Version 1.10.0

• Bump fmt to version 8.1.1.
• Added file event handlers #2165, #2169 Thanks @seker.
  You can get callbacks from spdlog before/after log file has been opened or closed.
  This is useful for cleanup procedures or for adding something to the start/end of the log files. Example:

  void file_events_example()
  {
    // pass the spdlog::file_event_handlers to file sinks for open/close log file notifications
    spdlog::file_event_handlers handlers;
    handlers.before_open = [](spdlog::filename_t filename) { spdlog::info("Before opening {}", filename); };
    handlers.after_open = [](spdlog::filename_t filename, std::FILE *fstream) { fputs("After opening\n", fstream); };
    handlers.before_close = [](spdlog::filename_t filename, std::FILE *fstream) { fputs("Before closing\n", fstream); };
    handlers.after_close = [](spdlog::filename_t filename) { spdlog::info("After closing {}", filename); };
    auto my_logger = spdlog::basic_logger_st("some_logger", "logs/events-sample.txt", true, handlers);        
  }

• Fixed rotating file sink: when disk is full log rotation resulted zero size log files. #2261. (thanks @kishorekrd for reporting).
• Added new udp_sink #2090. Thanks @CJLove
• (Experimental) Option to depend on std::format instead of fmtlib (set SPDLOG_USE_STD_FORMAT and use C++20). #2170 Thanks @sylveon .
• Improved file name for hourly file sink #2047. Thanks @seker .
• Added code location information for error handler #2048. Thanks @D-r-P-3-p-p-3-r .
• Fixed qt_sinks ctor #2056. Thanks @mguludag .
• List Debian instructions in the README #2057. Thanks @mr-c ,
• Updated to latest Travis CI Build Status #2094. Thanks @jspraul .
• Fixed unhandled errors in udp sink. #2096. Thanks @mmarkeloff .
• CMake improvement regarding cmake_minimum_required and policy. #2098. Thanks @reddwarf69 .
• Fixed mongo_sink compile in older gcc versions #2102 . Thanks @yzz-ihep .
• Remove mutable keyword from mutex_ member in of sinks. #2140 . Thanks @sunlong169 .
• Fix typos #2171. Thanks @rex4539 .
• Fixed udp sink build on FreeBSD #2172. Thanks @keith-dev .
• Avoid c-style casting in stdout sinks. #2179. Thanks @ibmibmibm .
• Fixed tweakme.h compile error under msvcs when SPDLOG_FUNCTION is defined #2182. Thanks @Light3039 .
• Fixed compiling errors on AIX #2181. Thanks @lisr .
• Fixed runtime when build with -fsanitize=cfi #1972. Thanks @bansan85 .
• Remove extraneous semicolon #2190. Thanks @sylveon.
• Added example how to replace default logger. #2194. Thanks @rioki .
• Fixed usage of ranges and to_hex in the same compile unit #2195. Thanks @patrickroocks .
• Reduce warnings with pedantic compiler -Wuseless-cast #2216. Thanks @vnepogodin .
• Support using std::span in to_hex #2228. Thanks @timblechmann .
• Reset current size if rotated files on open #2234. Thanks @SpriteOvO .
• Allow forward-declaration of level_enum #2245. Thanks @daverigby .
• Call localtime() only if pattern_formatter really needs it #2246. Thanks @doug1234 .
• Removed unneeded spaces from code. #2249. Thanks @PixelParas .
• Added a few missing files/directories to the gitignore #2255. Thanks @LeonBrands .
• Fixed issue #2201 (Pattern width is not applied for missing source information). #2269. Thanks @kyuheon-kr .
• Limit max number of rotating files to 200000. (Fixed #1905). Thanks @surfycui (#2273)
• pattern_formatter: fix reorder-ctor warning #2278. Thanks @adriweb .
• Fixed spdlogConfig.cmake when built with SPDLOG_FMT_EXTERNAL_HO #2300. Thanks @adamcalhoon .
• Fixed fopen_s(..) error handling when PREVENT_CHILD_FD is defined #2305. Thanks @nUl1.
• Fixed compiler error when building on Windows with #define UNICODE #2317. Thanks @risa2000 .
• Added option to enable formatting of systemd sink #2324, #2320. Thanks @Delgan .
• Added optional "ident" argument to systemd sink constructor #2328. Thanks @Delgan .

