SPDLOG_INLINE logger *registry::get_default_raw() { return default_logger_.get()
 // 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_);
-    // remove previous default logger from the map
-    if (default_logger_ != nullptr) {
-        loggers_.erase(default_logger_->name());
-    }
     if (new_default_logger != nullptr) {
         loggers_[new_default_logger->name()] = new_default_logger;
     }

include/spdlog/details/registry.h

@@ -42,8 +42,10 @@ public:
     // another.
     logger *get_default_raw();
 
-    // set default logger.
+    // set default logger and add it to the registry if not registered already.
     // default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
+    // Note: Make sure to unregister it when no longer needed or before calling again with a new
+    // logger.
     void set_default_logger(std::shared_ptr<logger> new_default_logger);
 
     void set_tp(std::shared_ptr<thread_pool> tp);
@@ -68,6 +70,11 @@ public:
         periodic_flusher_ = details::make_unique<periodic_worker>(clbk, interval);
     }
 
+    std::unique_ptr<periodic_worker> &get_flusher() {
+        std::lock_guard<std::mutex> lock(flusher_mutex_);
+        return periodic_flusher_;
+    }
+
     void set_error_handler(err_handler handler);
 
     void apply_all(const std::function<void(const std::shared_ptr<logger>)> &fun);

include/spdlog/fmt/bin_to_hex.h

@@ -102,7 +102,7 @@ namespace
 
 template <typename T>
 struct formatter<spdlog::details::dump_info<T>, char> {
-    const char delimiter = ' ';
+    char delimiter = ' ';
     bool put_newlines = true;
     bool put_delimiters = true;
     bool use_uppercase = false;

include/spdlog/fmt/bundled/args.h

@@ -1,4 +1,4 @@
-// Formatting library for C++ - dynamic format arguments
+// Formatting library for C++ - dynamic argument lists
 //
 // Copyright (c) 2012 - present, Victor Zverovich
 // All rights reserved.
@@ -8,34 +8,39 @@
 #ifndef FMT_ARGS_H_
 #define FMT_ARGS_H_
 
-#include <functional>  // std::reference_wrapper
-#include <memory>      // std::unique_ptr
-#include <vector>
+#ifndef FMT_MODULE
+#  include <functional>  // std::reference_wrapper
+#  include <memory>      // std::unique_ptr
+#  include <vector>
+#endif
 
-#include "core.h"
+#include "format.h"  // std_string_view
 
 FMT_BEGIN_NAMESPACE
-
 namespace detail {
 
 template <typename T> struct is_reference_wrapper : std::false_type {};
 template <typename T>
 struct is_reference_wrapper<std::reference_wrapper<T>> : std::true_type {};
 
-template <typename T> const T& unwrap(const T& v) { return v; }
-template <typename T> const T& unwrap(const std::reference_wrapper<T>& v) {
+template <typename T> auto unwrap(const T& v) -> const T& { return v; }
+template <typename T>
+auto unwrap(const std::reference_wrapper<T>& v) -> const T& {
   return static_cast<const T&>(v);
 }
 
-class dynamic_arg_list {
-  // Workaround for clang's -Wweak-vtables. Unlike for regular classes, for
-  // templates it doesn't complain about inability to deduce single translation
-  // unit for placing vtable. So storage_node_base is made a fake template.
-  template <typename = void> struct node {
+// node is defined outside dynamic_arg_list to workaround a C2504 bug in MSVC
+// 2022 (v17.10.0).
+//
+// Workaround for clang's -Wweak-vtables. Unlike for regular classes, for
+// templates it doesn't complain about inability to deduce single translation
+// unit for placing vtable. So node is made a fake template.
+template <typename = void> struct node {
   virtual ~node() = default;
   std::unique_ptr<node<>> next;
-  };
+};
 
+class dynamic_arg_list {
   template <typename T> struct typed_node : node<> {
     T value;
 
@@ -50,7 +55,7 @@ class dynamic_arg_list {
   std::unique_ptr<node<>> head_;
 
  public:
-  template <typename T, typename Arg> const T& push(const Arg& arg) {
+  template <typename T, typename Arg> auto push(const Arg& arg) -> const T& {
     auto new_node = std::unique_ptr<typed_node<T>>(new typed_node<T>(arg));
     auto& value = new_node->value;
     new_node->next = std::move(head_);
@@ -61,28 +66,18 @@ class dynamic_arg_list {
 }  // namespace detail
 
 /**
-  \rst
-  A dynamic version of `fmt::format_arg_store`.
-  It's equipped with a storage to potentially temporary objects which lifetimes
-  could be shorter than the format arguments object.
-
-  It can be implicitly converted into `~fmt::basic_format_args` for passing
-  into type-erased formatting functions such as `~fmt::vformat`.
-  \endrst
+ * A dynamic list of formatting arguments with storage.
+ *
+ * It can be implicitly converted into `fmt::basic_format_args` for passing
+ * into type-erased formatting functions such as `fmt::vformat`.
  */
-template <typename Context>
-class dynamic_format_arg_store
-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
-    // Workaround a GCC template argument substitution bug.
-    : public basic_format_args<Context>
-#endif
-{
+template <typename Context> class dynamic_format_arg_store {
  private:
   using char_type = typename Context::char_type;
 
   template <typename T> struct need_copy {
     static constexpr detail::type mapped_type =
-        detail::mapped_type_constant<T, Context>::value;
+        detail::mapped_type_constant<T, char_type>::value;
 
     enum {
       value = !(detail::is_reference_wrapper<T>::value ||
@@ -95,7 +90,7 @@ class dynamic_format_arg_store
   };
 
   template <typename T>
-  using stored_type = conditional_t<
+  using stored_t = conditional_t<
       std::is_convertible<T, std::basic_string<char_type>>::value &&
           !detail::is_reference_wrapper<T>::value,
       std::basic_string<char_type>, T>;
@@ -110,79 +105,71 @@ class dynamic_format_arg_store
 
   friend class basic_format_args<Context>;
 
-  unsigned long long get_types() const {
-    return detail::is_unpacked_bit | data_.size() |
-           (named_info_.empty()
-                ? 0ULL
-                : static_cast<unsigned long long>(detail::has_named_args_bit));
-  }
-
-  const basic_format_arg<Context>* data() const {
+  auto data() const -> const basic_format_arg<Context>* {
     return named_info_.empty() ? data_.data() : data_.data() + 1;
   }
 
   template <typename T> void emplace_arg(const T& arg) {
-    data_.emplace_back(detail::make_arg<Context>(arg));
+    data_.emplace_back(arg);
   }
 
   template <typename T>
   void emplace_arg(const detail::named_arg<char_type, T>& arg) {
-    if (named_info_.empty()) {
-      constexpr const detail::named_arg_info<char_type>* zero_ptr{nullptr};
-      data_.insert(data_.begin(), {zero_ptr, 0});
-    }
-    data_.emplace_back(detail::make_arg<Context>(detail::unwrap(arg.value)));
+    if (named_info_.empty())
+      data_.insert(data_.begin(), basic_format_arg<Context>(nullptr, 0));
+    data_.emplace_back(detail::unwrap(arg.value));
     auto pop_one = [](std::vector<basic_format_arg<Context>>* data) {
       data->pop_back();
     };
     std::unique_ptr<std::vector<basic_format_arg<Context>>, decltype(pop_one)>
         guard{&data_, pop_one};
     named_info_.push_back({arg.name, static_cast<int>(data_.size() - 2u)});
-    data_[0].value_.named_args = {named_info_.data(), named_info_.size()};
+    data_[0] = {named_info_.data(), named_info_.size()};
     guard.release();
   }
 
  public:
   constexpr dynamic_format_arg_store() = default;
 
+  operator basic_format_args<Context>() const {
+    return basic_format_args<Context>(data(), static_cast<int>(data_.size()),
+                                      !named_info_.empty());
+  }
+
   /**
-    \rst
-    Adds an argument into the dynamic store for later passing to a formatting
-    function.
-
-    Note that custom types and string types (but not string views) are copied
-    into the store dynamically allocating memory if necessary.
-
-    **Example**::
-
-      fmt::dynamic_format_arg_store<fmt::format_context> store;
-      store.push_back(42);
-      store.push_back("abc");
-      store.push_back(1.5f);
-      std::string result = fmt::vformat("{} and {} and {}", store);
-    \endrst
+   * Adds an argument into the dynamic store for later passing to a formatting
+   * function.
+   *
+   * Note that custom types and string types (but not string views) are copied
+   * into the store dynamically allocating memory if necessary.
+   *
+   * **Example**:
+   *
+   *     fmt::dynamic_format_arg_store<fmt::format_context> store;
+   *     store.push_back(42);
+   *     store.push_back("abc");
+   *     store.push_back(1.5f);
+   *     std::string result = fmt::vformat("{} and {} and {}", store);
    */
   template <typename T> void push_back(const T& arg) {
     if (detail::const_check(need_copy<T>::value))
-      emplace_arg(dynamic_args_.push<stored_type<T>>(arg));
+      emplace_arg(dynamic_args_.push<stored_t<T>>(arg));
     else
       emplace_arg(detail::unwrap(arg));
   }
 
   /**
-    \rst
-    Adds a reference to the argument into the dynamic store for later passing to
-    a formatting function.
-
-    **Example**::
-
-      fmt::dynamic_format_arg_store<fmt::format_context> store;
-      char band[] = "Rolling Stones";
-      store.push_back(std::cref(band));
-      band[9] = 'c'; // Changing str affects the output.
-      std::string result = fmt::vformat("{}", store);
-      // result == "Rolling Scones"
-    \endrst
+   * Adds a reference to the argument into the dynamic store for later passing
+   * to a formatting function.
+   *
+   * **Example**:
+   *
+   *     fmt::dynamic_format_arg_store<fmt::format_context> store;
+   *     char band[] = "Rolling Stones";
+   *     store.push_back(std::cref(band));
+   *     band[9] = 'c'; // Changing str affects the output.
+   *     std::string result = fmt::vformat("{}", store);
+   *     // result == "Rolling Scones"
    */
   template <typename T> void push_back(std::reference_wrapper<T> arg) {
     static_assert(
@@ -192,9 +179,9 @@ class dynamic_format_arg_store
   }
 
   /**
-    Adds named argument into the dynamic store for later passing to a formatting
-    function. ``std::reference_wrapper`` is supported to avoid copying of the
-    argument. The name is always copied into the store.
+   * Adds named argument into the dynamic store for later passing to a
+   * formatting function. `std::reference_wrapper` is supported to avoid
+   * copying of the argument. The name is always copied into the store.
    */
   template <typename T>
   void push_back(const detail::named_arg<char_type, T>& arg) {
@@ -202,31 +189,30 @@ class dynamic_format_arg_store
         dynamic_args_.push<std::basic_string<char_type>>(arg.name).c_str();
     if (detail::const_check(need_copy<T>::value)) {
       emplace_arg(
-          fmt::arg(arg_name, dynamic_args_.push<stored_type<T>>(arg.value)));
+          fmt::arg(arg_name, dynamic_args_.push<stored_t<T>>(arg.value)));
     } else {
       emplace_arg(fmt::arg(arg_name, arg.value));
     }
   }
 
-  /** Erase all elements from the store */
+  /// Erase all elements from the store.
   void clear() {
     data_.clear();
     named_info_.clear();
-    dynamic_args_ = detail::dynamic_arg_list();
+    dynamic_args_ = {};
   }
 
-  /**
-    \rst
-    Reserves space to store at least *new_cap* arguments including
-    *new_cap_named* named arguments.
-    \endrst
-  */
+  /// Reserves space to store at least `new_cap` arguments including
+  /// `new_cap_named` named arguments.
   void reserve(size_t new_cap, size_t new_cap_named) {
     FMT_ASSERT(new_cap >= new_cap_named,
-               "Set of arguments includes set of named arguments");
+               "set of arguments includes set of named arguments");
     data_.reserve(new_cap);
     named_info_.reserve(new_cap_named);
   }
+
+  /// Returns the number of elements in the store.
+  size_t size() const noexcept { return data_.size(); }
 };
 
 FMT_END_NAMESPACE

include/spdlog/fmt/bundled/color.h

@@ -11,7 +11,7 @@
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 enum class color : uint32_t {
   alice_blue = 0xF0F8FF,               // rgb(240,248,255)
@@ -203,7 +203,7 @@ struct rgb {
   uint8_t b;
 };
 
-FMT_BEGIN_DETAIL_NAMESPACE
+namespace detail {
 
 // color is a struct of either a rgb color or a terminal color.
 struct color_type {
@@ -225,22 +225,21 @@ struct color_type {
     uint32_t rgb_color;
   } value;
 };
+}  // namespace detail
 
-FMT_END_DETAIL_NAMESPACE
-
-/** A text style consisting of foreground and background colors and emphasis. */
+/// A text style consisting of foreground and background colors and emphasis.
 class text_style {
  public:
   FMT_CONSTEXPR text_style(emphasis em = emphasis()) noexcept
       : set_foreground_color(), set_background_color(), ems(em) {}
 
-  FMT_CONSTEXPR text_style& operator|=(const text_style& rhs) {
+  FMT_CONSTEXPR auto operator|=(const text_style& rhs) -> text_style& {
     if (!set_foreground_color) {
       set_foreground_color = rhs.set_foreground_color;
       foreground_color = rhs.foreground_color;
     } else if (rhs.set_foreground_color) {
       if (!foreground_color.is_rgb || !rhs.foreground_color.is_rgb)
-        FMT_THROW(format_error("can't OR a terminal color"));
+        report_error("can't OR a terminal color");
       foreground_color.value.rgb_color |= rhs.foreground_color.value.rgb_color;
     }
 
@@ -249,7 +248,7 @@ class text_style {
       background_color = rhs.background_color;
     } else if (rhs.set_background_color) {
       if (!background_color.is_rgb || !rhs.background_color.is_rgb)
-        FMT_THROW(format_error("can't OR a terminal color"));
+        report_error("can't OR a terminal color");
       background_color.value.rgb_color |= rhs.background_color.value.rgb_color;
     }
 
@@ -258,29 +257,29 @@ class text_style {
     return *this;
   }
 
-  friend FMT_CONSTEXPR text_style operator|(text_style lhs,
-                                            const text_style& rhs) {
+  friend FMT_CONSTEXPR auto operator|(text_style lhs, const text_style& rhs)
+      -> text_style {
     return lhs |= rhs;
   }
 
-  FMT_CONSTEXPR bool has_foreground() const noexcept {
+  FMT_CONSTEXPR auto has_foreground() const noexcept -> bool {
     return set_foreground_color;
   }
-  FMT_CONSTEXPR bool has_background() const noexcept {
+  FMT_CONSTEXPR auto has_background() const noexcept -> bool {
     return set_background_color;
   }
-  FMT_CONSTEXPR bool has_emphasis() const noexcept {
+  FMT_CONSTEXPR auto has_emphasis() const noexcept -> bool {
     return static_cast<uint8_t>(ems) != 0;
   }
-  FMT_CONSTEXPR detail::color_type get_foreground() const noexcept {
+  FMT_CONSTEXPR auto get_foreground() const noexcept -> detail::color_type {
     FMT_ASSERT(has_foreground(), "no foreground specified for this style");
     return foreground_color;
   }
-  FMT_CONSTEXPR detail::color_type get_background() const noexcept {
+  FMT_CONSTEXPR auto get_background() const noexcept -> detail::color_type {
     FMT_ASSERT(has_background(), "no background specified for this style");
     return background_color;
   }
-  FMT_CONSTEXPR emphasis get_emphasis() const noexcept {
+  FMT_CONSTEXPR auto get_emphasis() const noexcept -> emphasis {
     FMT_ASSERT(has_emphasis(), "no emphasis specified for this style");
     return ems;
   }
@@ -298,9 +297,11 @@ class text_style {
     }
   }
 
-  friend FMT_CONSTEXPR text_style fg(detail::color_type foreground) noexcept;
+  friend FMT_CONSTEXPR auto fg(detail::color_type foreground) noexcept
+      -> text_style;
 
-  friend FMT_CONSTEXPR text_style bg(detail::color_type background) noexcept;
+  friend FMT_CONSTEXPR auto bg(detail::color_type background) noexcept
+      -> text_style;
 
   detail::color_type foreground_color;
   detail::color_type background_color;
@@ -309,24 +310,27 @@ class text_style {
   emphasis ems;
 };
 
-/** Creates a text style from the foreground (text) color. */
-FMT_CONSTEXPR inline text_style fg(detail::color_type foreground) noexcept {
+/// Creates a text style from the foreground (text) color.
+FMT_CONSTEXPR inline auto fg(detail::color_type foreground) noexcept
+    -> text_style {
   return text_style(true, foreground);
 }
 
-/** Creates a text style from the background color. */
-FMT_CONSTEXPR inline text_style bg(detail::color_type background) noexcept {
+/// Creates a text style from the background color.
+FMT_CONSTEXPR inline auto bg(detail::color_type background) noexcept
+    -> text_style {
   return text_style(false, background);
 }
 
-FMT_CONSTEXPR inline text_style operator|(emphasis lhs, emphasis rhs) noexcept {
+FMT_CONSTEXPR inline auto operator|(emphasis lhs, emphasis rhs) noexcept
+    -> text_style {
   return text_style(lhs) | rhs;
 }
 
-FMT_BEGIN_DETAIL_NAMESPACE
+namespace detail {
 
 template <typename Char> struct ansi_color_escape {
-  FMT_CONSTEXPR ansi_color_escape(detail::color_type text_color,
+  FMT_CONSTEXPR ansi_color_escape(color_type text_color,
                                   const char* esc) noexcept {
     // If we have a terminal color, we need to output another escape code
     // sequence.
@@ -385,9 +389,9 @@ template <typename Char> struct ansi_color_escape {
   }
   FMT_CONSTEXPR operator const Char*() const noexcept { return buffer; }
 
-  FMT_CONSTEXPR const Char* begin() const noexcept { return buffer; }
-  FMT_CONSTEXPR_CHAR_TRAITS const Char* end() const noexcept {
-    return buffer + std::char_traits<Char>::length(buffer);
+  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();
   }
 
  private:
@@ -401,194 +405,152 @@ template <typename Char> struct ansi_color_escape {
     out[2] = static_cast<Char>('0' + c % 10);
     out[3] = static_cast<Char>(delimiter);
   }
-  static FMT_CONSTEXPR bool has_emphasis(emphasis em, emphasis mask) noexcept {
+  static FMT_CONSTEXPR auto has_emphasis(emphasis em, emphasis mask) noexcept
+      -> bool {
     return static_cast<uint8_t>(em) & static_cast<uint8_t>(mask);
   }
 };
 
 template <typename Char>
-FMT_CONSTEXPR ansi_color_escape<Char> make_foreground_color(
-    detail::color_type foreground) noexcept {
+FMT_CONSTEXPR auto make_foreground_color(color_type foreground) noexcept
+    -> ansi_color_escape<Char> {
   return ansi_color_escape<Char>(foreground, "\x1b[38;2;");
 }
 
 template <typename Char>
-FMT_CONSTEXPR ansi_color_escape<Char> make_background_color(
-    detail::color_type background) noexcept {
+FMT_CONSTEXPR auto make_background_color(color_type background) noexcept
+    -> ansi_color_escape<Char> {
   return ansi_color_escape<Char>(background, "\x1b[48;2;");
 }
 
 template <typename Char>
-FMT_CONSTEXPR ansi_color_escape<Char> make_emphasis(emphasis em) noexcept {
+FMT_CONSTEXPR auto make_emphasis(emphasis em) noexcept
+    -> ansi_color_escape<Char> {
   return ansi_color_escape<Char>(em);
 }
 
-template <typename Char> inline void fputs(const Char* chars, FILE* stream) {
-  int result = std::fputs(chars, stream);
-  if (result < 0)
-    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
-}
-
-template <> inline void fputs<wchar_t>(const wchar_t* chars, FILE* stream) {
-  int result = std::fputws(chars, stream);
-  if (result < 0)
-    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
-}
-
-template <typename Char> inline void reset_color(FILE* stream) {
-  fputs("\x1b[0m", stream);
-}
-
-template <> inline void reset_color<wchar_t>(FILE* stream) {
-  fputs(L"\x1b[0m", stream);
-}
-
 template <typename Char> inline void reset_color(buffer<Char>& buffer) {
   auto reset_color = string_view("\x1b[0m");
   buffer.append(reset_color.begin(), reset_color.end());
 }
 
-template <typename T> struct styled_arg {
+template <typename T> struct styled_arg : view {
   const T& value;
   text_style style;
+  styled_arg(const T& v, text_style s) : value(v), style(s) {}
 };
 
 template <typename Char>
 void vformat_to(buffer<Char>& buf, const text_style& ts,
-                basic_string_view<Char> format_str,
-                basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+                basic_string_view<Char> fmt,
+                basic_format_args<buffered_context<Char>> args) {
   bool has_style = false;
   if (ts.has_emphasis()) {
     has_style = true;
-    auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
+    auto emphasis = make_emphasis<Char>(ts.get_emphasis());
     buf.append(emphasis.begin(), emphasis.end());
   }
   if (ts.has_foreground()) {
     has_style = true;
-    auto foreground = detail::make_foreground_color<Char>(ts.get_foreground());
+    auto foreground = make_foreground_color<Char>(ts.get_foreground());
     buf.append(foreground.begin(), foreground.end());
   }
   if (ts.has_background()) {
     has_style = true;
-    auto background = detail::make_background_color<Char>(ts.get_background());
+    auto background = make_background_color<Char>(ts.get_background());
     buf.append(background.begin(), background.end());
   }
-  detail::vformat_to(buf, format_str, args, {});
-  if (has_style) detail::reset_color<Char>(buf);
+  vformat_to(buf, fmt, args);
+  if (has_style) reset_color<Char>(buf);
 }
+}  // namespace detail
 
-FMT_END_DETAIL_NAMESPACE
-
-template <typename S, typename Char = char_t<S>>
-void vprint(std::FILE* f, const text_style& ts, const S& format,
-            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buf;
-  detail::vformat_to(buf, ts, detail::to_string_view(format), args);
-  if (detail::is_utf8()) {
-    detail::print(f, basic_string_view<Char>(buf.begin(), buf.size()));
-  } else {
-    buf.push_back(Char(0));
-    detail::fputs(buf.data(), f);
-  }
+inline void vprint(FILE* f, const text_style& ts, string_view fmt,
+                   format_args args) {
+  auto buf = memory_buffer();
+  detail::vformat_to(buf, ts, fmt, args);
+  print(f, FMT_STRING("{}"), string_view(buf.begin(), buf.size()));
 }
 
