Known Issues

These are patches from library authors which were found too late to be fixed in the release.

• Config

  • Support for libcpp15 which removes std::unary_function and std::binary_function. Patch.
• Filesystem

  • Directory iterators may fail to construct for a network share on Windows prior to 10, see PR#246 and #245. Patch.
  • On Windows, weakly_canonical fails to process paths that start with the "\\?\" prefix, see #247. Patch.
  • On POSIX systems that don't support *at APIs, compilation fails due to a missing include, see #250. Patch.
• Unordered

  • Containers are not in a valid state after moving, see #139. Patch.
  • Fix MSVC /RTCc build runtime failures. Patch.

New Libraries

• No new libraries.

Updated Libraries

• Asio:

  • Added a deduced trailing return type to all asynchronous operations, to enable the new form of async_result for C++11.
  • Moved append, prepend, as_tuple, and deferred to the boost::asio namespace, and made them compatible with C++11.
  • Made experimental::parallel_group compatible with C++11.
  • Added buffer() overloads for contiguous containers, such as std::span.
  • Added the ability for awaitable<>-based coroutines to directly co_await operations that are packaged as function objects.
  • Changed spawn() to be a completion token-based asynchronous operation, and added support for cancellation. The basic_yield_context token now supports move-only and variadic result types. When targeting C++11 and later, spawn() and basic_yield_context are implemented in terms of Boost.Context directly.
  • Added the is_async_operation trait and async_operation concept.
  • Added the completion_signature_of trait.
  • Added converting move construction/assignment to posix descriptors, serial ports, pipes, Windows object_handle, Windows stream handles, and Windows random-access handles.
  • Added release() member functions to pipes, Windows stream handles, and Windows random-access handles.
  • Enabled support for Endpoint implementations that return void pointers from their data() member functions, as per the documented Endpoint type requirements.
  • Removed all() and race() from experimental::promise, as experimental::parallel_group covers this functionality.
  • Added source locations to exceptions and error codes produced by the synchronous and asynchronous operations.
  • Fixed compatibility with OpenSSL 3.0.4 and later.
  • Fixed compatibility with with -masm=intel.
  • Explicitly stated that socket shutdown() calls are thread-safe with respect to certain other synchronous operations on the same socket.
  • Optimised the move construction of I/O objects where only the executor type differs.
  • Fixed the detection of std::invoke_result for clang/libc++.
  • Fixed an issue where experimental::parallel_group initiation incorrectly moved arguments instead of forwarding them.
  • Fixed a sequencing issue in the implementation of post(), dispatch(), and defer().
  • Fixed the awaitable<> implementation to propagate exceptions from awaited initiation functions through the current completion handler.
  • Fixed detection of std::aligned_alloc with gcc 7.
  • Changed to avoid using the soon-to-be-deprecated std::aligned_storage on newer compilers.
  • Fixed detection of std::aligned_alloc for older Apple platforms.
  • Removed faulty assertions from experimental::coro implementation.
  • Added defence against Qt-defined macros when building with Intel C++.
  • Changed the implementation of the select_reactor, on Windows, to ensure that any exception resulting from failure to recreate its interrupter's sockets will be allowed to propagate out through io_context::run().
  • Fixed various compiler warnings.
  • Updated all composed operations examples, and the C++11 timeouts example, to use the new async_result form.
  • Added composed operation and coroutine examples for C++20.
  • Consult the Revision History for further details.
• Atomic:

  • Improved portability of endianness checks on ARM, AArch32 and AArch64 targets. (#59)
  • Fixed compilation with MSVC 14.0 (Visual Studio 2015) in C++17 mode. (#61)
• Filesystem:

  • On Windows, added a fallback implementation for querying file attributes in case if the file cannot be opened with ERROR_ACCESS_DENIED error. This may allow status and symlink_status to succeed for system files and directories that are not reparse points or symlinks. (#234)
  • On Windows, added a workaround for FAT/exFAT filesystems that produce ERROR_INVALID_PARAMETER when querying file attributes. This affected status and symlink_status, which reported that files do not exist, and directory iterators, which failed to construct, as well as other dependent operations. (#236, #237)
  • Worked around a compilation problem on RTEMS. (PR#240)
  • On Linux, corrected switching to sendfile copy_file implementation if copy_file_range failed with ENOSYS in runtime. The sendfile fallback implementation used to skip the filesystem type check and could fail for some filesystems.
  • On POSIX systems supporting openat and related APIs defined in POSIX.1-2008 and on Windows Vista and later, improved protection of remove_all against CVE-2022-21658 that was implemented in the previous release. The previous fix could still result in removing unintended files in certain conditions. Other systems remain vulnerable.
• GIL: NOTICE: We are planning BREAKING switch to C++17 as minimum required C++ language version in one or two releases after Boost 1.80 (#676)