Special thanks to @tt4g for his support in answering community questions and issues.

Version 1.9.2

• Fixed clang compiler errors when using spdlog in c++20. Thanks @dkavolis (#2037, #2034).
• Fixed the Qt sinks to accurately trim the newline chars. Thanks @MadMax411 (#2015).
• Improved and simplified Qt sinks implementation. Thanks @mguludag (#2016, #2018).
• Fixed macro SPDLOG_LEVEL_NAME_xxx to always translate to the spdlog namespace. Thanks @ashley-b for reporting (#2022).
• Fixed typo in readme. Thanks @p-ranav (#2024).
• Fixed the MongoDB sink compilation in c++11. Thanks @jabartek (#2025).
• Fixed double include of same file in thread_pool.h . Thanks @hbwang15 (#2026).
• Ensure that the CMake exported package is relocatable. Thanks @daverigby (#2029).
• Remove std::distance usage for possible performance gain. Thanks @neheb (#2030).
• Support of inclusion of bin_to_hex.h in any order with spdlog.h. Thanks @dmerkushov (#2035).
• Fixed install instructions for "header only" dir. Thanks @madeso (#2036).

Version 1.9.1

• Support for {fmt}'s compile time validation of format strings (#2008). Thanks @dkavolis !
  In C++20:

  spdlog::info("{:d}", "bad format_arg"); // should not compile

  In C++14/17 - format string can be validated at compile time using FMT_STRING:

  spdlog::info(FMT_STRING("{:d}"), "bad format_arg");  // should not compile

• Fixed compilation error in Clang 13 with C++20 (#2011, #2013) Thanks @sjanel !

Version 1.9.0

What's new

• Support for {fmt} lib version 8.x.
• New MongoDB sink #1981 . Thanks @mguludag.
• New QTextEdit and QPlainTextEdit sinks #1986. Thanks @mguludag.

Fixes and Improvements

• Fixed #1790 (build failed with v140_xp, v141_xp toolset flags ). Thanks @LonghronShen.
• Fixed #1916 (fix Xcode compiler warning). Thanks @haifengkao.
• Made mutex member variable mutable #1918. Thanks @matt77hias.
• Changed c-style casts to reinterpret casts in tcp_client #1924. Thanks @ lnovey .
• Fix #533 . Rethrnow non std exceptions.
• Avoid harmless warning about unreachable statement in MSVS build #1930. Thanks @vadz.
• Fixed warning about testing _WIN64 which might be undefined #1931. THanks @vadz.
• Small code improvement (std::find) #1933. Thanks @neheb .
• Added support for CMake policy CMP0077 #1946. Thanks @jb-55,
• Allow compilation with nvc++ (and possibly PGI) #1958. Thanks @mlund .
• Fixed C++20 build resulting in deprecated implicit copy assignment operator warning #1961. Thanks @jb-55.
• Fix signed/unsigned mismatch in VS #1970 . Thanks @bansan85.
• Use std::function for the global error handler #1971. Thanks @SpriteOvO .
• Fixed dup sink compile warnings in older compilers with back_inserter.
• Added a color-terminal type #1984 to the color terminals list - to show colors in in RISC-V64 machines. Thanks @hctym1995.

Version 1.8.5

Fix compiling with C++17: remove constexpr on level_string_views. Thanks @stevenlunt (#1889).

Version 1.8.4

Remove version requirement from find_package when searching external fmt. #1890. Thanks @prince-chrismc