 /**
-  \rst
-  Formats a string and prints it to the specified file stream using ANSI
-  escape sequences to specify text formatting.
-
-  **Example**::
-
-    fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
-               "Elapsed time: {0:.2f} seconds", 1.23);
-  \endrst
+ * Formats a string and prints it to the specified file stream using ANSI
+ * escape sequences to specify text formatting.
+ *
+ * **Example**:
+ *
+ *     fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
+ *                "Elapsed time: {0:.2f} seconds", 1.23);
  */
-template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_string<S>::value)>
-void print(std::FILE* f, const text_style& ts, const S& format_str,
-           const Args&... args) {
-  vprint(f, ts, format_str,
-         fmt::make_format_args<buffer_context<char_t<S>>>(args...));
+template <typename... T>
+void print(FILE* f, const text_style& ts, format_string<T...> fmt,
+           T&&... args) {
+  vprint(f, ts, fmt.str, vargs<T...>{{args...}});
 }
 
 /**
-  \rst
-  Formats a string and prints it to stdout using ANSI escape sequences to
-  specify text formatting.
-
-  **Example**::
-
-    fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
-               "Elapsed time: {0:.2f} seconds", 1.23);
-  \endrst
+ * Formats a string and prints it to stdout using ANSI escape sequences to
+ * specify text formatting.
+ *
+ * **Example**:
+ *
+ *     fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
+ *                "Elapsed time: {0:.2f} seconds", 1.23);
  */
-template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_string<S>::value)>
-void print(const text_style& ts, const S& format_str, const Args&... args) {
-  return print(stdout, ts, format_str, args...);
+template <typename... T>
+void print(const text_style& ts, format_string<T...> fmt, T&&... args) {
+  return print(stdout, ts, fmt, std::forward<T>(args)...);
 }
 
-template <typename S, typename Char = char_t<S>>
-inline std::basic_string<Char> vformat(
-    const text_style& ts, const S& format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buf;
-  detail::vformat_to(buf, ts, detail::to_string_view(format_str), args);
+inline auto vformat(const text_style& ts, string_view fmt, format_args args)
+    -> std::string {
+  auto buf = memory_buffer();
+  detail::vformat_to(buf, ts, fmt, args);
   return fmt::to_string(buf);
 }
 
 /**
-  \rst
-  Formats arguments and returns the result as a string using ANSI
-  escape sequences to specify text formatting.
-
-  **Example**::
-
-    #include <fmt/color.h>
-    std::string message = fmt::format(fmt::emphasis::bold | fg(fmt::color::red),
-                                      "The answer is {}", 42);
-  \endrst
-*/
-template <typename S, typename... Args, typename Char = char_t<S>>
-inline std::basic_string<Char> format(const text_style& ts, const S& format_str,
-                                      const Args&... args) {
-  return fmt::vformat(ts, detail::to_string_view(format_str),
-                      fmt::make_format_args<buffer_context<Char>>(args...));
-}
-
-/**
-  Formats a string with the given text_style and writes the output to ``out``.
+ * Formats arguments and returns the result as a string using ANSI escape
+ * sequences to specify text formatting.
+ *
+ * **Example**:
+ *
+ * ```
+ * #include <fmt/color.h>
+ * std::string message = fmt::format(fmt::emphasis::bold | fg(fmt::color::red),
+ *                                   "The answer is {}", 42);
+ * ```
  */
-template <typename OutputIt, typename Char,
-          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
-OutputIt vformat_to(
-    OutputIt out, const text_style& ts, basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  auto&& buf = detail::get_buffer<Char>(out);
-  detail::vformat_to(buf, ts, format_str, args);
-  return detail::get_iterator(buf);
+template <typename... T>
+inline auto format(const text_style& ts, format_string<T...> fmt, T&&... args)
+    -> std::string {
+  return fmt::vformat(ts, fmt.str, vargs<T...>{{args...}});
+}
+
+/// Formats a string with the given text_style and writes the output to `out`.
+template <typename OutputIt,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
+auto vformat_to(OutputIt out, const text_style& ts, string_view fmt,
+                format_args args) -> OutputIt {
+  auto&& buf = detail::get_buffer<char>(out);
+  detail::vformat_to(buf, ts, fmt, args);
+  return detail::get_iterator(buf, out);
 }
 
 /**
-  \rst
-  Formats arguments with the given text_style, writes the result to the output
-  iterator ``out`` and returns the iterator past the end of the output range.
-
-  **Example**::
-
-    std::vector<char> out;
-    fmt::format_to(std::back_inserter(out),
-                   fmt::emphasis::bold | fg(fmt::color::red), "{}", 42);
-  \endrst
-*/
-template <typename OutputIt, typename S, typename... Args,
-          bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value&&
-              detail::is_string<S>::value>
-inline auto format_to(OutputIt out, const text_style& ts, const S& format_str,
-                      Args&&... args) ->
-    typename std::enable_if<enable, OutputIt>::type {
-  return vformat_to(out, ts, detail::to_string_view(format_str),
-                    fmt::make_format_args<buffer_context<char_t<S>>>(args...));
+ * Formats arguments with the given text style, writes the result to the output
+ * iterator `out` and returns the iterator past the end of the output range.
+ *
+ * **Example**:
+ *
+ *     std::vector<char> out;
+ *     fmt::format_to(std::back_inserter(out),
+ *                    fmt::emphasis::bold | fg(fmt::color::red), "{}", 42);
+ */
+template <typename OutputIt, typename... T,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
+inline auto format_to(OutputIt out, const text_style& ts,
+                      format_string<T...> fmt, T&&... args) -> OutputIt {
+  return vformat_to(out, ts, fmt.str, vargs<T...>{{args...}});
 }
 
 template <typename T, typename Char>
@@ -597,47 +559,44 @@ struct formatter<detail::styled_arg<T>, Char> : formatter<T, Char> {
   auto format(const detail::styled_arg<T>& arg, FormatContext& ctx) const
       -> decltype(ctx.out()) {
     const auto& ts = arg.style;
-    const auto& value = arg.value;
     auto out = ctx.out();
 
     bool has_style = false;
     if (ts.has_emphasis()) {
       has_style = true;
       auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
-      out = std::copy(emphasis.begin(), emphasis.end(), out);
+      out = detail::copy<Char>(emphasis.begin(), emphasis.end(), out);
     }
     if (ts.has_foreground()) {
       has_style = true;
       auto foreground =
           detail::make_foreground_color<Char>(ts.get_foreground());
-      out = std::copy(foreground.begin(), foreground.end(), out);
+      out = detail::copy<Char>(foreground.begin(), foreground.end(), out);
     }
     if (ts.has_background()) {
       has_style = true;
       auto background =
           detail::make_background_color<Char>(ts.get_background());
-      out = std::copy(background.begin(), background.end(), out);
+      out = detail::copy<Char>(background.begin(), background.end(), out);
     }
-    out = formatter<T, Char>::format(value, ctx);
+    out = formatter<T, Char>::format(arg.value, ctx);
     if (has_style) {
       auto reset_color = string_view("\x1b[0m");
-      out = std::copy(reset_color.begin(), reset_color.end(), out);
+      out = detail::copy<Char>(reset_color.begin(), reset_color.end(), out);
     }
     return out;
   }
 };
 
 /**
-  \rst
-  Returns an argument that will be formatted using ANSI escape sequences,
-  to be used in a formatting function.
-
-  **Example**::
-
-    fmt::print("Elapsed time: {0:.2f} seconds",
-               fmt::styled(1.23, fmt::fg(fmt::color::green) |
-                                 fmt::bg(fmt::color::blue)));
-  \endrst
+ * Returns an argument that will be formatted using ANSI escape sequences,
+ * to be used in a formatting function.
+ *
+ * **Example**:
+ *
+ *     fmt::print("Elapsed time: {0:.2f} seconds",
+ *                fmt::styled(1.23, fmt::fg(fmt::color::green) |
+ *                                  fmt::bg(fmt::color::blue)));
  */
 template <typename T>
 FMT_CONSTEXPR auto styled(const T& value, text_style ts)
@@ -645,7 +604,7 @@ FMT_CONSTEXPR auto styled(const T& value, text_style ts)
   return detail::styled_arg<remove_cvref_t<T>>{value, ts};
 }
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_COLOR_H_

include/spdlog/fmt/bundled/compile.h

@@ -8,134 +8,41 @@
 #ifndef FMT_COMPILE_H_
 #define FMT_COMPILE_H_
 
+#ifndef FMT_MODULE
+#  include <iterator>  // std::back_inserter
+#endif
+
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-namespace detail {
-
-template <typename Char, typename InputIt>
-FMT_CONSTEXPR inline counting_iterator copy_str(InputIt begin, InputIt end,
-                                                counting_iterator it) {
-  return it + (end - begin);
-}
-
-template <typename OutputIt> class truncating_iterator_base {
- protected:
-  OutputIt out_;
-  size_t limit_;
-  size_t count_ = 0;
-
-  truncating_iterator_base() : out_(), limit_(0) {}
-
-  truncating_iterator_base(OutputIt out, size_t limit)
-      : out_(out), limit_(limit) {}
-
- public:
-  using iterator_category = std::output_iterator_tag;
-  using value_type = typename std::iterator_traits<OutputIt>::value_type;
-  using difference_type = std::ptrdiff_t;
-  using pointer = void;
-  using reference = void;
-  FMT_UNCHECKED_ITERATOR(truncating_iterator_base);
-
-  OutputIt base() const { return out_; }
-  size_t count() const { return count_; }
-};
-
-// An output iterator that truncates the output and counts the number of objects
-// written to it.
-template <typename OutputIt,
-          typename Enable = typename std::is_void<
-              typename std::iterator_traits<OutputIt>::value_type>::type>
-class truncating_iterator;
-
-template <typename OutputIt>
-class truncating_iterator<OutputIt, std::false_type>
-    : public truncating_iterator_base<OutputIt> {
-  mutable typename truncating_iterator_base<OutputIt>::value_type blackhole_;
-
- public:
-  using value_type = typename truncating_iterator_base<OutputIt>::value_type;
-
-  truncating_iterator() = default;
-
-  truncating_iterator(OutputIt out, size_t limit)
-      : truncating_iterator_base<OutputIt>(out, limit) {}
-
-  truncating_iterator& operator++() {
-    if (this->count_++ < this->limit_) ++this->out_;
-    return *this;
-  }
-
-  truncating_iterator operator++(int) {
-    auto it = *this;
-    ++*this;
-    return it;
-  }
-
-  value_type& operator*() const {
-    return this->count_ < this->limit_ ? *this->out_ : blackhole_;
-  }
-};
-
-template <typename OutputIt>
-class truncating_iterator<OutputIt, std::true_type>
-    : public truncating_iterator_base<OutputIt> {
- public:
-  truncating_iterator() = default;
-
-  truncating_iterator(OutputIt out, size_t limit)
-      : truncating_iterator_base<OutputIt>(out, limit) {}
-
-  template <typename T> truncating_iterator& operator=(T val) {
-    if (this->count_++ < this->limit_) *this->out_++ = val;
-    return *this;
-  }
-
-  truncating_iterator& operator++() { return *this; }
-  truncating_iterator& operator++(int) { return *this; }
-  truncating_iterator& operator*() { return *this; }
-};
 
 // A compile-time string which is compiled into fast formatting code.
-class compiled_string {};
+FMT_EXPORT class compiled_string {};
 
 template <typename S>
 struct is_compiled_string : std::is_base_of<compiled_string, S> {};
 
+namespace detail {
+
 /**
-  \rst
-  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
-  ``constexpr if`` compiler support.
-
-  **Example**::
-
-    // Converts 42 into std::string using the most efficient method and no
-    // runtime format string processing.
-    std::string s = fmt::format(FMT_COMPILE("{}"), 42);
-  \endrst
+ * 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
+ * `constexpr if` compiler support.
+ *
+ * **Example**:
+ *
+ *     // Converts 42 into std::string using the most efficient method and no
+ *     // runtime format string processing.
+ *     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
  */
 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
-#  define FMT_COMPILE(s) \
-    FMT_STRING_IMPL(s, fmt::detail::compiled_string, explicit)
+#  define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::compiled_string)
 #else
 #  define FMT_COMPILE(s) FMT_STRING(s)
 #endif
 
-#if FMT_USE_NONTYPE_TEMPLATE_ARGS
-template <typename Char, size_t N,
-          fmt::detail_exported::fixed_string<Char, N> Str>
-struct udl_compiled_string : compiled_string {
-  using char_type = Char;
-  explicit constexpr operator basic_string_view<char_type>() const {
-    return {Str.data, N - 1};
-  }
-};
-#endif
-
 template <typename T, typename... Tail>
-const T& first(const T& value, const Tail&...) {
+auto first(const T& value, const Tail&...) -> const T& {
   return value;
 }
 
@@ -153,6 +60,29 @@ constexpr const auto& get([[maybe_unused]] const T& first,
     return detail::get<N - 1>(rest...);
 }
 
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+template <int N, typename T, typename... Args, typename Char>
+constexpr auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
+  if constexpr (is_static_named_arg<T>()) {
+    if (name == T::name) return N;
+  }
+  if constexpr (sizeof...(Args) > 0)
+    return get_arg_index_by_name<N + 1, Args...>(name);
+  (void)name;  // Workaround an MSVC bug about "unused" parameter.
+  return -1;
+}
+#  endif
+
+template <typename... Args, typename Char>
+FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+  if constexpr (sizeof...(Args) > 0)
+    return get_arg_index_by_name<0, Args...>(name);
+#  endif
+  (void)name;
+  return -1;
+}
+
 template <typename Char, typename... Args>
 constexpr int get_arg_index_by_name(basic_string_view<Char> name,
                                     type_list<Args...>) {
@@ -196,7 +126,8 @@ template <typename Char> struct code_unit {
 
   template <typename OutputIt, typename... Args>
   constexpr OutputIt format(OutputIt out, const Args&...) const {
-    return write<Char>(out, value);
+    *out++ = value;
+    return out;
   }
 };
 
@@ -220,7 +151,13 @@ template <typename Char, typename T, int N> struct field {
 
   template <typename OutputIt, typename... Args>
   constexpr OutputIt format(OutputIt out, const Args&... args) const {
-    return write<Char>(out, get_arg_checked<T, N>(args...));
+    const T& arg = get_arg_checked<T, N>(args...);
+    if constexpr (std::is_convertible<T, basic_string_view<Char>>::value) {
+      auto s = basic_string_view<Char>(arg);
+      return copy<Char>(s.begin(), s.end(), out);
+    } else {
+      return write<Char>(out, arg);
+    }
   }
 };
 
@@ -308,13 +245,12 @@ constexpr size_t parse_text(basic_string_view<Char> str, size_t pos) {
 }
 
 template <typename Args, size_t POS, int ID, typename S>
-constexpr auto compile_format_string(S format_str);
+constexpr auto compile_format_string(S fmt);
 
 template <typename Args, size_t POS, int ID, typename T, typename S>
-constexpr auto parse_tail(T head, S format_str) {
-  if constexpr (POS !=
-                basic_string_view<typename S::char_type>(format_str).size()) {
-    constexpr auto tail = compile_format_string<Args, POS, ID>(format_str);
+constexpr auto parse_tail(T head, S fmt) {
+  if constexpr (POS != basic_string_view<typename S::char_type>(fmt).size()) {
+    constexpr auto tail = compile_format_string<Args, POS, ID>(fmt);
     if constexpr (std::is_same<remove_cvref_t<decltype(tail)>,
                                unknown_format>())
       return tail;
@@ -331,14 +267,14 @@ template <typename T, typename Char> struct parse_specs_result {
   int next_arg_id;
 };
 
-constexpr int manual_indexing_id = -1;
+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) {
   str.remove_prefix(pos);
-  auto ctx = compile_parse_context<Char>(str, max_value<int>(), nullptr, {},
-                                         next_arg_id);
+  auto ctx =
+      compile_parse_context<Char>(str, max_value<int>(), nullptr, next_arg_id);
   auto f = formatter<T, Char>();
   auto end = f.parse(ctx);
   return {f, pos + fmt::detail::to_unsigned(end - str.data()),
@@ -346,36 +282,36 @@ constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
 }
 
 template <typename Char> struct arg_id_handler {
+  arg_id_kind kind;
   arg_ref<Char> arg_id;
 
-  constexpr int operator()() {
+  constexpr int on_auto() {
     FMT_ASSERT(false, "handler cannot be used with automatic indexing");
     return 0;
   }
-  constexpr int operator()(int id) {
+  constexpr int on_index(int id) {
+    kind = arg_id_kind::index;
     arg_id = arg_ref<Char>(id);
     return 0;
   }
-  constexpr int operator()(basic_string_view<Char> id) {
+  constexpr int on_name(basic_string_view<Char> id) {
+    kind = arg_id_kind::name;
     arg_id = arg_ref<Char>(id);
     return 0;
   }
-
-  constexpr void on_error(const char* message) {
-    FMT_THROW(format_error(message));
-  }
 };
 
 template <typename Char> struct parse_arg_id_result {
+  arg_id_kind kind;
   arg_ref<Char> arg_id;
   const Char* arg_id_end;
 };
 
 template <int ID, typename Char>
 constexpr auto parse_arg_id(const Char* begin, const Char* end) {
-  auto handler = arg_id_handler<Char>{arg_ref<Char>{}};
+  auto handler = arg_id_handler<Char>{arg_id_kind::none, arg_ref<Char>{}};
   auto arg_id_end = parse_arg_id(begin, end, handler);
-  return parse_arg_id_result<Char>{handler.arg_id, arg_id_end};
+  return parse_arg_id_result<Char>{handler.kind, handler.arg_id, arg_id_end};
 }
 
 template <typename T, typename Enable = void> struct field_type {
@@ -389,14 +325,13 @@ struct field_type<T, enable_if_t<detail::is_named_arg<T>::value>> {
 
 template <typename T, typename Args, size_t END_POS, int ARG_INDEX, int NEXT_ID,
           typename S>
-constexpr auto parse_replacement_field_then_tail(S format_str) {
+constexpr auto parse_replacement_field_then_tail(S fmt) {
   using char_type = typename S::char_type;
-  constexpr auto str = basic_string_view<char_type>(format_str);
+  constexpr auto str = basic_string_view<char_type>(fmt);
   constexpr char_type c = END_POS != str.size() ? str[END_POS] : char_type();
   if constexpr (c == '}') {
     return parse_tail<Args, END_POS + 1, NEXT_ID>(
-        field<char_type, typename field_type<T>::type, ARG_INDEX>(),
-        format_str);
+        field<char_type, typename field_type<T>::type, ARG_INDEX>(), fmt);
   } else if constexpr (c != ':') {
     FMT_THROW(format_error("expected ':'"));
   } else {
@@ -409,7 +344,7 @@ constexpr auto parse_replacement_field_then_tail(S format_str) {
       return parse_tail<Args, result.end + 1, result.next_arg_id>(
           spec_field<char_type, typename field_type<T>::type, ARG_INDEX>{
               result.fmt},
-          format_str);
+          fmt);
     }
   }
 }
@@ -417,22 +352,21 @@ constexpr auto parse_replacement_field_then_tail(S format_str) {
 // Compiles a non-empty format string and returns the compiled representation
 // or unknown_format() on unrecognized input.
 template <typename Args, size_t POS, int ID, typename S>
-constexpr auto compile_format_string(S format_str) {
+constexpr auto compile_format_string(S fmt) {
   using char_type = typename S::char_type;
-  constexpr auto str = basic_string_view<char_type>(format_str);
+  constexpr auto str = basic_string_view<char_type>(fmt);
   if constexpr (str[POS] == '{') {
     if constexpr (POS + 1 == str.size())
       FMT_THROW(format_error("unmatched '{' in format string"));
     if constexpr (str[POS + 1] == '{') {
-      return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
+      return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), fmt);
     } else if constexpr (str[POS + 1] == '}' || str[POS + 1] == ':') {
       static_assert(ID != manual_indexing_id,
                     "cannot switch from manual to automatic argument indexing");
       constexpr auto next_id =
           ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
       return parse_replacement_field_then_tail<get_type<ID, Args>, Args,
-                                               POS + 1, ID, next_id>(
-          format_str);
+                                               POS + 1, ID, next_id>(fmt);
     } else {
       constexpr auto arg_id_result =
           parse_arg_id<ID>(str.data() + POS + 1, str.data() + str.size());
@@ -440,68 +374,62 @@ constexpr auto compile_format_string(S format_str) {
       constexpr char_type c =
           arg_id_end_pos != str.size() ? str[arg_id_end_pos] : char_type();
       static_assert(c == '}' || c == ':', "missing '}' in format string");
-      if constexpr (arg_id_result.arg_id.kind == arg_id_kind::index) {
+      if constexpr (arg_id_result.kind == arg_id_kind::index) {
         static_assert(
             ID == manual_indexing_id || ID == 0,
             "cannot switch from automatic to manual argument indexing");
-        constexpr auto arg_index = arg_id_result.arg_id.val.index;
+        constexpr auto arg_index = arg_id_result.arg_id.index;
         return parse_replacement_field_then_tail<get_type<arg_index, Args>,
                                                  Args, arg_id_end_pos,
                                                  arg_index, manual_indexing_id>(
-            format_str);
-      } else if constexpr (arg_id_result.arg_id.kind == arg_id_kind::name) {
+            fmt);
+      } else if constexpr (arg_id_result.kind == arg_id_kind::name) {
         constexpr auto arg_index =
-            get_arg_index_by_name(arg_id_result.arg_id.val.name, Args{});
-        if constexpr (arg_index != invalid_arg_index) {
+            get_arg_index_by_name(arg_id_result.arg_id.name, Args{});
+        if constexpr (arg_index >= 0) {
           constexpr auto next_id =
               ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
           return parse_replacement_field_then_tail<
               decltype(get_type<arg_index, Args>::value), Args, arg_id_end_pos,
-              arg_index, next_id>(format_str);
-        } else {
-          if constexpr (c == '}') {
+              arg_index, next_id>(fmt);
+        } else if constexpr (c == '}') {
           return parse_tail<Args, arg_id_end_pos + 1, ID>(
-                runtime_named_field<char_type>{arg_id_result.arg_id.val.name},
-                format_str);
+              runtime_named_field<char_type>{arg_id_result.arg_id.name}, fmt);
         } else if constexpr (c == ':') {
           return unknown_format();  // no type info for specs parsing
         }
       }
     }
-    }
   } else if constexpr (str[POS] == '}') {
     if constexpr (POS + 1 == str.size())
       FMT_THROW(format_error("unmatched '}' in format string"));
-    return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
+    return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), fmt);
   } else {
     constexpr auto end = parse_text(str, POS + 1);
     if constexpr (end - POS > 1) {
-      return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
-                                       format_str);
+      return parse_tail<Args, end, ID>(make_text(str, POS, end - POS), fmt);
     } else {
-      return parse_tail<Args, end, ID>(code_unit<char_type>{str[POS]},
-                                       format_str);
+      return parse_tail<Args, end, ID>(code_unit<char_type>{str[POS]}, fmt);
     }
   }
 }
 
 template <typename... Args, typename S,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
-constexpr auto compile(S format_str) {
-  constexpr auto str = basic_string_view<typename S::char_type>(format_str);
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
+constexpr auto compile(S fmt) {
+  constexpr auto str = basic_string_view<typename S::char_type>(fmt);
   if constexpr (str.size() == 0) {
     return detail::make_text(str, 0, 0);
   } else {
     constexpr auto result =
-        detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
-            format_str);
+        detail::compile_format_string<detail::type_list<Args...>, 0, 0>(fmt);
     return result;
   }
 }
 #endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 }  // namespace detail
 
