Note about the new Visual Studio release

Visual Studio 15.5 was released too late for us to test this release with it.

New Libraries

• Beast: Portable HTTP, WebSocket, and network operations using only C++11 and Boost.Asio, from Vinnie Falco.
• CallableTraits: A spiritual successor to Boost.FunctionTypes, Boost.CallableTraits is a header-only C++11 library for the compile-time inspection and manipulation of all 'callable' types. Additional support for C++17 features, from Barrett Adair.
• Mp11: A C++11 metaprogramming library, from Peter Dimov.

Updated Libraries

• Asio:

  • Implemented interface changes to reflect the Networking TS (N4656).

    • See the list of new interfaces and, where applicable, the corresponding old interfaces that have been superseded.
    • The service template parameters, and the corresponding classes, are disabled by default. For example, instead of basic_socket<Protocol, SocketService> we now have simply basic_socket<Protocol>. The old interface can be enabled by defining the BOOST_ASIO_ENABLE_OLD_SERVICES macro.
  • Removed previously deprecated functions.
  • Added support for customised handler tracking.
  • Added reactor-related (i.e. descriptor readiness) events to handler tracking.
  • Added special "concurrency hint" values that may be used to disable locking on a per io_context basis.
  • Enabled perfect forwarding for the first ssl::stream<> constructor argument.
  • Added ability to release ownership of the underlying native socket. (Requires Windows 8.1 or later when using the I/O completion port backend.)
• Atomic:

  • Implemented a set of experimental extended atomic operations for integral types:

    • fetch_negate, fetch_complement - atomically replaces the value with a negated or binary complemented value and returns the original value
    • opaque_<op> - equivalent to fetch_<op> except that it doesn't return the original value
    • <op>_and_test - atomically applies <op> and returns true if the result is zero. Note: The result of these operations will change to the opposite in Boost 1.67. The code that uses these functions will need to be updated.
    • bit_test_and_set, bit_test_and_reset, bit_test_and_complement - atomically sets, resets or complements the specified bit and returns the original value of the bit
  • Following C++17 (P0558R1), arithmetic operations for pointers to non-object types are no longer provided.
  • Also following C++17 exposed atomic<T>::value_type and atomic<T>::difference_type member typedefs, where applicable, to the user's code.
  • Improved compatibility with gcc 7. In particular, using 128-bit operations on x86-64 should no longer require linking with libatomic (the compiler-supplied library).
• DateTime:

  • The library has been converted to use Boost.WinAPI as the abstraction layer for Windows SDK.
  • Fixed an integral overflow that could cause incorrect results when adding or subtracting many years from a date (see here).
• Fiber:

  • synchronization with CUDA streams
  • synchronization with ROCm/HIP streams
• Format:

  • Improvements:

    • Accept new conversion specifiers:

      • a: sets flags fixed | scientific (i.e. hexfloat)
      • b: sets flag boolalpha
      • A: same as a plus flag uppercase
      • F: same as f plus flag uppercase
    • 42 Accept new argument types j and z from ISO C99 (parsed and ignored like all others).
    • 44 Accept new argument types I, I32, I64, and w from Microsoft (parsed and ignored like all others).
    • 33 Added a development tool called format_matrix that exercises as many different combinations of format strings as possible and logs them to a file:

      • helps prevent regressions in between boost releases
      • allows for comparison against snprintf
  • Bugfixes:

    • 36 Safely allow volatile arguments to be used with operator%
    • 4636 Explicit clamping provided to allow MSVC /RTCc to succeed
    • 7477 Fix compatibility with MSVC /Za
    • 10324 Const-correct cast issue resolved
    • 11632 Fix -fsanitize=undefined issue in alt_sstream.hpp
• Fusion:

  • PR#149 isspace(c) is not a macro in Dinkum clib for VxWorks, thanks to Brian Kuhl(@kuhlenough).
  • PR#150 Remove circular preprocessor include, thanks to Gregor Jasny(@gjasny).
  • PR#151 Change base of fusion::tuple.
  • PR#153 Fixed compile error with std::array.
  • PR#154 Fixed bugs nesting and copying on c++03.
• Geometry:

  • Improvements:

    • Add distance for geographic PointLike/AnyGeometry.
  • Bugfixes:

    • Fixes in results of union/intersection/difference which could be incorrect in very complex cases
    • Fixes in validity of union/intersection/difference/buffer
    • Fixes in set and relational operations for non-cartesian coordinate systems.
• Iterator:

  • next()/prior() functions now support user's iterators that don't specify nested types such as iterator_category, difference_type, etc. and instead specialize std::iterator_traits to define those types. The compiler must support C++17-compatible std::iterator_traits for this to work.
• Log:

  • Bug fixes:

    • Fixed a bug in file_collector::scan_for_files that could cause incorrectly named log files in the target directory after the user's application restart.
  • See changelog for more details.
• Math:

  • New Features:

    • Add Gauss and Gauss-Kronrod quadrature routines.
    • Add double-exponential (tanh-sinh, exp-sinh and sinh-sinh) quadrature routines.
    • Add Chebyshev polynomial evaluation, roots, integration, differentiation, and interpolation routines.
• Multi-index Containers:

  • Made modify and modify_key more robust so that the modified element is erased if the modifier throws or the rollback functor does not properly restore the element (full discussion at ticket #12542). This is technically backwards incompatible; for instance, the following code:

    c.modify(c.begin(),[](auto&){throw 0;});
    

    keeps the container c untouched in former versions of Boost whereas now c.begin() is erased. Thanks to Jon Kalb for raising the issue.
  • Maintenance fixes.
• Optional:

  • On newer compilers optional is now trivially-copyable for scalar Ts. This uses a different storage (just T rather than aligned_storage). We require the compiler to support defaulted functions.
  • Changed the implementation of operator== to get rid of the -Wmaybe-uninitialized false-positive warning from GCC.
• PolyCollection:

  • Boost.PolyCollection has been backported to GCC 4.8 to 4.9 and Clang 3.3 to 3.6. The version of libstdc++-v3 shipped with GCC 4.8 (which can also be used by Clang) has deficiencies that result in the following limitations when using Boost.PolyCollection:

    • Stateful allocators are not properly supported.
    • Allocator-extended move construction decays to allocator-extended copy construction.
    • Copy construction crashes if an exception is thrown during element copying.
  • Maintenance fixes.
• Predef:

  • Improved Windows Universal Platform detection. (from James E. King, III)
  • Add detection for CloudABI with cloudlibc. (from James E. King, III)
  • Various other bug fixes.
• Regex:

  • Bug fixes:

    • Numerous small fixes for security issues discovered by de-fuzzing.
• Stacktrace:

  • Now works out-of-the-box on MinGW-w64.
  • Now works on MinGW (without -w64) if libbacktrace is properly installed. See "MinGW specific notes" section in documentation for more info.
• Thread:

  • Bugs Fixes

    • #12323 windows - boost/thread/win32/mfc_thread_init.hpp has wrong signature for _pRawDllMainOrig
    • #12730 windows - static threads library is incompatible with MSVC 2017 RC
    • #12976 Boost Thread Executors documentation mistakes
    • #12949 using sleep_for in a thread context without including boost/thread/thread.hpp yields incorrect behaviour when BOOST_THREAD_HAS_CONDATTR_SET_CLOCK_MONOTONIC is defined
    • #13019 ABI compatibility for BOOST_THREAD_PROVIDES_INTERRUPTIONS incomplete
    • #13069 Boost unit test "sync_pq_multi_thread_p_lib.exe" hung in thread library
    • #13163 boost::detail::heap_new does not have a variadic variant
    • #13226 getpagesize() is deprecated since 199506L
    • #132 VS 2017.4 Preview deadlocks on Test 10964
    • #133 windows - Spurious timing test failures on windows
    • #134 VS 2017.4 Preview deadlock in sync_pq_multi_thread_p_lib.exe
    • #135 VS 2017.4 Preview test_scheduled_tp_p.exe deadlock
    • #136 VS 2017.4 Preview test_scheduler_p.exe deadlock
    • #137 VS 2017.4 Preview executor_ex.exe deadlock
    • #143 Failures on msvc-12.0
    • #145 Clang build error with BOOST_THREAD_ATTRIBUTE_MAY_ALIAS
  • New Experimental Feature

