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TBD

  • Fixed a signal handler shutdown issue where crashes after Backend::stop() could hang while trying to flush() through a stopped backend worker. (#906)
  • Fixed duplicate atexit handler registration on repeated Backend::start()/Backend::stop() cycles.

v11.1.0

  • Fixed thread-local context duplication across shared libraries (#890)
  • Added a nullptr check in macro-free log functions (LogFunctions.h) to allow calls with an uninitialized logger. Macro-based logging remains deliberately unchanged (#894)
  • Suppress GCC false-positive warnings during LTO builds.
  • Added backend worker poll loop hooks backend_worker_on_poll_begin/ backend_worker_on_poll_end (#897)
  • Added opt-in sequential thread IDs via QUILL_USE_SEQUENTIAL_THREAD_ID with QUILL_DEFINE_SEQUENTIAL_THREAD_ID (#898)

v11.0.2

  • Fixed UBSAN warning when logging empty std::string_view (#885)
  • Updated ConsoleSink constructor to accept an optional FileEventNotifier parameter for consistency with other sinks (#886)

v11.0.1

  • Fix BacktraceStorage index reset to prevent SIGSEGV when using LOG_BACKTRACE

v11.0.0

  • Update bundled libfmt to v12.1.0
  • Minor correction to _last_sink_flush_time update when fflush() fails
  • Added retry logic and shared access handling for file open and rotation on Windows
  • Use ::WriteFile instead of fwrite to prevent \r\r\n line endings on Windows
  • Avoid file descriptor leaks by setting O_CLOEXEC on Unix and HANDLE_FLAG_INHERIT on Windows
  • Added SimpleSetup.h convenience header for trivial program cases to easily setup a logger. For example 
     #include "quill/SimpleSetup.h"
 #include "quill/LogMacros.h"

 int main()
 {
   auto* logger = quill::simple_logger();
   LOG_INFO(logger, "Hello from {}!", "Quill");

   auto* logger2 = quill::simple_logger("test.log");
   LOG_INFO(logger2, "This message goes to a file");
 }
  • Fixed argument forwarding when encoding user-defined types with DeferredFormatCodec or STL containers to properly handle rvalue references. For example, the following move-only type will now work correctly: 
    class MoveOnlyType {
public:
  MoveOnlyType(std::string name, std::string value, uint32_t count)
    : name(std::move(name)), value(std::move(value)), count(count) {}
  MoveOnlyType(MoveOnlyType&&) = default;
  MoveOnlyType(MoveOnlyType const&) = delete;
  std::string name;
  std::string value;
  uint32_t count;
};

template <>
struct fmtquill::formatter<MoveOnlyType> {
  constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
  auto format(MoveOnlyType const& obj, format_context& ctx) const {
    return fmtquill::format_to(ctx.out(), "MoveOnlyType(name: {}, value: {}, count: {})",
                               obj.name, obj.value, obj.count);
  }
};

template <>
struct quill::Codec<MoveOnlyType> : quill::DeferredFormatCodec<MoveOnlyType> {};

MoveOnlyType obj{"Test", "Value1", 42};
LOG_INFO(logger, "obj: {}", std::move(obj));  // Properly forwards and moves

v10.2.0

  • Added fuzzing tests to CI to catch memory and undefined behavior issues
  • Fixed PatternFormatter automatic newline appending by making the suffix ('\n') configurable or optionally disabled via PatternFormatterOptions
  • Fixed segmentation fault when DirectFormatCodec was used with enums types (#848)
  • Fixed segmentation fault when DirectFormatCodec was used with STL containers of enums
  • Fixed a compiler error when LOG_DYNAMIC is used with QUILL_DISABLE_FILE_INFO (#847)
  • Fixed process ID capture in BackendWorker to support fork() correctly (#860)
  • Fixed undefined behavior caused by passing nullptr to memcpy when encoding empty std::vector
  • Updated BackendOptions::check_printable_char to allow tab (\t) and carriage return (\r) characters by default (#856)
  • Increased RdtscClock resync lag thresholds to improve cross-system compatibility
  • Added QUILL_ENABLE_ASSERTIONS CMake option and preprocessor flag to enable assertions in release builds
  • Allow RotatingSink to rotate the file on creation with rotation_on_creation()
  • Improved SignalHandlerOptions configurability by replacing hardcoded logger exclusion string with excluded_logger_substrings option
  • Silence MSVC warnings (4324, 4996) in source code instead of CMake

v10.1.0

  • Fixed potential conflicts by adding unique prefixes to internal macro variables to prevent conflicts with user variable names in the same scope. (#799)
  • Fixed potential UBSan warnings by adding overflow check when doubling resync interval in RdtscClock::resync() (#809)
  • Minor improvements in Utility::to_hex function and StringFromTime
  • Fixed an issue where BackendWorker::_exit was always executed during destruction, even when the backend thread had already stopped (#815)
  • Fixed RotatingFileSink to correctly handle FilenameAppendOption::StartDate configuration (#822)
  • Fixed unnecessary allocation caused by empty std::vector while BackendWorker is idle on Windows (#827)
  • Fixed FileSink::open_mode string comparison for file mode flags
  • Adjusted default BackendOptions values for broader system compatibility and typical usage patterns

v10.0.1

  • Fixed PatternFormatter test to work with any repository name instead of hardcoded quill (#795)
  • Fixed Windows compiler warnings when clang-cl >= 19 is used

v10.0.0

New Features

  • There is a new macro-free mode that allows logging without macros. You have two options: either #include "quill/LogMacros.h" or #include "quill/LogFunctions.h". The macro mode still remains the recommended and main method for logging. The new macro-free log has higher overhead than using macros. To use the macro-free mode, for example:

    quill::debug(logger, "A {} message with number {}", "test", 123);

    See macro-free mode documentation here for details.

  • Added BinaryDataDeferredFormatCodec for efficient binary data logging. This codec allows efficient logging of variable-sized binary data by copying the raw bytes on the hot path and deferring the formatting to the backend thread. This is particularly useful for logging binary protocol messages (like SBE or custom binary formats), network packets, and raw binary data without impacting application performance. See the example sbe_logging and binary_protocol_logging for details. For documentation, see here.

  • The immediate flush feature has been enhanced to support interval-based flushing and moved to runtime. This feature helps with debugging by ensuring log statements are flushed to the sink, blocking the caller thread. (#660)

  • Added source_location_path_strip_prefix option in PatternFormatterOptions to customize the display of the %(source_location) attribute of PatternFormatter. When set, any paths that contain this prefix will have the prefix and everything before it stripped from the displayed path. For example, with prefix "projects", a source location like "/home/user/projects/app/main.cpp:5" would be displayed as "app/main.cpp: 5". (#772)

  • Added source_location_remove_relative_paths option in PatternFormatterOptions to remove relative path components from the %(source_location) attribute of PatternFormatter. When enabled, relative path components like "../" are processed and removed, simplifying paths from __FILE__ which might contain relative paths like "../../../test/main.cpp". (#778)

  • Added the QUILL_DISABLE_FILE_INFO preprocessor flag and CMake option.
    This disables __FILE__ and __LINE__ information in log statements at compile time when location-related patterns (%(file_name), %(line_number), %(short_source_location), %(source_location)) are not needed in the PatternFormatter. This removes embedded source path strings from built binaries from the security viewpoint.

  • Added the QUILL_DETAILED_FUNCTION_NAME CMake option. When enabled, this option uses compiler-specific detailed function signatures (such as __PRETTY_FUNCTION__ on GCC/Clang or __FUNCSIG__ on MSVC) instead of the standard __FUNCTION__ in log macros. This provides more complete function information, including return types, namespaces, and parameter types. This option is only relevant when %(caller_function) is used in the pattern formatter. (#785)

  • Added process_function_name customisation point in PatternFormatterOptions. This function allows custom processing of the function signature before it's displayed in logs. This makes more sense to use when QUILL_DETAILED_FUNCTION_NAME is used. This provides flexibility to trim, format, or otherwise modify function signatures to improve readability in log output when using the %(caller_function) pattern. (#785)

  • Added helper macros for easy logging of user-defined types. Two new macros are available in quill/HelperMacros.h:

    • QUILL_LOGGABLE_DIRECT_FORMAT(Type): For types that contain pointers or have lifetime dependencies
    • QUILL_LOGGABLE_DEFERRED_FORMAT(Type): For types that only contain value types and are safe to copy

    Note that these macros require you to provide either an operator<< for your type and they are just shortcuts to existing functionality. (#777)

    Example usage:

    class User { /* ... */ };
std::ostream& operator<<(std::ostream& os, User const& user) { /* ... */ }

// For types with pointers - will format immediately
QUILL_LOGGABLE_DIRECT_FORMAT(User)

class Product { /* ... */ };
std::ostream& operator<<(std::ostream& os, Product const& product) { /* ... */ }

// For types with only value members - can format asynchronously
QUILL_LOGGABLE_DEFERRED_FORMAT(Product)

Improvements

  • Internally, refactored how runtime metadata are handled for more flexibility, providing three macros for logging with runtime metadata:

    • QUILL_LOG_RUNTIME_METADATA_DEEP - Takes a deep copy of fmt, file, function and tags. Most flexible option, useful for forwarding logs from another logging library.
    • QUILL_LOG_RUNTIME_METADATA_HYBRID - Will take a deep copy of fmt and tags and will take file and function as reference. This is used for the new macro-free mode.
    • QUILL_LOG_RUNTIME_METADATA_SHALLOW - Will take everything as reference. This is used when logging with compile-time metadata and using, for example, a dynamic log-level such as LOG_DYNAMIC.

  • When using a sink with overridden PatternFormatterOptions, the option add_metadata_to_multi_line_logs will now be correctly applied at the Sink level. Previously, this option was only available and effective at the Logger level PatternFormatter.

  • When a Sink with override PatternFormatterOptions is used and if no other sink exists using the Logger PatternFormatterOptions, then the backend thread will no longer perform a redundant format log statement.

  • When using a sink with overridden PatternFormatterOptions, the log_statement that is passed to the Filter::filter() will now be formatted based on the overridden options instead of using the Logger PatternFormatterOptions.

  • Update bundled libfmt to v11.2.0

API Changes

  • If you were previously setting QUILL_ENABLE_IMMEDIATE_FLUSH to 1, this functionality has been moved to runtime with more flexibility. Instead of using a boolean flag, you can now specify the flush interval by calling logger->set_immediate_flush(flush_every_n_messages) on each logger instance. Set it to 1 for per-message flushing, or to a higher value to flush after that many messages. Setting it to 0 disables flushing which is the default behaviour. QUILL_ENABLE_IMMEDIATE_FLUSH still exists as a compile-time preprocessor flag and is set to 1 by default. Setting QUILL_ENABLE_IMMEDIATE_FLUSH 0 in the preprocessor will eliminate the if branch from the hot path and disable this feature entirely, regardless of the value passed to set_immediate_flush(flush_every_n_messages).