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 
@@ -523,7 +451,7 @@ constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
                                                            Args&&... args) {
   if constexpr (std::is_same<typename S::char_type, char>::value) {
@@ -550,7 +478,7 @@ FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
 }
 
 template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
   constexpr auto compiled = detail::compile<Args...>(S());
   if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
@@ -565,47 +493,47 @@ FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
 #endif
 
 template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
-format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
-                                         const S& format_str, Args&&... args) {
-  auto it = fmt::format_to(detail::truncating_iterator<OutputIt>(out, n),
-                           format_str, std::forward<Args>(args)...);
-  return {it.base(), it.count()};
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
+auto format_to_n(OutputIt out, size_t n, const S& fmt, Args&&... args)
+    -> format_to_n_result<OutputIt> {
+  using traits = detail::fixed_buffer_traits;
+  auto buf = detail::iterator_buffer<OutputIt, char, traits>(out, n);
+  fmt::format_to(std::back_inserter(buf), fmt, std::forward<Args>(args)...);
+  return {buf.out(), buf.count()};
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
-FMT_CONSTEXPR20 size_t formatted_size(const S& format_str,
-                                      const Args&... args) {
-  return fmt::format_to(detail::counting_iterator(), format_str, args...)
-      .count();
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
+FMT_CONSTEXPR20 auto formatted_size(const S& fmt, const Args&... args)
+    -> size_t {
+  auto buf = detail::counting_buffer<>();
+  fmt::format_to(appender(buf), fmt, args...);
+  return buf.count();
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
-void print(std::FILE* f, const S& format_str, const Args&... args) {
-  memory_buffer buffer;
-  fmt::format_to(std::back_inserter(buffer), format_str, args...);
-  detail::print(f, {buffer.data(), buffer.size()});
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
+void print(std::FILE* f, const S& fmt, const Args&... args) {
+  auto buf = memory_buffer();
+  fmt::format_to(appender(buf), fmt, args...);
+  detail::print(f, {buf.data(), buf.size()});
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
-void print(const S& format_str, const Args&... args) {
-  print(stdout, format_str, args...);
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
+void print(const S& fmt, const Args&... args) {
+  print(stdout, fmt, args...);
 }
 
 #if FMT_USE_NONTYPE_TEMPLATE_ARGS
 inline namespace literals {
-template <detail_exported::fixed_string Str> constexpr auto operator""_cf() {
-  using char_t = remove_cvref_t<decltype(Str.data[0])>;
-  return detail::udl_compiled_string<char_t, sizeof(Str.data) / sizeof(char_t),
-                                     Str>();
+template <detail::fixed_string Str> constexpr auto operator""_cf() {
+  return FMT_COMPILE(Str.data);
 }
 }  // namespace literals
 #endif
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_COMPILE_H_

include/spdlog/fmt/bundled/locale.h

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

include/spdlog/fmt/bundled/os.h

@@ -8,17 +8,19 @@
 #ifndef FMT_OS_H_
 #define FMT_OS_H_
 
-#include <cerrno>
-#include <cstddef>
-#include <cstdio>
-#include <system_error>  // std::system_error
-
-#if defined __APPLE__ || defined(__FreeBSD__)
-#  include <xlocale.h>  // for LC_NUMERIC_MASK on OS X
-#endif
-
 #include "format.h"
 
+#ifndef FMT_MODULE
+#  include <cerrno>
+#  include <cstddef>
+#  include <cstdio>
+#  include <system_error>  // std::system_error
+
+#  if FMT_HAS_INCLUDE(<xlocale.h>)
+#    include <xlocale.h>  // LC_NUMERIC_MASK on macOS
+#  endif
+#endif  // FMT_MODULE
+
 #ifndef FMT_USE_FCNTL
 // UWP doesn't provide _pipe.
 #  if FMT_HAS_INCLUDE("winapifamily.h")
@@ -46,6 +48,7 @@
 
 // Calls to system functions are wrapped in FMT_SYSTEM for testability.
 #ifdef FMT_SYSTEM
+#  define FMT_HAS_SYSTEM
 #  define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
 #else
 #  define FMT_SYSTEM(call) ::call
@@ -71,143 +74,89 @@
 #define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
 
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 /**
-  \rst
-  A reference to a null-terminated string. It can be constructed from a C
-  string or ``std::string``.
-
-  You can use one of the following type aliases for common character types:
-
-  +---------------+-----------------------------+
-  | Type          | Definition                  |
-  +===============+=============================+
-  | cstring_view  | basic_cstring_view<char>    |
-  +---------------+-----------------------------+
-  | wcstring_view | basic_cstring_view<wchar_t> |
-  +---------------+-----------------------------+
-
-  This class is most useful as a parameter type to allow passing
-  different types of strings to a function, for example::
-
-    template <typename... Args>
-    std::string format(cstring_view format_str, const Args & ... args);
-
-    format("{}", 42);
-    format(std::string("{}"), 42);
-  \endrst
+ * A reference to a null-terminated string. It can be constructed from a C
+ * string or `std::string`.
+ *
+ * You can use one of the following type aliases for common character types:
+ *
+ * +---------------+-----------------------------+
+ * | Type          | Definition                  |
+ * +===============+=============================+
+ * | cstring_view  | basic_cstring_view<char>    |
+ * +---------------+-----------------------------+
+ * | wcstring_view | basic_cstring_view<wchar_t> |
+ * +---------------+-----------------------------+
+ *
+ * This class is most useful as a parameter type for functions that wrap C APIs.
  */
 template <typename Char> class basic_cstring_view {
  private:
   const Char* data_;
 
  public:
-  /** Constructs a string reference object from a C string. */
+  /// Constructs a string reference object from a C string.
   basic_cstring_view(const Char* s) : data_(s) {}
 
-  /**
-    \rst
-    Constructs a string reference from an ``std::string`` object.
-    \endrst
-   */
+  /// Constructs a string reference from an `std::string` object.
   basic_cstring_view(const std::basic_string<Char>& s) : data_(s.c_str()) {}
 
-  /** Returns the pointer to a C string. */
-  const Char* c_str() const { return data_; }
+  /// Returns the pointer to a C string.
+  auto c_str() const -> const Char* { return data_; }
 };
 
 using cstring_view = basic_cstring_view<char>;
 using wcstring_view = basic_cstring_view<wchar_t>;
 
-template <typename Char> struct formatter<std::error_code, Char> {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-
-  template <typename FormatContext>
-  FMT_CONSTEXPR auto format(const std::error_code& ec, FormatContext& ctx) const
-      -> decltype(ctx.out()) {
-    auto out = ctx.out();
-    out = detail::write_bytes(out, ec.category().name(),
-                              basic_format_specs<Char>());
-    out = detail::write<Char>(out, Char(':'));
-    out = detail::write<Char>(out, ec.value());
-    return out;
-  }
-};
-
 #ifdef _WIN32
 FMT_API const std::error_category& system_category() noexcept;
 
-FMT_BEGIN_DETAIL_NAMESPACE
-// A converter from UTF-16 to UTF-8.
-// It is only provided for Windows since other systems support UTF-8 natively.
-class utf16_to_utf8 {
- private:
-  memory_buffer buffer_;
-
- public:
-  utf16_to_utf8() {}
-  FMT_API explicit utf16_to_utf8(basic_string_view<wchar_t> s);
-  operator string_view() const { return string_view(&buffer_[0], size()); }
-  size_t size() const { return buffer_.size() - 1; }
-  const char* c_str() const { return &buffer_[0]; }
-  std::string str() const { return std::string(&buffer_[0], size()); }
-
-  // Performs conversion returning a system error code instead of
-  // throwing exception on conversion error. This method may still throw
-  // in case of memory allocation error.
-  FMT_API int convert(basic_string_view<wchar_t> s);
-};
-
+namespace detail {
 FMT_API void format_windows_error(buffer<char>& out, int error_code,
                                   const char* message) noexcept;
-FMT_END_DETAIL_NAMESPACE
+}
 
-FMT_API std::system_error vwindows_error(int error_code, string_view format_str,
+FMT_API std::system_error vwindows_error(int error_code, string_view fmt,
                                          format_args args);
 
 /**
- \rst
- Constructs a :class:`std::system_error` object with the description
- of the form
-
- .. parsed-literal::
-   *<message>*: *<system-message>*
-
- where *<message>* is the formatted message and *<system-message>* is the
- system message corresponding to the error code.
- *error_code* is a Windows error code as given by ``GetLastError``.
- If *error_code* is not a valid error code such as -1, the system message
- will look like "error -1".
-
- **Example**::
-
-   // This throws a system_error with the description
-   //   cannot open file 'madeup': The system cannot find the file specified.
-   // or similar (system message may vary).
-   const char *filename = "madeup";
-   LPOFSTRUCT of = LPOFSTRUCT();
-   HFILE file = OpenFile(filename, &of, OF_READ);
-   if (file == HFILE_ERROR) {
-     throw fmt::windows_error(GetLastError(),
-                              "cannot open file '{}'", filename);
-   }
- \endrst
-*/
-template <typename... Args>
-std::system_error windows_error(int error_code, string_view message,
-                                const Args&... args) {
-  return vwindows_error(error_code, message, fmt::make_format_args(args...));
+ * Constructs a `std::system_error` object with the description of the form
+ *
+ *     <message>: <system-message>
+ *
+ * where `<message>` is the formatted message and `<system-message>` is the
+ * system message corresponding to the error code.
+ * `error_code` is a Windows error code as given by `GetLastError`.
+ * If `error_code` is not a valid error code such as -1, the system message
+ * will look like "error -1".
+ *
+ * **Example**:
+ *
+ *     // This throws a system_error with the description
+ *     //   cannot open file 'madeup': The system cannot find the file
+ * specified.
+ *     // or similar (system message may vary).
+ *     const char *filename = "madeup";
+ *     LPOFSTRUCT of = LPOFSTRUCT();
+ *     HFILE file = OpenFile(filename, &of, OF_READ);
+ *     if (file == HFILE_ERROR) {
+ *       throw fmt::windows_error(GetLastError(),
+ *                                "cannot open file '{}'", filename);
+ *     }
+ */
+template <typename... T>
+auto windows_error(int error_code, string_view message, const T&... args)
+    -> std::system_error {
+  return vwindows_error(error_code, message, vargs<T...>{{args...}});
 }
 
 // Reports a Windows error without throwing an exception.
 // Can be used to report errors from destructors.
 FMT_API void report_windows_error(int error_code, const char* message) noexcept;
 #else
-inline const std::error_category& system_category() noexcept {
+inline auto system_category() noexcept -> const std::error_category& {
   return std::system_category();
 }
 #endif  // _WIN32
@@ -215,8 +164,8 @@ inline const std::error_category& system_category() noexcept {
 // std::system is not available on some platforms such as iOS (#2248).
 #ifdef __OSX__
 template <typename S, typename... Args, typename Char = char_t<S>>
-void say(const S& format_str, Args&&... args) {
-  std::system(format("say \"{}\"", format(format_str, args...)).c_str());
+void say(const S& fmt, Args&&... args) {
+  std::system(format("say \"{}\"", format(fmt, args...)).c_str());
 }
 #endif
 
@@ -227,24 +176,24 @@ class buffered_file {
 
   friend class file;
 
-  explicit buffered_file(FILE* f) : file_(f) {}
+  inline explicit buffered_file(FILE* f) : file_(f) {}
 
  public:
   buffered_file(const buffered_file&) = delete;
   void operator=(const buffered_file&) = delete;
 
   // Constructs a buffered_file object which doesn't represent any file.
-  buffered_file() noexcept : file_(nullptr) {}
+  inline buffered_file() noexcept : file_(nullptr) {}
 
   // Destroys the object closing the file it represents if any.
   FMT_API ~buffered_file() noexcept;
 
  public:
-  buffered_file(buffered_file&& other) noexcept : file_(other.file_) {
+  inline buffered_file(buffered_file&& other) noexcept : file_(other.file_) {
     other.file_ = nullptr;
   }
 
-  buffered_file& operator=(buffered_file&& other) {
+  inline auto operator=(buffered_file&& other) -> buffered_file& {
     close();
     file_ = other.file_;
     other.file_ = nullptr;
@@ -258,21 +207,20 @@ class buffered_file {
   FMT_API void close();
 
   // Returns the pointer to a FILE object representing this file.
-  FILE* get() const noexcept { return file_; }
+  inline auto get() const noexcept -> FILE* { return file_; }
 
-  FMT_API int descriptor() const;
+  FMT_API auto descriptor() const -> int;
 
-  void vprint(string_view format_str, format_args args) {
-    fmt::vprint(file_, format_str, args);
-  }
-
-  template <typename... Args>
-  inline void print(string_view format_str, const Args&... args) {
-    vprint(format_str, fmt::make_format_args(args...));
+  template <typename... T>
+  inline void print(string_view fmt, const T&... args) {
+    fmt::vargs<T...> vargs = {{args...}};
+    detail::is_locking<T...>() ? fmt::vprint_buffered(file_, fmt, vargs)
+                               : fmt::vprint(file_, fmt, vargs);
   }
 };
 
 #if FMT_USE_FCNTL
+
 // A file. Closed file is represented by a file object with descriptor -1.
 // Methods that are not declared with noexcept may throw
 // fmt::system_error in case of failure. Note that some errors such as
@@ -286,6 +234,8 @@ class FMT_API file {
   // Constructs a file object with a given descriptor.
   explicit file(int fd) : fd_(fd) {}
 
+  friend struct pipe;
+
  public:
   // Possible values for the oflag argument to the constructor.
   enum {
@@ -298,7 +248,7 @@ class FMT_API file {
   };
 
   // Constructs a file object which doesn't represent any file.
-  file() noexcept : fd_(-1) {}
+  inline file() noexcept : fd_(-1) {}
 
   // Opens a file and constructs a file object representing this file.
   file(cstring_view path, int oflag);
@@ -307,10 +257,10 @@ class FMT_API file {
   file(const file&) = delete;
   void operator=(const file&) = delete;
 
-  file(file&& other) noexcept : fd_(other.fd_) { other.fd_ = -1; }
+  inline file(file&& other) noexcept : fd_(other.fd_) { other.fd_ = -1; }
 
   // Move assignment is not noexcept because close may throw.
-  file& operator=(file&& other) {
+  inline auto operator=(file&& other) -> file& {
     close();
     fd_ = other.fd_;
     other.fd_ = -1;
@@ -321,24 +271,24 @@ class FMT_API file {
   ~file() noexcept;
 
   // Returns the file descriptor.
-  int descriptor() const noexcept { return fd_; }
+  inline auto descriptor() const noexcept -> int { return fd_; }
 
   // Closes the file.
   void close();
 
   // Returns the file size. The size has signed type for consistency with
   // stat::st_size.
-  long long size() const;
+  auto size() const -> long long;
 
   // Attempts to read count bytes from the file into the specified buffer.
-  size_t read(void* buffer, size_t count);
+  auto read(void* buffer, size_t count) -> size_t;
 
   // Attempts to write count bytes from the specified buffer to the file.
-  size_t write(const void* buffer, size_t count);
+  auto write(const void* buffer, size_t count) -> size_t;
 
   // Duplicates a file descriptor with the dup function and returns
   // the duplicate as a file object.
-  static file dup(int fd);
+  static auto dup(int fd) -> file;
 
   // Makes fd be the copy of this file descriptor, closing fd first if
   // necessary.
@@ -348,24 +298,35 @@ class FMT_API file {
   // necessary.
   void dup2(int fd, std::error_code& ec) noexcept;
 
-  // Creates a pipe setting up read_end and write_end file objects for reading
-  // and writing respectively.
-  static void pipe(file& read_end, file& write_end);
-
   // Creates a buffered_file object associated with this file and detaches
   // this file object from the file.
-  buffered_file fdopen(const char* mode);
+  auto fdopen(const char* mode) -> buffered_file;
+
+#  if defined(_WIN32) && !defined(__MINGW32__)
+  // Opens a file and constructs a file object representing this file by
+  // wcstring_view filename. Windows only.
+  static file open_windows_file(wcstring_view path, int oflag);
+#  endif
+};
+
+struct FMT_API pipe {
+  file read_end;
+  file write_end;
+
+  // Creates a pipe setting up read_end and write_end file objects for reading
+  // and writing respectively.
+  pipe();
 };
 
 // Returns the memory page size.
-long getpagesize();
+auto getpagesize() -> long;
 
-FMT_BEGIN_DETAIL_NAMESPACE
+namespace detail {
 
 struct buffer_size {
-  buffer_size() = default;
+  constexpr buffer_size() = default;
   size_t value = 0;
-  buffer_size operator=(size_t val) const {
+  FMT_CONSTEXPR auto operator=(size_t val) const -> buffer_size {
     auto bs = buffer_size();
     bs.value = val;
     return bs;
@@ -376,7 +337,7 @@ struct ostream_params {
   int oflag = file::WRONLY | file::CREATE | file::TRUNC;
   size_t buffer_size = BUFSIZ > 32768 ? BUFSIZ : 32768;
 
-  ostream_params() {}
+  constexpr ostream_params() {}
 
   template <typename... T>
   ostream_params(T... params, int new_oflag) : ostream_params(params...) {
@@ -397,82 +358,70 @@ struct ostream_params {
 #  endif
 };
 
-FMT_END_DETAIL_NAMESPACE
+}  // namespace detail
 
-// Added {} below to work around default constructor error known to
-// occur in Xcode versions 7.2.1 and 8.2.1.
-constexpr detail::buffer_size buffer_size{};
+FMT_INLINE_VARIABLE constexpr auto buffer_size = detail::buffer_size();
 
-/** A fast output stream which is not thread-safe. */
-class FMT_API ostream final : private detail::buffer<char> {
+/// A fast buffered output stream for writing from a single thread. Writing from
+/// multiple threads without external synchronization may result in a data race.
+class FMT_API ostream : private detail::buffer<char> {
  private:
   file file_;
 
-  void grow(size_t) override;
+  ostream(cstring_view path, const detail::ostream_params& params);
 
-  ostream(cstring_view path, const detail::ostream_params& params)
-      : file_(path, params.oflag) {
-    set(new char[params.buffer_size], params.buffer_size);
-  }
+  static void grow(buffer<char>& buf, size_t);
 
  public:
-  ostream(ostream&& other)
-      : detail::buffer<char>(other.data(), other.size(), other.capacity()),
-        file_(std::move(other.file_)) {
-    other.clear();
-    other.set(nullptr, 0);
-  }
-  ~ostream() {
-    flush();
-    delete[] data();
+  ostream(ostream&& other) noexcept;
+  ~ostream();
+
+  operator writer() {
+    detail::buffer<char>& buf = *this;
+    return buf;
   }
 
-  void flush() {
+  inline void flush() {
     if (size() == 0) return;
-    file_.write(data(), size());
+    file_.write(data(), size() * sizeof(data()[0]));
     clear();
   }
 
   template <typename... T>
-  friend ostream output_file(cstring_view path, T... params);
+  friend auto output_file(cstring_view path, T... params) -> ostream;
 
-  void close() {
+  inline void close() {
     flush();
     file_.close();
   }
 
-  /**
-    Formats ``args`` according to specifications in ``fmt`` and writes the
-    output to the file.
-   */
+  /// Formats `args` according to specifications in `fmt` and writes the
+  /// output to the file.
   template <typename... T> void print(format_string<T...> fmt, T&&... args) {
-    vformat_to(detail::buffer_appender<char>(*this), fmt,
-               fmt::make_format_args(args...));
+    vformat_to(appender(*this), fmt.str, vargs<T...>{{args...}});
   }
 };
 
 /**
-  \rst
-  Opens a file for writing. Supported parameters passed in *params*:
-
-  * ``<integer>``: Flags passed to `open
-    <https://pubs.opengroup.org/onlinepubs/007904875/functions/open.html>`_
-    (``file::WRONLY | file::CREATE | file::TRUNC`` by default)
-  * ``buffer_size=<integer>``: Output buffer size
-
-  **Example**::
-
-    auto out = fmt::output_file("guide.txt");
-    out.print("Don't {}", "Panic");
-  \endrst
+ * Opens a file for writing. Supported parameters passed in `params`:
+ *
+ * - `<integer>`: Flags passed to [open](
+ *   https://pubs.opengroup.org/onlinepubs/007904875/functions/open.html)
+ *   (`file::WRONLY | file::CREATE | file::TRUNC` by default)
+ * - `buffer_size=<integer>`: Output buffer size
+ *
+ * **Example**:
+ *
+ *     auto out = fmt::output_file("guide.txt");
+ *     out.print("Don't {}", "Panic");
  */
 template <typename... T>
-inline ostream output_file(cstring_view path, T... params) {
+inline auto output_file(cstring_view path, T... params) -> ostream {
   return {path, detail::ostream_params(params...)};
 }
 #endif  // FMT_USE_FCNTL
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_OS_H_

include/spdlog/fmt/bundled/ostream.h

@@ -8,108 +8,53 @@
 #ifndef FMT_OSTREAM_H_
 #define FMT_OSTREAM_H_
 
-#include <fstream>
-#include <ostream>
-#if defined(_WIN32) && defined(__GLIBCXX__)
-#  include <ext/stdio_filebuf.h>
-#  include <ext/stdio_sync_filebuf.h>
-#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
-#  include <__std_stream>
+#ifndef FMT_MODULE
+#  include <fstream>  // std::filebuf
 #endif
 
-#include "format.h"
+#ifdef _WIN32
+#  ifdef __GLIBCXX__
+#    include <ext/stdio_filebuf.h>
+#    include <ext/stdio_sync_filebuf.h>
+#  endif
+#  include <io.h>
+#endif
+
+#include "chrono.h"  // formatbuf
+
+#ifdef _MSVC_STL_UPDATE
+#  define FMT_MSVC_STL_UPDATE _MSVC_STL_UPDATE
+#elif defined(_MSC_VER) && _MSC_VER < 1912  // VS 15.5
+#  define FMT_MSVC_STL_UPDATE _MSVC_LANG
+#else
+#  define FMT_MSVC_STL_UPDATE 0
+#endif
 
 FMT_BEGIN_NAMESPACE
-
-template <typename OutputIt, typename Char> class basic_printf_context;
-
 namespace detail {
 