    • #116 [Proposal] Add APIs for deferred set_value/exception
• Utility:

  • boost/next_prior.hpp has been moved to Boost.Iterator. No changes needed to the user's code.
• Uuid:

  • Improvements:

    • 26 Refactored name_generator to support a configurable hash provider concept and provide an optional MD5 hash implementation per RFC-4122. This will make it easier to support whatever becomes the next standard hash algorithm.
    • 34 Added RFC-4122 namespaces in boost::uuids::ns.
  • Bugfixes:

    • 8630 11482 12253 Various deficiencies in string_generator were resolved.
    • 10665 name_generator::operator() is now const, matching docs.
    • Detail headers were moved into the detail subdirectory. No changes needed to user's code, however you may get build warnings if you use the old header location.
• Variant:

  • boost::apply_visitor now does perfect forwarding of visitables #6971. Great thanks to Levon Tarakchyan for implementing this feature.

Compilers Tested

Boost's primary test compilers are:

• Linux:

  • Clang: 3.0, 4.0.1, 5.0.1
  • Clang, C++0x: 3.0
  • Clang, C++11: 3.0, 3.1, 3.2, 3.3, 3.4, 4.0.1, 5.0.1
  • Clang, C++14: 3.5.0, 3.6.0, 3.7.1, 3.8.0, 3.9.1, 4.0.0, 4.0.1, 5.0.1
  • Clang, C++17: 5.0.1
  • GCC: 4.4.7, 4.5.3, 4.6.3, 4.7.2, 5.4.0, 7.2.0
  • GCC, C++0x: 4.4.7
  • GCC, C++11: 4.7.2, 4.7.3, 4.8.5, 4.9.4, 6.4.0, 7.1.0, 7.2.0
  • GCC, C++14: 5.4.1, 6.3.0, 6.4.0, 7.1.0, 7.2.0, 7.2.1
  • GCC, C++17: 7.2.0
  • Intel: 18.0
• OS X:

  • Clang: 9.0.0
  • Clang, C++11: 9.0.0
  • Clang, C++14: 9.0.0
  • Clang, C++1z: 9.0.0
• 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
  • Visual C++: 7.1, 8.0, 9.0, 10.0, 11.0, 12.0, 14.0, 14.1
• Android:

  • Clang: 3.6, 3.7, 3.8
  • GCC: 4.9, 5.4
  • GCC, C++14: 6.2
• FreeBSD:

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

  • QCC, C++0x: 4.4.2
  • QCC, C++11: 4.7.3

Boost's additional test compilers include:

• Linux:

  • Clang: 3.0, 3.8.1, 4.0.1, 5.0.1
  • Clang, C++0x: 3.0
  • Clang, C++11: 3.0, 3.1, 3.2, 3.3, 3.4, 4.0.1, 5.0.1
  • Clang, C++14: 3.5.0, 3.6.0, 3.7.1, 3.8.0, 3.9.1, 4.0.0, 4.0.1, 5.0.1
  • Clang, C++17: 5.0.1
  • GCC: 4.4.7, 4.5.3, 4.6.3, 4.7.2, 5.4.0, 7.2.0
  • GCC, C++0x: 4.4.7
  • GCC, C++11: 4.7.2, 4.7.3, 4.8.5, 4.9.4, 5.4.0, 6.4.0, 7.1.0, 7.2.0
  • GCC, C++14: 5.4.1, 6.3.0, 6.4.0, 7.1.0, 7.2.0, 7.2.1, 8.0.0
  • GCC, C++17: 7.2.0
  • Intel: 18.0
• OS X:

  • Clang: 9.0.0
  • Clang, C++11: 9.0.0
  • Clang, C++14: 9.0.0
  • Clang, C++1z: 9.0.0
• 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, 7.1.0
  • Visual C++: 7.1, 8.0, 9.0, 10.0, 11.0, 12.0, 14.0, 14.1
• Android:

  • Clang: 3.6, 3.7, 3.8
  • GCC: 4.9, 5.4
  • GCC, C++14: 6.2
• FreeBSD:

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

  • QCC, C++0x: 4.4.2
  • QCC, C++11: 4.7.3

Acknowledgements

Beman Dawes, Daniel James, Vladimir Prus and Marshall Clow managed this release.