IMPORTANT: Dropping Visual Studio 2015 compatibility. It is no longer able to compile the thread pool source.

• Implement LOG4CPLUS_ASSERT_FMT() - formats assertion message using C-style format string.

• New configuration property: log4cplus.threadPoolBlockOnFull. When this property is true (default), threads will block when internal thread pool queue is full.

• Warn about full internal thread pool queue when dropping events due to log4cplus.threadPoolBlockOnFull being false.

What's Changed

• Add missing source files to MSVC project files.

• Resolve environment variables in include directive in configuration file. (#593, Martin Engelmann)

Full Changelog: REL_2_1_0...REL_2_1_1

• Throw exception on nonexistent properties file, if requested by fThrow flag.

• Generate pkgconfig file with CMake.

• Add locale support to ConsoleAppender. (Choy Kho Yee)

• Initialize thread pool for async logging on demand.

• SysLogAppender: Allow non-FQDN hostname in syslog messages.

• Update Catch2 to v2.13.9.

• Add CMake alias libraries. GitHub issue #511.

• Add an option to disable tests to configure script. (Fabrice Fontaine)

• Fix C++11 compatibility: C++11 does not have basic_string_view.

• Look for Android's log library. GitHub issue #543.

• Fix handling of ,aux extension for FileAppender. GitHub issue
  #534. (Pieter du Preez)

• filename should not be empty for TimeBasedRollingFileAppender. GitHub
  issue #517. (Fox Chen)

• Fix compilation with C++20 compiler, use std::invoke_result.

• TimeBasedRollingFileAppender: Clear files before MaxHistory when
  CleanHistoryOnStart=false.

• Update embedded Catch2 to version v2.13.7 to fix compilation with current
  Glibc. GitHub issue #519.

• Fixes to internal thread pool.

• Internal thread pool can now be disabled during compilation. Use
  --disable-thread-pool with Autotools based build or set
  LOG4CPLUS_ENABLE_THREAD_POOL to OFF with CMake based build.

• Improved SONAME handling in CMake.

• Update Catch to 2.13.4 to fix compilation on MacOS X on AArch64.

• Modernized CMake build.

• Update iOS support to build for current hardware architectures. (Patch by Pawel Maczewski)

• Fix issue with std::va_list value reuse.

• Fix parsing of include in configuration when included file path contains =. (Patch by Peter Pei)

• Fix build issue #455. Source file callbackappender.cxx is missing from Visual Studio project for static library.

• Fix issue #415. Wrong base source file name is provided if path on Windows contains /.

• Change of default behaviour: Instantiate thread pool with only 4 threads.

• Fix Catch2 include path. GitHub issue #379.

• Disable POSIX signals reception in thread before creating pool
  threads. GitHub issue #385 and follow up issue #390.

• Fix compilation with NVCC in CUDA mode. GitHub issue #375.

• Fix compilation with Visual Studio in C++17 mode. GitHub issue #401.

• Allow disabling implicit initialization through configure script option
  --disable-implicit-initialization, or CMake build option
  LOG4CPLUS_REQUIRE_EXPLICIT_INITIALIZATION. (MaksymB)

• Remove android directory with obsolete Android support. GitHub
  issue #283.

• Link with libatomic when necessary. (Fabrice Fontaine)

• GitHub issue #375. Fixed compilation with NVCC in CUDA mode.

• Small documentation tweaks.

• Fix compilation on systems without O_CLOEXEC. This affects, e.g., Solaris 10. GitHub issue #326. (Patch by Jiangrz).

• Provide log4cplus::deinitialize() to make the API symmetric (log4cplus::initialize() already exists) and to allow de-/initialization without log4cplus::Initializer instance. GitHub issue #340.

• Deal with register keyword being generated in SWIG based bindings. The keyword is unused and reserved in C++17. Remove use of std::unary_function, it was removed in C++17.

• Add ability to define new log levels using C API. Add reconfiguration API. (Jens Rehsack)

• Add NDCMatchFilter and MDCMatchFilter. (Franck)