-// Checks if T has a user-defined operator<<.
-template <typename T, typename Char, typename Enable = void>
-class is_streamable {
- private:
-  template <typename U>
-  static auto test(int)
-      -> bool_constant<sizeof(std::declval<std::basic_ostream<Char>&>()
-                              << std::declval<U>()) != 0>;
-
-  template <typename> static auto test(...) -> std::false_type;
-
-  using result = decltype(test<T>(0));
-
- public:
-  is_streamable() = default;
-
-  static const bool value = result::value;
-};
-
-// Formatting of built-in types and arrays is intentionally disabled because
-// it's handled by standard (non-ostream) formatters.
-template <typename T, typename Char>
-struct is_streamable<
-    T, Char,
-    enable_if_t<
-        std::is_arithmetic<T>::value || std::is_array<T>::value ||
-        std::is_pointer<T>::value || std::is_same<T, char8_type>::value ||
-        std::is_convertible<T, fmt::basic_string_view<Char>>::value ||
-        std::is_same<T, std_string_view<Char>>::value ||
-        (std::is_convertible<T, int>::value && !std::is_enum<T>::value)>>
-    : std::false_type {};
-
 // Generate a unique explicit instantion in every translation unit using a tag
 // type in an anonymous namespace.
 namespace {
 struct file_access_tag {};
 }  // namespace
-template <class Tag, class BufType, FILE* BufType::*FileMemberPtr>
+template <typename Tag, typename BufType, FILE* BufType::*FileMemberPtr>
 class file_access {
   friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
 };
 
-#if FMT_MSC_VERSION
+#if FMT_MSVC_STL_UPDATE
 template class file_access<file_access_tag, std::filebuf,
                            &std::filebuf::_Myfile>;
 auto get_file(std::filebuf&) -> FILE*;
-#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
-template class file_access<file_access_tag, std::__stdoutbuf<char>,
-                           &std::__stdoutbuf<char>::__file_>;
-auto get_file(std::__stdoutbuf<char>&) -> FILE*;
 #endif
 
-inline bool write_ostream_unicode(std::ostream& os, fmt::string_view data) {
-#if FMT_MSC_VERSION
-  if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
-    if (FILE* f = get_file(*buf)) return write_console(f, data);
-#elif defined(_WIN32) && defined(__GLIBCXX__)
-  auto* rdbuf = os.rdbuf();
-  FILE* c_file;
-  if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
-    c_file = fbuf->file();
-  else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
-    c_file = fbuf->file();
-  else
-    return false;
-  if (c_file) return write_console(c_file, data);
-#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
-  if (auto* buf = dynamic_cast<std::__stdoutbuf<char>*>(os.rdbuf()))
-    if (FILE* f = get_file(*buf)) return write_console(f, data);
-#else
-  ignore_unused(os, data);
-#endif
-  return false;
-}
-inline bool write_ostream_unicode(std::wostream&,
-                                  fmt::basic_string_view<wchar_t>) {
-  return false;
-}
-
 // Write the content of buf to os.
 // It is a separate function rather than a part of vprint to simplify testing.
 template <typename Char>
 void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
   const Char* buf_data = buf.data();
-  using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
+  using unsigned_streamsize = make_unsigned_t<std::streamsize>;
   unsigned_streamsize size = buf.size();
   unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>());
   do {
@@ -120,20 +65,9 @@ void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
   } while (size != 0);
 }
 
-template <typename Char, typename T>
-void format_value(buffer<Char>& buf, const T& value,
-                  locale_ref loc = locale_ref()) {
-  auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf);
-  auto&& output = std::basic_ostream<Char>(&format_buf);
-#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
-  if (loc) output.imbue(loc.get<std::locale>());
-#endif
-  output << value;
-  output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
-}
-
-template <typename T> struct streamed_view { const T& value; };
-
+template <typename T> struct streamed_view {
+  const T& value;
+};
 }  // namespace detail
 
 // Formats an object of type T that has an overloaded ostream operator<<.
@@ -141,11 +75,14 @@ template <typename Char>
 struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
   void set_debug_format() = delete;
 
-  template <typename T, typename OutputIt>
-  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) const
-      -> OutputIt {
+  template <typename T, typename Context>
+  auto format(const T& value, Context& ctx) const -> decltype(ctx.out()) {
     auto buffer = basic_memory_buffer<Char>();
-    format_value(buffer, value, ctx.locale());
+    auto&& formatbuf = detail::formatbuf<std::basic_streambuf<Char>>(buffer);
+    auto&& output = std::basic_ostream<Char>(&formatbuf);
+    output.imbue(std::locale::classic());  // The default is always unlocalized.
+    output << value;
+    output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
     return formatter<basic_string_view<Char>, Char>::format(
         {buffer.data(), buffer.size()}, ctx);
   }
@@ -156,80 +93,72 @@ using ostream_formatter = basic_ostream_formatter<char>;
 template <typename T, typename Char>
 struct formatter<detail::streamed_view<T>, Char>
     : basic_ostream_formatter<Char> {
-  template <typename OutputIt>
-  auto format(detail::streamed_view<T> view,
-              basic_format_context<OutputIt, Char>& ctx) const -> OutputIt {
+  template <typename Context>
+  auto format(detail::streamed_view<T> view, Context& ctx) const
+      -> decltype(ctx.out()) {
     return basic_ostream_formatter<Char>::format(view.value, ctx);
   }
 };
 
 /**
-  \rst
-  Returns a view that formats `value` via an ostream ``operator<<``.
-
-  **Example**::
-
-    fmt::print("Current thread id: {}\n",
-               fmt::streamed(std::this_thread::get_id()));
-  \endrst
+ * Returns a view that formats `value` via an ostream `operator<<`.
+ *
+ * **Example**:
+ *
+ *     fmt::print("Current thread id: {}\n",
+ *                fmt::streamed(std::this_thread::get_id()));
  */
 template <typename T>
-auto streamed(const T& value) -> detail::streamed_view<T> {
+constexpr auto streamed(const T& value) -> detail::streamed_view<T> {
   return {value};
 }
 
-namespace detail {
-
-// Formats an object of type T that has an overloaded ostream operator<<.
-template <typename T, typename Char>
-struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
-    : basic_ostream_formatter<Char> {
-  using basic_ostream_formatter<Char>::format;
-};
-
-inline void vprint_directly(std::ostream& os, string_view format_str,
-                            format_args args) {
+inline void vprint(std::ostream& os, string_view fmt, format_args args) {
   auto buffer = memory_buffer();
-  detail::vformat_to(buffer, format_str, args);
-  detail::write_buffer(os, buffer);
-}
-
-}  // namespace detail
-
-FMT_MODULE_EXPORT template <typename Char>
-void vprint(std::basic_ostream<Char>& os,
-            basic_string_view<type_identity_t<Char>> format_str,
-            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  auto buffer = basic_memory_buffer<Char>();
-  detail::vformat_to(buffer, format_str, args);
-  if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()})) return;
+  detail::vformat_to(buffer, fmt, args);
+  FILE* f = nullptr;
+#if FMT_MSVC_STL_UPDATE && FMT_USE_RTTI
+  if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
+    f = detail::get_file(*buf);
+#elif defined(_WIN32) && defined(__GLIBCXX__) && FMT_USE_RTTI
+  auto* rdbuf = os.rdbuf();
+  if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
+    f = sfbuf->file();
+  else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
+    f = fbuf->file();
+#endif
+#ifdef _WIN32
+  if (f) {
+    int fd = _fileno(f);
+    if (_isatty(fd)) {
+      os.flush();
+      if (detail::write_console(fd, {buffer.data(), buffer.size()})) return;
+    }
+  }
+#endif
+  detail::ignore_unused(f);
   detail::write_buffer(os, buffer);
 }
 
 /**
-  \rst
-  Prints formatted data to the stream *os*.
-
-  **Example**::
-
-    fmt::print(cerr, "Don't {}!", "panic");
-  \endrst
+ * Prints formatted data to the stream `os`.
+ *
+ * **Example**:
+ *
+ *     fmt::print(cerr, "Don't {}!", "panic");
  */
-FMT_MODULE_EXPORT template <typename... T>
+FMT_EXPORT template <typename... T>
 void print(std::ostream& os, format_string<T...> fmt, T&&... args) {
-  const auto& vargs = fmt::make_format_args(args...);
-  if (detail::is_utf8())
-    vprint(os, fmt, vargs);
-  else
-    detail::vprint_directly(os, fmt, vargs);
+  fmt::vargs<T...> vargs = {{args...}};
+  if (detail::const_check(detail::use_utf8)) return vprint(os, fmt.str, vargs);
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, fmt.str, vargs);
+  detail::write_buffer(os, buffer);
 }
 
-FMT_MODULE_EXPORT
-template <typename... Args>
-void print(std::wostream& os,
-           basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
-           Args&&... args) {
-  vprint(os, fmt, fmt::make_format_args<buffer_context<wchar_t>>(args...));
+FMT_EXPORT template <typename... T>
+void println(std::ostream& os, format_string<T...> fmt, T&&... args) {
+  fmt::print(os, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
 }
 
 FMT_END_NAMESPACE

include/spdlog/fmt/bundled/printf.h

@@ -8,107 +8,121 @@
 #ifndef FMT_PRINTF_H_
 #define FMT_PRINTF_H_
 
-#include <algorithm>  // std::max
-#include <limits>     // std::numeric_limits
+#ifndef FMT_MODULE
+#  include <algorithm>  // std::max
+#  include <limits>     // std::numeric_limits
+#endif
 
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
-template <typename T> struct printf_formatter { printf_formatter() = delete; };
-
-template <typename Char>
-class basic_printf_parse_context : public basic_format_parse_context<Char> {
-  using basic_format_parse_context<Char>::basic_format_parse_context;
+template <typename T> struct printf_formatter {
+  printf_formatter() = delete;
 };
 
-template <typename OutputIt, typename Char> class basic_printf_context {
+template <typename Char> class basic_printf_context {
  private:
-  OutputIt out_;
+  basic_appender<Char> out_;
   basic_format_args<basic_printf_context> args_;
 
+  static_assert(std::is_same<Char, char>::value ||
+                    std::is_same<Char, wchar_t>::value,
+                "Unsupported code unit type.");
+
  public:
   using char_type = Char;
-  using format_arg = basic_format_arg<basic_printf_context>;
-  using parse_context_type = basic_printf_parse_context<Char>;
+  using parse_context_type = parse_context<Char>;
   template <typename T> using formatter_type = printf_formatter<T>;
+  enum { builtin_types = 1 };
 
-  /**
-    \rst
-    Constructs a ``printf_context`` object. References to the arguments are
-    stored in the context object so make sure they have appropriate lifetimes.
-    \endrst
-   */
-  basic_printf_context(OutputIt out,
+  /// Constructs a `printf_context` object. References to the arguments are
+  /// stored in the context object so make sure they have appropriate lifetimes.
+  basic_printf_context(basic_appender<Char> out,
                        basic_format_args<basic_printf_context> args)
       : out_(out), args_(args) {}
 
-  OutputIt out() { return out_; }
-  void advance_to(OutputIt it) { out_ = it; }
+  auto out() -> basic_appender<Char> { return out_; }
+  void advance_to(basic_appender<Char>) {}
 
-  detail::locale_ref locale() { return {}; }
+  auto locale() -> detail::locale_ref { return {}; }
 
-  format_arg arg(int id) const { return args_.get(id); }
-
-  FMT_CONSTEXPR void on_error(const char* message) {
-    detail::error_handler().on_error(message);
+  auto arg(int id) const -> basic_format_arg<basic_printf_context> {
+    return args_.get(id);
   }
 };
 
-FMT_BEGIN_DETAIL_NAMESPACE
+namespace detail {
+
+// Return the result via the out param to workaround gcc bug 77539.
+template <bool IS_CONSTEXPR, typename T, typename Ptr = const T*>
+FMT_CONSTEXPR auto find(Ptr first, Ptr last, T value, Ptr& out) -> bool {
+  for (out = first; out != last; ++out) {
+    if (*out == value) return true;
+  }
+  return false;
+}
+
+template <>
+inline auto find<false, char>(const char* first, const char* last, char value,
+                              const char*& out) -> bool {
+  out =
+      static_cast<const char*>(memchr(first, value, to_unsigned(last - first)));
+  return out != nullptr;
+}
 
 // Checks if a value fits in int - used to avoid warnings about comparing
 // signed and unsigned integers.
 template <bool IsSigned> struct int_checker {
-  template <typename T> static bool fits_in_int(T value) {
-    unsigned max = max_value<int>();
+  template <typename T> static auto fits_in_int(T value) -> bool {
+    unsigned max = to_unsigned(max_value<int>());
     return value <= max;
   }
-  static bool fits_in_int(bool) { return true; }
+  inline static auto fits_in_int(bool) -> bool { return true; }
 };
 
 template <> struct int_checker<true> {
-  template <typename T> static bool fits_in_int(T value) {
+  template <typename T> static auto fits_in_int(T value) -> bool {
     return value >= (std::numeric_limits<int>::min)() &&
            value <= max_value<int>();
   }
-  static bool fits_in_int(int) { return true; }
+  inline static auto fits_in_int(int) -> bool { return true; }
 };
 
-class printf_precision_handler {
- public:
+struct printf_precision_handler {
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
-  int operator()(T value) {
+  auto operator()(T value) -> int {
     if (!int_checker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
-      FMT_THROW(format_error("number is too big"));
+      report_error("number is too big");
     return (std::max)(static_cast<int>(value), 0);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
-  int operator()(T) {
-    FMT_THROW(format_error("precision is not integer"));
+  auto operator()(T) -> int {
+    report_error("precision is not integer");
     return 0;
   }
 };
 
 // An argument visitor that returns true iff arg is a zero integer.
-class is_zero_int {
- public:
+struct is_zero_int {
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
-  bool operator()(T value) {
+  auto operator()(T value) -> bool {
     return value == 0;
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
-  bool operator()(T) {
+  auto operator()(T) -> bool {
     return false;
   }
 };
 
 template <typename T> struct make_unsigned_or_bool : std::make_unsigned<T> {};
 
-template <> struct make_unsigned_or_bool<bool> { using type = bool; };
+template <> struct make_unsigned_or_bool<bool> {
+  using type = bool;
+};
 
 template <typename T, typename Context> class arg_converter {
  private:
@@ -131,24 +145,19 @@ template <typename T, typename Context> class arg_converter {
     using target_type = conditional_t<std::is_same<T, void>::value, U, T>;
     if (const_check(sizeof(target_type) <= sizeof(int))) {
       // Extra casts are used to silence warnings.
-      if (is_signed) {
-        arg_ = detail::make_arg<Context>(
-            static_cast<int>(static_cast<target_type>(value)));
-      } else {
       using unsigned_type = typename make_unsigned_or_bool<target_type>::type;
-        arg_ = detail::make_arg<Context>(
-            static_cast<unsigned>(static_cast<unsigned_type>(value)));
-      }
+      if (is_signed)
+        arg_ = static_cast<int>(static_cast<target_type>(value));
+      else
+        arg_ = static_cast<unsigned>(static_cast<unsigned_type>(value));
     } else {
-      if (is_signed) {
       // glibc's printf doesn't sign extend arguments of smaller types:
       //   std::printf("%lld", -42);  // prints "4294967254"
       // but we don't have to do the same because it's a UB.
-        arg_ = detail::make_arg<Context>(static_cast<long long>(value));
-      } else {
-        arg_ = detail::make_arg<Context>(
-            static_cast<typename make_unsigned_or_bool<U>::type>(value));
-      }
+      if (is_signed)
+        arg_ = static_cast<long long>(value);
+      else
+        arg_ = static_cast<typename make_unsigned_or_bool<U>::type>(value);
     }
   }
 
@@ -162,7 +171,7 @@ template <typename T, typename Context> class arg_converter {
 // unsigned).
 template <typename T, typename Context, typename Char>
 void convert_arg(basic_format_arg<Context>& arg, Char type) {
-  visit_format_arg(arg_converter<T, Context>(arg, type), arg);
+  arg.visit(arg_converter<T, Context>(arg, type));
 }
 
 // Converts an integer argument to char for printf.
@@ -175,8 +184,7 @@ template <typename Context> class char_converter {
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   void operator()(T value) {
-    arg_ = detail::make_arg<Context>(
-        static_cast<typename Context::char_type>(value));
+    arg_ = static_cast<typename Context::char_type>(value);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
@@ -186,150 +194,148 @@ template <typename Context> class char_converter {
 // An argument visitor that return a pointer to a C string if argument is a
 // string or null otherwise.
 template <typename Char> struct get_cstring {
-  template <typename T> const Char* operator()(T) { return nullptr; }
-  const Char* operator()(const Char* s) { return s; }
+  template <typename T> auto operator()(T) -> const Char* { return nullptr; }
+  auto operator()(const Char* s) -> const Char* { return s; }
 };
 
 // Checks if an argument is a valid printf width specifier and sets
 // left alignment if it is negative.
-template <typename Char> class printf_width_handler {
+class printf_width_handler {
  private:
-  using format_specs = basic_format_specs<Char>;
-
   format_specs& specs_;
 
  public:
-  explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
+  inline explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
-  unsigned operator()(T value) {
+  auto operator()(T value) -> unsigned {
     auto width = static_cast<uint32_or_64_or_128_t<T>>(value);
     if (detail::is_negative(value)) {
-      specs_.align = align::left;
+      specs_.set_align(align::left);
       width = 0 - width;
     }
-    unsigned int_max = max_value<int>();
-    if (width > int_max) FMT_THROW(format_error("number is too big"));
+    unsigned int_max = to_unsigned(max_value<int>());
+    if (width > int_max) report_error("number is too big");
     return static_cast<unsigned>(width);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
-  unsigned operator()(T) {
-    FMT_THROW(format_error("width is not integer"));
+  auto operator()(T) -> unsigned {
+    report_error("width is not integer");
     return 0;
   }
 };
 
-// The ``printf`` argument formatter.
-template <typename OutputIt, typename Char>
+// Workaround for a bug with the XL compiler when initializing
+// printf_arg_formatter's base class.
+template <typename Char>
+auto make_arg_formatter(basic_appender<Char> iter, format_specs& s)
+    -> arg_formatter<Char> {
+  return {iter, s, locale_ref()};
+}
+
+// The `printf` argument formatter.
+template <typename Char>
 class printf_arg_formatter : public arg_formatter<Char> {
  private:
   using base = arg_formatter<Char>;
-  using context_type = basic_printf_context<OutputIt, Char>;
-  using format_specs = basic_format_specs<Char>;
+  using context_type = basic_printf_context<Char>;
 
   context_type& context_;
 
-  OutputIt write_null_pointer(bool is_string = false) {
+  void write_null_pointer(bool is_string = false) {
     auto s = this->specs;
-    s.type = presentation_type::none;
-    return write_bytes(this->out, is_string ? "(null)" : "(nil)", s);
+    s.set_type(presentation_type::none);
+    write_bytes<Char>(this->out, is_string ? "(null)" : "(nil)", s);
+  }
+
+  template <typename T> void write(T value) {
+    detail::write<Char>(this->out, value, this->specs, this->locale);
   }
 
  public:
-  printf_arg_formatter(OutputIt iter, format_specs& s, context_type& ctx)
-      : base{iter, s, locale_ref()}, context_(ctx) {}
+  printf_arg_formatter(basic_appender<Char> iter, format_specs& s,
+                       context_type& ctx)
+      : base(make_arg_formatter(iter, s)), context_(ctx) {}
 
-  OutputIt operator()(monostate value) { return base::operator()(value); }
+  void operator()(monostate value) { write(value); }
 
   template <typename T, FMT_ENABLE_IF(detail::is_integral<T>::value)>
-  OutputIt operator()(T value) {
+  void operator()(T value) {
     // MSVC2013 fails to compile separate overloads for bool and Char so use
     // std::is_same instead.
-    if (std::is_same<T, Char>::value) {
-      format_specs fmt_specs = this->specs;
-      if (fmt_specs.type != presentation_type::none &&
-          fmt_specs.type != presentation_type::chr) {
+    if (!std::is_same<T, Char>::value) {
+      write(value);
+      return;
+    }
+    format_specs s = this->specs;
+    if (s.type() != presentation_type::none &&
+        s.type() != presentation_type::chr) {
       return (*this)(static_cast<int>(value));
     }
-      fmt_specs.sign = sign::none;
-      fmt_specs.alt = false;
-      fmt_specs.fill[0] = ' ';  // Ignore '0' flag for char types.
+    s.set_sign(sign::none);
+    s.clear_alt();
+    s.set_fill(' ');  // Ignore '0' flag for char types.
     // align::numeric needs to be overwritten here since the '0' flag is
     // ignored for non-numeric types
-      if (fmt_specs.align == align::none || fmt_specs.align == align::numeric)
-        fmt_specs.align = align::right;
-      return write<Char>(this->out, static_cast<Char>(value), fmt_specs);
-    }
-    return base::operator()(value);
+    if (s.align() == align::none || s.align() == align::numeric)
+      s.set_align(align::right);
+    detail::write<Char>(this->out, static_cast<Char>(value), s);
   }
 
   template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
-  OutputIt operator()(T value) {
-    return base::operator()(value);
+  void operator()(T value) {
+    write(value);
   }
 
-  /** Formats a null-terminated C string. */
-  OutputIt operator()(const char* value) {
-    if (value) return base::operator()(value);
-    return write_null_pointer(this->specs.type != presentation_type::pointer);
+  void operator()(const char* value) {
+    if (value)
+      write(value);
+    else
+      write_null_pointer(this->specs.type() != presentation_type::pointer);
   }
 
-  /** Formats a null-terminated wide C string. */
-  OutputIt operator()(const wchar_t* value) {
-    if (value) return base::operator()(value);
-    return write_null_pointer(this->specs.type != presentation_type::pointer);
+  void operator()(const wchar_t* value) {
+    if (value)
+      write(value);
+    else
+      write_null_pointer(this->specs.type() != presentation_type::pointer);
   }
 
-  OutputIt operator()(basic_string_view<Char> value) {
-    return base::operator()(value);
+  void operator()(basic_string_view<Char> value) { write(value); }
+
+  void operator()(const void* value) {
+    if (value)
+      write(value);
+    else
+      write_null_pointer();
   }
 
