New Libraries

• No new libraries

Updated Libraries

• Asio:

  • Added ip::scope_id_type type alias.
  • Added ip::port_type type alias.
  • Added std::hash specialisations for IP addresses.
  • Added std::hash specialisations for ip::basic_endpoint<>.
  • Refactored SFINAE usage to improve compile times.
  • Added friendship support to customisation points, and made most customisations private.
  • Changed any_io_executor to a "strong typedef"-style class.
  • Fixed experimental::as_single to work with handler hook deprecation.
  • Ensured pthread condition variable attributes are cleaned up on all platforms.
  • Clarified thread safety notes on sockets and descriptors.
  • Ensured errno is not overwritten if socket() fails on macOS/FreeBSD.
  • Fixed work tracking for io_context and thread_pool executors when move-assigned.
  • Ensured internal call_stack objects are accessed only from implementation files.
  • Fixed I/O object move-assignment to ensure the executor is left in a valid state.
  • Fixed detection of compiler support for defaulted template argument on functions with MSVC.
  • Prevented the blocking.always property from being used with strand<>, as it did not produce the correct semantics.
  • Removed deprecated file asio/impl/src.cpp.
• Atomic:

  • Fixed compilation with MSVC for ARM. (PR#49)
• Beast:

  • This update brings minor bug fixes and revamped CI reporting.
  • We'd love to know how you or your company use Beast, consider adding an entry to the Companies and Individuals Using Beast list.
  • See the full Release Notes for a complete list of changes.
• Bind:

  • Add support for using the standard C++11 placeholders with boost::bind.
  • Update boost::apply to use variadic templates and perfect forwarding.
• Container:

  • Added [[no-discard]] attribute in all containers to catch bugs related to unused return values.
  • Replaced default standard exception classes with Boost.Container own classes, reducing considerably the included files overhead. Example: in MSVC 19 boost/container/vector.hpp preprocessed file size reduces from 1,5MB to 930KB. If you still want to use standard exception classes, you can define BOOST_CONTAINER_USE_STD_EXCEPTIONS before using any Boost.Container class.
  • Fixed bugs/issues:

    • GitHub #102: "flat_map::insert ambiguous with initializer list & pairs that need to convert".
    • GitHub #139: "flat_map merge and iterators".
    • GitHub #141: "small_vector does not propagate no throw properties of move operation of contained type".
    • GitHub #164: "Compile error when using pmr::map with a std::pair; works when using a std::tuple".
    • GitHub #171: "deque::clear() uses undefined behaviour".
• Core:

  • Add implicit conversion between compatible reference wrappers.
  • Add boost/core/cmath.hpp, a portable implementation of the floating point classification functions from <cmath>.
  • Add boost/core/bit.hpp, a portable implementation of the C++20 standard header <bit>.
  • Fix BOOST_TEST_EQ, BOOST_TEST_NE for character types under C++20.
  • Revise allocator access utilities (now support VS2013, and no workarounds use allocator_traits.)
• DLL:

  • BREAKING CHANGE: boost::dll::import was renamed to boost::dll::import_symbol to avoid collision with C++20 import keyword.
  • Updated docs, including FAQ section.
• Filesystem:

  • Updated compatibility with WASI platform. (PR#169)
  • Fixed an exception being thrown by path::remove_filename if the path is "////". (#176)
  • Fixed create_directories disregarding errors from file status query operations issued internally. This could result in incorrect error codes returned by create_directories. (#182)
• Geometry:

  • Improvements

    • PR#670 New IOs to_wkt() and from_wkt() (thanks to Baidyanath Kundu).
    • PR#756 Non cartesian and robust convex hulls.
    • PR#768 Umbrella strategies for relops, setops, index, buffer and more (undocumented for now).
    • PR#797 New azimuth() algorithm.
    • PR#801 Improved accuracy in geographic area computations.
    • PR#820 Parameter scale added to svg_mapper.
  • Bugfixes

    • PR#808 Fixed compilation error with rtree serialization enabled (thanks to Tristan Carel).
    • PR#815 Fixed issue in buffer().
    • Various fixes in set operations and buffer.
  • Breaking changes

    • Removed strategy convex_hull::graham_andrew.
• GIL:

  • BREAKING: In next release, we are going to drop support for GCC 5. We will also change the required minimum C++ version from C++11 to C++14.
• Histogram:

  • This release contains critical fixes, please check that your results are not affected.
  • See Release Notes for details.
• Intrusive:

  • Reduced compile-time dependencies:

    • linear_slist_algorithms use a simple node_ptr instead of std::pair on return.
    • list/slist use operator </operator == instead of std::equal_to/std::less.
  • Fixed GitHub #54: set.rbegin() looks like O(log(N))
• Interprocess:

  • Added wchar_t API support for named resources in operating systems that offer native wide character API (e.g. Windows). The following classes were updated with wchar_t name support:

    • file_mapping
    • managed_mapped_file
    • managed_shared_memory
    • managed_windows_shared_memory
    • shared_memory_object
    • windows_shared_memory_object
    • file_lock
    • named_condition
    • named_condition_any
    • named_mutex
    • named_recursive_mutex
    • named_semaphore
    • named_sharable_mutex
    • named_upgradable_mutex
    • message_queue
  • Added BOOST_INTERPROCESS_FORCE_NATIVE_EMULATION macro option to disable the use of generic emulation code for process shared synchronization primitives instead of native POSIX or Winapi functions.
  • Fixed bugs:

    • GitHub #76 ("Cygwin compilation errors").
    • GitHub #83 ("Add BOOST_INTERPROCESS_FORCE_NATIVE_EMULATION option").
    • GitHub #92 ("bufferstream: Correct MSVC compilation warning").
    • GitHub #106 ("Use fallocate on truncate_file").
    • GitHub #120 ("segment_manager customization").
    • GitHub #122 ("Mark constructors/assignment/swap noexcept where possible").
    • GitHub #126 ("_ReadWriteBarrier is deprecated warning when compiling with clang-cl.exe").
• JSON:

  • Security Report from Bishop Fox.
  • (#481) Refactored value_from implementation; user customizations are now always preferred over library-provided overloads.
  • (#484) Fix imprecise parsing for some floating point numbers.
  • (#485) Fix link errors in standalone mode, when used alongside Boost.
  • (#497) Fix Boost.Build builds on GCC 4.8.
• LexicalCast:

  • Dropped dependency on Boost.Math (thanks to Peter Dimov #37, #39).
  • Fixes for the CI and coverage (thanks to Sam Darwin from "The C++ Alliance" #38, #42).
• Log:

  • Bug fixes:

    • Corrected a formal race condition in the thread-safe log record queue implementation used in the unbounded_fifo_queue policy of the asynchronous_sink frontend. The race could be detected by TSAN, but it was not a real problem on most current CPU architectures and compilers. (#139)
    • When copying a logger with a channel attribute (e.g. channel_logger), the channel attribute is now deep-copied from the original logger. This means that modifying the channel in the new logger will no longer affect the original logger.
    • Replaced the use of std::allocator<void> in template parameters with a new tag type boost::log::use_std_allocator to silence libc++ warnings about the former being deprecated in C++17 and later. The tag indicates that the instantiated template should be using a specialization of std::allocator internally to allocate dynamic memory, so the change has no functional effect. (#141)
    • Boost.Log no longer defines __MSVCRT_VERSION__ macro on MinGW and MinGW-w64. Defining this macro caused incompatibility with UCRT, which is available as an option in recent MinGW-w64. (PR#149)
  • See changelog for more details.
• Math:

  • Breaking Change: C++03 support is now removed, a C++11 or later conformant compiler is now required to use this library.
  • Added Z-test.
  • Added execution policy support to univariate and bivariate statistics: enables parallel execution (requires C++17 and <execution>).
  • Big update/improvement on CI testing.
  • Bivariate statistics now have integer support.
  • T-Test now has integer support.
  • Linear regression now has integer support.
  • Correct PDF of the beta distribution at the endpoints.
  • Correct use of Stirling's approximation in certain multiprecision cases, fixes #396.
  • Eliminate -Wimplicit-int-float-conversion on clang.
  • Fix some constexpr issues in quaternion/octonion.
  • Minor performance fix to tanh_sinh integration.
  • Update hypergeometric functions internal scaling to allow for 64-bit (long long) exponents with multiprecision types.
• Move:

  • Git Issue #35: "New nothrow move traits are incomplete".
• Multiprecision:

  • BREAKING CHANGE: Massive refactoring and code simplification makes C++11 an absolute requirement.
  • Use BOOST_TRY/CATCH in headers so code can be used in exception-free environments.
  • Correct corner case in pow, fixes #277.
  • Correct exception type thrown to match docs in lsb/msb: fixes #257.
  • Allow moves and operators between related but different types (ie types with the same allocator), fixes #278.
• Nowide:

  • Fix discarding of characters for text file streams when seek or sync functions are used and newlines were converted (e.g. on Windows)
  • Fix potential use-after-free bug when reusing (via open) a file stream that has been closed
  • Fix potential invalid memory access when using a file stream that has been moved or swapped to where the source had a put-back character or was set to unbuffered mode
  • Fix compatibility with ucrt runtime by not defining __MSVCRT_VERSION__
  • Known issues: Read performance for text files is degraded. Binary files and writing is unaffected.
• Optional:

  • Fixed MSVC warning C4702.
• Outcome:

  • Announcements:

    • BREAKING CHANGE: After a year and three major Boost releases announcing this upcoming change, this is the FIRST RELEASE of the v2.2 branch. This branch has a number of major breaking changes to the Outcome v2.1 which shipped in Boost 1.75 and earlier, see the documentation for details.
  • Enhancements:

    • VS2019.8 changed how to enable Coroutines, which caused Outcome to not compile on that compiler.
    • If on C++ 20, we now use C++ 20 [[likely]] instead of compiler-specific markup to indicate when TRY has likely success or failure.
    • BREAKING CHANGE: Previously the value of spare_storage(const basic_result|basic_outcome *) noexcept was not propagated over BOOST_OUTCOME_TRY, which causes things like stack backtraces captured at the point of construction of an errored result to get dropped at every TRY point. This has been fixed by adding an optional spare_storage to success_type<T> and failure_type<T>, as well as to auto success(T &&, ...) and auto failure(T &&, ...).
  • Bug fixes:

    • Boost.Outcome should now compile with BOOST_NO_EXCEPTIONS defined. Thanks to Emil, maintainer of Boost.Exception, making a change for me, Boost.Outcome should now compile with C++ exceptions globally disabled. You won't be able to use boost::exception_ptr as it can't be included if C++ exceptions are globally disabled.
    • BREAKING CHANGE #244 It came as a shock to learn that BOOST_OUTCOME_TRY had been broken since the inception of this library for certain corner case code, which required a breaking change in how TRY works. See the changelog in the documentation for more detail.
• Parameter:

  • Added a workaround for MSVC 2015 code miscompilation when an rvalue was used as a default value of a named parameter of a function. (PR#109, #132)
• PFR:

  • Fixed reflection of types with missing const in SFINAE expressions in template constructor. Now reflection of aggregates with std::optional<std::chrono::duration<???>> fields works on any Standard Library implementation, even if LWG3050 is not fixed.
  • Comparison functions are now constexpr #52
  • Fixed numerous typos in docs (thanks to Phil Miller #63)
• PolyCollection:

  • Worked around GCC bug affecting GCC versions 9.3-10.2 (issue #20).
• Predef:

  • Version 1.13
  • Add ARCH_PPC_64 predef.
  • Fix ARCH_WORD_BITS* redefinition warnings/errors.
  • Add ARCH_E2K, Elbrus 2000, architecture from Konstantin Ivlev.
  • Fix not handling recent C++ version that go above 10.x version.
  • Version 1.12
  • Switch to using the endian.h header on OpenBSD. (Brad Smith)
  • Fix not handling recent versions of stdcxx that go above version 9.
  • Fix including sub-BSD OS headers directly causing redef warnings.
  • Add CI testing of direct inclusion of all headers.
  • Add CI testing on FreeBSD for clang and gcc.
  • Add WORD_BITS set of predefs to detect the architecture word size. Initial implementation inspired by submission from Mikhail Komarov.
  • Add CI testing for Cygwin 32 and 64.
• PropertyTree:

  • Property Tree has a new maintainer.
  • Fix usage of deprecated Boost.Bind features.
  • Link to Wikipedia fixed.
  • Use BOOST_OVERRIDE to fix GCC warnings.
  • Add extensive CI testing.
• Regex:

  • Regex is now header only except in C++03 mode.
  • Support for C++03 is now deprecated.
  • The library can now be used "standalone" without the rest of Boost being present.
• Stacktrace:

  • Better support for pre-C++11 builds on clang #102.
  • Bigger warning for do not use boost::stacktrace::stacktrace in signal handlers #71.
• TypeTraits:

  • Fix for Visual Studio managed code projects.
• Variant2:

  • Improved generated code for the double buffered case.

Updated Tools

• Build:

  • Includes release of B2 version 4.4.1.