  • The QUILL_LOG_RUNTIME_METADATA macro requires file, function and fmt to be passed as char const* and line_number as uint32_t. This is a breaking change from the previous version.

v9.0.3

  • Add support for void* formatting (#759)
  • Fix a bug in RotatingJsonFileSink.h where file size-based rotation wasn't triggering properly (#767)
  • Fix false positive -Wstringop-overread warning in GCC (#766)

v9.0.2

  • Add missing namespace in QUILL_LOG_RUNTIME_METADATA (#743)

v9.0.1

  • Fix crash when LOG_BACKTRACE is used (#744)
  • Add missing namespace in QUILL_LOG_RUNTIME_METADATA (#743)
  • Check for nullptr Logger* before setting log level via QUILL_LOG_LEVEL environment variable (#749)
  • Change default mode of FileSink fopen to a to avoid overwriting existing files

v9.0.0

API Changes

  • Replaced the bool huge_pages_enabled flag in FrontendOptions with quill::HugePagesPolicy huge_pages_policy enum, allowing huge page allocation to be attempted with a fallback to normal pages if unavailable. If you are using a custom FrontendOptions type, you will need to update it to use the new flag. (#707)
  • Previously, QueueType::UnboundedDropping and QueueType::UnboundedBlocking could grow up to 2 GB in size. This limit is now configurable via FrontendOptions::unbounded_queue_max_capacity, which defaults to 2 GB.
  • QueueType::UnboundedUnlimited has been removed, as the same behavior can now be achieved by setting FrontendOptions::unbounded_queue_max_capacity to the maximum value.
  • The ConsoleSink constructor now optionally accepts a ConsoleSinkConfig, similar to other sinks. If no ConsoleSinkConfig is provided, a default one is used, logging to stdout with ColourMode::Automatic. For example: 
    Frontend::create_or_get_sink<ConsoleSink>("console_sink",
                                          []()
                                          {
                                            ConsoleSinkConfig config;
                                            config.set_colour_mode(ConsoleSinkConfig::ColourMode::Never);
                                            config.set_stream("stderr");
                                            return config;
                                          }());

New Features

  • The default log level for each Logger can now be configured using the environment variable QUILL_LOG_LEVEL. Supported values: "tracel3", "tracel2", "tracel1", "debug", "info", "notice", "warning", "error", "critical", "none". When set, the logger is initialized with the corresponding log level. If logger->set_log_level(level) is explicitly called in code, it will override the log level set via the environment variable.

  • Added the LOG_RUNTIME_METADATA(logger, log_level, file, line_number, function, fmt, ...) macro.
    This enables passing runtime metadata (such as file, line number, and function) along with a log message,
    providing greater flexibility when forwarding logs from other logging libraries. (#696)

    LOG_RUNTIME_METADATA(logger, quill::LogLevel::Info, "main.cpp", 20, "foo()", "Hello number {}", 8);

  • Added a runtime check to detect duplicate backend worker threads caused by inconsistent linkage
    (e.g., mixing static and shared libraries). If needed, this check can be disabled using the
    check_backend_singleton_instance flag in BackendOptions. (#687)

  • Added the QUILL_DISABLE_FUNCTION_NAME preprocessor flag and CMake option.
    This allows disabling __FUNCTION__ in LOG_* macros when %(caller_function) is not used in PatternFormatter,
    eliminating Clang-Tidy warnings when logging inside lambdas.

  • It is now possible to override a logger's PatternFormatter on a per-sink basis. This allows the same logger to output different formats for different sinks. Previously, achieving this required creating a custom sink type, but this functionality is now built-in. See the example: sink_formatter_override.

  • Added Frontend::remove_logger_blocking(...), which blocks the caller thread until the specified logger is fully removed.

  • Added Frontend::shrink_thread_local_queue(capacity) and Frontend::get_thread_local_queue_capacity(). These functions allow dynamic management of thread-local SPSC queues when using an unbounded queue configuration. They enable on-demand shrinking of a queue that has grown due to bursty logging, helping to reduce memory usage, although in typical scenarios they won't be required.

  • Added the SyslogSink, which logs messages to the system's syslog.

    auto sink = quill::Frontend::create_or_get_sink<quill::SyslogSink>(
  "app", []()
  {
    quill::SyslogSinkConfig config;
    config.set_identifier("app");
    return config;
  }());

  • Added the SystemdSink, which logs messages to systemd.

    auto sink = quill::Frontend::create_or_get_sink<quill::SystemdSink>(
  "app", []()
  {
    quill::SystemdSinkConfig config;
    config.set_identifier("app");
    return config;
  }());

  • Added the AndroidSink, which integrates with Android's logging system.

    auto sink = quill::Frontend::create_or_get_sink<quill::AndroidSink>(
  "s1", []()
  {
    quill::AndroidSinkConfig config;
    config.set_tag("app");
    config.set_format_message(true);
    return config;
  }());

Improvements

  • Updated bundled libfmt to 11.1.4.

  • When add_metadata_to_multi_line_logs in the PatternFormatter was set to false, fixed a bug where the last character of the log message was dropped and added protection for empty messages.

  • Updated LOG_EVERY_N macros to log on the first occurrence (0th call) instead of waiting until the Nth call.

  • Added a nullptr check for char* and const char* during encoding, ensuring the library handles nullptr values gracefully (#735)

  • The CsvWriter could previously be used with RotatingFileSink via the constructor that accepted
    std::shared_ptr<Sink>, but rotated files did not include the CSV header.
    This has now been improved—when using the new constructor that accepts quill::RotatingFileSinkConfig,
    the CSV header is written at the start of each new rotated file. (#700)

    quill::RotatingFileSinkConfig sink_config;
sink_config.set_open_mode('w');
sink_config.set_filename_append_option(FilenameAppendOption::None);
sink_config.set_rotation_max_file_size(512);
sink_config.set_rotation_naming_scheme(RotatingFileSinkConfig::RotationNamingScheme::Index);

quill::CsvWriter<OrderCsvSchema, quill::FrontendOptions> csv_writer{"orders.csv", sink_config};
for (size_t i = 0; i < 40; ++i)
{
  csv_writer.append_row(132121122 + i, "AAPL", i, 100.1, "BUY");
}

  • When using CsvWriter with open_mode == 'a', the header will no longer be rewritten if the file already exists.

  • On Linux, setting a long backend thread name now truncates it instead of failing. (#691)

  • Fixed BSD builds. (#688)

  • Added adaptive termination for stable measurements in rdtsc calibration during init

  • Fixed QUILL_ATTRIBUTE_HOT and QUILL_ATTRIBUTE_COLD clang detection

  • CMake improvements: switched to range syntax for minimum required version and bumped minimum required CMake version to 3.12. (#686)

  • Correct the installation location of pkg-config files. They are now properly placed in /usr/local/lib. (#715)

  • Removed deprecated TriviallyCopyableTypeCodec

v8.2.0

  • Added DeferredFormatCodec and DirectFormatCodec for easier logging of user-defined types and smoother migration from pre-v4 versions. Previously, users had to define a custom Codec for every non-trivially copyable user-defined type they wanted to log.

    template <>
struct quill::Codec<UserTypeA> : quill::DeferredFormatCodec<UserTypeA>
{
};
   
template <>
struct quill::Codec<UserTypeB> : quill::DirectFormatCodec<UserTypeB>
{
};
    • DeferredFormatCodec now supports both trivially and non-trivially copyable types:
      • For trivially copyable types, it behaves the same as TriviallyCopyableTypeCodec.
      • For non-trivially copyable types, it works similarly to pre-v4 by taking a copy of the object using the copy constructor and placement new.
    • DirectFormatCodec formats the object immediately in the hot path, serving as a shortcut to explicitly formatting the object when logging.
    • For advanced use cases, a custom Codec can still be defined for finer control over encoding/decoding.

    See:

  • Added codec support for C-style arrays of user-defined types in std/Array.h

  • Fixed warnings: -Wimplicit-int-float-conversion, -Wfloat-equal, and -Wdocumentation.

  • Marked TriviallyCopyableTypeCodec as deprecated. DeferredFormatCodec should be used instead, requiring no further changes.

  • Raised minimum CMake required version from 3.8 to 3.10 to avoid deprecation warnings.

v8.1.1

  • Updated bazel rules_cc to 0.1.1 (#664)

v8.1.0

  • Updated bundled libfmt to 11.1.3
  • Suppressed clang-19 warning when building the tests with C++17. (#646)
  • Fixed windows linkage error when shared library is used.
  • Fixed redefinition of struct fmt_detail::time_zone error (#649)

v8.0.0

  • Unified JsonFileSink.h and JsonConsoleSink.h into a single header, JsonSink.h, with both classes now sharing a common implementation

  • Users can now inherit from JsonFileSink or JsonConsoleSink and override the generate_json_message(...) function to implement their own custom JSON log formats

  • Removed JsonFileSinkConfig. Please rename it to FileSinkConfig, which retains the same API and is fully compatible.

  • Added RotatingJsonFileSink. Functions like RotatingFileSink, but specifically designed for rotating JSON log files. (#637)

  • Simplified ConsoleSink by applying ANSI colour codes universally across all platforms, including Windows. The previous Windows-specific implementation has been removed. Note that quill::ConsoleColours has been replaced with quill::ConsoleSink::Colours, and quill::ConsoleColours::ColourMode has been renamed to quill::ConsoleSink::ColourMode.

  • Changed class member visibility in FileSink, JsonSink, and RotatingSink from private to protected, enabling easier customization through inheritance for user-defined implementations.

  • Added a new sink_min_flush_interval option in BackendOptions, which specifies the minimum time interval (in milliseconds) before the backend thread flushes the output buffers calling flush_sink() for all sinks, with a default value of 200ms; The backend thread ensures sinks aren't flushed more frequently than this interval, while explicit calls to logger->flush_log() trigger an immediate flush, and flushing may occur less frequently if the backend thread is busy, with this setting applying globally to all sinks. Setting this value to 0 disables the feature. (#641)

  • Updated bundled libfmt to 11.1.2

  • Added a StopWatch utility for easy logging of elapsed time. It can log the time elapsed since construction in various formats. You can use either quill::StopWatchTsc for high-resolution TSC-based timing or quill::StopWatchChrono for standard std::chrono-based timing. (#640)

    For example:

      #include "quill/StopWatch.h"

  quill::StopWatchTsc swt;
  std::this_thread::sleep_for(std::chrono::seconds(1));
  LOG_INFO(logger, "After 1s, elapsed: {:.6}s", swt); // => After 1s, elapsed: 1.00849s
  std::this_thread::sleep_for(std::chrono::milliseconds(500));
  LOG_INFO(logger, "After 500ms, elapsed: {}s", swt); // => After 500ms, elapsed: 1.521880274s
  LOG_INFO(logger, "elapsed: {}", swt.elapsed_as<std::chrono::nanoseconds>()); // => elapsed: 1521807324ns

  • Suppress -Wredundant-decls warning in GCC builds.

  • Remove -Wno-gnu-zero-variadic-macro-arguments for GCC in CMake.

v7.5.0

  • In previous versions, logging on Windows automatically included windows.h in all components. The frontend will no longer include windows.h. By following the recommended usage example provided here as guidance, you can create a wrapper library around Quill for the backend, allowing you to log on Windows without including windows.h in the frontend or main program. (#618)

  • The LOG_LEVEL_LIMIT time-based rate-limiting macros now log the count of how many times a message would be logged when throttled. For example, a log message may appear as A log message with number 123 (21x) to indicate that the message would have been logged 21 times. (#616)

  • New macros LOG_LEVEL_LIMIT_EVERY_N have been added, allowing for count-based rate limiting and giving developers greater control over logging frequency. (#616)

  • Renamed PACKED used in libfmt to QUILLPACKED to avoid naming collisions. (#620)

  • The set_thread_name function has been fixed to provide accurate error reporting, ensuring that the correct error message is displayed in the event of a failure.

v7.4.0

  • Fixed a build issue when compiling with -fno-rtti. This ensures compatibility with projects that disable RTTI. (#604)

  • Fixed an incorrectly triggered assertion in debug builds when BackendOptions::log_timestamp_ordering_grace_period is set to 0 (#605)

  • Fixed a compile-time error in CsvWriter that occurred when passing a custom FrontendOptions type as a template parameter. (#609)

  • Added accessors to Logger for sinks, user clock source, clock source type, and pattern formatter options that can be used to create another Logger with similar configuration.