-  /** Formats a pointer. */
-  OutputIt operator()(const void* value) {
-    return value ? base::operator()(value) : write_null_pointer();
-  }
-
-  /** Formats an argument of a custom (user-defined) type. */
-  OutputIt operator()(typename basic_format_arg<context_type>::handle handle) {
-    auto parse_ctx =
-        basic_printf_parse_context<Char>(basic_string_view<Char>());
+  void operator()(typename basic_format_arg<context_type>::handle handle) {
+    auto parse_ctx = parse_context<Char>({});
     handle.format(parse_ctx, context_);
-    return this->out;
   }
 };
 
 template <typename Char>
-void parse_flags(basic_format_specs<Char>& specs, const Char*& it,
-                 const Char* end) {
+void parse_flags(format_specs& specs, const Char*& it, const Char* end) {
   for (; it != end; ++it) {
     switch (*it) {
-    case '-':
-      specs.align = align::left;
-      break;
-    case '+':
-      specs.sign = sign::plus;
-      break;
-    case '0':
-      specs.fill[0] = '0';
-      break;
+    case '-': specs.set_align(align::left); break;
+    case '+': specs.set_sign(sign::plus); break;
+    case '0': specs.set_fill('0'); break;
     case ' ':
-      if (specs.sign != sign::plus) {
-        specs.sign = sign::space;
-      }
+      if (specs.sign() != sign::plus) specs.set_sign(sign::space);
       break;
-    case '#':
-      specs.alt = true;
-      break;
-    default:
-      return;
+    case '#': specs.set_alt(); break;
+    default:  return;
     }
   }
 }
 
 template <typename Char, typename GetArg>
-int parse_header(const Char*& it, const Char* end,
-                 basic_format_specs<Char>& specs, GetArg get_arg) {
+auto parse_header(const Char*& it, const Char* end, format_specs& specs,
+                  GetArg get_arg) -> int {
   int arg_index = -1;
   Char c = *it;
   if (c >= '0' && c <= '9') {
@@ -340,11 +346,11 @@ int parse_header(const Char*& it, const Char* end,
       ++it;
       arg_index = value != -1 ? value : max_value<int>();
     } else {
-      if (c == '0') specs.fill[0] = '0';
+      if (c == '0') specs.set_fill('0');
       if (value != 0) {
         // Nonzero value means that we parsed width and don't need to
         // parse it or flags again, so return now.
-        if (value == -1) FMT_THROW(format_error("number is too big"));
+        if (value == -1) report_error("number is too big");
         specs.width = value;
         return arg_index;
       }
@@ -355,23 +361,47 @@ int parse_header(const Char*& it, const Char* end,
   if (it != end) {
     if (*it >= '0' && *it <= '9') {
       specs.width = parse_nonnegative_int(it, end, -1);
-      if (specs.width == -1) FMT_THROW(format_error("number is too big"));
+      if (specs.width == -1) report_error("number is too big");
     } else if (*it == '*') {
       ++it;
-      specs.width = static_cast<int>(visit_format_arg(
-          detail::printf_width_handler<Char>(specs), get_arg(-1)));
+      specs.width = static_cast<int>(
+          get_arg(-1).visit(detail::printf_width_handler(specs)));
     }
   }
   return arg_index;
 }
 
+inline auto parse_printf_presentation_type(char c, type t, bool& upper)
+    -> presentation_type {
+  using pt = presentation_type;
+  constexpr auto integral_set = sint_set | uint_set | bool_set | char_set;
+  switch (c) {
+  case 'd': return in(t, integral_set) ? pt::dec : pt::none;
+  case 'o': return in(t, integral_set) ? pt::oct : pt::none;
+  case 'X': upper = true; FMT_FALLTHROUGH;
+  case 'x': return in(t, integral_set) ? pt::hex : pt::none;
+  case 'E': upper = true; FMT_FALLTHROUGH;
+  case 'e': return in(t, float_set) ? pt::exp : pt::none;
+  case 'F': upper = true; FMT_FALLTHROUGH;
+  case 'f': return in(t, float_set) ? pt::fixed : pt::none;
+  case 'G': upper = true; FMT_FALLTHROUGH;
+  case 'g': return in(t, float_set) ? pt::general : pt::none;
+  case 'A': upper = true; FMT_FALLTHROUGH;
+  case 'a': return in(t, float_set) ? pt::hexfloat : pt::none;
+  case 'c': return in(t, integral_set) ? pt::chr : pt::none;
+  case 's': return in(t, string_set | cstring_set) ? pt::string : pt::none;
+  case 'p': return in(t, pointer_set | cstring_set) ? pt::pointer : pt::none;
+  default:  return pt::none;
+  }
+}
+
 template <typename Char, typename Context>
 void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
              basic_format_args<Context> args) {
-  using OutputIt = buffer_appender<Char>;
-  auto out = OutputIt(buf);
-  auto context = basic_printf_context<OutputIt, Char>(out, args);
-  auto parse_ctx = basic_printf_parse_context<Char>(format);
+  using iterator = basic_appender<Char>;
+  auto out = iterator(buf);
+  auto context = basic_printf_context<Char>(out, args);
+  auto parse_ctx = parse_context<Char>(format);
 
   // Returns the argument with specified index or, if arg_index is -1, the next
   // argument.
@@ -387,26 +417,24 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
   const Char* end = parse_ctx.end();
   auto it = start;
   while (it != end) {
-    if (!detail::find<false, Char>(it, end, '%', it)) {
-      it = end;  // detail::find leaves it == nullptr if it doesn't find '%'
+    if (!find<false, Char>(it, end, '%', it)) {
+      it = end;  // find leaves it == nullptr if it doesn't find '%'.
       break;
     }
     Char c = *it++;
     if (it != end && *it == c) {
-      out = detail::write(
-          out, basic_string_view<Char>(start, detail::to_unsigned(it - start)));
+      write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
       start = ++it;
       continue;
     }
-    out = detail::write(out, basic_string_view<Char>(
-                                 start, detail::to_unsigned(it - 1 - start)));
+    write(out, basic_string_view<Char>(start, to_unsigned(it - 1 - start)));
 
-    basic_format_specs<Char> specs;
-    specs.align = align::right;
+    auto specs = format_specs();
+    specs.set_align(align::right);
 
     // Parse argument index, flags and width.
     int arg_index = parse_header(it, end, specs, get_arg);
-    if (arg_index == 0) parse_ctx.on_error("argument not found");
+    if (arg_index == 0) report_error("argument not found");
 
     // Parse precision.
     if (it != end && *it == '.') {
@@ -416,8 +444,8 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
         specs.precision = parse_nonnegative_int(it, end, 0);
       } else if (c == '*') {
         ++it;
-        specs.precision = static_cast<int>(
-            visit_format_arg(detail::printf_precision_handler(), get_arg(-1)));
+        specs.precision =
+            static_cast<int>(get_arg(-1).visit(printf_precision_handler()));
       } else {
         specs.precision = 0;
       }
@@ -426,32 +454,31 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
     auto arg = get_arg(arg_index);
     // For d, i, o, u, x, and X conversion specifiers, if a precision is
     // specified, the '0' flag is ignored
-    if (specs.precision >= 0 && arg.is_integral())
-      specs.fill[0] =
-          ' ';  // Ignore '0' flag for non-numeric types or if '-' present.
-    if (specs.precision >= 0 && arg.type() == detail::type::cstring_type) {
-      auto str = visit_format_arg(detail::get_cstring<Char>(), arg);
+    if (specs.precision >= 0 && is_integral_type(arg.type())) {
+      // Ignore '0' for non-numeric types or if '-' present.
+      specs.set_fill(' ');
+    }
+    if (specs.precision >= 0 && arg.type() == type::cstring_type) {
+      auto str = arg.visit(get_cstring<Char>());
       auto str_end = str + specs.precision;
       auto nul = std::find(str, str_end, Char());
-      arg = detail::make_arg<basic_printf_context<OutputIt, Char>>(
-          basic_string_view<Char>(
-              str, detail::to_unsigned(nul != str_end ? nul - str
-                                                      : specs.precision)));
+      auto sv = basic_string_view<Char>(
+          str, to_unsigned(nul != str_end ? nul - str : specs.precision));
+      arg = sv;
+    }
+    if (specs.alt() && arg.visit(is_zero_int())) specs.clear_alt();
+    if (specs.fill_unit<Char>() == '0') {
+      if (is_arithmetic_type(arg.type()) && specs.align() != align::left) {
+        specs.set_align(align::numeric);
+      } else {
+        // Ignore '0' flag for non-numeric types or if '-' flag is also present.
+        specs.set_fill(' ');
       }
-    if (specs.alt && visit_format_arg(detail::is_zero_int(), arg))
-      specs.alt = false;
-    if (specs.fill[0] == '0') {
-      if (arg.is_arithmetic() && specs.align != align::left)
-        specs.align = align::numeric;
-      else
-        specs.fill[0] = ' ';  // Ignore '0' flag for non-numeric types or if '-'
-                              // flag is also present.
     }
 
     // Parse length and convert the argument to the required type.
     c = it != end ? *it++ : 0;
     Char t = it != end ? *it : 0;
-    using detail::convert_arg;
     switch (c) {
     case 'h':
       if (t == 'h') {
@@ -471,170 +498,136 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
         convert_arg<long>(arg, t);
       }
       break;
-    case 'j':
-      convert_arg<intmax_t>(arg, t);
-      break;
-    case 'z':
-      convert_arg<size_t>(arg, t);
-      break;
-    case 't':
-      convert_arg<std::ptrdiff_t>(arg, t);
-      break;
+    case 'j': convert_arg<intmax_t>(arg, t); break;
+    case 'z': convert_arg<size_t>(arg, t); break;
+    case 't': convert_arg<std::ptrdiff_t>(arg, t); break;
     case 'L':
       // printf produces garbage when 'L' is omitted for long double, no
       // need to do the same.
       break;
-    default:
-      --it;
-      convert_arg<void>(arg, c);
+    default: --it; convert_arg<void>(arg, c);
     }
 
     // Parse type.
-    if (it == end) FMT_THROW(format_error("invalid format string"));
+    if (it == end) report_error("invalid format string");
     char type = static_cast<char>(*it++);
-    if (arg.is_integral()) {
+    if (is_integral_type(arg.type())) {
       // Normalize type.
       switch (type) {
       case 'i':
-      case 'u':
-        type = 'd';
-        break;
+      case 'u': type = 'd'; break;
       case 'c':
-        visit_format_arg(
-            detail::char_converter<basic_printf_context<OutputIt, Char>>(arg),
-            arg);
+        arg.visit(char_converter<basic_printf_context<Char>>(arg));
         break;
       }
     }
-    specs.type = parse_presentation_type(type);
-    if (specs.type == presentation_type::none)
-      parse_ctx.on_error("invalid type specifier");
+    bool upper = false;
+    specs.set_type(parse_printf_presentation_type(type, arg.type(), upper));
+    if (specs.type() == presentation_type::none)
+      report_error("invalid format specifier");
+    if (upper) specs.set_upper();
 
     start = it;
 
     // Format argument.
-    out = visit_format_arg(
-        detail::printf_arg_formatter<OutputIt, Char>(out, specs, context), arg);
+    arg.visit(printf_arg_formatter<Char>(out, specs, context));
   }
-  detail::write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
+  write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
 }
-FMT_END_DETAIL_NAMESPACE
+}  // namespace detail
 
-template <typename Char>
-using basic_printf_context_t =
-    basic_printf_context<detail::buffer_appender<Char>, Char>;
-
-using printf_context = basic_printf_context_t<char>;
-using wprintf_context = basic_printf_context_t<wchar_t>;
+using printf_context = basic_printf_context<char>;
+using wprintf_context = basic_printf_context<wchar_t>;
 
 using printf_args = basic_format_args<printf_context>;
 using wprintf_args = basic_format_args<wprintf_context>;
 
-/**
-  \rst
-  Constructs an `~fmt::format_arg_store` object that contains references to
-  arguments and can be implicitly converted to `~fmt::printf_args`.
-  \endrst
- */
-template <typename... T>
-inline auto make_printf_args(const T&... args)
-    -> format_arg_store<printf_context, T...> {
-  return {args...};
+/// Constructs an `format_arg_store` object that contains references to
+/// arguments and can be implicitly converted to `printf_args`.
+template <typename Char = char, typename... T>
+inline auto make_printf_args(T&... args)
+    -> decltype(fmt::make_format_args<basic_printf_context<Char>>(args...)) {
+  return fmt::make_format_args<basic_printf_context<Char>>(args...);
 }
 
-/**
-  \rst
-  Constructs an `~fmt::format_arg_store` object that contains references to
-  arguments and can be implicitly converted to `~fmt::wprintf_args`.
-  \endrst
- */
-template <typename... T>
-inline auto make_wprintf_args(const T&... args)
-    -> format_arg_store<wprintf_context, T...> {
-  return {args...};
-}
+template <typename Char> struct vprintf_args {
+  using type = basic_format_args<basic_printf_context<Char>>;
+};
 
-template <typename S, typename Char = char_t<S>>
-inline auto vsprintf(
-    const S& fmt,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
+template <typename Char>
+inline auto vsprintf(basic_string_view<Char> fmt,
+                     typename vprintf_args<Char>::type args)
     -> std::basic_string<Char> {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, detail::to_string_view(fmt), args);
-  return to_string(buffer);
+  auto buf = basic_memory_buffer<Char>();
+  detail::vprintf(buf, fmt, args);
+  return {buf.data(), buf.size()};
 }
 
 /**
-  \rst
-  Formats arguments and returns the result as a string.
-
-  **Example**::
-
-    std::string message = fmt::sprintf("The answer is %d", 42);
-  \endrst
-*/
-template <typename S, typename... T,
-          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
+ * Formats `args` according to specifications in `fmt` and returns the result
+ * as as string.
+ *
+ * **Example**:
+ *
+ *     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> {
-  using context = basic_printf_context_t<Char>;
   return vsprintf(detail::to_string_view(fmt),
-                  fmt::make_format_args<context>(args...));
+                  fmt::make_format_args<basic_printf_context<Char>>(args...));
 }
 
-template <typename S, typename Char = char_t<S>>
-inline auto vfprintf(
-    std::FILE* f, const S& fmt,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
-    -> int {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, detail::to_string_view(fmt), args);
-  size_t size = buffer.size();
-  return std::fwrite(buffer.data(), sizeof(Char), size, f) < size
+template <typename Char>
+inline 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();
+  return std::fwrite(buf.data(), sizeof(Char), size, f) < size
              ? -1
              : static_cast<int>(size);
 }
 
 /**
-  \rst
-  Prints formatted data to the file *f*.
-
-  **Example**::
-
-    fmt::fprintf(stderr, "Don't %s!", "panic");
-  \endrst
+ * Formats `args` according to specifications in `fmt` and writes the output
+ * to `f`.
+ *
+ * **Example**:
+ *
+ *     fmt::fprintf(stderr, "Don't %s!", "panic");
  */
-template <typename S, typename... T, typename Char = char_t<S>>
+template <typename S, typename... T, typename Char = detail::char_t<S>>
 inline auto fprintf(std::FILE* f, const S& fmt, const T&... args) -> int {
-  using context = basic_printf_context_t<Char>;
   return vfprintf(f, detail::to_string_view(fmt),
-                  fmt::make_format_args<context>(args...));
+                  make_printf_args<Char>(args...));
 }
 
-template <typename S, typename Char = char_t<S>>
-inline auto vprintf(
-    const S& fmt,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
+template <typename Char>
+FMT_DEPRECATED inline auto vprintf(basic_string_view<Char> fmt,
+                                   typename vprintf_args<Char>::type args)
     -> int {
-  return vfprintf(stdout, detail::to_string_view(fmt), args);
+  return vfprintf(stdout, fmt, args);
 }
 
 /**
-  \rst
-  Prints formatted data to ``stdout``.
-
-  **Example**::
-
-    fmt::printf("Elapsed time: %.2f seconds", 1.23);
-  \endrst
+ * Formats `args` according to specifications in `fmt` and writes the output
+ * to `stdout`.
+ *
+ * **Example**:
+ *
+ *   fmt::printf("Elapsed time: %.2f seconds", 1.23);
  */
-template <typename S, typename... T, FMT_ENABLE_IF(detail::is_string<S>::value)>
-inline auto printf(const S& fmt, const T&... args) -> int {
-  return vprintf(
-      detail::to_string_view(fmt),
-      fmt::make_format_args<basic_printf_context_t<char_t<S>>>(args...));
+template <typename... 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_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_PRINTF_H_

include/spdlog/fmt/bundled/std.h

@@ -8,127 +8,354 @@
 #ifndef FMT_STD_H_
 #define FMT_STD_H_
 
-#include <thread>
-#include <type_traits>
-#include <utility>
-
+#include "format.h"
 #include "ostream.h"
 
-#if FMT_HAS_INCLUDE(<version>)
-#  include <version>
-#endif
-// Checking FMT_CPLUSPLUS for warning suppression in MSVC.
-#if FMT_CPLUSPLUS >= 201703L
-#  if FMT_HAS_INCLUDE(<filesystem>)
+#ifndef FMT_MODULE
+#  include <atomic>
+#  include <bitset>
+#  include <complex>
+#  include <cstdlib>
+#  include <exception>
+#  include <functional>
+#  include <memory>
+#  include <thread>
+#  include <type_traits>
+#  include <typeinfo>
+#  include <utility>
+#  include <vector>
+
+// Check FMT_CPLUSPLUS to suppress a bogus warning in MSVC.
+#  if FMT_CPLUSPLUS >= 201703L
+#    if FMT_HAS_INCLUDE(<filesystem>) && \
+        (!defined(FMT_CPP_LIB_FILESYSTEM) || FMT_CPP_LIB_FILESYSTEM != 0)
 #      include <filesystem>
 #    endif
 #    if FMT_HAS_INCLUDE(<variant>)
 #      include <variant>
 #    endif
+#    if FMT_HAS_INCLUDE(<optional>)
+#      include <optional>
+#    endif
+#  endif
+// Use > instead of >= in the version check because <source_location> may be
+// available after C++17 but before C++20 is marked as implemented.
+#  if FMT_CPLUSPLUS > 201703L && FMT_HAS_INCLUDE(<source_location>)
+#    include <source_location>
+#  endif
+#  if FMT_CPLUSPLUS > 202002L && FMT_HAS_INCLUDE(<expected>)
+#    include <expected>
+#  endif
+#endif  // FMT_MODULE
+
+#if FMT_HAS_INCLUDE(<version>)
+#  include <version>
 #endif
 
-#ifdef __cpp_lib_filesystem
+// GCC 4 does not support FMT_HAS_INCLUDE.
+#if FMT_HAS_INCLUDE(<cxxabi.h>) || defined(__GLIBCXX__)
+#  include <cxxabi.h>
+// Android NDK with gabi++ library on some architectures does not implement
+// abi::__cxa_demangle().
+#  ifndef __GABIXX_CXXABI_H__
+#    define FMT_HAS_ABI_CXA_DEMANGLE
+#  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
+#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
+#endif
+
+#if FMT_CPP_LIB_FILESYSTEM
 FMT_BEGIN_NAMESPACE
 
 namespace detail {
 
-template <typename Char>
+template <typename Char, typename PathChar>
+auto get_path_string(const std::filesystem::path& p,
+                     const std::basic_string<PathChar>& native) {
+  if constexpr (std::is_same_v<Char, char> && std::is_same_v<PathChar, wchar_t>)
+    return to_utf8<wchar_t>(native, to_utf8_error_policy::replace);
+  else
+    return p.string<Char>();
+}
+
+template <typename Char, typename PathChar>
 void write_escaped_path(basic_memory_buffer<Char>& quoted,
-                        const std::filesystem::path& p) {
-  write_escaped_string<Char>(std::back_inserter(quoted), p.string<Char>());
-}
-#  ifdef _WIN32
-template <>
-inline void write_escaped_path<char>(basic_memory_buffer<char>& quoted,
-                                     const std::filesystem::path& p) {
-  auto s = p.u8string();
-  write_escaped_string<char>(
-      std::back_inserter(quoted),
-      string_view(reinterpret_cast<const char*>(s.c_str()), s.size()));
-}
-#  endif
-template <>
-inline void write_escaped_path<std::filesystem::path::value_type>(
-    basic_memory_buffer<std::filesystem::path::value_type>& quoted,
-    const std::filesystem::path& p) {
+                        const std::filesystem::path& p,
+                        const std::basic_string<PathChar>& native) {
+  if constexpr (std::is_same_v<Char, char> &&
+                std::is_same_v<PathChar, wchar_t>) {
+    auto buf = basic_memory_buffer<wchar_t>();
+    write_escaped_string<wchar_t>(std::back_inserter(buf), native);
+    bool valid = to_utf8<wchar_t>::convert(quoted, {buf.data(), buf.size()});
+    FMT_ASSERT(valid, "invalid utf16");
+  } else if constexpr (std::is_same_v<Char, PathChar>) {
     write_escaped_string<std::filesystem::path::value_type>(
-      std::back_inserter(quoted), p.native());
+        std::back_inserter(quoted), native);
+  } else {
+    write_escaped_string<Char>(std::back_inserter(quoted), p.string<Char>());
+  }
 }
 