Compilers Tested

Boost's primary test compilers are:

• Linux:

  • Clang: 3.0, 4.0.1, 6.0.1
  • Clang, C++0x: 3.0
  • Clang, C++11: 3.0, 3.1, 3.2, 3.3, 3.4, 4.0.1, 6.0.1, 7.0.0, 8.0.0, 9.0.0, 10.0.0, 11.0.0
  • Clang, C++14: 3.5.0, 3.6.0, 3.7.1, 3.8.0, 3.9.1, 4.0.0, 4.0.1, 5.0.2, 6.0.1, 7.0.0, 8.0.0, 9.0.0, 10.0.0, 11.0.0
  • Clang, C++17: 5.0.2, 6.0.1, 7.0.0, 8.0.0, 9.0.0, 10.0.0, 11.0.0
  • GCC: 4.4.7, 4.5.3, 4.6.3, 5.4.0, 8.0.1
  • GCC, C++0x: 4.4.7
  • GCC, C++11: 4.7.3, 4.8.5, 4.9.4, 5.4.0, 6.4.0, 7.1.0, 8.0.1
  • GCC, C++14: 5.4.0, 5.5.0, 6.4.0, 7.1.0, 7.3.0, 8.0.1
  • GCC, C++17: 7.3.0, 8.0.1
  • Intel, C++14: 18.0
• OS X:

  • Apple Clang: 9.0.0, 9.1.0, 10.0.0, 11.0.0
  • Apple Clang, C++11: 9.0.0, 9.1.0, 10.0.0, 11.0.0
  • Apple Clang, C++14: 9.0.0, 9.1.0, 10.0.0, 11.0.0
  • Apple Clang, C++17: 9.1.0, 10.0.0, 11.0.0
  • Apple Clang, C++1z: 9.0.0
  • Apple Clang, C++2a: 10.0.0, 11.0.0
• Windows:

  • GCC: 3.4.5, 4.1.2, 4.2.4, 4.3.3, 4.4.0, 4.5.4
  • GCC, C++0x: 4.6.4
  • GCC, C++11: 4.7.3, 4.8.1, 4.9.3
  • GCC, C++14: 5.1.0, 5.2.0, 5.3.0, 6.1.0, 6.2.0, 6.3.0, 6.4.0
  • GCC, C++17: 7.1.0, 7.2.0, 7.3.0
  • Visual C++: 7.1, 8.0, 9.0, 10.0, 11.0, 12.0, 14.0, 14.1
• FreeBSD:

  • Clang: 4.0.0
  • Clang, C++11: 4.0.0
  • Clang, C++14: 4.0.0
  • Clang, C++1z: 4.0.0

Boost's additional test compilers include:

• Linux:

  • Clang: 3.0, 3.8.1, 3.9.1, 4.0.1, 5.0.2, 6.0.1
  • Clang, C++0x: 3.0
  • Clang, C++11: 3.0, 3.1, 3.2, 3.3, 3.4, 4.0.1, 6.0.1, 7.0.0, 8.0.0
  • Clang, C++14: 3.5.0, 3.6.0, 3.7.1, 3.8.0, 3.9.1, 4.0.0, 4.0.1, 5.0.2, 6.0.1, 7.0.0, 8.0.0
  • Clang, C++17: 5.0.2, 6.0.1, 7.0.0, 8.0.0
  • GCC: 4.4.7, 4.5.3, 4.6.3, 4.9.4, 5.4.0, 5.5.0, 8.0.1
  • GCC, C++0x: 4.4.7
  • GCC, C++11: 4.7.3, 4.8.5, 4.9.4, 5.4.0, 6.4.0, 7.1.0, 8.0.1
  • GCC, C++14: 5.4.0, 5.5.0, 6.3.0, 6.4.0, 7.1.0, 7.3.0, 8.0.1, 8.1.0
  • GCC, C++17: 7.3.0, 8.0.1
  • Intel, C++14: 18.0
• OS X:

  • Apple Clang: 9.0.0, 9.1.0, 10.0.0
  • Apple Clang, C++11: 9.0.0, 9.1.0, 10.0.0
  • Apple Clang, C++14: 9.0.0, 9.1.0, 10.0.0
  • Apple Clang, C++17: 9.1.0, 10.0.0
  • Apple Clang, C++1z: 9.0.0
  • Apple Clang, C++2a: 10.0.0
• Windows:

  • GCC: 3.4.5, 4.1.2, 4.2.4, 4.3.3, 4.4.0, 4.5.4
  • GCC, C++0x: 4.6.4
  • GCC, C++11: 4.7.3, 4.8.1, 4.9.3
  • GCC, C++14: 5.1.0, 5.2.0, 5.3.0, 6.1.0, 6.2.0, 6.3.0, 6.4.0
  • GCC, C++17: 7.1.0, 7.2.0, 7.3.0
  • Visual C++: 7.1, 8.0, 9.0, 10.0, 11.0, 12.0, 14.0, 14.1
• FreeBSD:

  • Clang: 4.0.0
  • Clang, C++11: 4.0.0
  • Clang, C++14: 4.0.0
  • Clang, C++1z: 4.0.0

Acknowledgements

Marshall Clow, Michael Caisse and Glen Fernandes managed this release.