  • Added ConsoleColours::ColourMode to ConsoleSink, allowing colors to be explicitly forced or conditionally enabled based on the environment. Previously, colors were only conditionally enabled. (#611).

    For example:

      quill::Frontend::create_or_get_sink<quill::ConsoleSink>(
    "sink_id_1", quill::ConsoleColours::ColourMode::Automatic);

v7.3.0

  • Added the option to explicitly specify the Logger used by the built-in SignalHandler for logging errors during application crashes. (#590)
  • Prevented error logs from the SignalHandler from being output to CSV files when a CsvWriter is in use. (#588)
  • Introduced SignalHandlerOptions to simplify and unify the API. Backend::start_with_signal_handler is now deprecated, replaced by a new Backend::start overload that accepts SignalHandlerOptions for enabling signal handling.
  • Added a new create_or_get_logger overload that accepts a std::vector<std::shared_ptr<Sink>>, improving flexibility by allowing a variable number of sinks to be passed at runtime when creating a logger.
  • Added a new overload to create_or_get_logger to create a logger that inherits configuration options from a specified logger. (#596)
  • Implemented a workaround to resolve false positive warnings from clang-tidy on Windows.

v7.2.2

  • Fixed race condition during DLL unload by ensuring safe cleanup of ThreadContext when calling flush_log() (#586)

v7.2.1

  • Fixed an unused variable warning treated as an error on MSVC.

v7.2.0

Bug Fixes:

  • Fixed compile error in BackendTscClock (#577)
  • Added a missing header include in TriviallyCopyableCodec.h. (#560)
  • Fixed incorrect log level short codes introduced in v7 after adding the new log level NOTICE. Using %(log_level_short_code) in the pattern formatter could incorrectly map LOG_ERROR to "C" and LOG_WARNING to "E". (#564)
  • Fixed an overflow issue when logging more than uint32_t::max() bytes in a single log message. For example, attempting to log std::string s(std::numeric_limits<uint32_t>::max(), 'a'); would previously cause a crash.

Improvements:

  • Optimised dynamic log level handling and size calculation for fundamental types, std::string and std:: string_view on the hot path.
  • Several enhancements to the backend worker thread, resulting in an overall 10% backend throughput increase. Key optimizations include the simplification of TransitEventBuffer, reducing the memory footprint of TransitEvent, introducing support for custom buffer sizes in file streams and tuning transit_events_soft_limit and transit_events_hard_limit default values
  • Improved readability of queue allocation notification messages. Capacities are now displayed in KiB, e.g., 20:59:25 Quill INFO: Allocated a new SPSC queue with a capacity of 1024 KB (previously 512 KB) from thread 31158.

New Features:

  • Introduced support for custom buffer sizes in file streams for FileSink and RotatingFileSink. Buffer size is now configurable via FileSinkConfig::set_write_buffer_size(size_value) with a default of 64 KB.
  • Added an optional fsync interval to control the minimum time between consecutive fsync calls, reducing disk wear from frequent fsync operations. This option is only applicable when fsync is enabled. (#557)
  • Implemented support for appending a custom timestamp format to log filenames via StartCustomTimestampFormat. Example usage: 
    auto file_sink = quill::Frontend::create_or_get_sink<quill::FileSink>("logfile.log", []()
{
  quill::FileSinkConfig cfg;
  cfg.set_filename_append_option(quill::FilenameAppendOption::StartCustomTimestampFormat, "%m%d");
  return cfg;
}());
    This will create a log file named logfile0919.log, where 0919 represents the month and day.
  • When using %(named_args) in the pattern formatter or logging in JSON format, extra arguments without key names are now included in JSON output with keys corresponding to their positional indexes. This allows additional details to be included in the JSON while keeping the log message clean. For example (#563): 
    LOG_INFO(hybrid_logger, "Operation {name} completed with code {code}", "Update", 123, "Data synced successfully");
    This will output: 
    Operation Update completed with code 123
    And the corresponding JSON will be: 
    {"timestamp":"1726582319816776867","file_name":"json_file_logging.cpp","line":"71","thread_id":"25462","logger":"hybrid_logger","log_level":"INFO","message":"Operation {name} completed with code {code}","name":"Update","code":"123","_2":"Data synced successfully"}

v7.1.0

  • Fixed crash when using QueueType::BoundedDropping or QueueType::UnboundedDropping after a message drops. (#553)
  • Improved performance of ForwardList decoding.
  • Corrected reported dropped message count; previously, log flush attempts were incorrectly included.
  • Removed leftover files after running some unit tests.
  • Stabilized regression tests.
  • Suppressed false-positive -Wstringop-overflow warnings (e.g., with GCC 13).
  • Fixed MinGW build and added MinGW builds to GitHub Actions.

v7.0.0

  • Simplified the log tags API. The Tags class has been removed. You now pass a char const* directly to the macros. Additionally, macros previously named WITH_TAGS have been renamed to _TAGS. For example, LOG_INFO_WITH_TAGS is now LOG_INFO_TAGS.

  • Renamed backend_cpu_affinity to cpu_affinity in BackendOptions to improve consistency.

  • Simplified project structure by removing the extra quill directory and made minor CMake improvements; include/quill is now directly in the root.

  • Added support for std::string with custom allocator. (#524)

  • Added a new log level NOTICE, for capturing significant events that aren't errors or warnings. It fits between INFO and WARNING for logging important runtime events that require attention. (#526)

  • Enhanced static assert error message for unsupported codecs, providing clearer guidance for STL and user-defined types.

  • Improved frontend performance by caching the ThreadContext pointer in Logger class to avoid repeated function calls. On Linux, this is now further optimised with __thread for thread-local storage, while other platforms still use thread_local.

  • Minor performance enhancement in the frontend by replacing std::vector<size_t> with an InlinedVector<uint32_t, 12> for caching sizes (e.g. string arguments).

  • Fixed order of evaluation for Codec::pair<T1,T2>::compute_encoded_size() to prevent side effects observed on MSVC

  • Introduced the add_metadata_to_multi_line_logs option in PatternFormatter. This option, now enabled by default, appends metadata such as timestamps and log levels to every line of multiline log entries, ensuring consistent log output. To restore the previous behavior, set this option to false when creating a Logger using Frontend::create_or_get_logger(...). Note that this option is ignored when logging JSON using named arguments in the format message. (#534)

  • JSON sinks now automatically remove any \n characters from format messages, ensuring the emission of valid JSON messages even when \n is present in the format.

  • Replaced static variables with static constexpr in the ConsoleColours class.

  • Fixed compiler errors in a few rarely used macros. Added a comprehensive test for all macros to prevent similar issues in the future.

  • Expanded terminal list for color detection in console applications on Linux

  • Fixed an issue where char* and char[] types could be incorrectly selected by the Codec template in Array.h

  • The library no longer defines __STDC_WANT_LIB_EXT1__, as the bounds-checking functions from the extensions are no longer needed.

  • StringFromTime constructor no longer relies on the system's current time, improving performance in simulations where timestamps differ from system time. (#541)

  • The Frontend::create_or_get_logger(...) function now accepts a PatternFormatterOptions parameter, simplifying the API. This is a breaking change. To migrate quickly, wrap the existing formatting parameters in a PatternFormatterOptions object.

    Before:

      quill::Logger* logger =
    quill::Frontend::create_or_get_logger("root", std::move(file_sink),
                                          "%(time) [%(thread_id)] %(short_source_location:<28) "
                                          "LOG_%(log_level:<9) %(logger:<12) %(message)",
                                          "%H:%M:%S.%Qns", quill::Timezone::GmtTime);

    After:

      quill::Logger* logger =
    quill::Frontend::create_or_get_logger("root", std::move(file_sink), quill::PatternFormatterOptions {
                                          "%(time) [%(thread_id)] %(short_source_location:<28) "
                                          "LOG_%(log_level:<9) %(logger:<12) %(message)",
                                          "%H:%M:%S.%Qns", quill::Timezone::GmtTime});

v6.1.2

  • Fix pkg-config file on windows

v6.1.1

  • Fix pkg-config file

v6.1.0

  • Fix various compiler warnings
  • Minor serialisation improvements in Array.h and Chrono.h
  • Introduced Backend::acquire_manual_backend_worker() as an advanced feature, enabling users to manage the backend worker on a custom thread. This feature is intended for advanced use cases where greater control over threading is required. (#519)
  • Add new CsvWriter utility class for asynchronous CSV file writing. For example: 
    #include "quill/Backend.h"
#include "quill/core/FrontendOptions.h"
#include "quill/CsvWriter.h"

struct OrderCsvSchema
{
  static constexpr char const* header = "order_id,symbol,quantity,price,side";
  static constexpr char const* format = "{},{},{},{:.2f},{}";
};

int main()
{
  quill::BackendOptions backend_options;
  quill::Backend::start(backend_options);
  
  quill::CsvWriter<OrderCsvSchema, quill::FrontendOptions> csv_writer {"orders.csv"};
  csv_writer.append_row(13212123, "AAPL", 100, 210.32321, "BUY");
  csv_writer.append_row(132121123, "META", 300, 478.32321, "SELL");
  csv_writer.append_row(13212123, "AAPL", 120, 210.42321, "BUY");
}

v6.0.0

  • Added a Cheat Sheet to help users get the most out of the logging library

  • Removed ArgSizeCalculator<>, Encoder<>, and Decoder<> classes. These have been consolidated into a single Codec class. Users who wish to pass user-defined objects should now specialize this single Codec class instead of managing three separate classes. For guidance, please refer to the updated advanced example

  • Added TriviallyCopyableCodec.h to facilitate serialization for trivially copyable user-defined types. For example

      struct TCStruct
  {
    int a;
    double b;
    char c[12];
    
    friend std::ostream& operator<<(std::ostream& os, TCStruct const& arg)
    {
      os << "a: " << arg.a << ", b: " << arg.b << ", c: " << arg.c;
      return os;
    }
  };
  
  template <>
  struct fmtquill::formatter<TCStruct> : fmtquill::ostream_formatter
  {
  };
  
  template <>
  struct quill::Codec<TCStruct> : quill::TriviallyCopyableTypeCodec<TCStruct>
  {
  };
  
  int main()
  {
    // init code ...
    
    TCStruct tc;
    tc.a = 123;
    tc.b = 321;
    tc.c[0] = '\0';
    LOG_INFO(logger, "{}", tc);
  }

  • Added support for passing arithmetic or enum c style arrays when std/Array.h is included. For example

      #include "quill/std/Array.h"

  int a[6] = {123, 456};
  LOG_INFO(logger, "a {}", a);

  • Added support for void const* formatting. For example

        int a = 123;
    int* b = &a;
    LOG_INFO(logger, "{}", fmt::ptr(b));

  • Added support for formatting std::chrono::time_point and std::chrono::duration with the inclusion of quill/std/Chrono.h

    #include "quill/std/Chrono.h"

std::chrono::system_clock::time_point now = std::chrono::system_clock::now();
LOG_INFO(logger, "time is {}", now);

  • Removed unused method from ConsoleSink

v5.1.0

  • Fix unit tests on FreeBSD (#496)
  • Resolved unused variable warning on MSVC.
  • Updated CMake to avoid adding -fno-exceptions to the entire target when QUILL_NO_EXCEPTIONS=ON (#499)
  • Fix an issue where timestamps were incorrectly calculated when using quill::Timezone::LocalTime. This bug affected timezones that did not have an exact hour difference from UTC, leading to incorrect timestamp calculations. (#498)
  • The newline character \n is now considered printable by default and will no longer be sanitized. Users can now include new lines in their logs directly. In versions 4.4.1 and earlier, \n was not sanitized, and this behavior is restored in this update, eliminating the need for a custom check_printable_char function in BackendOptions.
  • On Windows, when colors are enabled in ConsoleSink, GetConsoleScreenBufferInfo may fail in the debug console. Previously, this would result in an error being displayed but no logs being written. This issue is now resolved: the error is reported once, and logs will be written to the console without colors.
  • Improved performance of StringFromTime and TimestampFormatter used by the backend worker thread.
  • Replaced std::mutex with a spinlock, resulting in minor performance improvement for backend worker. This change also avoids including <mutex> in the frontend, particularly when following the recommended_usage example
  • Update bundled libfmt to 11.0.2

v5.0.0

  • Fix build failure on Windows Arm64 (#485)

  • Previously, wide string support was included in Codec.h. Wide string functionality has now been moved to a separate header file, WideStrings.h. On Windows, logging wide strings now requires the inclusion of quill/std/WideStrings.h.