 }  // namespace detail
 
-template <typename Char>
-struct formatter<std::filesystem::path, Char>
-    : formatter<basic_string_view<Char>> {
+FMT_EXPORT
+template <typename Char> struct formatter<std::filesystem::path, Char> {
+ private:
+  format_specs specs_;
+  detail::arg_ref<Char> width_ref_;
+  bool debug_ = false;
+  char path_type_ = 0;
+
+ public:
+  FMT_CONSTEXPR void set_debug_format(bool set = true) { debug_ = set; }
+
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) {
+    auto it = ctx.begin(), end = ctx.end();
+    if (it == end) return it;
+
+    it = detail::parse_align(it, end, specs_);
+    if (it == end) return it;
+
+    Char c = *it;
+    if ((c >= '0' && c <= '9') || c == '{')
+      it = detail::parse_width(it, end, specs_, width_ref_, ctx);
+    if (it != end && *it == '?') {
+      debug_ = true;
+      ++it;
+    }
+    if (it != end && (*it == 'g')) path_type_ = detail::to_ascii(*it++);
+    return it;
+  }
+
   template <typename FormatContext>
-  auto format(const std::filesystem::path& p, FormatContext& ctx) const ->
-      typename FormatContext::iterator {
-    basic_memory_buffer<Char> quoted;
-    detail::write_escaped_path(quoted, p);
-    return formatter<basic_string_view<Char>>::format(
-        basic_string_view<Char>(quoted.data(), quoted.size()), ctx);
+  auto format(const std::filesystem::path& p, FormatContext& ctx) const {
+    auto specs = specs_;
+    auto path_string =
+        !path_type_ ? p.native()
+                    : p.generic_string<std::filesystem::path::value_type>();
+
+    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
+                                ctx);
+    if (!debug_) {
+      auto s = detail::get_path_string<Char>(p, path_string);
+      return detail::write(ctx.out(), basic_string_view<Char>(s), specs);
+    }
+    auto quoted = basic_memory_buffer<Char>();
+    detail::write_escaped_path(quoted, p, path_string);
+    return detail::write(ctx.out(),
+                         basic_string_view<Char>(quoted.data(), quoted.size()),
+                         specs);
+  }
+};
+
+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
+FMT_EXPORT
+template <std::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.
+  struct writer {
+    const std::bitset<N>& bs;
+
+    template <typename OutputIt>
+    FMT_CONSTEXPR auto operator()(OutputIt out) -> OutputIt {
+      for (auto pos = N; pos > 0; --pos) {
+        out = detail::write<Char>(out, bs[pos - 1] ? Char('1') : Char('0'));
+      }
+
+      return out;
+    }
+  };
+
+ public:
+  template <typename FormatContext>
+  auto format(const std::bitset<N>& bs, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return this->write_padded(ctx, writer{bs});
+  }
+};
+
+FMT_EXPORT
+template <typename Char>
+struct formatter<std::thread::id, Char> : basic_ostream_formatter<Char> {};
+FMT_END_NAMESPACE
+
+#ifdef __cpp_lib_optional
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<std::optional<T>, Char,
+                 std::enable_if_t<is_formattable<T, Char>::value>> {
+ private:
+  formatter<T, Char> underlying_;
+  static constexpr basic_string_view<Char> optional =
+      detail::string_literal<Char, 'o', 'p', 't', 'i', 'o', 'n', 'a', 'l',
+                             '('>{};
+  static constexpr basic_string_view<Char> none =
+      detail::string_literal<Char, 'n', 'o', 'n', 'e'>{};
+
+  template <class U>
+  FMT_CONSTEXPR static auto maybe_set_debug_format(U& u, bool set)
+      -> decltype(u.set_debug_format(set)) {
+    u.set_debug_format(set);
+  }
+
+  template <class U>
+  FMT_CONSTEXPR static void maybe_set_debug_format(U&, ...) {}
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) {
+    maybe_set_debug_format(underlying_, true);
+    return underlying_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(const std::optional<T>& opt, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    if (!opt) return detail::write<Char>(ctx.out(), none);
+
+    auto out = ctx.out();
+    out = detail::write<Char>(out, optional);
+    ctx.advance_to(out);
+    out = underlying_.format(*opt, ctx);
+    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
+
+FMT_EXPORT
+template <typename T, typename E, typename Char>
+struct formatter<std::expected<T, E>, Char,
+                 std::enable_if_t<(std::is_void<T>::value ||
+                                   is_formattable<T, Char>::value) &&
+                                  is_formattable<E, Char>::value>> {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const std::expected<T, E>& value, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+
+    if (value.has_value()) {
+      out = detail::write<Char>(out, "expected(");
+      if constexpr (!std::is_void<T>::value)
+        out = detail::write_escaped_alternative<Char>(out, *value);
+    } else {
+      out = detail::write<Char>(out, "unexpected(");
+      out = detail::write_escaped_alternative<Char>(out, value.error());
+    }
+    *out++ = ')';
+    return out;
+  }
+};
+FMT_END_NAMESPACE
+#endif  // __cpp_lib_expected
+
+#ifdef __cpp_lib_source_location
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <> struct formatter<std::source_location> {
+  FMT_CONSTEXPR auto parse(parse_context<>& ctx) { return ctx.begin(); }
+
+  template <typename FormatContext>
+  auto format(const std::source_location& loc, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::write(out, loc.file_name());
+    out = detail::write(out, ':');
+    out = detail::write<char>(out, loc.line());
+    out = detail::write(out, ':');
+    out = detail::write<char>(out, loc.column());
+    out = detail::write(out, ": ");
+    out = detail::write(out, loc.function_name());
+    return out;
   }
 };
 FMT_END_NAMESPACE
 #endif
 
+#if FMT_CPP_LIB_VARIANT
 FMT_BEGIN_NAMESPACE
-template <typename Char>
-struct formatter<std::thread::id, Char> : basic_ostream_formatter<Char> {};
-FMT_END_NAMESPACE
-
-#ifdef __cpp_lib_variant
-FMT_BEGIN_NAMESPACE
-template <typename Char> struct formatter<std::monostate, Char> {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-
-  template <typename FormatContext>
-  auto format(const std::monostate&, FormatContext& ctx) const
-      -> decltype(ctx.out()) {
-    auto out = ctx.out();
-    out = detail::write<Char>(out, "monostate");
-    return out;
-  }
-};
-
 namespace detail {
 
 template <typename T>
 using variant_index_sequence =
     std::make_index_sequence<std::variant_size<T>::value>;
 
-// variant_size and variant_alternative check.
-template <typename T, typename U = void>
-struct is_variant_like_ : std::false_type {};
-template <typename T>
-struct is_variant_like_<T, std::void_t<decltype(std::variant_size<T>::value)>>
-    : std::true_type {};
+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
+// formattable element check.
 template <typename T, typename C> class is_variant_formattable_ {
-  template <std::size_t... I>
+  template <std::size_t... Is>
   static std::conjunction<
-      is_formattable<std::variant_alternative_t<I, T>, C>...>
-      check(std::index_sequence<I...>);
+      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;
 };
 
-template <typename Char, typename OutputIt, typename T>
-auto write_variant_alternative(OutputIt out, const T& v) -> OutputIt {
-  if constexpr (is_string<T>::value)
-    return write_escaped_string<Char>(out, detail::to_string_view(v));
-  else if constexpr (std::is_same_v<T, Char>)
-    return write_escaped_char(out, v);
-  else
-    return write<Char>(out, v);
-}
-
 }  // namespace detail
 
 template <typename T> struct is_variant_like {
@@ -140,13 +367,26 @@ template <typename T, typename C> struct is_variant_formattable {
       detail::is_variant_formattable_<T, C>::value;
 };
 
+FMT_EXPORT
+template <typename Char> struct formatter<std::monostate, Char> {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const std::monostate&, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return detail::write<Char>(ctx.out(), "monostate");
+  }
+};
+
+FMT_EXPORT
 template <typename Variant, typename Char>
 struct formatter<
     Variant, Char,
     std::enable_if_t<std::conjunction_v<
         is_variant_like<Variant>, is_variant_formattable<Variant, Char>>>> {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
     return ctx.begin();
   }
 
@@ -156,16 +396,331 @@ struct formatter<
     auto out = ctx.out();
 
     out = detail::write<Char>(out, "variant(");
+    FMT_TRY {
       std::visit(
           [&](const auto& v) {
-          out = detail::write_variant_alternative<Char>(out, v);
+            out = detail::write_escaped_alternative<Char>(out, v);
           },
           value);
+    }
+    FMT_CATCH(const std::bad_variant_access&) {
+      detail::write<Char>(out, "valueless by exception");
+    }
     *out++ = ')';
     return out;
   }
 };
 FMT_END_NAMESPACE
+#endif  // FMT_CPP_LIB_VARIANT
+
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <> struct formatter<std::error_code> {
+ private:
+  format_specs specs_;
+  detail::arg_ref<char> width_ref_;
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<>& ctx) -> const char* {
+    auto it = ctx.begin(), end = ctx.end();
+    if (it == end) return it;
+
+    it = detail::parse_align(it, end, specs_);
+    if (it == end) return it;
+
+    char c = *it;
+    if ((c >= '0' && c <= '9') || c == '{')
+      it = detail::parse_width(it, end, specs_, width_ref_, ctx);
+    return it;
+  }
+
+  template <typename FormatContext>
+  FMT_CONSTEXPR20 auto format(const std::error_code& ec,
+                              FormatContext& ctx) const -> decltype(ctx.out()) {
+    auto specs = specs_;
+    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
+                                ctx);
+    memory_buffer buf;
+    buf.append(string_view(ec.category().name()));
+    buf.push_back(':');
+    detail::write<char>(appender(buf), ec.value());
+    return detail::write<char>(ctx.out(), string_view(buf.data(), buf.size()),
+                               specs);
+  }
+};
+
+#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
+
+FMT_EXPORT
+template <typename Char>
+struct formatter<std::type_info, Char  // DEPRECATED! Mixing code unit types.
+                 > {
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<Char>& 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);
+  }
+};
 #endif
 
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<
+    T, Char,  // DEPRECATED! Mixing code unit types.
+    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* {
+    auto it = ctx.begin();
+    auto end = ctx.end();
+    if (it == end || *it == '}') return it;
+    if (*it == 't') {
+      ++it;
+      with_typename_ = FMT_USE_RTTI != 0;
+    }
+    return it;
+  }
+
+  template <typename Context>
+  auto format(const std::exception& ex, Context& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+#if FMT_USE_RTTI
+    if (with_typename_) {
+      out = detail::write_demangled_name<Char>(out, typeid(ex));
+      *out++ = ':';
+      *out++ = ' ';
+    }
+#endif
+    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.
+FMT_EXPORT
+template <typename BitRef, typename Char>
+struct formatter<BitRef, Char,
+                 enable_if_t<detail::is_bit_reference_like<BitRef>::value>>
+    : formatter<bool, Char> {
+  template <typename FormatContext>
+  FMT_CONSTEXPR auto format(const BitRef& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<bool, Char>::format(v, ctx);
+  }
+};
+
+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();
+}
+
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<std::atomic<T>, Char,
+                 enable_if_t<is_formattable<T, Char>::value>>
+    : formatter<T, Char> {
+  template <typename FormatContext>
+  auto format(const std::atomic<T>& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<T, Char>::format(v.load(), ctx);
+  }
+};
+
+#ifdef __cpp_lib_atomic_flag_test
+FMT_EXPORT
+template <typename Char>
+struct formatter<std::atomic_flag, Char> : formatter<bool, Char> {
+  template <typename FormatContext>
+  auto format(const std::atomic_flag& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<bool, Char>::format(v.test(), ctx);
+  }
+};
+#endif  // __cpp_lib_atomic_flag_test
+
+FMT_EXPORT
+template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
+ private:
+  detail::dynamic_format_specs<Char> specs_;
+
+  template <typename FormatContext, typename OutputIt>
+  FMT_CONSTEXPR auto do_format(const std::complex<T>& c,
+                               detail::dynamic_format_specs<Char>& specs,
+                               FormatContext& ctx, OutputIt out) const
+      -> OutputIt {
+    if (c.real() != 0) {
+      *out++ = Char('(');
+      out = detail::write<Char>(out, c.real(), specs, ctx.locale());
+      specs.set_sign(sign::plus);
+      out = detail::write<Char>(out, c.imag(), specs, ctx.locale());
+      if (!detail::isfinite(c.imag())) *out++ = Char(' ');
+      *out++ = Char('i');
+      *out++ = Char(')');
+      return out;
+    }
+    out = detail::write<Char>(out, c.imag(), specs, ctx.locale());
+    if (!detail::isfinite(c.imag())) *out++ = Char(' ');
+    *out++ = Char('i');
+    return out;
+  }
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    if (ctx.begin() == ctx.end() || *ctx.begin() == '}') return ctx.begin();
+    return parse_format_specs(ctx.begin(), ctx.end(), specs_, ctx,
+                              detail::type_constant<T, Char>::value);
+  }
+
+  template <typename FormatContext>
+  auto format(const std::complex<T>& c, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto specs = specs_;
+    if (specs.dynamic()) {
+      detail::handle_dynamic_spec(specs.dynamic_width(), specs.width,
+                                  specs.width_ref, ctx);
+      detail::handle_dynamic_spec(specs.dynamic_precision(), specs.precision,
+                                  specs.precision_ref, ctx);
+    }
+
+    if (specs.width == 0) return do_format(c, specs, ctx, ctx.out());
+    auto buf = basic_memory_buffer<Char>();
+
+    auto outer_specs = format_specs();
+    outer_specs.width = specs.width;
+    outer_specs.copy_fill_from(specs);
+    outer_specs.set_align(specs.align());
+
+    specs.width = 0;
+    specs.set_fill({});
+    specs.set_align(align::none);
+
+    do_format(c, specs, ctx, basic_appender<Char>(buf));
+    return detail::write<Char>(ctx.out(),
+                               basic_string_view<Char>(buf.data(), buf.size()),
+                               outer_specs);
+  }
+};
+
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<std::reference_wrapper<T>, Char,
+                 enable_if_t<is_formattable<remove_cvref_t<T>, Char>::value>>
+    : formatter<remove_cvref_t<T>, Char> {
+  template <typename FormatContext>
+  auto format(std::reference_wrapper<T> ref, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<remove_cvref_t<T>, Char>::format(ref.get(), ctx);
+  }
+};
+
+FMT_END_NAMESPACE
 #endif  // FMT_STD_H_

include/spdlog/fmt/bundled/xchar.h

@@ -8,52 +8,131 @@
 #ifndef FMT_XCHAR_H_
 #define FMT_XCHAR_H_
 
-#include <cwchar>
-
+#include "color.h"
 #include "format.h"
+#include "ostream.h"
+#include "ranges.h"
+
+#ifndef FMT_MODULE
+#  include <cwchar>
+#  if FMT_USE_LOCALE
+#    include <locale>
+#  endif
+#endif
 
 FMT_BEGIN_NAMESPACE
 namespace detail {
+
 template <typename T>
 using is_exotic_char = bool_constant<!std::is_same<T, char>::value>;
-}
 
-FMT_MODULE_EXPORT_BEGIN
+template <typename S, typename = void> struct format_string_char {};
+
+template <typename S>
+struct format_string_char<
+    S, void_t<decltype(sizeof(detail::to_string_view(std::declval<S>())))>> {
+  using type = char_t<S>;
+};
+
+template <typename S>
+struct format_string_char<
+    S, enable_if_t<std::is_base_of<detail::compile_string, S>::value>> {
+  using type = typename S::char_type;
+};
+
+template <typename S>
+using format_string_char_t = typename format_string_char<S>::type;
+
+inline auto write_loc(basic_appender<wchar_t> out, loc_value value,
+                      const format_specs& specs, locale_ref loc) -> bool {
+#if FMT_USE_LOCALE
+  auto& numpunct =
+      std::use_facet<std::numpunct<wchar_t>>(loc.get<std::locale>());
+  auto separator = std::wstring();
+  auto grouping = numpunct.grouping();
+  if (!grouping.empty()) separator = std::wstring(1, numpunct.thousands_sep());
+  return value.visit(loc_writer<wchar_t>{out, specs, separator, grouping, {}});
+#endif
+  return false;
+}
+}  // namespace detail
+
+FMT_BEGIN_EXPORT
 
 using wstring_view = basic_string_view<wchar_t>;
-using wformat_parse_context = basic_format_parse_context<wchar_t>;
-using wformat_context = buffer_context<wchar_t>;
+using wformat_parse_context = parse_context<wchar_t>;
+using wformat_context = buffered_context<wchar_t>;
 using wformat_args = basic_format_args<wformat_context>;
 using wmemory_buffer = basic_memory_buffer<wchar_t>;
 
-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
-// Workaround broken conversion on older gcc.
-template <typename... Args> using wformat_string = wstring_view;
-inline auto runtime(wstring_view s) -> wstring_view { return s; }
-#else
-template <typename... Args>
-using wformat_string = basic_format_string<wchar_t, type_identity_t<Args>...>;
-inline auto runtime(wstring_view s) -> basic_runtime<wchar_t> { return {{s}}; }
-#endif
+template <typename Char, typename... T> struct basic_fstring {
+ private:
+  basic_string_view<Char> str_;
+
+  static constexpr int num_static_named_args =
+      detail::count_static_named_args<T...>();
+
+  using checker = detail::format_string_checker<
+      Char, static_cast<int>(sizeof...(T)), num_static_named_args,
+      num_static_named_args != detail::count_named_args<T...>()>;
+
+  using arg_pack = detail::arg_pack<T...>;
+
+ public:
+  using t = basic_fstring;
+
+  template <typename S,
+            FMT_ENABLE_IF(
+                std::is_convertible<const S&, basic_string_view<Char>>::value)>
+  FMT_CONSTEVAL FMT_ALWAYS_INLINE basic_fstring(const S& s) : str_(s) {
+    if (FMT_USE_CONSTEVAL)
+      detail::parse_format_string<Char>(s, checker(s, arg_pack()));
+  }
+  template <typename S,
+            FMT_ENABLE_IF(std::is_base_of<detail::compile_string, S>::value&&
+                              std::is_same<typename S::char_type, Char>::value)>
+  FMT_ALWAYS_INLINE basic_fstring(const S&) : str_(S()) {
+    FMT_CONSTEXPR auto sv = basic_string_view<Char>(S());
+    FMT_CONSTEXPR int ignore =
+        (parse_format_string(sv, checker(sv, arg_pack())), 0);
+    detail::ignore_unused(ignore);
+  }
+  basic_fstring(runtime_format_string<Char> fmt) : str_(fmt.str) {}
+
+  operator basic_string_view<Char>() const { return str_; }
+  auto get() const -> basic_string_view<Char> { return str_; }
+};
+
+template <typename Char, typename... T>
+using basic_format_string = basic_fstring<Char, T...>;
+
+template <typename... T>
+using wformat_string = typename basic_format_string<wchar_t, T...>::t;
+inline auto runtime(wstring_view s) -> runtime_format_string<wchar_t> {
+  return {{s}};
+}
 
 template <> struct is_char<wchar_t> : std::true_type {};
-template <> struct is_char<detail::char8_type> : std::true_type {};
 template <> struct is_char<char16_t> : std::true_type {};
 template <> struct is_char<char32_t> : std::true_type {};
 
-template <typename... Args>
-constexpr format_arg_store<wformat_context, Args...> make_wformat_args(
-    const Args&... args) {
-  return {args...};
+#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...)) {
+  return fmt::make_format_args<wformat_context>(args...);
 }
 
+#if !FMT_USE_NONTYPE_TEMPLATE_ARGS
 inline namespace literals {
-#if FMT_USE_USER_DEFINED_LITERALS && !FMT_USE_NONTYPE_TEMPLATE_ARGS
-constexpr detail::udl_arg<wchar_t> operator"" _a(const wchar_t* s, size_t) {
+inline auto operator""_a(const wchar_t* s, size_t) -> detail::udl_arg<wchar_t> {
   return {s};
 }
-#endif
 }  // namespace literals
+#endif
 
 template <typename It, typename Sentinel>
 auto join(It begin, Sentinel end, wstring_view sep)
@@ -61,9 +140,9 @@ auto join(It begin, Sentinel end, wstring_view sep)
   return {begin, end, sep};
 }
 
-template <typename Range>
+template <typename Range, FMT_ENABLE_IF(!is_tuple_like<Range>::value)>
 auto join(Range&& range, wstring_view sep)
-    -> join_view<detail::iterator_t<Range>, detail::sentinel_t<Range>,
+    -> join_view<decltype(std::begin(range)), decltype(std::end(range)),
                  wchar_t> {
   return join(std::begin(range), std::end(range), sep);
 }
@@ -74,13 +153,19 @@ auto join(std::initializer_list<T> list, wstring_view sep)
   return join(std::begin(list), std::end(list), 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> {
+  return {tuple, sep};
+}
+
 template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
-auto vformat(basic_string_view<Char> format_str,
-             basic_format_args<buffer_context<type_identity_t<Char>>> args)
+auto vformat(basic_string_view<Char> fmt,
+             typename detail::vformat_args<Char>::type args)
     -> std::basic_string<Char> {
-  basic_memory_buffer<Char> buffer;
-  detail::vformat_to(buffer, format_str, args);
-  return to_string(buffer);
+  auto buf = basic_memory_buffer<Char>();
+  detail::vformat_to(buf, fmt, args);
+  return {buf.data(), buf.size()};
 }
 
 template <typename... T>
@@ -88,119 +173,130 @@ auto format(wformat_string<T...> fmt, T&&... args) -> std::wstring {
   return vformat(fmt::wstring_view(fmt), fmt::make_wformat_args(args...));
 }
 
+template <typename OutputIt, typename... T>
+auto format_to(OutputIt out, wformat_string<T...> fmt, T&&... args)
+    -> OutputIt {
+  return vformat_to(out, fmt::wstring_view(fmt),
+                    fmt::make_wformat_args(args...));
+}
+
 // Pass char_t as a default template parameter instead of using
 // std::basic_string<char_t<S>> to reduce the symbol size.
-template <typename S, typename... Args, typename Char = char_t<S>,
+template <typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
           FMT_ENABLE_IF(!std::is_same<Char, char>::value &&
                         !std::is_same<Char, wchar_t>::value)>
-auto format(const S& format_str, Args&&... args) -> std::basic_string<Char> {
-  return vformat(detail::to_string_view(format_str),
-                 fmt::make_format_args<buffer_context<Char>>(args...));
+auto format(const S& fmt, T&&... args) -> std::basic_string<Char> {
+  return vformat(detail::to_string_view(fmt),
+                 fmt::make_format_args<buffered_context<Char>>(args...));
 }
 
-template <typename Locale, typename S, typename Char = char_t<S>,
+template <typename Locale, typename S,
+          typename Char = detail::format_string_char_t<S>,
           FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
                             detail::is_exotic_char<Char>::value)>
-inline auto vformat(
-    const Locale& loc, const S& format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args)
+inline auto vformat(const Locale& loc, const S& fmt,
+                    typename detail::vformat_args<Char>::type args)
     -> std::basic_string<Char> {
-  return detail::vformat(loc, detail::to_string_view(format_str), args);
+  auto buf = basic_memory_buffer<Char>();
+  detail::vformat_to(buf, detail::to_string_view(fmt), args,
+                     detail::locale_ref(loc));
+  return {buf.data(), buf.size()};
 }
 
-template <typename Locale, typename S, typename... Args,
-          typename Char = char_t<S>,
+template <typename Locale, typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
           FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
                             detail::is_exotic_char<Char>::value)>
-inline auto format(const Locale& loc, const S& format_str, Args&&... args)
+inline auto format(const Locale& loc, const S& fmt, T&&... args)
     -> std::basic_string<Char> {
-  return detail::vformat(loc, detail::to_string_view(format_str),
-                         fmt::make_format_args<buffer_context<Char>>(args...));
+  return vformat(loc, detail::to_string_view(fmt),
+                 fmt::make_format_args<buffered_context<Char>>(args...));
 }
 
-template <typename OutputIt, typename S, typename Char = char_t<S>,
+template <typename OutputIt, typename S,
+          typename Char = detail::format_string_char_t<S>,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
                             detail::is_exotic_char<Char>::value)>
-auto vformat_to(OutputIt out, const S& format_str,
-                basic_format_args<buffer_context<type_identity_t<Char>>> args)
-    -> OutputIt {
+auto vformat_to(OutputIt out, const S& fmt,
+                typename detail::vformat_args<Char>::type args) -> OutputIt {
   auto&& buf = detail::get_buffer<Char>(out);
-  detail::vformat_to(buf, detail::to_string_view(format_str), args);
-  return detail::get_iterator(buf);
+  detail::vformat_to(buf, detail::to_string_view(fmt), args);
+  return detail::get_iterator(buf, out);
 }
 