Version 1.8.3

• New hourly file sink . Creates new file every hour. Can be limited to retain only the last N files. Thanks @BVonk (#1763).
• New daily sink filename custom formatting. Users now can pass custom strftime pattern to the log filename. For example: daily_logger_format_mt("loggername", "log-%Y%m%d:%H:%M.txt", hours, minutes);. Thanks @fawdlstty (#1847).
• Fix windows event sink log compilation with UNICODE preprocessor. Thanks @iko1 (#1760).
• Add SPDLOG_DISABLE_DEFAULT_LOGGER as a CMake option. Thanks @shimaowo (#1765, #1766).
• Improve color terminal detection. Thanks @dominicpoeschko (#1768).
• Prevent windows color sink to leak windows headers into user code Thanks @Ryan-rsm-McKenzie (#1771).
• Ensure SPDLOG_FMT_EXTERNAL is honored in the bench program. Thanks @Ryan-rsm-McKenzie (#1773).
• Skip CMake module mode when finding fmt. Thanks @Ryan-rsm-McKenzie (#1774).
• Better support for "/" separators on Windows, and improve wchar filename test coverage. Thanks @sylveon (#1787).
• Open files with "ab" mode even if truncating to better support logrotate(8). Thanks @graydon (#1795).
• Fix compiling error and typo in hourly file sink. Thanks @sillykelvin (#1805).
• Add constexpr to SPDLOG_LEVEL_NAMES declaration. Thanks @gv-me (#1798).
• Initializer list style consistency. Thanks @ChristianPanov (#1807).
• Fix call to non-constexpr function (#1811).
• Better numeric_limits<>::max/min fix when SPDLOG_WCHAR_TO_UTF8_SUPPORT is defined. Thanks @nukeulater (#1819).
• Fix to prevent MSVC warning flags to propagate to CUDA. Thanks @prateek9623 (#1825, #1829).
• Fix windows stdout_sink raising exception when used GUI Windows Apps that lack a console. Thanks @dgehri for reporting (#1828).
• Simplified wincolor sink code and intensify the red and yellow colors.
• Set default value to registry::err_handler_ to resolve Klocwork warning. . Thanks @jneruda (#1835).
• Formatter bench: Fix compilation by avoiding function name decay mechanics. Thanks @MathiasMagnus (#1846).
• Add build2 package support in readme. Thanks @Klaim (#1851).
• Make sure __cplusplus is defined under msvc CMakeLists.txt
• Fixed VS2019 W4 cast warning (#1876).
• Fix warning whe the compilation flag -Wswitch-default is present. Thanks @imSherlock (#1882).

Version 1.8.2

• Bump fmt to version 7.1.3
• Download automatically googlebenchmark for bench tests (#1709) Thanks @kitattyor.
• Add CPack debian package settings (#1712) and fix typo in comment (#1711). Thanks @ChristofKaufmann.
• Perfect forwarding fmt arguments (#1726). Thanks @dkavolis.
• Fix dup_filter_sink to log current log call's level, instead of the filtered log call's level (#1710). Thanks @Tridacnid for reporting.
• Ability to get size of messages queue of async thread pool (#1735) Thanks @o2gy84.
• Add missing include (#1742). Thanks @jwittbrodt.
• Updated bin_to_hex example in the readme (#1744). Thanks @ArnaudBienner.
• Fix async periodic flush test (#1749). Thanks @bluescarni.

Version 1.8.1

• Fixed load_env_levels() and load_argv_levels() #1680 (thanks @Tridacnid ).
• Fixed stdout sink that produced extra carriage returns on Windows #1675 (thanks @chris-t-w ).
• Fixed msvc_sink including windows.h #1667 (thanks @Ryan-rsm-McKenzie).
• Fixed stopwatch's clock to use chrono::steady_clock #1676 (thanks @SuperWig).
• Added support for Rcpp (R cpp compiler) #1685 (thanks @eddelbuettel).

Version 1.8.0

• Upgraded bundled fmt to version 7.0.3.
• New stopwatch utility for quick & easy logging of elapsed time:

#include "spdlog/stopwatch.h"
void stopwatch_example()
{
    spdlog::stopwatch sw;    
    // do some work..
    spdlog::debug("Elapsed: {} seconds", sw);    // =>  "Elapsed 0.005116733 seconds"
    spdlog::debug("Elapsed: {:.3} seconds", sw);  // =>  "Elapsed 0.005 seconds"
}

• Raised CMake requirement to 3.10 and cleanup CMakeLists.txt (#1624). Thanks @tambry.
• Added get_level() and should_log() functions to the spdlog:: namespace (#1628). Thanks @eyalroz.
• Fixed tcp_client for macOS (#1640). Thanks @dkruempe.
• Fixed cfg::load_env_levels() function declaration (#1651). Thanks @bareya.
• Updated Fedora install info in the readme (#1653). Thanks @gk6k6k.
• Fixed #1617 (aligned function pattern flag is broken). Thanks @VelocityRa for reporting.
• Fixed #1581 (compiling under msys in win10).