  • Added QUILL_IMMEDIATE_FLUSH preprocessor variable. This variable can be defined before including LogMacros.h or passed as a compiler flag. When QUILL_IMMEDIATE_FLUSH is defined, the library will flush the log on each log statement. This causes the caller thread to wait for the log to be processed and written to the log file by the backend thread before continuing, significantly impacting performance. This feature is useful for debugging the application when synchronized logs are required. (#488)

  • Introduced log_level_descriptions and log_level_short_codes in BackendOptions to allow customization of LogLevel descriptions and short codes, replacing previously hardcoded values. This enhancement enables users to define their own descriptions and short codes for each log level. For instance, instead of displaying LOG_WARNING, it can now be configured to show LOG_WARN. (#489)

    quill::BackendOptions backend_options;
backend_options.log_level_descriptions[static_cast<uint32_t>(quill::LogLevel::Warning)] = "WARN";
quill::Backend::start(backend_options);

  • Introduced LOGV_LEVEL, LOGV_LEVEL_LIMIT, and LOGV_LEVEL_WITH_TAGS macros. These new macros simplify logging by automatically printing variable names and values without explicitly specifying each variable name or using {} placeholders in the format string. Each macro can handle up to 26 arguments. The format string is concatenated at compile time, there is no runtime overhead for using these macros. For example:

      int a = 123;
  double b = 3.17;
  LOGV_INFO(logger, "A message with two variables", a, b)

    outputs A message with two variables [a: 123, b: 3.17]

  • Introduced LOGJ_LEVEL, LOGJ_LEVEL_LIMIT, and LOGJ_LEVEL_WITH_TAGS macros. These new macros simplify JSON logging by automatically embedding the name of each passed variable as a named argument in the format string. Each macro can handle up to 26 arguments. The format string is concatenated at compile time, there is no runtime overhead for using these macros. For example:

      int var_a = 123;
  std::string var_b = "test";
  LOGJ_INFO(logger, "A json message", var_a, var_b);

    outputs {"log_level":"INFO","message":"A json message {var_a}, {var_b}","var_a":"123","var_b":"test"}

  • Enhanced the filter function to also receive the formatted log_message alongside the log_statement, enabling the comparison and filtering of log_message while disregarding elements like timestamps from the full log_statement. (#493)

  • Renamed log_message to log_statement and should_log_message to should_log_statement in Logger

  • Replaced %(log_level_id) with %(log_level_short_code) in the PatternFormatter.

  • Fix a CMakeLists error for old CMake versions prior to 3.19. (#491)

v4.5.0

  • The backend now automatically sanitizes non-printable characters in log messages by converting them to their hexadecimal representation. This feature ensures logs contain only safe, readable characters. You can customize or disable this feature through the backend options by modifying the check_printable_char callback in BackendOptions.

    std::function<bool(char c)> check_printable_char = [](char c) { return c >= ' ' && c <= '~'; };

  • Added StringRef, a utility for passing string arguments by reference without copying. Suitable for string literals or immutable strings with a guaranteed persistent lifetime. For example

    #include "quill/StringRef.h"

static constexpr std::string_view sv {"string_view"};
LOG_INFO(logger, "{} {}", quill::utility::StringRef{sv}, quill::utility::StringRef{"string_literal"});

  • Renamed write_log_message to write_log in Sink. The formatted log_message and process_id are now also provided. This enhancement supports use cases where the formatted log_statement passed to the Sink can be ignored and overwritten with a custom format, allowing a single Logger to output different formats to various Sinks. (#476)

  • Fixed a bug in JSON logging where previously cached named arguments could erroneously append to subsequent log statements. (#482)

v4.4.1

  • Fixed multiple definitions of quill::detail::get_error_message (#469)
  • Fixed an issue causing a SIGABRT when creating directories with a symlink folder path using GCC versions 8 or 9 (#468)
  • Added an assertion to prevent the use of custom FrontendOptions together with default FrontendOptions (#453)

v4.4.0

  • Introduced log_timestamp_ordering_grace_period parameter, replacing enable_strict_log_timestamp_order in BackendOptions. Enables strict timestamp ordering with configurable grace period.
  • Fixed an issue where symbols were not properly exported with hidden visibility when compiling as a shared library. (#463)
  • Move version info into quill namespace (#465)
  • Upstreamed Meson build integration. See details here
  • Upstreamed Bazel build integration. See details here

v4.3.0

  • Refactored BacktraceStorage to simplify the code.
  • Fixed multiple definitions of on_alarm in SignalHandler.h
  • Fixed a bug in the backend thread where flush() and run_periodic_tasks() were skipped for certain sinks. All sinks are now correctly processed.

v4.2.1

  • Added -Wno-gnu-zero-variadic-macro-arguments as an interface compiler flag in CMake

v4.2.0

  • Fixed the compile-time exclusion of log levels. Renamed the QUILL_COMPILE_OUT_LOG_LEVEL preprocessor flag to QUILL_COMPILE_ACTIVE_LOG_LEVEL.
  • Fixed build error when UnboundedDropping queue is used.
  • Fixed a bug introduced in v4.1.0, which resulted in messages being logged out of order when the transit_events_soft_limit was reached. Additionally, this issue affected the behavior of flush_log(), prematurely unblocking the thread before all messages were flushed.
  • Fixed -Wno-unused-parameter and -Wdocumentation warnings.
  • Improved backend worker _exit() functionality and reduced code duplication in other areas of the backend worker code.
  • Added signal_handler_timeout_seconds parameter, which controls the timeout duration for the signal handler. Only available on Linux platforms.
  • Added sleep_duration_ns parameter to the flush_log(...) function. This parameter specifies the duration in nanoseconds to sleep between retries between checks for the flush completion and when a blocking queue is used, and it is full. The default sleep duration is 100 nanoseconds, but users can now customize this duration according to their needs. If a zero sleep duration is passed, the thread might yield instead.
  • Removed uses of std::this_thread::sleep_for(...), std::string, std::vector in the signal handler when waiting for the log to be flushed.

v4.1.0

  • Following the transition from a compiled to a header-only library, the target_compile_options previously applied to the compiled library were mistakenly propagated to all programs linking against the header-only library. This issue is now fixed by removing those flags and explicitly adding them to tests and examples. As a result, executable targets no longer inherit flags from the library.
  • Removed unnecessary template specializations and merged their logic into the primary template for ArgSizeCalculator, Encoder, and Decoder using if constexpr.
  • Eliminated <functional> header dependency in the frontend
  • Replaced %(structured_keys) with %(named_args) in the PatternFormatter. This change now appends the entire key-value pair of named args to the message, not just the names.
  • Relocated certain classes to the detail namespace
  • Replaced sprintf with snprintf to fix macOS warning.
  • Reviewed and removed gcc cold attribute from a few functions.
  • Minor backend thread optimisations when logging c style strings or char arrays
  • Improved backend thread variable and function names and fixed a bug for an edge case when the transit event hard limit is reached

v4.0.0

This version represents a major revamp of the library, aiming to simplify and modernize it, resulting in the removal of a few features. Please read through the changes carefully before upgrading, as it is not backwards compatible with previous versions and some effort will be required to migrate.

I understand that these changes may inconvenience some existing users. However, they have been made with good intentions, aiming to improve and refine the logging library. This involved significant effort and dedication.

Bug fixes and releases for v3 will continue to be supported under the v3.x.x branch.

Comparison

  • This version significantly improves compile times. Taking a look at some compiler profiling for a Release build with clang 15, we can see the difference. Below are the two compiler flamegraphs for building the recommended_usage example from the new version and the wrapper_lib example from the previous version.

The below flamegraph shows the difference in included headers between the two versions

Version Compiler FlameGraph
v4.0.0 quill_v4_compiler_profile.speedscope.png
v3.8.0 quill_v3_compiler_profile.speedscope.png

A new compiler benchmark has been introduced. A Python script generates 2000 distinct log statements with various arguments. You can find the benchmark here. Compilation now takes only about 30 seconds, whereas the previous version required over 4 minutes.

Version Compiler FlameGraph
v4.0.0 quill_v4_compiler_bench.speedscope.png
v3.8.0 quill_v3_compiler_bench.speedscope.png
  • Minor increase in backend thread throughput compared to the previous version.
Version Backend Throughput
v4.0.0 4.56 million msgs/sec average, total time elapsed: 876 ms for 4000000 log messages
v3.8.0 4.39 million msgs/sec average, total time elapsed: 910 ms for 4000000 log messages
  • Significant boost in hot path latency when logging complex types such as std::vector. The performance remains consistent when logging only primitive types or strings in both versions. Refer here for updated and detailed benchmarks.

Changes

  • Improved compile times

The library has been restructured to minimize the number of required headers. Refactoring efforts have focused on decoupling the frontend from the backend, resulting in reduced dependencies. Accessing the frontend logging functions now does not demand inclusion of any backend logic components.

 "quill/Backend.h" - It can be included once to start the backend logging thread, typically in main.cpp 
                     or in a wrapper library.
 
 "quill/Frontend.h"` - Used to create or obtain a `Logger*` or a `Sink`. It can be included in limited 
                       files, since an obtained `Logger*` has pointer stability and can be passed around.
 
 "quill/Logger.h", "quill/LogMacros.h" - These two files are the only ones needed for logging and will have 
                                         to be included in every file that requires logging functionality.
  • Backend formatting for user-defined and standard library types

One of the significant changes lies in the support for formatting both user-defined and standard library types. Previously, the backend thread handled the formatting of these types sent by the frontend. It involved making a copy for any object passed to the LOG_ macros as an argument using the copy constructor of a complex type instead of directly serializing the data to the SPSC queue. While this method facilitated logging copy-constructible user-defined types with ease, it also posed numerous challenges for asynchronous logging:

  • Error-Prone Asynchronous Logging: Copying and formatting user-defined types on the backend thread in an asynchronous logging setup could lead to errors. Previous versions attempted to address this issue with type trait checks, which incurred additional template instantiations and compile times.
  • Uncertainty in Type Verification: It is challenging to confidently verify types, as some trivially copiable types, such as struct A { int* m; }, could still lead to issues due to potential modifications by the user before formatting.
  • Hidden Performance Penalties: Logging non-trivially copiable types could introduce hidden cache coherence performance penalties due to memory allocations and deallocations across threads. For instance, consider std::vector<int> passed as a log argument. The vector is emplaced into the SPSC queue by the frontend, invoking the copy constructor dynamically allocating memory as the only members copied to SPSC queue are size, capacity, and data*. The backend thread reads the object, formats it, and then invokes the destructor, which in turn synchronizes the freed memory back to the frontend.