  • Added

    • GSoC 2020: Added Perona-Malik anisotropic diffusion algorithm (PR#500)
    • GSoC 2020: Added histogram class and related functionality (PR#499)
    • GSoC 2020: Added histogram equalization feature (PR#514)
    • GSoC 2020: Added histogram matching algorithm (PR#515)
    • GSoC 2020: Added ability to stack images either horizontally (hstack) or vertically (vstack) (PR#506)
    • GSoC 2020: Added adaptive histogram equalization algorithm (PR#516)
    • GSoC 2020: Added Standard Hough Transform and circle rasterization (PR#512)
    • GSoC 2020: Added Bresenham's algorithm for line rasterization (PR#512)
    • GSoC 2021: Added rotation of image by arbitrary angle around its center (PR#565)
    • GSoC 2021: Added rasterization support for ellipse based on "An Efficient Ellipse-Drawing Algorithm" by Jerry Van Aken (PR#585)
    • Added image constructor from compatible view (PR#520)
    • Added inverse function for affine matrix3x2 (PR#527)
    • Added standard morphological transformations (PR#541)
    • Added for_each_pixel overload for any_image (PR#648)
    • Added C++17 polymorphic memory resource typedefs for image class (PR#529)
  • Changed

    • BREAKING: The required minimum C++ version is changed from from C++11 to C++14. Currently, large parts of GIL still compile with a C++11 compiler. However, there is no guarantee that it stays that way, and any compilers that do not support at least C++14 are considered unsupported as of now.
    • BREAKING: any_color_converted_view() is deprecated and will be removed in the next release. Use color_converted_view() instead, which provides the same feature.
    • BREAKING: apply_operation for any_image is deprecated and will be removed in the next release. Use variant2::visit instead, which provides the same feature. (PR#656)
    • Moved numeric extension to core (PR#573)
    • Added support for C++17's <filesystem> (PR#636) The availability of the std::filesystem is detected automatically, unless the BOOST_GIL_IO_USE_BOOST_FILESYSTEM macro is defined that forces the preference of the Boost.Filesystem.
    • Renamed pixel_multiply_t to pixel_multiplies_t and pixel_divide_t to pixel_divides_t (PR#655)
    • Renamed io/dynamic_io_new.hpp to io/detail/dynamic.hpp (PR#653)
    • Moved function construct_matched into boost::gil::detail namespace as it was only used by other implementation details (PR#653)
    • Made packed_pixel trivially copyable and assignable (PR#679)
    • Replace deprecated libtiff v4.3 typedefs with C99 fixed-size integers (PR#685)
  • Removed

    • BREAKING: Removed support for GCC 5 (PR#572)
    • Removed deprecated.hpp (PR#627)
  • Fixed

    • Fixed conversion from RGB to HSL (PR#505)
    • Fixed conversion from RGB to signed CMYK (PR#522)
    • Removed unnecessary numeric cast in hsv.hpp (PR#530)
    • Fixed default constructor for homogeneous_color_base for reference pixel elements (PR#542)
    • Fixed returning reference to local temporary object in subchroma_image_view (PR#556)
    • Added missing header guards in diffusion.hpp (PR#568)
    • Fixed any_image_view<>::const_t (PR#526)
    • Fixed C++20 incompatibilities in I/O extensions (PR#617)
    • Ensured all examples build without errors (PR#628)
    • Fixed convolve_2d for images with float32_t channel model (PR#577)
    • Fixed for_each_pixel for non-1d iterable views (PR#621)
    • Fixed: is_equal_to_sixteen in PNG I/O was less-than test (PR#650)
    • Re-allow devicen_t with two components (PR#654) It was unintentionally removed in Boost 1.72
    • Fixed memory leak in image class for empty dimensions (PR#649)
  • Acknowledgements

    • Cypre55, Samuel Debionne, Mike-Devel, Edward Diener, Peter Dimov, Omar Emara, Dhruva Gole, Nicolas Herry, Eugene K, Avinal Kumar, Gaurav Kumar, Marco Langer, Pranam Lashkari, Mateusz Łoskot, Giovanni Mascellani, Debabrata Mandal, Gopi Krishna Menon, René Ferdinand Rivera Morell, Felix Morgner, Harshit Pant, Paul92, André Schröder, Scramjet911, Siddharth, Dirk Stolle, Prathamesh Tagore, theroyn, Olzhas Zhumabek
• Graph:

  • Bug fixes:

    • Fix bug in stoer_wagner_min_cut where vertices are not merged at the end of each mincut phase (#286)
    • Fix conversion warning for return type of strong_components (#293)
    • Fix compilation failure of boykov_kolmogorov_max_flow named parameter overload (#232)
  • General code improvements:

    • Remove redundant call to combine in astar_search_no_init_tree (#260)
    • Remove redundant child_idx argument of d_ary_heap_indirect<>::child (#261)
    • Improve documentation for traversal categories (#303)
  • Acknowledgements

    • Viktor Pti, Sebastian Brockmeyer, Etienne dg
• Histogram:

  • Fixed segfault in indexed when trying to iterate over histogram with axes of zero size (physical or logical) under certain conditions
  • Removed previously deprecated API

    • class accumulators::thread_safe: use accumulators::count<T, true>
    • Methods accumulators::sum::large and accumulators::sum::small: use accumulators::sum::large_part and accumulators::sum::small_part
    • Type alias algorithm::reduce_option: use algorithm::reduce_command
    • Template function axis::traits::static_options: use axis::traits::get_options
    • Template function axis::traits::static_is_inclusive: use axis::traits::is_inclusive
    • Type alias indexed::range_iterator: use indexed::iterator
    • Type alias indexed::accessor::reference: use indexed::accessor::const_reference
• Iterator:

  • For C++11 and later, added support for perfect forwarding of values written to function_output_iterator. (PR#73)
  • Added protection against writing to function_output_iterator a result of dereferencing another function_output_iterator.
• JSON:

  • Added non-const value::at overloads.
  • Added the ability to manually choose endianness of the platform.
  • Added string::subview() overload.
  • Fixed segfault in array::erase(it).
  • Fixed low performance of serialize on libc++.
  • Fixed ambigious conversion to std::string_view on GCC 8.
  • Fixed parsing on big-endian platforms.
  • Fixed handling of comment after trailing comma.
• LEAF:

  • API breaking change: throw leaf::exception(....) now becomes leaf::throw_exception(....)
  • Fixed a bug in support for a rare build configuration (exception handling enabled, diagnostics disabled)
  • Using nullptr instead of 0 throughout
  • Fixed pedantic warnings
• Locale:

  • Deprecated support for C++03 and earlier, C++11 will be required in the next release
  • Provide -sICU_LINK_LOCALE as a temporary replacement for -sICU_LINK which is incompatible with Boost.Regex. -sICU_LINK_LOCALE and -sICU_LINK are deprecated and will be replaced by ICU_*_NAME options to be compatible with Boost.Regex
  • Fix UB/assertion failure in the ICU collator implementation when transforming empty strings
  • Fix some issues related to visibility of classes in shared libraries (Unix only)
  • Fix compatibility with C++20 mode
  • Fix compatibility with BOOST_USE_WINDOWS_H
  • Fix build failures due to missing includes
  • Handle or suppress many warnings which makes the build log cleaner
• Log:

  • Bug fixes:

    • Fixed binding incorrect local address in UDP socket-based syslog_backend when IPv6 address is used for the syslog server. (#181)
    • Added a workaround for a bug in libstdc++ from gcc 11.2. When max_size_decor was used on a formatting stream, std::codecvt::do_length incorrectly accessed the input buffer and caused a buffer overflow.
  • See changelog for more details.
• Math:

  • Deprecated C++11 support: from 2023 we will require C++14 as a minimum standard. This will mean GCC-5 or MSVC-14.1 as a minimal requirement.
  • Add constexpr fma support, see 734.
  • Add support for the Chatterjee Correlation Coefficient, see 770.
  • Added support for the logarithm of the PDF for all the distributions.
  • Improve support for building with no exception or RTTI support.
  • Some minor bug fixes for [sub 1]F[sub 1] corner cases, see 778.
• Multiprecision:

  • Mark C++11 support as deprecated: from 2023 we will move to requiring C++14 as a minimum standard level. That will drop support for GCC versions prior to 5 and MSVC prior to 14.1.
  • Fix conflict between boost/cstdfloat.hpp and this library.
  • Clean up lots of gcc and clang warnings.
  • Fix input streaming of composite types (complex, interval rational) where there is a trailing delimeter in the stream and no whitespace.
  • Fix constexpr integer square root where the input is 1, 2 or 3.
  • Add missing #include of <memory> to float128.hpp.
  • Correct 2-arg constructor for class number to prevent ambiguity in some cases.
  • Correct and make more consistent behaviour of divide-by-zero in gmp.hpp.
• Multi-index Containers:

  • Maintenance work.
• Nowide:

  • Major performance improvement for Bulk I/O with files
  • basic_filebuf: Fix wrong return value of sync when fflush failed
  • basic_filebuf: Fix possible undefined behavior in a corner case when nothing was actually written but buffer is in "write" mode
  • basic_filebuf: Limit putback of characters (i.e. pbackfail) only allowing putback of buffered characters (may be only 1 character)
• Optional:

  • Added specializations for std::hash<boost::optional<T>>. This is a breaking change for programs that define such specializations themselves. For more details see specs.
• STLInterfaces:

  • Fix #53: "missing 'typename' prior to dependent type name 'C::const_iterator'"
  • Fix #54: "Concept check fails on .data() of a view on contiguous iterator_interface instantiations"
  • New additions to make it easy to write views and view adaptors that work like, and interoperate with, the ones in the standard library:

    • Add workalikes for C++23's std::bind_back() and std::range_adaptor_closure for pre-C++23 code.
    • Add templates closure and adaptor to make writing view adaptors easier, following the examples in P2387.
• System:

  • When an error_code is converted to std::error_code and then back to error_code, the original is now restored, if possible.
  • Reworked the conversion from error_category to std::error_category to avoid the one-time allocation that shows up on leak checkers.
  • Added a constructor that allows replacing the source location of an error_code, and a corresponding assign.
  • Added a converting constructor to result.
• Unordered: Major update:

  • Refactor internal implementation to be dramatically faster
  • Allow final Hasher and KeyEqual objects
  • Update documentation, adding benchmark graphs and notes on the new internal data structures
• Utility:

  • In string_view/string_ref, fixed max_size returning incorrect value. (#91)
  • Removed noexcept specifier from string_view::compare as it may throw on some input arguments. (#94)
  • In string_view/string_ref, added support for calling substr with no arguments. (#96)
  • Added string_view::contains methods that were introduced in C++23. (#93)
  • In string_view, added asserts in remove_prefix/remove_suffix methods to enforce the precondition that the prefix/suffix length does not exceed the string view size. The previous (undocumented) behavior of silently clamping the prefix/suffix length is deprecated and will be removed in a future release. (#92)
• Wave: Fixed bugs:

  • #24: Line numbers wrong after conditional section
  • #160: one test fails with error C2660 and error C2440 under msvc /permissive- mode
  • #161: BOOST_WAVE_THROW_NAME_CTX does not result in a context callback and always throws
  • #162: When Boost headers are included in the preprocessed translation unit, Wave fails in boost/integer.hpp(99)

Updated Tools

• Build:

  • Includes release of B2 version 4.9.2.

Compilers Tested

Boost's primary test compilers are:

Boost's primary test compilers are:

• Linux:

  • Clang: 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 12.0.0, 13.0.0, 14.0.0
  • Clang, C++11: 3.4, 11.0.0, 13.0.0, 14.0.0
  • Clang, C++14: 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 5.0, 12.0.0, 13.0.0, 14.0.0
  • Clang, C++17: 6.0.1, 7.0.0, 8.0.0, 9.0.0, 10.0.0, 11.0.0, 12.0.0, 13.0.0, 14.0.0
  • Clang, C++20: 11.0.0, 12.0.0, 13.0.0, 14.0.0
  • GCC: 4.6.3, 11, 12
  • GCC, C++11: 4.7.3, 4.8.5, 11, 12
  • GCC, C++14: 5.4.0, 6.4.0, 7.3.0, 8.0.1, 9.1.0, 11, 12
  • GCC, C++17: 7.3.0, 8.0.1, 9.1.0, 11, 12
  • GCC, C++20: 8.0.1, 9.1.0, 10, 11, 12
• OS X:

  • Apple Clang: 11.0.3
  • Apple Clang, C++11: 11.0.3
  • Apple Clang, C++14: 11.0.3
  • Apple Clang, C++17: 11.0.3
  • Apple Clang, C++20: 11.0.3
• Windows:

  • Visual C++: 10.0, 11.0, 12.0, 14.0, 14.1, 14.2, 14.3

Acknowledgements

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