-template <typename OutputIt, typename S, typename... Args,
-          typename Char = char_t<S>,
-          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
-                            detail::is_exotic_char<Char>::value)>
-inline auto format_to(OutputIt out, const S& fmt, Args&&... args) -> OutputIt {
+template <typename OutputIt, typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value &&
+                        !std::is_same<Char, char>::value &&
+                        !std::is_same<Char, wchar_t>::value)>
+inline auto format_to(OutputIt out, const S& fmt, T&&... args) -> OutputIt {
   return vformat_to(out, detail::to_string_view(fmt),
-                    fmt::make_format_args<buffer_context<Char>>(args...));
+                    fmt::make_format_args<buffered_context<Char>>(args...));
 }
 
 template <typename Locale, typename S, typename OutputIt, typename... Args,
-          typename Char = char_t<S>,
+          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& format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) -> OutputIt {
+inline auto vformat_to(OutputIt out, const Locale& loc, const S& fmt,
+                       typename detail::vformat_args<Char>::type args)
+    -> OutputIt {
   auto&& buf = detail::get_buffer<Char>(out);
-  vformat_to(buf, detail::to_string_view(format_str), args,
-             detail::locale_ref(loc));
-  return detail::get_iterator(buf);
+  vformat_to(buf, detail::to_string_view(fmt), args, detail::locale_ref(loc));
+  return detail::get_iterator(buf, out);
 }
 
-template <
-    typename OutputIt, typename Locale, typename S, typename... Args,
-    typename Char = char_t<S>,
-    bool enable = detail::is_output_iterator<OutputIt, Char>::value&&
-        detail::is_locale<Locale>::value&& detail::is_exotic_char<Char>::value>
-inline auto format_to(OutputIt out, const Locale& loc, const S& format_str,
-                      Args&&... args) ->
+template <typename Locale, typename OutputIt, typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
+          bool enable = detail::is_output_iterator<OutputIt, Char>::value &&
+                        detail::is_locale<Locale>::value &&
+                        detail::is_exotic_char<Char>::value>
+inline auto format_to(OutputIt out, const Locale& loc, const S& fmt,
+                      T&&... args) ->
     typename std::enable_if<enable, OutputIt>::type {
-  return vformat_to(out, loc, to_string_view(format_str),
-                    fmt::make_format_args<buffer_context<Char>>(args...));
+  return vformat_to(out, loc, detail::to_string_view(fmt),
+                    fmt::make_format_args<buffered_context<Char>>(args...));
 }
 
 template <typename OutputIt, typename Char, typename... Args,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
                             detail::is_exotic_char<Char>::value)>
-inline auto vformat_to_n(
-    OutputIt out, size_t n, basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args)
+inline auto vformat_to_n(OutputIt out, size_t n, basic_string_view<Char> fmt,
+                         typename detail::vformat_args<Char>::type args)
     -> format_to_n_result<OutputIt> {
-  detail::iterator_buffer<OutputIt, Char, detail::fixed_buffer_traits> buf(out,
-                                                                           n);
-  detail::vformat_to(buf, format_str, args);
+  using traits = detail::fixed_buffer_traits;
+  auto buf = detail::iterator_buffer<OutputIt, Char, traits>(out, n);
+  detail::vformat_to(buf, fmt, args);
   return {buf.out(), buf.count()};
 }
 
-template <typename OutputIt, typename S, typename... Args,
-          typename Char = char_t<S>,
+template <typename OutputIt, typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
                             detail::is_exotic_char<Char>::value)>
-inline auto format_to_n(OutputIt out, size_t n, const S& fmt,
-                        const Args&... args) -> format_to_n_result<OutputIt> {
-  return vformat_to_n(out, n, detail::to_string_view(fmt),
-                      fmt::make_format_args<buffer_context<Char>>(args...));
+inline auto format_to_n(OutputIt out, size_t n, const S& fmt, T&&... args)
+    -> format_to_n_result<OutputIt> {
+  return vformat_to_n(out, n, fmt::basic_string_view<Char>(fmt),
+                      fmt::make_format_args<buffered_context<Char>>(args...));
 }
 
-template <typename S, typename... Args, typename Char = char_t<S>,
+template <typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
           FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)>
-inline auto formatted_size(const S& fmt, Args&&... args) -> size_t {
-  detail::counting_buffer<Char> buf;
+inline auto formatted_size(const S& fmt, T&&... args) -> size_t {
+  auto buf = detail::counting_buffer<Char>();
   detail::vformat_to(buf, detail::to_string_view(fmt),
-                     fmt::make_format_args<buffer_context<Char>>(args...));
+                     fmt::make_format_args<buffered_context<Char>>(args...));
   return buf.count();
 }
 
 inline void vprint(std::FILE* f, wstring_view fmt, wformat_args args) {
-  wmemory_buffer buffer;
-  detail::vformat_to(buffer, fmt, args);
-  buffer.push_back(L'\0');
-  if (std::fputws(buffer.data(), f) == -1)
+  auto buf = wmemory_buffer();
+  detail::vformat_to(buf, fmt, args);
+  buf.push_back(L'\0');
+  if (std::fputws(buf.data(), f) == -1)
     FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
 }
 
@@ -217,13 +313,61 @@ template <typename... T> void print(wformat_string<T...> fmt, T&&... args) {
   return vprint(wstring_view(fmt), fmt::make_wformat_args(args...));
 }
 
-/**
-  Converts *value* to ``std::wstring`` using the default format for type *T*.
- */
+template <typename... T>
+void println(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
+  return print(f, L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+template <typename... T> void println(wformat_string<T...> fmt, T&&... args) {
+  return print(L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+inline auto vformat(const text_style& ts, wstring_view fmt, wformat_args args)
+    -> std::wstring {
+  auto buf = wmemory_buffer();
+  detail::vformat_to(buf, ts, fmt, args);
+  return {buf.data(), buf.size()};
+}
+
+template <typename... T>
+inline auto format(const text_style& ts, wformat_string<T...> fmt, T&&... args)
+    -> std::wstring {
+  return fmt::vformat(ts, fmt, fmt::make_wformat_args(args...));
+}
+
+template <typename... T>
+FMT_DEPRECATED void print(std::FILE* f, const text_style& ts,
+                          wformat_string<T...> fmt, const T&... args) {
+  vprint(f, ts, fmt, fmt::make_wformat_args(args...));
+}
+
+template <typename... T>
+FMT_DEPRECATED void print(const text_style& ts, wformat_string<T...> fmt,
+                          const T&... args) {
+  return print(stdout, ts, fmt, args...);
+}
+
+inline void vprint(std::wostream& os, wstring_view fmt, wformat_args args) {
+  auto buffer = basic_memory_buffer<wchar_t>();
+  detail::vformat_to(buffer, fmt, args);
+  detail::write_buffer(os, buffer);
+}
+
+template <typename... T>
+void print(std::wostream& os, wformat_string<T...> fmt, T&&... args) {
+  vprint(os, fmt, fmt::make_format_args<buffered_context<wchar_t>>(args...));
+}
+
+template <typename... T>
+void println(std::wostream& os, wformat_string<T...> fmt, T&&... args) {
+  print(os, L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+/// Converts `value` to `std::wstring` using the default format for type `T`.
 template <typename T> inline auto to_wstring(const T& value) -> std::wstring {
   return format(FMT_STRING(L"{}"), value);
 }
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_XCHAR_H_

include/spdlog/fmt/fmt.h

@@ -20,10 +20,6 @@
     #ifndef FMT_USE_WINDOWS_H
         #define FMT_USE_WINDOWS_H 0
     #endif
-    // enable the 'n' flag in for backward compatibility with fmt 6.x
-    #define FMT_DEPRECATED_N_SPECIFIER
-    // enable ostream formatting for backward compatibility with fmt 8.x
-    #define FMT_DEPRECATED_OSTREAM
 
     #include <spdlog/fmt/bundled/core.h>
     #include <spdlog/fmt/bundled/format.h>

include/spdlog/mdc.h

@@ -0,0 +1,50 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#if defined(SPDLOG_NO_TLS)
+    #error "This header requires thread local storage support, but SPDLOG_NO_TLS is defined."
+#endif
+
+#include <map>
+#include <string>
+
+#include <spdlog/common.h>
+
+// MDC is a simple map of key->string values stored in thread local storage whose content will be printed by the loggers.
+// Note: Not supported in async mode (thread local storage - so the async thread pool have different copy).
+//
+// Usage example:
+// spdlog::mdc::put("mdc_key_1", "mdc_value_1");
+// spdlog::info("Hello, {}", "World!");  // => [2024-04-26 02:08:05.040] [info] [mdc_key_1:mdc_value_1] Hello, World!
+
+namespace spdlog {
+class SPDLOG_API mdc {
+public:
+    using mdc_map_t = std::map<std::string, std::string>;
+
+    static void put(const std::string &key, const std::string &value) {
+        get_context()[key] = value;
+    }
+
+    static std::string get(const std::string &key) {
+        auto &context = get_context();
+        auto it = context.find(key);
+        if (it != context.end()) {
+            return it->second;
+        }
+        return "";
+    }
+
+    static void remove(const std::string &key) { get_context().erase(key); }
+
+    static void clear() { get_context().clear(); }
+
+    static mdc_map_t &get_context() {
+        static thread_local mdc_map_t context;
+        return context;
+    }
+};
+
+}  // namespace spdlog

include/spdlog/pattern_formatter-inl.h

@@ -10,6 +10,11 @@
 #include <spdlog/details/fmt_helper.h>
 #include <spdlog/details/log_msg.h>
 #include <spdlog/details/os.h>
+
+#ifndef SPDLOG_NO_TLS
+    #include <spdlog/mdc.h>
+#endif
+
 #include <spdlog/fmt/fmt.h>
 #include <spdlog/formatter.h>
 
@@ -65,6 +70,9 @@ public:
             pad_it(remaining_pad_);
         } else if (padinfo_.truncate_) {
             long new_size = static_cast<long>(dest_.size()) + remaining_pad_;
+            if (new_size < 0) {
+                new_size = 0;
+            }
             dest_.resize(static_cast<size_t>(new_size));
         }
     }
@@ -175,7 +183,7 @@ public:
 
 // Abbreviated month
 static const std::array<const char *, 12> months{
-    {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sept", "Oct", "Nov", "Dec"}};
+    {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}};
 
 template <typename ScopedPadder>
 class b_formatter final : public flag_formatter {
@@ -259,7 +267,7 @@ public:
         : flag_formatter(padinfo) {}
 
     void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override {
-        const size_t field_size = 10;
+        const size_t field_size = 8;
         ScopedPadder p(field_size, padinfo_, dest);
 
         fmt_helper::pad2(tm_time.tm_mon + 1, dest);
@@ -783,6 +791,49 @@ private:
     log_clock::time_point last_message_time_;
 };
 
+// Class for formatting Mapped Diagnostic Context (MDC) in log messages.
+// Example: [logger-name] [info] [mdc_key_1:mdc_value_1 mdc_key_2:mdc_value_2] some message
+#ifndef SPDLOG_NO_TLS
+template <typename ScopedPadder>
+class mdc_formatter : public flag_formatter {
+public:
+    explicit mdc_formatter(padding_info padinfo)
+        : flag_formatter(padinfo) {}
+
+    void format(const details::log_msg &, const std::tm &, memory_buf_t &dest) override {
+        auto &mdc_map = mdc::get_context();
+        if (mdc_map.empty()) {
+            ScopedPadder p(0, padinfo_, dest);
+            return;
+        } else {
+            format_mdc(mdc_map, dest);
+        }
+    }
+
+    void format_mdc(const mdc::mdc_map_t &mdc_map, memory_buf_t &dest) {
+        auto last_element = --mdc_map.end();
+        for (auto it = mdc_map.begin(); it != mdc_map.end(); ++it) {
+            auto &pair = *it;
+            const auto &key = pair.first;
+            const auto &value = pair.second;
+            size_t content_size = key.size() + value.size() + 1;  // 1 for ':'
+
+            if (it != last_element) {
+                content_size++;  // 1 for ' '
+            }
+
+            ScopedPadder p(content_size, padinfo_, dest);
+            fmt_helper::append_string_view(key, dest);
+            fmt_helper::append_string_view(":", dest);
+            fmt_helper::append_string_view(value, dest);
+            if (it != last_element) {
+                fmt_helper::append_string_view(" ", dest);
+            }
+        }
+    }
+};
+#endif
+
 // Full info formatter
 // pattern: [%Y-%m-%d %H:%M:%S.%e] [%n] [%l] [%s:%#] %v
 class full_formatter final : public flag_formatter {
@@ -858,6 +909,17 @@ public:
             dest.push_back(']');
             dest.push_back(' ');
         }
+
+#ifndef SPDLOG_NO_TLS
+        // add mdc if present
+        auto &mdc_map = mdc::get_context();
+        if (!mdc_map.empty()) {
+            dest.push_back('[');
+            mdc_formatter_.format_mdc(mdc_map, dest);
+            dest.push_back(']');
+            dest.push_back(' ');
+        }
+#endif
         // fmt_helper::append_string_view(msg.msg(), dest);
         fmt_helper::append_string_view(msg.payload, dest);
     }
@@ -865,6 +927,10 @@ public:
 private:
     std::chrono::seconds cache_timestamp_{0};
     memory_buf_t cached_datetime_;
+
+#ifndef SPDLOG_NO_TLS
+    mdc_formatter<null_scoped_padder> mdc_formatter_{padding_info {}};
+#endif
 };
 
 }  // namespace details
@@ -1159,6 +1225,12 @@ SPDLOG_INLINE void pattern_formatter::handle_flag_(char flag, details::padding_i
                     padding));
             break;
 
+#ifndef SPDLOG_NO_TLS  // mdc formatter requires TLS support
+        case ('&'):
+            formatters_.push_back(details::make_unique<details::mdc_formatter<Padder>>(padding));
+            break;
+#endif
+
         default:  // Unknown flag appears as is
             auto unknown_flag = details::make_unique<details::aggregate_formatter>();
 

include/spdlog/sinks/ansicolor_sink-inl.h

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

include/spdlog/sinks/ansicolor_sink.h

@@ -36,11 +36,11 @@ public:
 
     void set_color(level::level_enum color_level, string_view_t color);
     void set_color_mode(color_mode mode);
-    bool should_color();
+    bool should_color() const;
 
     void log(const details::log_msg &msg) override;
     void flush() override;
-    void set_pattern(const std::string &pattern) final;
+    void set_pattern(const std::string &pattern) final override;
     void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override;
 
     // Formatting codes
@@ -84,8 +84,9 @@ private:
     bool should_do_colors_;
     std::unique_ptr<spdlog::formatter> formatter_;
     std::array<std::string, level::n_levels> colors_;
-    void print_ccode_(const string_view_t &color_code);
-    void print_range_(const memory_buf_t &formatted, size_t start, size_t end);
+    void set_color_mode_(color_mode mode);
+    void print_ccode_(const string_view_t &color_code) const;
+    void print_range_(const memory_buf_t &formatted, size_t start, size_t end) const;
     static std::string to_string_(const string_view_t &sv);
 };
 

include/spdlog/sinks/base_sink.h

@@ -28,10 +28,10 @@ public:
     base_sink &operator=(const base_sink &) = delete;
     base_sink &operator=(base_sink &&) = delete;
 
-    void log(const details::log_msg &msg) final;
-    void flush() final;
-    void set_pattern(const std::string &pattern) final;
-    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) final;
+    void log(const details::log_msg &msg) final override;
+    void flush() final override;
+    void set_pattern(const std::string &pattern) final override;
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) final override;
 
 protected:
     // sink formatter

include/spdlog/sinks/basic_file_sink-inl.h

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

include/spdlog/sinks/basic_file_sink.h

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

include/spdlog/sinks/callback_sink.h

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

include/spdlog/sinks/daily_file_sink.h

@@ -62,6 +62,8 @@ struct daily_filename_format_calculator {
  * Rotating file sink based on date.
  * If truncate != false , the created file will be truncated.
  * If max_files > 0, retain only the last max_files and delete previous.
+ * Note that old log files from previous executions will not be deleted by this class,
+ * rotation and deletion is only applied while the program is running.
  */
 template <typename Mutex, typename FileNameCalc = daily_filename_calculator>
 class daily_file_sink final : public base_sink<Mutex> {

include/spdlog/sinks/dup_filter_sink.h

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

include/spdlog/sinks/hourly_file_sink.h

@@ -39,6 +39,8 @@ struct hourly_filename_calculator {
  * Rotating file sink based on time.
  * If truncate != false , the created file will be truncated.
  * If max_files > 0, retain only the last max_files and delete previous.
+ * Note that old log files from previous executions will not be deleted by this class,
+ * rotation and deletion is only applied while the program is running.
  */
 template <typename Mutex, typename FileNameCalc = hourly_filename_calculator>
 class hourly_file_sink final : public base_sink<Mutex> {

include/spdlog/sinks/msvc_sink.h

@@ -32,7 +32,7 @@ class msvc_sink : public base_sink<Mutex> {
 public:
     msvc_sink() = default;
     msvc_sink(bool check_debugger_present)
-        : check_debugger_present_{check_debugger_present} {};
+        : check_debugger_present_{check_debugger_present} {}
 
 protected:
     void sink_it_(const details::log_msg &msg) override {

include/spdlog/sinks/null_sink.h

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

include/spdlog/sinks/qt_sinks.h

@@ -4,7 +4,7 @@
 #pragma once
 
 //
-// Custom sink for QPlainTextEdit or QTextEdit and its childs(QTextBrowser...
+// Custom sink for QPlainTextEdit or QTextEdit and its children (QTextBrowser...
 // etc) Building and using requires Qt library.
 //
 // Warning: the qt_sink won't be notified if the target widget is destroyed.
@@ -56,7 +56,7 @@ private:
     std::string meta_method_;
 };
 
-// QT color sink to QTextEdit.
+// Qt color sink to QTextEdit.
 // Color location is determined by the sink log pattern like in the rest of spdlog sinks.
 // Colors can be modified if needed using sink->set_color(level, qtTextCharFormat).
 // max_lines is the maximum number of lines that the sink will hold before removing the oldest
@@ -282,7 +282,7 @@ inline std::shared_ptr<logger> qt_logger_st(const std::string &logger_name,
     return Factory::template create<sinks::qt_sink_st>(logger_name, qt_object, meta_method);
 }
 
-// log to QTextEdit with colorize output
+// log to QTextEdit with colorized output
 template <typename Factory = spdlog::synchronous_factory>
 inline std::shared_ptr<logger> qt_color_logger_mt(const std::string &logger_name,
                                                   QTextEdit *qt_text_edit,

include/spdlog/sinks/rotating_file_sink-inl.h

@@ -60,7 +60,7 @@ SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::calc_filename(const filename
 
     filename_t basename, ext;
     std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
-    return fmt_lib::format(SPDLOG_FILENAME_T("{}.{}{}"), basename, index, ext);
+    return fmt_lib::format(SPDLOG_FMT_STRING(SPDLOG_FILENAME_T("{}.{}{}")), basename, index, ext);
 }
 
 template <typename Mutex>
@@ -69,6 +69,12 @@ SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::filename() {
     return file_helper_.filename();
 }
 
+template <typename Mutex>
+SPDLOG_INLINE void rotating_file_sink<Mutex>::rotate_now() {
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    rotate_();
+}
+
 template <typename Mutex>
 SPDLOG_INLINE void rotating_file_sink<Mutex>::sink_it_(const details::log_msg &msg) {
     memory_buf_t formatted;

include/spdlog/sinks/rotating_file_sink.h

@@ -28,6 +28,7 @@ public:
                        const file_event_handlers &event_handlers = {});
     static filename_t calc_filename(const filename_t &filename, std::size_t index);
     filename_t filename();
+    void rotate_now();
 
 protected:
     void sink_it_(const details::log_msg &msg) override;

include/spdlog/sinks/stdout_sinks-inl.h

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

include/spdlog/sinks/syslog_sink.h

@@ -64,13 +64,14 @@ protected:
     //
     // Simply maps spdlog's log level to syslog priority level.
     //
-    int syslog_prio_from_level(const details::log_msg &msg) const {
+    virtual int syslog_prio_from_level(const details::log_msg &msg) const {
         return syslog_levels_.at(static_cast<levels_array::size_type>(msg.level));
     }
 
-private:
     using levels_array = std::array<int, 7>;
     levels_array syslog_levels_;
+
+private:
     // must store the ident because the man says openlog might use the pointer as
     // is and not a string copy
     const std::string ident_;

include/spdlog/sinks/wincolor_sink-inl.h

@@ -134,9 +134,18 @@ void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::print_range_(const memory_buf_t
                                                              size_t start,
                                                              size_t end) {
     if (end > start) {
+#if defined(SPDLOG_UTF8_TO_WCHAR_CONSOLE)
+        wmemory_buf_t wformatted;
+        details::os::utf8_to_wstrbuf(string_view_t(formatted.data() + start, end - start),
+            wformatted);
+        auto size = static_cast<DWORD>(wformatted.size());
+        auto ignored = ::WriteConsoleW(static_cast<HANDLE>(out_handle_), wformatted.data(), size,
+            nullptr, nullptr);
+#else
         auto size = static_cast<DWORD>(end - start);
         auto ignored = ::WriteConsoleA(static_cast<HANDLE>(out_handle_), formatted.data() + start,
                                        size, nullptr, nullptr);
+#endif
         (void)(ignored);
     }
 }

include/spdlog/stopwatch.h

@@ -39,6 +39,10 @@ public:
         return std::chrono::duration<double>(clock::now() - start_tp_);
     }
 
+    std::chrono::milliseconds elapsed_ms() const {
+        return std::chrono::duration_cast<std::chrono::milliseconds>(clock::now() - start_tp_);
+    }
+
     void reset() { start_tp_ = clock::now(); }
 };
 }  // namespace spdlog

include/spdlog/tweakme.h

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

include/spdlog/version.h

@@ -4,8 +4,8 @@
 #pragma once
 
 #define SPDLOG_VER_MAJOR 1
-#define SPDLOG_VER_MINOR 13
-#define SPDLOG_VER_PATCH 0
+#define SPDLOG_VER_MINOR 15
+#define SPDLOG_VER_PATCH 2
 
 #define SPDLOG_TO_VERSION(major, minor, patch) (major * 10000 + minor * 100 + patch)
 #define SPDLOG_VERSION SPDLOG_TO_VERSION(SPDLOG_VER_MAJOR, SPDLOG_VER_MINOR, SPDLOG_VER_PATCH)

src/bundled_fmtlib_format.cpp

@@ -1,4 +1,4 @@
-// Slightly modified version of fmt lib's format.cc (version 1.9.1) source file.
+// Slightly modified version of fmt lib's format.cc source file.
 // Copyright (c) 2012 - 2016, Victor Zverovich
 // All rights reserved.
 
@@ -13,37 +13,40 @@
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
-template FMT_API auto dragonbox::to_decimal(float x) noexcept -> dragonbox::decimal_fp<float>;
-template FMT_API auto dragonbox::to_decimal(double x) noexcept -> dragonbox::decimal_fp<double>;
+template FMT_API auto dragonbox::to_decimal(float x) noexcept
+    -> dragonbox::decimal_fp<float>;
+template FMT_API auto dragonbox::to_decimal(double x) noexcept
+    -> dragonbox::decimal_fp<double>;
 
-    #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
-template FMT_API locale_ref::locale_ref(const std::locale &loc);
+#if FMT_USE_LOCALE
+// DEPRECATED! locale_ref in the detail namespace
+template FMT_API locale_ref::locale_ref(const std::locale& loc);
 template FMT_API auto locale_ref::get<std::locale>() const -> std::locale;
-    #endif
+#endif
 
 // Explicit instantiations for char.
 