Additionally, after years of professional use and based on experience, it has been observed that user-defined types are often logged during program initialization, with fewer occurrences on the hot path where mostly built-in types are logged. In such scenarios, the overhead of string formatting on the frontend during initialization is not an issue.

In this new version, the use of the copy constructor for emplacing objects in the queue has been abandoned. Only POD types are copied, ensuring that only raw, tangible data is handled without any underlying pointers pointing to other memory locations. The only exception to this are the pointers to Metadata, LoggerBase and DecodeFunction that are passed internally for each log message. Log arguments sent from the frontend must undergo serialization beforehand. While this approach resolves the above issues, it does introduce more complexity when dealing with user-defined or standard library types.

Built-in types and strings are logged by default, with the formatting being offloaded to the backend. Additionally, there is built-in support for most standard library types, which can also be directly passed to the logger by including the relevant header from quill/std.

The recommendation for user-defined types is to format them into strings before passing them to the LOG_ macros using your preferred method. You can find an example of this here.

It's also possible to extend the library by providing template specializations to serialize the user-defined types and offload their formatting to the backend. However, this approach should only be pursued if you cannot tolerate the formatting overhead in that part of your program. For further guidance, refer to this example.

  • Header-Only library

The library is now header-only. This change simplifies exporting the library as a C++ module in the future. See here on how to build a wrapper static library which includes the backend and will minimise the compile times.

  • Preprocessor flags moved to template parameters

Most preprocessor flags have been moved to template parameters, with only a few remaining as CMake options. This change simplifies exporting the library as a C++ module in the future.

  • Renamed Handlers to Sinks

To enhance clarity, handlers have been renamed to sinks.

  • PatternFormatter moved to Logger

The PatternFormatter has been relocated from Sink to Logger, enabling a logger object to log in a specific format. This allows for different formats within the same output file, a feature not previously possible.

  • Split Configuration

The configuration settings have been divided into FrontendOptions and BackendOptions.

  • Refactoring of backend classes

MacroMetadata and many backend classes have undergone refactoring, resulting in reduced memory requirements.

  • Improved wide strings handling on Windows

The library now offers significant performance enhancements for handling wide strings on Windows platforms. It's important to note that only wide strings containing ASCII characters are supported. Previously, wide strings were converted to narrow strings at the frontend, impacting the critical path of the application. With this update, the underlying wide char buffer is copied and the conversion to UTF-8 encoding is deferred to the backend logging thread. Additionally, this update adds support for logging STL containers consisting of wide strings

  • Default logger removal

The default logger, along with the configuration inheritance feature during logger creation, has been removed. Now, when creating a new logger instance, configurations such as the Sink and log pattern format must be explicitly specified each time. This simplifies the codebase.

  • Global logger removal

The static global logger* variable that was initialised during quill::start() used to obtain the default logger has been removed. It is possible to add this on the user side. If you require a global logger you can have a look at this example

  • Removal of printf style formatting support

The support for printf style formatting has been removed due to its limited usage and the increased complexity. Users requiring this feature should stay on v3.x.x versions to maintain compatibility.

  • Removal of external libfmt usage

The option to build the library with external libfmt has been removed. It becomes difficult to maintain and backwards support previous versions of libfmt. Instead, libfmt is now an internal component of the library, accessible under the namespace fmtquill. You can use the bundled version of fmtquill by including the necessary headers from quill/bundled/fmt. Alternatively, you have the freedom to integrate your own version. Since libfmt is encapsulated within a distinct namespace, there are no conflicts even if you link your own libfmt alongside the logging library.

Migration Guidance

  • Revise include files to accommodate the removal of Quill.h
  • Update the code that starts the backend thread and the logger/sink creation. You can refer to any of the updated examples, such as this one
  • When logging statements involving user-defined types, make sure these types are formatted into strings using your preferred method. Refer to this link for guidance. Alternatively, if you prefer delaying the conversion to strings until the backend thread and only passing a binary copy of the user-defined type on the hot path, you can provide the necessary class template specializations for each user-defined type. See an example here

v3.9.0

  • Fix bug in ConsoleHandler when dynamic log level is used (#421)
  • Fix bug in TransitEvent when dynamic log level is used (#427)
  • Fix build error for Intel compiler classic (#414)
  • Added JsonConsoleHandler (#413)
  • Fix fold expression argument evaluation. This bug could occur when logging c style strings

v3.8.0

  • Refactored MacroMetadata class to reduce its size.
  • Renamed some attributes in the PatternFormatter class for clarity. If you are using a custom format pattern, update the attribute names in your code to match the new names.
  • Improved accuracy of log statement timestamps. Previously, the timestamp was taken after checking if the queue had enough space to push the message, which could make it less accurate. Additionally, in the case of a blocking queue, the timestamp could be later in time. Now, the timestamp is taken and stored right after the log statement is issued, before checking for the queue size.
  • Reduced template instantiations during logging operations on the hot path. Fold expressions are now used for encoding/decoding arguments, minimizing template recursion overhead.
  • Removed compile-time format checks due to their significant impact on template instantiations, especially considering that only a few cases are invalid. For instance, while fmt::format("{}", 1, 2) is considered valid, fmt::format("{} {}", 1) is deemed invalid. In cases where an invalid format string is detected, the backend worker thread catches the generated exception and logs an error.
  • The throughput of the backend worker thread has been improved by approximately 5%. This enhancement is reflected in the new throughput value of 4.20 million msgs/sec, compared to the previous throughput of 3.98 million msgs/sec.
  • Detect tmux as colour terminal. (#410)

v3.7.0

  • Fixed crash triggered by insufficient space in the queue upon invocation of flush(). (#398)
  • Fixed windows clang-cl build error. (#400)
  • Fixed compilation errors encountered on FreeBSD and extended get_thread_id() support to various other BSD operating systems. (#401)
  • Fix open_file in the FileHandler to also create the parent path before opening the file. (#395)
  • Enhance logic for backend thread's flush() invocation; it now triggers only if the handler has previously written data. (#395)
  • Address an uncaught exception in the backend thread that could occur when a user manually removes the log file from the terminal while the logger is running. (#395)
  • Ensure that after a logger is removed, there are no subsequent calls to the Handler's flush() or run_loop(), provided the Handler is not shared. (#395)
  • Ignore the virtual destructor missing warning for the CustomTags class. (#402)
  • Update bundled libfmt to v10.2.1

v3.6.0

  • Fixed QUILL_LOGGER_CALL_NOFN_LIMIT macros. (#381)
  • Resolved a bug that caused reading destructed arguments when structured logging format was used.
  • Modified member access from private to protected in ConsoleHandler for potential inheritance purposes.
  • Eliminated redundant whitespaces within JsonFileHandler.
  • Fixed JsonFileHandler to notify the file event notifier before log message writes.
  • Implemented a new attribute called %(structured_keys) within the PatternFormatter to facilitate the inclusion of keys in messages when using structured log formatting. This addition is useful for instances where logging occurs in both JSON and regular log formats, enabling the display of keys within the regular log-formatted messages. See updated example_json_structured_log.cpp

v3.5.1

  • Resolved issue with accessing the name() method within the Logger class. (#378)
  • Fixed a compilation error in SignalHandler specific to Windows when QUILL_DISABLE_NON_PREFIXED_MACROS is defined. (#380)

v3.5.0

  • Fixed LOG_TRACE_CFORMAT macros.
  • Added support for compile-time custom tags in quill::MacroMetadata to enhance message filtering and incorporate static information. New log macros suffixed with _WITH_TAGS introduced for this feature. Additionally, %(custom_tags) parameter added to PatternFormatter. (#349) See example_custom_tags.cpp
  • Improvements to reduce compilation time

v3.4.1

  • Reduce backend worker unnecessary allocation. (#368)
  • Adjusted handling for empty std::string_view instances, addressing an issue where logging empty strings triggered an unintended memcpy with zero size and a nullptr, leading to address sanitizer warnings.
  • Fix clang build error when using -DQUILL_NO_EXCEPTIONS:BOOL=ON. (#357)

v3.4.0

  • Resolved bad_variant_access error occurring when using Quill as a pre-compiled library with a distinct queue type. (#276)

  • Resolved a bug in RotatingFileHandler associated with logfiles located outside the working directory, specifically when used with open_mode a. (#340)

  • Added a name() method to the Logger class which provides the logger name. (#345)

  • Fixed library and include paths in the pkg-config configuration. (#352)

  • Move get_root_logger() definition from cpp to the header file (#348)

  • Introduced support for logging character arrays. You can now log character arrays, even when they don't contain a null-terminating character. Additionally, character arrays with null characters in the middle are supported, and the logger will capture the content until the null character is encountered. (#353)

    For example

        union
  {
    char no_0[2];
    char mid_0[6]{'1', '2', '3', '4', '\0', 6};
  } char_arrays;

  // only output "12" even if there's no '\0' at the end
  LOG_INFO(logger, R"(This is a log info example for char array without '\0': {})", char_arrays.no_0);

  // output "1234" until the '\0'
  LOG_INFO(logger, R"(This is a log info example for char array with '\0' in middle: {})",
           char_arrays.mid_0);

  • Minor improvements in the bounded queue and throughput. (#362)

    Previous: 2.21 million msgs/sec average, total time elapsed: 1809 ms for 4000000 log messages.

    New: 2.24 million msgs/sec average, total time elapsed: 1787 ms for 4000000 log messages.

  • Disable fmt::join(data, "") at compile time. (#356)

  • Fix compile error in Apple Clang 12. (#360)

  • Add guards for redefined preprocessor variables.

  • Fix uint64_t to time_t implicit conversion error in Clang 18.

  • Update bundled libfmt to v10.1.1

v3.3.1

  • Fixed RotatingFileHandler to prevent accidental removal of non-log files when using open mode w and set_remove_old_files(true)

v3.3.0

  • Added a quill::get_handler(handler_name) function that allows easy lookup of an existing Handler by name. This function proves helpful when you want to retrieve a handler and pass it to a new logger.

  • Fix build failure of Intel Compiler Classic. (#332)

  • Introduced QUILL_BLOCKING_QUEUE_RETRY_INTERVAL_NS option for user-configurable retry interval in the blocking queue. Default value is 800 nanoseconds. (#330)

  • Improved backend thread handling. Now verifies that all producer SPSC queues are empty before entering sleep.

  • Fixed a race condition and potential crash in quill::remove_logger(Logger*) when called without prior quill::flush().

  • Added protection to prevent removal of the root logger with quill::remove_logger(Logger*).

  • Improved exception handling on the backend thread when calling fmt::format().

    While compile-time checks ensure that the format string and arguments match, runtime errors can still occur. Previously, such exceptions would affect and drop subsequent log records. Now, exceptions are caught and logged in the log file and reported via the backend thread notification handler (default is cerr).

    For example, if a dynamic precision is used (LOG_INFO(logger, "Support for floats {:.{}f}", 1.23456, 3.321312)), the log file will show the following error message:

    LOG_INFO root [format: "Support for floats {:.{}f}", error: "precision is not integer"]

    Additionally, an error message will be printed to cerr

    Quill ERROR: [format: "Support for floats {:.{}f}", error: "precision is not integer"]

  • Fixed a bug in timestamp formatting that occasionally displayed an hour component of 0 as 24. (#329)

  • Added support for specifying a runtime log level, allowing dynamic log level configuration at runtime. The new runtime log level feature provides flexibility when needed, with a minor overhead cost. It is recommended to continue using the existing static log level macros for optimal performance. (#321)

    For example

      std::array<quill::LogLevel, 4> const runtime_log_levels = {quill::LogLevel::Debug,
                                                             quill::LogLevel::Info,
                                                             quill::LogLevel::Warning,
                                                             quill::LogLevel::Error};

  for (auto const& log_level : runtime_log_levels)
  {
    LOG_DYNAMIC(logger, log_level, "Runtime {} {}", "log", "level");
  }

  • Added support for printf-style formatting with _CFORMAT macros. These macros use the printf format string syntax, simplifying the migration of legacy codebases using printf statements.

    For example

      std::array<uint32_t, 4> arr = {1, 2, 3, 4};
  LOG_INFO(logger, "This is a log info example using fmt format {}", arr);
  
  LOG_INFO_CFORMAT(logger, "printf style %s supported %d %f", "also", 5, 2.32);

  • Added a metadata() member function to the TransitEvent class. It provides access to the Metadata object associated with the log record, simplifying syntax for retrieving log record metadata in custom Handlers.

    For example

    void CustomHandler::write(fmt_buffer_t const& formatted_log_message, quill::TransitEvent const& log_event)
{
  MacroMetadata const macro_metadata = log_event.metadata();
}

  • Simplified file handler configuration. Now, instead of passing multiple arguments to the constructor, you only need to provide a single FileHandlerConfig object. This change makes creating file handlers objects much easier and more flexible.

    For example

    quill::FileHandlerConfig file_handler_cfg;
file_handler_cfg.set_open_mode('w');
file_handler_cfg.set_append_to_filename(quill::FilenameAppend::StartDateTime);

std::shared_ptr<quill::Handler> file_handler = quill::file_handler("application.log", file_handler_cfg);
quill::Logger* logger_foo = quill::create_logger("my_logger", std::move(file_handler));

LOG_INFO(my_logger, "Hello from {}", "application");

  • Combined the functionalities of RotatingFileHandler (rotating based on file size) and TimeRotatingFileHandler (rotating on a time interval) into a single, more versatile RotatingFileHandler. Users can now conveniently rotate logs based on both file size and time intervals simultaneously. The updated RotatingFileHandler offers a variety of customization options for improved flexibility. For more information on available configurations, refer to the RotatingFileHandlerConfig documentation.

    For example

      // Create a rotating file handler which rotates daily at 18:30 or when the file size reaches 2GB
std::shared_ptr<quill::Handler> file_handler =
  quill::rotating_file_handler(filename,
                               []()
                               {
                                 quill::RotatingFileHandlerConfig cfg;
                                 cfg.set_rotation_time_daily("18:30");
                                 cfg.set_rotation_max_file_size(2'000'000'000);
                                 return cfg;
                               }());

// Create a logger using this handler
quill::Logger* logger_bar = quill::create_logger("daily_logger", std::move(file_handler));

  • Improved compatibility with older versions of external libfmt. Quill now compiles for all versions of libfmt >= 8.0.0.

v3.2.0

  • Addition of std::is_trivially_copyable to default copy loggable types. (#318)

  • By default, the static library now builds with '-fPIC' to generate position-independent code. To disable this feature, you can use the CMake option 'QUILL_DISABLE_POSITION_INDEPENDENT_CODE'.

  • The LOG_<LEVEL>_LIMIT macros now support using std::chrono duration types for specifying the log interval. Instead of providing a raw number, you can use:

        LOG_INFO_LIMIT(std::chrono::milliseconds {100} , quill::get_logger(), "log message");

v3.1.0

  • It is now possible to set a minimum logging interval for specific logs. For example:

      for (uint64_t i = 0; i < 10; ++i)
  {
    LOG_INFO_LIMIT(2000, default_logger, "log in a loop with limit 1 message every 2000 micros for i {}", i);
    std::this_thread::sleep_for(std::chrono::microseconds{1000});
  }

  • quill::utility::to_string() now uses fmt::to_string()

  • Quill now utilizes a custom namespace (fmtquill) for the bundled fmt library. This enables smooth integration with your own external fmt library, even if it's a different version.

v3.0.2

  • Add missing header on clang when QUILL_X86ARCH is defined.

v3.0.1

  • Enhanced the reported message for reallocation of the unbounded queue to include the thread id.

v3.0.0

  • The previous unbounded queue constantly reallocated memory, risking system memory exhaustion, especially when handling intensive logging from multiple threads. Starting from v3.0.0, the default behavior has been improved to limit the queue capacity to 2 GB. When this limit is reached, the queue blocks the hot thread instead of further reallocation. To modify the default behavior, there is no need to recompile the quill library. Recompile your application with one of the following header-only flags.

    # Previous behavior in v2.*.*: Reallocates new queues indefinitely when max capacity is reached
-DCMAKE_CXX_FLAGS:STRING="-DQUILL_USE_UNBOUNDED_NO_MAX_LIMIT_QUEUE"

# Default behavior in v3.*.*: Starts small, reallocates up to 2GB, then hot thread blocks
-DCMAKE_CXX_FLAGS:STRING="-DQUILL_USE_UNBOUNDED_BLOCKING_QUEUE"

# Starts small, reallocates up to 2GB, then hot thread drops log messages
-DCMAKE_CXX_FLAGS:STRING="-DQUILL_USE_UNBOUNDED_DROPPING_QUEUE"

# Fixed queue size, no reallocations, hot thread drops log messages
-DCMAKE_CXX_FLAGS:STRING="-DQUILL_USE_BOUNDED_QUEUE"         

# Fixed queue size, no reallocations, hot thread blocks
-DCMAKE_CXX_FLAGS:STRING="-DQUILL_USE_BOUNDED_BLOCKING_QUEUE"

  • Added support for huge pages on Linux. Enabling this feature allows bounded or unbounded queues to utilize huge pages, resulting in optimised memory allocation.

      quill::Config cfg;
  cfg.enable_huge_pages_hot_path = true;
  
  quill::configure(cfg);
  quill::start();

  • Added support for logging std::optional, which is also now supported in libfmt v10.0.0.

      LOG_INFO(default_logger, "some optionals [{}, {}]", std::optional<std::string>{},
           std::optional<std::string>{"hello"});

  • Introduced a new function run_loop in the Handler base class, which allows users to override and execute periodic tasks. This enhancement provides users with the flexibility to perform various actions at regular intervals, such as batch committing data to a database.

  • In scenarios where a hot thread is blocked and unable to push messages to the queue in blocking mode, this situation will now be reported through the backend_thread_notifications_handler to the standard error stream cerr.

v2.9.2

  • Fix increased compile times due to x86intrin headers. (#298)
  • Fix compile error when using QUILL_X86ARCH on windows.
  • Fix bugs when quill is build as a shared library on windows. (#302)

v2.9.1

  • Removed CMAKE_INSTALL_RPATH from cmake. (#284)

  • Fix compile warning on Apple M1. (#291)

  • Update bundled libfmt to v10.0.0

  • Fix for CMAKE_MODULE_PATH (#295)

  • Fixed a bug in TimeRotatingFileHandler when quill::FilenameAppend::None is used. (#296)

  • Fixed TimeRotatingFileHandler and RotatingFileHandler to work when /dev/null is used as a filename (#297)

  • Added NullHandler that can be used to discard the logs. For example:

    int main()
{
  quill::start();
  
  std::shared_ptr<quill::Handler> file_handler =
    quill::null_handler();

  quill::Logger* logger_bar = quill::create_logger("nullhandler", std::move(file_handler));

  for (uint32_t i = 0; i < 150; ++i)
  {
    LOG_INFO(logger_bar, "Hello");
  }

v2.9.0

Fixes

  • Fixed a bug in TimeRotatingFileHandler. (#287)

Improvements

  • Renamed backend_thread_error_handler to backend_thread_notifications_handler in Config.h. Previously this handler was used only to report errors from the backend worker thread to the user. This callback will also now report info messages to the user.
  • Report unbounded spsc queue reallocation via the backend_thread_notifications_handler. (#286)
  • Report bounded spsc queue dropped messages via the backend_thread_notifications_handler.

v2.8.0

Breaking Changes (see improvements section for more details)

  • If you were previously compiling with -DQUILL_USE_BOUNDED_QUEUE or QUILL_X86ARCH you should now pass the flag to you target as it is not propagated by CMake anymore.
  • There is a change in the API in Quill.h instead of quill::Handler* you should now use std::shared_ptr< quill::Handler > and also move it to the created logger.

Improvements

  • Add append_to_filename parameter when creating quill::time_rotating_file_handler and quill::rotating_file_handler
  • Fix Handlers failing to find the file when the working directory of the application is changed in runtime. (#247)
  • When the given output directory of a log file passed to a Handler does not exist, it will now get automatically created.
  • Support Windows 10 LTSB 2016, 1607 and Server 2016. (#251)
  • Add back backend_thread_sleep_duration in Config.h (#256)
  • For quill::rotating_file_handler(...) and quill::time_rotating_file_handler(...) the backup_count argument is now default to std::numeric_limits<std::uint32_t>::max()
  • When the logging file is deleted from the command line while the logger is still using it, then a new file will be reopened for writing.
  • Added quill::Clock which enables taking and converting TSC timestamps to system clock timestamps. When TimestampClockType::Tsc is used as the default clock type in Config.h this class can also be used to generate timestamps that are in sync with the timestamps in the log file. (#264)
  • Both Unbounded and Bounded queue modes can now be used without having to recompile quill library. This is still not a runtime option, you still need to recompile your target and pass QUILL_USE_BOUNDED_QUEUE as a flag. See example_bounded_queue_message_dropping.cpp
  • Added QUILL_USE_BOUNDED_BLOCKING_QUEUE option that makes possible to use a bounded queue which blocks the hot thread rather than dropping messages (#270) See example_bounded_queue_blocking.cpp
  • Renamed backend_thread_max_transit_events to backend_thread_transit_events_soft_limit in Config.h (#270)
  • Added backend_thread_transit_events_hard_limit in Config.h (#270)
  • Added backend_thread_use_transit_buffer in Config.h (#270)
  • CMake: QUILL_X86ARCH and QUILL_USE_BOUNDED_QUEUE options have been removed. The users can decide on enabling these options on their side and quill doesn't need to be recompiled as a library. For example : 
       target_compile_definitions(<target> PUBLIC QUILL_X86ARCH QUILL_USE_BOUNDED_QUEUE)
  • Added quill::remove_logger(Logger* logger) in Quill.h. This makes it possible to remove a logger in a thread safe way. When a logger is removed any associated FileHandlers with that logger will also be removed and the files will also be closed as long as they are not being used by another logger. The logger is asynchronously removed by the logging thread after all the messages are written. To achieve this the API had to change to return a std::shared_ptr< quill::Handler > instead of quill::Handler*. See example_file_callbacks.cpp
  • Added quill::wake_up_logging_thread() in Quill.h. This thread safe function can be used to wake up the backend logging thread on demand. (#280)
  • Round up queue capacity to the nearest power of 2. (#282)

v2.7.0

Fixes

  • Remove references to build directory path from the compiled library's symbols. (#221)
  • Fix when compiled as shared library with hidden visibility. (#222)
  • Fix equal timestamp log messages appearing out of order. (#223)
  • Reduce padding in some structs.
  • Fix 'rename_file' throwing an exception while being marked as noexcept. (#230)
  • Fix crash with std::bad_alloc and compiler warnings in gcc 7.3.1. (#235)
  • The additional compiler definitions will now be propagated to the parent targets when enabling options in CMake. (#235)

Improvements

  • Improved performance and throughput of the backend logging thread by approximately ~25%

  • Add missing quill::json_file_handler(...) that creates a JsonFileHandler in Quill.h.

  • Simplified and refactored the logic in BoundedQueue.