-template FMT_API auto thousands_sep_impl(locale_ref) -> thousands_sep_result<char>;
+template FMT_API auto thousands_sep_impl(locale_ref)
+    -> thousands_sep_result<char>;
 template FMT_API auto decimal_point_impl(locale_ref) -> char;
 
-template FMT_API void buffer<char>::append(const char *, const char *);
+// DEPRECATED!
+template FMT_API void buffer<char>::append(const char*, const char*);
 
 // DEPRECATED!
-// There is no correspondent extern template in format.h because of
-// incompatibility between clang and gcc (#2377).
-template FMT_API void vformat_to(buffer<char> &,
-                                 string_view,
-                                 basic_format_args<FMT_BUFFER_CONTEXT(char)>,
-                                 locale_ref);
+template FMT_API void vformat_to(buffer<char>&, string_view,
+                                 typename vformat_args<>::type, locale_ref);
 
 // Explicit instantiations for wchar_t.
 
-template FMT_API auto thousands_sep_impl(locale_ref) -> thousands_sep_result<wchar_t>;
+template FMT_API auto thousands_sep_impl(locale_ref)
+    -> thousands_sep_result<wchar_t>;
 template FMT_API auto decimal_point_impl(locale_ref) -> wchar_t;
 
-template FMT_API void buffer<wchar_t>::append(const wchar_t *, const wchar_t *);
+template FMT_API void buffer<wchar_t>::append(const wchar_t*, const wchar_t*);
 
 }  // namespace detail
 FMT_END_NAMESPACE
 
+
 #endif  // !SPDLOG_FMT_EXTERNAL

tests/CMakeLists.txt

@@ -48,7 +48,8 @@ set(SPDLOG_UTESTS_SOURCES
     test_cfg.cpp
     test_time_point.cpp
     test_stopwatch.cpp
-    test_circular_q.cpp)
+    test_circular_q.cpp
+    test_bin_to_hex.cpp)
 
 if(NOT SPDLOG_NO_EXCEPTIONS)
     list(APPEND SPDLOG_UTESTS_SOURCES test_errors.cpp)
@@ -58,10 +59,6 @@ if(systemd_FOUND)
     list(APPEND SPDLOG_UTESTS_SOURCES test_systemd.cpp)
 endif()
 
-if(NOT SPDLOG_USE_STD_FORMAT)
-    list(APPEND SPDLOG_UTESTS_SOURCES test_bin_to_hex.cpp)
-endif()
-
 enable_testing()
 
 function(spdlog_prepare_test test_target spdlog_lib)
@@ -73,8 +70,10 @@ function(spdlog_prepare_test test_target spdlog_lib)
     endif()
     target_link_libraries(${test_target} PRIVATE Catch2::Catch2WithMain)
     if(SPDLOG_SANITIZE_ADDRESS)
-        spdlog_enable_sanitizer(${test_target})
-    endif()
+        spdlog_enable_addr_sanitizer(${test_target})
+    elseif (SPDLOG_SANITIZE_THREAD)
+        spdlog_enable_thread_sanitizer(${test_target})
+    endif ()
     add_test(NAME ${test_target} COMMAND ${test_target})
     set_tests_properties(${test_target} PROPERTIES RUN_SERIAL ON)
 endfunction()

tests/includes.h

@@ -26,6 +26,12 @@
 #include "spdlog/spdlog.h"
 #include "spdlog/async.h"
 #include "spdlog/details/fmt_helper.h"
+#include "spdlog/details/os.h"
+
+#ifndef SPDLOG_NO_TLS
+    #include "spdlog/mdc.h"
+#endif
+
 #include "spdlog/sinks/basic_file_sink.h"
 #include "spdlog/sinks/daily_file_sink.h"
 #include "spdlog/sinks/null_sink.h"

tests/test_cfg.cpp

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

tests/test_create_dir.cpp

@@ -81,3 +81,64 @@ TEST_CASE("dir_name", "[create_dir]") {
     REQUIRE(dir_name(SPDLOG_FILENAME_T("../file.txt")) == SPDLOG_FILENAME_T(".."));
     REQUIRE(dir_name(SPDLOG_FILENAME_T("./file.txt")) == SPDLOG_FILENAME_T("."));
 }
+
+#ifdef _WIN32
+
+    //
+    // test windows cases when drive letter is given e.g. C:\\some-folder
+    //
+    #include <windows.h>
+    #include <fileapi.h>
+
+std::string get_full_path(const std::string &relative_folder_path) {
+    char full_path[MAX_PATH];
+
+    DWORD result = ::GetFullPathNameA(relative_folder_path.c_str(), MAX_PATH, full_path, nullptr);
+    // Return an empty string if failed to get full path
+    return result > 0 && result < MAX_PATH ? std::string(full_path) : std::string();
+}
+
+std::wstring get_full_path(const std::wstring &relative_folder_path) {
+    wchar_t full_path[MAX_PATH];
+    DWORD result = ::GetFullPathNameW(relative_folder_path.c_str(), MAX_PATH, full_path, nullptr);
+    return result > 0 && result < MAX_PATH ? std::wstring(full_path) : std::wstring();
+}
+
+spdlog::filename_t::value_type find_non_existing_drive() {
+    for (char drive = 'A'; drive <= 'Z'; ++drive) {
+        std::string root_path = std::string(1, drive) + ":\\";
+        UINT drive_type = GetDriveTypeA(root_path.c_str());
+        if (drive_type == DRIVE_NO_ROOT_DIR) {
+            return static_cast<spdlog::filename_t::value_type>(drive);
+        }
+    }
+    return '\0';  // No available drive found
+}
+
+TEST_CASE("create_abs_path1", "[create_dir]") {
+    prepare_logdir();
+    auto abs_path = get_full_path(SPDLOG_FILENAME_T("test_logs\\logdir1"));
+    REQUIRE(!abs_path.empty());
+    REQUIRE(create_dir(abs_path) == true);
+}
+
+TEST_CASE("create_abs_path2", "[create_dir]") {
+    prepare_logdir();
+    auto abs_path = get_full_path(SPDLOG_FILENAME_T("test_logs/logdir2"));
+    REQUIRE(!abs_path.empty());
+    REQUIRE(create_dir(abs_path) == true);
+}
+
+TEST_CASE("non_existing_drive", "[create_dir]") {
+    prepare_logdir();
+    spdlog::filename_t path;
+
+    auto non_existing_drive = find_non_existing_drive();
+    path += non_existing_drive;
+    path += SPDLOG_FILENAME_T(":\\");
+    REQUIRE(create_dir(path) == false);
+    path += SPDLOG_FILENAME_T("subdir");
+    REQUIRE(create_dir(path) == false);
+}
+// #endif  // SPDLOG_WCHAR_FILENAMES
+#endif  // _WIN32

tests/test_custom_callbacks.cpp

@@ -16,7 +16,8 @@ TEST_CASE("custom_callback_logger", "[custom_callback_logger]") {
             spdlog::memory_buf_t formatted;
             formatter.format(msg, formatted);
             auto eol_len = strlen(spdlog::details::os::default_eol);
-            lines.emplace_back(formatted.begin(), formatted.end() - eol_len);
+            using diff_t = typename std::iterator_traits<decltype(formatted.end())>::difference_type; 
+            lines.emplace_back(formatted.begin(), formatted.end() - static_cast<diff_t>(eol_len));
         });
     std::shared_ptr<spdlog::sinks::test_sink_st> test_sink(new spdlog::sinks::test_sink_st);
 

tests/test_daily_logger.cpp

@@ -46,12 +46,10 @@ TEST_CASE("daily_logger with dateonly calculator", "[daily_logger]") {
 
 struct custom_daily_file_name_calculator {
     static spdlog::filename_t calc_filename(const spdlog::filename_t &basename, const tm &now_tm) {
-        filename_memory_buf_t w;
-        spdlog::fmt_lib::format_to(std::back_inserter(w), SPDLOG_FILENAME_T("{}{:04d}{:02d}{:02d}"),
+        
+        return spdlog::fmt_lib::format(SPDLOG_FILENAME_T("{}{:04d}{:02d}{:02d}"),
                                    basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1,
                                    now_tm.tm_mday);        
-
-        return SPDLOG_BUF_TO_STRING(w);
     }
 };
 

tests/test_errors.cpp

@@ -19,7 +19,7 @@ protected:
 };
 struct custom_ex {};
 
-#if !defined(SPDLOG_USE_STD_FORMAT)  // std formt doesn't fully support tuntime strings
+#if !defined(SPDLOG_USE_STD_FORMAT)  // std format doesn't fully support runtime strings
 TEST_CASE("default_error_handler", "[errors]") {
     prepare_logdir();
     spdlog::filename_t filename = SPDLOG_FILENAME_T(SIMPLE_LOG);

tests/test_file_helper.cpp

@@ -152,7 +152,7 @@ TEST_CASE("file_event_handlers", "[file_helper]") {
         helper.reopen(true);
         events.clear();
     }
-    // make sure that the file_helper destrcutor calls the close callbacks if needed
+    // make sure that the file_helper destructor calls the close callbacks if needed
     REQUIRE(events == std::vector<flags>{flags::before_close, flags::after_close});
     REQUIRE(file_contents(TEST_FILENAME) == "after_open\nbefore_close\n");
 }

tests/test_file_logging.cpp

@@ -45,6 +45,26 @@ TEST_CASE("flush_on", "[flush_on]") {
                                     default_eol, default_eol, default_eol));
 }
 
+TEST_CASE("simple_file_logger", "[truncate]") {
+    prepare_logdir();
+    const spdlog::filename_t filename = SPDLOG_FILENAME_T(SIMPLE_LOG);
+    const bool truncate = true;
+    const auto sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>(filename, truncate);
+    const auto logger = std::make_shared<spdlog::logger>("simple_file_logger", sink);
+
+    logger->info("Test message {}", 3.14);
+    logger->info("Test message {}", 2.71);
+    logger->flush();
+    REQUIRE(count_lines(SIMPLE_LOG) == 2);
+    
+    sink->truncate();
+    REQUIRE(count_lines(SIMPLE_LOG) == 0);
+
+    logger->info("Test message {}", 6.28);
+    logger->flush();
+    REQUIRE(count_lines(SIMPLE_LOG) == 1);
+}
+
 TEST_CASE("rotating_file_logger1", "[rotating_logger]") {
     prepare_logdir();
     size_t max_size = 1024 * 10;
@@ -101,3 +121,23 @@ TEST_CASE("rotating_file_logger3", "[rotating_logger]") {
     REQUIRE_THROWS_AS(spdlog::rotating_logger_mt("logger", basename, max_size, 0),
                       spdlog::spdlog_ex);
 }
+
+// test on-demand rotation of logs
+TEST_CASE("rotating_file_logger4", "[rotating_logger]") {
+    prepare_logdir();
+    size_t max_size = 1024 * 10;
+    spdlog::filename_t basename = SPDLOG_FILENAME_T(ROTATING_LOG);
+    auto sink = std::make_shared<spdlog::sinks::rotating_file_sink_st>(basename, max_size, 2);
+    auto logger = std::make_shared<spdlog::logger>("rotating_sink_logger", sink);
+
+    logger->info("Test message - pre-rotation");
+    logger->flush();
+
+    sink->rotate_now();
+
+    logger->info("Test message - post-rotation");
+    logger->flush();
+
+    REQUIRE(get_filesize(ROTATING_LOG) > 0);
+    REQUIRE(get_filesize(ROTATING_LOG ".1") > 0);
+}

tests/test_misc.cpp

@@ -1,3 +1,7 @@
+#ifdef _WIN32 // to prevent fopen warning on windows
+#define _CRT_SECURE_NO_WARNINGS
+#endif
+
 #include "includes.h"
 #include "test_sink.h"
 
@@ -105,9 +109,9 @@ TEST_CASE("clone-logger", "[clone]") {
 }
 
 TEST_CASE("clone async", "[clone]") {
-    using spdlog::sinks::test_sink_st;
+    using spdlog::sinks::test_sink_mt;
     spdlog::init_thread_pool(4, 1);
-    auto test_sink = std::make_shared<test_sink_st>();
+    auto test_sink = std::make_shared<test_sink_mt>();
     auto logger = std::make_shared<spdlog::async_logger>("orig", test_sink, spdlog::thread_pool());
     logger->set_pattern("%v");
     auto cloned = logger->clone("clone");
@@ -167,3 +171,52 @@ TEST_CASE("default logger API", "[default logger]") {
     spdlog::drop_all();
     spdlog::set_pattern("%v");
 }
+
+#if (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
+TEST_CASE("utf8 to utf16 conversion using windows api", "[windows utf]") {
+    spdlog::wmemory_buf_t buffer;
+
+    spdlog::details::os::utf8_to_wstrbuf("", buffer);
+    REQUIRE(std::wstring(buffer.data(), buffer.size()) == std::wstring(L""));
+
+    spdlog::details::os::utf8_to_wstrbuf("abc", buffer);
+    REQUIRE(std::wstring(buffer.data(), buffer.size()) == std::wstring(L"abc"));
+
+    spdlog::details::os::utf8_to_wstrbuf("\xc3\x28", buffer); // Invalid UTF-8 sequence.
+    REQUIRE(std::wstring(buffer.data(), buffer.size()) == std::wstring(L"\xfffd("));
+
+    spdlog::details::os::utf8_to_wstrbuf("\xe3\x81\xad\xe3\x81\x93", buffer); // "Neko" in hiragana.
+    REQUIRE(std::wstring(buffer.data(), buffer.size()) == std::wstring(L"\x306d\x3053"));
+}
+#endif
+
+struct auto_closer {
+    FILE* fp = nullptr;
+    explicit auto_closer(FILE* f) : fp(f) {}
+    auto_closer(const auto_closer&) = delete;
+    auto_closer& operator=(const auto_closer&) = delete;
+    ~auto_closer() {
+        if (fp != nullptr) (void)std::fclose(fp);
+    }
+};
+
+TEST_CASE("os::fwrite_bytes", "[os]") {
+    using spdlog::details::os::fwrite_bytes;
+    using spdlog::details::os::create_dir;
+    const char* filename = "log_tests/test_fwrite_bytes.txt";
+    const char *msg = "hello";
+    prepare_logdir();
+    REQUIRE(create_dir(SPDLOG_FILENAME_T("log_tests")) == true);
+    {
+        auto_closer closer(std::fopen(filename, "wb"));
+        REQUIRE(closer.fp != nullptr);
+        REQUIRE(fwrite_bytes(msg, std::strlen(msg), closer.fp) == true);
+        REQUIRE(fwrite_bytes(msg, 0, closer.fp) == true);
+        std::fflush(closer.fp);
+        REQUIRE(spdlog::details::os::filesize(closer.fp) == 5);
+    }
+    // fwrite_bytes should return false on write failure
+    auto_closer closer(std::fopen(filename, "r"));
+    REQUIRE(closer.fp != nullptr);
+    REQUIRE_FALSE(fwrite_bytes("Hello", 5, closer.fp));
+}

tests/test_pattern_formatter.cpp

@@ -1,6 +1,8 @@
 #include "includes.h"
 #include "test_sink.h"
 
+#include <chrono>
+
 using spdlog::memory_buf_t;
 using spdlog::details::to_string_view;
 
@@ -19,6 +21,21 @@ static std::string log_to_str(const std::string &msg, const Args &...args) {
     return oss.str();
 }
 
+// log to str and return it with time
+template <typename... Args>
+static std::string log_to_str_with_time(spdlog::log_clock::time_point log_time, const std::string &msg, const Args &...args) {
+    std::ostringstream oss;
+    auto oss_sink = std::make_shared<spdlog::sinks::ostream_sink_mt>(oss);
+    spdlog::logger oss_logger("pattern_tester", oss_sink);
+    oss_logger.set_level(spdlog::level::info);
+
+    oss_logger.set_formatter(
+        std::unique_ptr<spdlog::formatter>(new spdlog::pattern_formatter(args...)));
+
+    oss_logger.log(log_time, {}, spdlog::level::info, msg);
+    return oss.str();
+}
+
 TEST_CASE("custom eol", "[pattern_formatter]") {
     std::string msg = "Hello custom eol test";
     std::string eol = ";)";
@@ -58,6 +75,15 @@ TEST_CASE("date MM/DD/YY ", "[pattern_formatter]") {
             oss.str());
 }
 
+TEST_CASE("GMT offset ", "[pattern_formatter]") {
+    using namespace std::chrono_literals;
+    const auto now = std::chrono::system_clock::now();
+    const auto yesterday = now - 24h;
+
+    REQUIRE(log_to_str_with_time(yesterday, "Some message", "%z", spdlog::pattern_time_type::utc, "\n") ==
+            "+00:00\n");
+}
+
 TEST_CASE("color range test1", "[pattern_formatter]") {
     auto formatter = std::make_shared<spdlog::pattern_formatter>(
         "%^%v%$", spdlog::pattern_time_type::local, "\n");
@@ -500,3 +526,133 @@ TEST_CASE("override need_localtime", "[pattern_formatter]") {
         REQUIRE(to_string_view(formatted) == oss.str());
     }
 }
+
+#ifndef SPDLOG_NO_TLS
+TEST_CASE("mdc formatter test-1", "[pattern_formatter]") {
+    spdlog::mdc::put("mdc_key_1", "mdc_value_1");
+    spdlog::mdc::put("mdc_key_2", "mdc_value_2");
+
+    auto formatter = std::make_shared<spdlog::pattern_formatter>();
+    formatter->set_pattern("[%n] [%l] [%&] %v");
+
+    memory_buf_t formatted;
+    spdlog::details::log_msg msg(spdlog::source_loc{}, "logger-name", spdlog::level::info,
+                                 "some message");
+    formatter->format(msg, formatted);
+
+    auto expected = spdlog::fmt_lib::format(
+        "[logger-name] [info] [mdc_key_1:mdc_value_1 mdc_key_2:mdc_value_2] some message{}",
+        spdlog::details::os::default_eol);
+    REQUIRE(to_string_view(formatted) == expected);
+
+    SECTION("Tear down") { spdlog::mdc::clear(); }
+}
+
+TEST_CASE("mdc formatter value update", "[pattern_formatter]") {
+    spdlog::mdc::put("mdc_key_1", "mdc_value_1");
+    spdlog::mdc::put("mdc_key_2", "mdc_value_2");
+
+    auto formatter = std::make_shared<spdlog::pattern_formatter>();
+    formatter->set_pattern("[%n] [%l] [%&] %v");
+
+    memory_buf_t formatted_1;
+    spdlog::details::log_msg msg(spdlog::source_loc{}, "logger-name", spdlog::level::info,
+                                 "some message");
+    formatter->format(msg, formatted_1);
+
+    auto expected = spdlog::fmt_lib::format(
+        "[logger-name] [info] [mdc_key_1:mdc_value_1 mdc_key_2:mdc_value_2] some message{}",
+        spdlog::details::os::default_eol);
+
+    REQUIRE(to_string_view(formatted_1) == expected);
+
+    spdlog::mdc::put("mdc_key_1", "new_mdc_value_1");
+    memory_buf_t formatted_2;
+    formatter->format(msg, formatted_2);
+    expected = spdlog::fmt_lib::format(
+        "[logger-name] [info] [mdc_key_1:new_mdc_value_1 mdc_key_2:mdc_value_2] some message{}",
+        spdlog::details::os::default_eol);
+
+    REQUIRE(to_string_view(formatted_2) == expected);
+
+    SECTION("Tear down") { spdlog::mdc::clear(); }
+}
+
+TEST_CASE("mdc different threads", "[pattern_formatter]") {
+    auto formatter = std::make_shared<spdlog::pattern_formatter>();
+    formatter->set_pattern("[%n] [%l] [%&] %v");
+    spdlog::details::log_msg msg(spdlog::source_loc{}, "logger-name", spdlog::level::info,
+                                 "some message");
+
+    memory_buf_t formatted_2;
+
+    auto lambda_1 = [formatter, msg]() {
+        spdlog::mdc::put("mdc_key", "thread_1_id");
+        memory_buf_t formatted;
+        formatter->format(msg, formatted);
+
+        auto expected =
+            spdlog::fmt_lib::format("[logger-name] [info] [mdc_key:thread_1_id] some message{}",
+                                    spdlog::details::os::default_eol);
+
+        REQUIRE(to_string_view(formatted) == expected);
+    };
+
+    auto lambda_2 = [formatter, msg]() {
+        spdlog::mdc::put("mdc_key", "thread_2_id");
+        memory_buf_t formatted;
+        formatter->format(msg, formatted);
+
+        auto expected =
+            spdlog::fmt_lib::format("[logger-name] [info] [mdc_key:thread_2_id] some message{}",
+                                    spdlog::details::os::default_eol);
+
+        REQUIRE(to_string_view(formatted) == expected);
+    };
+
+    std::thread thread_1(lambda_1);
+    std::thread thread_2(lambda_2);
+
+    thread_1.join();
+    thread_2.join();
+
+    SECTION("Tear down") { spdlog::mdc::clear(); }
+}
+
+TEST_CASE("mdc remove key", "[pattern_formatter]") {
+    spdlog::mdc::put("mdc_key_1", "mdc_value_1");
+    spdlog::mdc::put("mdc_key_2", "mdc_value_2");
+    spdlog::mdc::remove("mdc_key_1");
+
+    auto formatter = std::make_shared<spdlog::pattern_formatter>();
+    formatter->set_pattern("[%n] [%l] [%&] %v");
+
+    memory_buf_t formatted;
+    spdlog::details::log_msg msg(spdlog::source_loc{}, "logger-name", spdlog::level::info,
+                                 "some message");
+    formatter->format(msg, formatted);
+
+    auto expected =
+        spdlog::fmt_lib::format("[logger-name] [info] [mdc_key_2:mdc_value_2] some message{}",
+                                spdlog::details::os::default_eol);
+    REQUIRE(to_string_view(formatted) == expected);
+
+    SECTION("Tear down") { spdlog::mdc::clear(); }
+}
+
+TEST_CASE("mdc empty", "[pattern_formatter]") {
+    auto formatter = std::make_shared<spdlog::pattern_formatter>();
+    formatter->set_pattern("[%n] [%l] [%&] %v");
+
+    memory_buf_t formatted;
+    spdlog::details::log_msg msg(spdlog::source_loc{}, "logger-name", spdlog::level::info,
+                                 "some message");
+    formatter->format(msg, formatted);
+
+    auto expected = spdlog::fmt_lib::format("[logger-name] [info] [] some message{}",
+                                            spdlog::details::os::default_eol);
+    REQUIRE(to_string_view(formatted) == expected);
+
+    SECTION("Tear down") { spdlog::mdc::clear(); }
+}
+#endif

tests/test_sink.h

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