  • Added the option do_fsync which also calls fsync() during the handler flush to all file handlers.

  • Replace backend_thread_sleep_duration with backend_thread_yield in Config.h

  • Remove trailing spaces in log levels strings. (#237)

  • The default log pattern has changed to "%(ascii_time) [%(thread)] %(fileline:<28) LOG_%(level_name:<9) %(logger_name:<12) %(message)")

  • Added file event notifiers, to get callbacks from quill before/after log file has been opened or closed. (#193) This is useful for cleanup procedures or for adding something to the start/end of the log files. for example

    int main()
{
  quill::start();

  quill::FileEventNotifier fen;

  fen.before_open = [](quill::fs::path const& filename)
  { std::cout << "before opening " << filename << std::endl; };

  fen.after_open = [](quill::fs::path const& filename, FILE* f)
  { std::cout << "after opening " << filename << std::endl; };

  fen.before_close = [](quill::fs::path const& filename, FILE* f)
  { std::cout << "before closing " << filename << std::endl; };

  fen.after_close = [](quill::fs::path const& filename)
  { std::cout << "after closing " << filename << std::endl; };

  quill::Handler* file_handler =
    quill::file_handler("myfile.log", "w", quill::FilenameAppend::None, std::move(fen));

  quill::Logger* mylogger = quill::create_logger("mylogger", file_handler);

  LOG_INFO(mylogger, "Hello world");
}

  • Added QUILL_X86ARCH in Tweakme.h. When enabled it will attempt to minimize the cache pollution on x86 cpus that support the instructions _mm_prefetch , _mm_clflush and _mm_clflushopt.

    To compile when this flag is enabled you should also pass -march to the compiler which is required, you can set this to your oldest cpu architecture among your systems.

    To enable this option, DQUILL_X86ARCH must always be defined in quill library and also in your executable, for example

    cmake -DCMAKE_CXX_FLAGS:STRING="-DQUILL_X86ARCH -march=native"

  • Added quill:get_root_logger() which gives quick access to the root logger object and can be used directly in the hot path. This gives applications that only wish to use the root logger the convenience of not having to store and pass Logger* objects anymore. for example quill existing log macros can be overwritten to not require a Logger* anymore

    #define MY_LOG_INFO(fmt, ...) QUILL_LOG_INFO(quill::get_root_logger(), fmt, ##__VA_ARGS__)

  • Added QUILL_ROOT_LOGGER_ONLY in Tweakme.h. Define ths if you only plan to use the single root logger object, When this is defined it will replace the LOG_ macros with the equivalent LOG_ macros but without the need of passing Logger* objects anymore. for example

    #define QUILL_ROOT_LOGGER_ONLY
#include "quill/Quill.h"

int main()
{
  quill::start();

  // because we defined QUILL_ROOT_LOGGER_ONLY we do not have to pass a logger* anymore, the root logger is always used
  LOG_INFO("Hello {}", "world");
  LOG_ERROR("This is a log error example {}", 7);
}

v2.6.0

Fixes

  • Fix filepath on Windows when MinGW is used. (#212)

Improvements

  • Removed the creation of static Metadata objects during initialisation time.
  • #define QUILL_QUEUE_CAPACITY has been removed.
  • Added Config option default_queue_capacity that can be used to specify the initial capacity of the queue.
  • When Unbounded queue is used the newly allocated queue will now have enough space to fit any object. (#215)

v2.5.1

Improvements

  • Reduced the allocations performed by the backend worker thread as the same objects are now being reused rather than destroyed.

Summary of changes since v2.3.2

In version 2.3.2 when multiple threads performed heavy logging, the backend logging thread incorrectly gave priority to the logs of the same threads. That made logs from the remaining threads to appear much later or sometimes never in the log files.

There was a series of fixes and releases to address this.

Below is the summary of the changes from v2.3.2

  • Previously when multiple threads were logging, the backend logging thread would first try to read the log messages of the same thread until its queue was completely empty before reading the log messages of the next thread. When one of the threads was logging a lot, it could result in only displaying the log of that thread, hiding the logs of the other threads. This has now been fixed and all log messages from all threads are read fairly.

  • Optimise the backend logging thread to read all log messages from each queue. Ensure all queues from all active threads are fairly read.

  • fmt::basic_memory_buffer buffer stack size has been reduced. The backend thread shows better performance with a reduced stack size. This also reduces the risk of a stack overflow when too many log messages are cached.lllllllllll

  • Reduced the allocations performed by the backend worker thread as the same objects are now being reused rather than destroyed.

  • Added a config option backend_thread_strict_log_timestamp_order. This option enables an extra timestamp check on the backend logging thread when each message is popped from the queues. It prevents a rare situation where log messages from different threads could appear in the log file in the wrong order. This flag is now enabled by default.

  • Added a config option backend_thread_empty_all_queues_before_exit. This option makes the backend logging thread to wait until all the queues are empty before exiting. This ensures no log messages are lost when the application exists. This flag is now enabled by default.

v2.5.0

Improvements

  • Performance improvements for the backend logging thread

v2.4.2

Fixes

  • Fixes an assertion that was triggered in debug mode due to changes in v2.4.1

v2.4.1

Improvements

  • Previously the backend worker thread would read all the log messages from the queue but not read the log messages when the buffer had wrapped around. It will now read all the messages.
  • Removed the min_available_bytes cache from the SPSC queue as an optimisation. It is not needed anymore as we now read all messages at once instead of reading message by message.

v2.4.0

Improvements

  • Added a config option backend_thread_strict_log_timestamp_order. This option enables an extra timestamp check on the backend logging thread when each message is popped from the queues. It prevents a rare situation where log messages from different threads could appear in the log file in the wrong order. This flag is now enabled by default.

  • Added a config option backend_thread_empty_all_queues_before_exit. This option makes the backend logging thread to wait until all the queues are empty before exiting. This ensures no log messages are lost when the application exists. This flag is now enabled by default.

v2.3.4

Improvements

  • Optimise the backend logging thread to read multiple log messages from the same queue, but still fairly read each queue from all active threads.

v2.3.3

Fixes

  • Previously when multiple threads were logging, Quill backend logging thread would first try reading the log messages of one thread until the queue was completely empty before reading the log messages of the next thread. When one of the threads was logging a lot, it could result in only displaying the log of that thread, hiding the logs of the other threads. This has now been fixed and all log messages from all threads are read fairly.

v2.3.2

Fixes

  • Fix code not compiling with treat warnings as errors set on Windows. (#198)

v2.3.1

Fixes

  • Optimise logging queue cache alignment of variables. It seems that v2.3.0 made the hot path slower by ~5 ns per message. This has been fixed in this version and the performance is now the same as in the previous versions.

v2.3.0

Improvements

  • Cache the available bytes for reading in the logging queue. This is meant to offer some minor performance improvement to the backend logging thread. #185

  • Fixed static code analysis and clang '-Wdocumentation' warnings.

  • The Handler.h API has changed in this version to support structured logs. If you have implemented your own custom Handler you will have to change it to follow the new API.

  • This version adds support for writing structured logs. Structured logs provide easier search through events. Structured logging is automatically enabled when named arguments are provided to the format string. Structured logs are only supported by the new quill::JsonFileHandler handler. The already existing FileHandler and ConsoleHandler are compatible with named arguments, but they will ignore them and output the log in its original format, as defined by the pattern formatter. Structured logs are not supported for wide characters at the moment. See example_json_structured_log.cpp

For example :

  quill::start();

  quill::Handler* json_handler =
    quill::create_handler<quill::JsonFileHandler>("json_output.log", "w");

  // create another logger tha logs e.g. to stdout and to the json file at the same time
  quill::Logger* logger = quill::create_logger("dual_logger", {quill::stdout_handler(), json_handler});
  for (int i = 2; i < 4; ++i)
  {
    LOG_INFO(logger, "{method} to {endpoint} took {elapsed} ms", "POST", "http://", 10 * i);
  }
  1. Will write to stdout (stdout_handler) :
23:37:19.850432433 [11811] example_json_structured_log.cpp:39 LOG_INFO      dual_logger  - POST to http:// took 20 ms
23:37:19.850440154 [11811] example_json_structured_log.cpp:39 LOG_INFO      dual_logger  - POST to http:// took 30 ms
  1. Will produce a JSON file (json_handler) :
{ "timestamp": "23:37:19.850432433", "file": "example_json_structured_log.cpp", "line": "39", "thread_id": "11811", "logger": "dual_logger", "level": "Info", "message": "{method} to {endpoint} took {elapsed} ms", "method": "POST", "endpoint": "http://", "elapsed": "20" }
{ "timestamp": "23:37:19.850440154", "file": "example_json_structured_log.cpp", "line": "39", "thread_id": "11811", "logger": "dual_logger", "level": "Info", "message": "{method} to {endpoint} took {elapsed} ms", "method": "POST", "endpoint": "http://", "elapsed": "30" }

v2.2.0

Improvements

  • Previously storing the default root logger by calling quill::get_logger() followed by quill::configure(cfg) would invalidate the pointer to the default root logger returned by the former function. This has now been fixed and the obtained Logger* pointer is still valid.
  • Disable fmt::streamed(). (#189)
  • Update bundled fmt to 9.1.0
  • logger->should_log(level) is removed. A compile time check was added to logger->should_log<level>() . (#187)

v2.1.0

Improvements

This version includes breaking changes to the API. Those changes are related to how quill is configured, before calling quill::start() to start the backend thread.

Check the updated examples.

Config.h - contains runtime configuration options

TweakMe.h - contains compile time configuration

For example quill::set_default_logger_handler(...) has been removed. To set a default filehandler :

  // create a handler
  quill::Handler* file_handler = quill::file_handler("test.log", "w");

  file_handler->set_pattern(
    "%(ascii_time) [%(thread)] %(fileline:<28) %(level_name) %(logger_name:<12) - %(message)",
    "%Y-%m-%d %H:%M:%S.%Qms", quill::Timezone::GmtTime);

  // set the handler as the default handler for any newly created logger in the config
  quill::Config cfg;
  cfg.default_handlers.emplace_back(file_handler);

  // configure must always be called prior to `start()`
  quill::configure(cfg);
  quill::start();
  • Removed some API functions from Quill.h that were previously used for configuration. Instead, quill::Config object has to be created. For example quill::config::set_backend_thread_cpu_affinity(1); has been removed and instead the following code is needed :
  quill::Config cfg;
  cfg.backend_thread_cpu_affinity = 1;
  quill::configure(cfg);
  • QUILL_CHRONO_CLOCK has been moved from TweakMe.h to Config.h. It is now possible to switch between rdtsc and system clocks without re-compiling. See example_trivial_system_clock.cpp
  • QUILL_RDTSC_RESYNC_INTERVAL has been moved from TweakMe.h to Config.h.
  • It is now possible to log user timestamps rather than the system's. This feature is useful for time simulations. See example_custom_clock.cpp and example_custom_clock_advanced.cpp
  • Previously the logger names were limited to a maximum of 22 characters. This limitation has been removed.
  • Added support for gcc 7.5.0. (#178)
  • Updated bundled fmt to 9.0.0

v2.0.2

Fixes

  • Fix crash when a std::string containing null-terminated characters is passed to the logger. (#176)

v2.0.1

Improvements

  • Add a flag to RotatingFileHandler to disable removing the old files when w mode is used.

v2.0.0

From version v2 and onwards only c++17 is supported.

This version is a major refactor.

Fixes

  • RotatingFileHandler will now correctly rotate the files when append mode is used (#123)

Improvements

  • Reduced and simplified codebase.
  • Improved backend worker thread performance.
  • QUILL_DUAL_QUEUE_MODE has been removed. A single queue now handles every case.
  • QUILL_STRING has been removed. That macro is no longer required when passing a format string to the PatternFormatter.

Differences

  • v1.7 compiles with c++14, v2 only compiles for c++17.
  • v1.7 on Windows supports wide character logging, v2 has limited wide character support such as logging wchar_t , std::wstring, std::wstring_view. For example, logging std::vector<std::wstring> is not supported.
  • v1.7 on Windows requires the filepath used for the handlers as a wide strings, v2 supports only filenames as narrow strings.

v1.7.3

Improvements/Fixes

  • Fix crash on windows when a long wstring (>500 chars) is logged (#173)
  • Fix compiler error when trying to compile with -DQUILL_DISABLE_NON_PREFIXED_MACROS (#174)
  • Fix a compile warning in clang (#175)

v1.7.2

Improvements/Fixes

  • Fix compile error when C++20 is used on windows (#162)

v1.7.1

Improvements/Fixes

  • Fix support for wide characters on Windows (#168)
  • Fix compilation error when Quill::Logger* is stored as a class member in templated classes
  • Add FilenameAppend::DateTime as an option when creating a file handler

v1.7.0

New Features

  • Add a new function quill::get_all_loggers() that returns all the existing loggers. (#114)
  • Add %(level_id) to pattern formatter. (#136)
  • Users can now specialise copy_loggable<T> to mark user defined types as safe to copy. (#132)

Improvements/Fixes

  • Fix initializations for C++17.
  • Fix compiler warning in check_format() function.
  • Replace QUILL_DUAL_QUEUE_MODE with QUILL_DISABLE_DUAL_QUEUE_MODE.
  • Update bundled fmt to 8.1.1
  • Minor performance and accuracy improvements to rdtsc clock used by the backend thread.
  • Fix compile error when C++20 is used. (#162)
  • Fix get_page_size() to only call sysconf once. (#160)
  • Fix incorrect timestamps in the log file when the system clock is updated. (#127)
  • Previously if quill:start(true) was called more than once in the application, the signal handlers would get initialised again. Now any subsequent calls to quill:start(true) will now have no effect (#167)
  • Previously when the max limit of rotated files in RotatingFileHandler was reached, quill would stop rotating and instead keep logging everything into the last log file. Now when the maximum limit of files is reached, quill will now keep rotating by replacing the oldest logs. (#157)
  • Improve the backend logging thread responsiveness when variables are logged in loops without any delay from multiple threads. (#116)
  • Fix some undefined behaviour issues reported via the AddressSantizer on the backend logging thread. (#166)

v1.6.3

Improvements/Fixes

  • Add support for %(thread_name) in PatternFormatter. (#97)
  • Add missing header needed for recent versions of fmt. (#95)
  • Force flush all active handlers on application exit.
  • Update bundled fmt to 8.0.1

v1.6.2

Fixes

  • Fix WIN32 compilation error when NOMINMAX is already defined.
  • Fix string to wstring MinGW conversion. (#92)
  • Log enums via the main queue. (#90)
  • Fix windows compiler error when min/max macros are defined. (#94)

v1.6.1

Improvements/Fixes

  • Fix windows C++20 build. (#83)
  • Fix ARM build on windows.
  • Fix example_backtrace and minor bug when destructing with empty backtrace.

v1.6.0

New Features

  • Dual queue mode offering even lower latencies on hot paths. See Dual Queue Mode.
  • Added a signal handler for linux and windows. The signal handler flushes the log when the app crashes or exits. (#1)
  • Added support for custom handlers. (#75)
  • Quill now compiles and runs on Cygwin.

Improvements/Fixes

  • The queue from the caller to the backend worker thread has been reworked. The new queue generates slightly better assembly than the previous one. Quill does no longer depend on mapping the same region of physical memory twice.
  • Replaced an assertion check that could trigger incorrectly. (#68)
  • Fixed build on ARM_ARCH < 6. (#78)
  • Fixed compile errors when QUILL_NOEXCEPTIONS, CMAKE_CXX_STANDARD 20, QUILL_USE_BOUNDED_QUEUE are set.
  • The unit tests have been moved to a separate binary with their own main(). This increased build times when building the tests, but the failures are now easier to debug on different CI platforms and the tests can also run faster in parallel.
  • Fixed minor compiler warnings on windows.
  • Upgraded bundled libfmt to 7.1.3

Note

  • If a custom queue capacity is defined using #define QUILL_QUEUE_CAPACITY after 1.6.0 the whole library needs to be recompiled.

v1.5.2

  • Removed the use of fmt::format() in FileUtilities.cpp as a workaround to the link errors in fmt v7. Use the header only version of libfmt when external libfmt is defiend is no longer required.

v1.5.1

  • When QUILL_FMT_EXTERNAL is defined, quill will use the header only version of libfmt. This is a workaround to the link errors after libftm v7

v1.5.0

  • Upgraded bundled libfmt to 7.1.2
  • Added Filters. The filter class can be used for filtering log records. Filters can be added to handler instances. See example_filters.cpp
  • It is now possible to set the log level severity on the handler objects. See example_filters.cpp (#49)
  • Timestamp formatting optimisation for the backend worker thread.
  • Free list allocator optimisation for the backend worker thread.
  • Fixed PatternFormatter ignoring a portion of the pattern was ignored, when no format specifiers were present. (#56)
  • When %(function_name) is used in PatternFormatter the namespace delimiter is replaced from :: to . (Windows only). (#61)
  • Arguments passed to the logger are no longer being evaluated when the log statement is not logged. (#67)
  • PatternFormatter enhancement. It is now possible to pass {fmt} string syntax to QUILL_STRING. The default PatternFormatter string has been changed to: "%(ascii_time) [%(thread)] %(fileline:<28) LOG_%(level_name) %(logger_name:<12) - %(message)". This results to the following log being properly aligned despite the different lengths of each filename and logger name.
22:31:07.995438465 [2666041] file1.h:11                   LOG_INFO      logger1      - Log from file.
22:31:07.995445699 [2666041] long_file2.h:11              LOG_INFO      logger_fl2   - Log from other file.
22:31:07.995457144 [2666041] a_longer_file_3.hpp:11       LOG_INFO      logger_fl2_l - Log from other file.
22:31:07.995462471 [2666041] example_trivial.cpp:30       LOG_TRACE_L3  root         - This is a log trace l3 example 1

v1.4.1

  • Do not force quill to always build as static library in cmake.
  • Minor fix when quill is compiled with no exceptions.
  • Add the option to disable the non prefixed macro definitions if QUILL_DISABLE_NON_PREFIXED_MACROS is defined. (#40)

v1.4.0

  • Added support for printing colour codes in the terminal. See ConsoleHandler
  • RotatingFileHandler improvements and minor change in API. See RotatingFileHandler
  • DailyFileHandler is removed and replaced by TimeRotatingFileHandler. See TimeRotatingFileHandler
  • Added backtrace logging. Log messages can be stored in a buffer and flushed later on demand. See Backtrace Logging
  • Added bundled doctest 2.4.0
  • Migrated all tests from gtest to doctest.
  • Upgraded bundled libfmt to 7.0.3

v1.3.3

  • Upgraded bundled libfmt to 7.0.2
  • Fixed compile error with libfmt versions > 7.0.0

v1.3.2

  • Add a CMake option QUILL_USE_BOUNDED_QUEUE for bounded queue.
  • Fixed a clang 10 warning
  • Fixed MinGw build

v1.3.1

  • Minor CMake fixes when QUILL_FMT_EXTERNAL option is used.

v1.3.0

New Features

  • Added option QUILL_NO_EXCEPTIONS to disable exceptions, std::abort() is called instead of an exception. (#16)
  • Exceptions thrown in the backend worker thread, will now call a user provided error handler callback to handle the error. (#21)
  • Compile time checks for unsafe to copy user defined types. Non trivial user defined types must be explicitly tagged as safe to copy with the use of QUILL_COPY_LOGGABLE;. Otherwise they have to be formatted and passed as a string to the logger by the user. The old unsafe mode is still usable by #define QUILL_MODE_UNSAFE (#20)
  • Added QUILL_USE_BOUNDED_QUEUE. In this mode no new queues get allocated but instead log messages get lost. Number of lost messages is reported to stderr.
  • Minor hot path optimisation. The pointer to the metadata for each log message is no logger copied to the queue but passed as a template argument instead.
  • Added a latency benchmark, easily extendable for any logger

Improvements/Fixes

  • QUILL_RDTSC_CLOCK option is replaced by QUILL_CHRONO_CLOCK which is by OFF by default.
  • Improve compiler error message when trying to log a non copy constructible user defined type
  • Fix buffer reallocation bug on TimestampFormatter. In previous versions any timestamp format set to 'set_pattern' expanding to a string longer than 32 bytes would cause a crash. (#24)
  • The backend logging thread will now copy all messages from the SPSC queue to a local priority queue. This keeps the SPSC less empty avoiding a potential allocation on the hot path.
  • std::string_view is now promoted to std::string to take a deep copy
  • The queue capacity has been moved from config to Tweakme.h.
  • Multiple formats patterns support for stdout and stderr handlers. See example_stdout_multiple_formatters.cpp
  • quill::start() will now block until the backend worker has started.
  • Upgraded bundled libfmt to 6.2.1

v1.2.3

  • CMake changes to support package installation in conan.

v1.2.2

  • Support for arm/arm64. (#19)
  • Add a cmake option QUILL_ENABLE_INSTALL to enable cpack.

v1.2.1

  • Improved QUILL_RDTSC_CLOCK tweak option. It is now possible to switch between using rdtsc or std::chrono clock without having to recompile quill as library.

v1.2.0

  • Linking and including an external version of fmt is now supported. See TweakMe.h
  • Fixed compiler warnings when using clang's -Wdocumentation. (#12)
  • Fixed a bug that wouldn't report a compile-time error for invalid format strings. (#13)
  • Added process ID to Formatter. (#14)
  • Enhanced timestamp formatting. The timestamp_format string passed in handler->set_pattern(format_pattern, timestamp_format, timezone) now accepts three additional specifiers %Qms , %Qus, %Qus that can be used to format the fractional seconds. See here. (#15)

v1.1.0

  • Daily file handler. The file handler rollover every 24 hours
  • Rotating file handler. The file handler will rollover based on the size of the file
  • MinGW compatibility
  • Added a CMake option QUILL_VERBOSE_MAKEFILE. Building Quill as a master project now defaults to non verbose makefile output unless -DQUILL_VERBOSE_MAKEFILE=ON is passed to CMake. (#6)
  • Flush policy improvement. Previously Quill backend worker thread would never flush. This made watching the live log of the application harder because the user has to wait for the operating system to flush or quill::flush() had to be called on the caller threads. This has now been fixed, when the backend thread worker has no more log messages to process it will automatically flush. (#8)
  • The log level names have been changed from "LOG_INFO", "LOG_DEBUG", etc to "INFO", "DEBUG", etc .. The default formatter string is now using "LOG_"%(level_name) instead of %(level_name) therefore there is now change in the behaviour. This change gives a lot of more flexibility to users who prefer to see e.g. INFO instead of LOG_INFO in the logs. (#7)
  • An option has been added to append the date to the filename when using a FileHandler quill::file_handler(filename, mode, FilenameAppend);. (#7)
  • It is now possible to specify the timezone of each handler timestamp. A new parameter is added to file_handler->set_pattern(...). See PatternFormatter::Timezone . (#7)
  • Rename emit as it can conflict with Qt macros. (#4)
  • Upgraded libfmt to 6.2.0.

v1.0.0

  • Initial release.
  • Using libfmt to 6.1.2.