Log Message:
Update to 1.70.0

Changelog:
New Libraries

    Outcome: A set of tools for reporting and handling function failures in \ 
contexts where directly using C++ exception handling is unsuitable, from Niall \ 
Douglas.
    Histogram: Fast and extensible multi-dimensional histograms with convenient \ 
interface for C++14, from Hans Dembinski.

Updated Libraries

    Asio:
        This release includes a number of new features, bug fixes, performance \ 
enhancements, and documentation improvements. Notable changes include:
            Added the ability to use custom I/O executors with I/O objects (such \ 
as sockets).
            Added a new async_result form with an initiate static member function.
            Updated the Coroutines TS support and promoted it to the asio namespace.
            Added a new DynamicBuffer_v2 concept which is CopyConstructible.
            Added a new async_compose function that simplifies the \ 
implementation of user-defined asynchronous operations.
            Added a make_strand helper function.
            Relaxed the completion condition type requirements to only require \ 
move-constructibility rather than copy-constructibility.
            Added a constructor for local::basic_endpoint that takes a string_view.
            Added the noexcept qualifier to various functions.
            Added a new BOOST_ASIO_DISABLE_VISIBILITY configuration #define.
            Enabled recycling of the memory used to type-erase a function object \ 
with the polymorphic executor.
            Changed receive operations to return the correct number of bytes \ 
transferred when truncation (error::message_size) occurs on a datagram-oriented \ 
socket.
            Fixed calculation of absolute timeout when the backend uses \ 
pthread_cond_timedwait.
            Changed the range-based asynchronous connect operation to deduce the \ 
EndpointSequence iterator type.
            Fixed buffer_sequence_begin and buffer_sequence_end to prevent \ 
implicit conversion.
            Ensured SSL handshake errors are propagated to the peer before the \ 
local operation completes.
            Suppressed the eof error on SSL shutdown as it actually indicates \ 
success.
            Added a fallback error code for when we OpenSSL produces an \ 
SSL_ERROR_SYSCALL result without an associated error.
            Changed composed asynchronous read and write operations to move \ 
buffer sequence objects.
            Fixed a macOS-specific warning about the deprecation of OSMemoryBarrier.
            Fixed compile errors that occur when using the composed read and \ 
write operations with MSVC 11.0.
            Improved dispatch, post and defer documentation.
            Fixed a Windows-specific memory leak that may occur when \ 
system_executor is used.
        Consult the Revision History for further details.
    Beast: BIG Update!!!
        Some APIs have changed.
        The reference shows a star ★ next to each new item.
        Beast needs your help!
            Tell Us how you or your company use Beast
            Please report any bugs, feature requests, or general feedback
            Join the C++ Slack Workspace for free and chat with us in the #beast \ 
and #boost channels
            Don't forget to star the repository ⭐!
        More tutorials, code like the pros!
            Networking Refresher teaches you from the ground up.
            Updated Asynchronous Echo example
            Updated Detect SSL composed operation tutorial
            websocket-chat-multi threaded chat server with a JavaScript browser \ 
client
        basic_stream and tcp_stream offer:
            Timeouts: async_read_some, async_write_some complete with \ 
error::timeout on expiration!
            Traffic-shaping policies simple and unlimited, or a user-defined \ 
RatePolicy!
            Put the strand directly on the socket using P1322R0, no more \ 
bind_executor at call sites!
        Base classes async_base and stable_async_base and handle all composed \ 
operation boilerplate for you.
        ssl_stream provides a movable, assignable SSL stream with a flat write \ 
optimization.
        All asynchronous operations use Asio's async_initiate for efficient \ 
integration with Coroutines TS.
        ⚡ faster compilation, define BOOST_BEAST_SEPARATE_COMPILATION and \ 
#include <boost/beast/src.hpp> in one of your .cpp files!
        See the full Release Notes for a complete list of changes.
    Context:
        #91: cleanup of stack if creating ucontext fails
        #97: add missing BOST_CONTEXT_DECL in stack_context
        #98: fix jump_i386_sysv_macho writing garbage to the x87 control word
    Coroutine2:
        #28: don't crash on pthread_cancel
    DLL:
        New macro BOOST_DLL_USE_STD_FS. Define it to 1 to make the Boost.DLL use \ 
C++17's std::filesystem::path, std::system_error and std::error_code (#21). Note \ 
that exception types change from boost::system::system_error to \ 
std::system_error, so make sure to update catches.
        Significant rewrite of the dynamic loadable detection and decoration \ 
logic. More precise errors are now reported in case of loading failures. Added \ 
shared_library::decorate() function that returns a decorated path to the library \ 
without doing any platform related queries and detections. Prefer using \ 
shared_library::load and shared_library constructors for better results (many \ 
thanks to Loïc Touraine for the work PR#23).
        CI hardening, docs updates, typos fixes, cleanups and mg
        #196: fix high contention on remote_ready_splk_
    Filesystem:
        Fixed a few instances of dereferencing std::string::end() in path \ 
implementation.
        Fixed program termination in case of out of memory condition in \ 
directory iteratorsnce to error_code. (#58)
        Fixed possible linking errors caused by missing definitions of static \ 
members of path. (#12759)
        Fixed possible use of uninitialized data in directory iterator increment \ 
operation on Linux.
        Added support fortatus query overloads for directory_entry. This avoids \ 
a relatively expensive OS query when file status is requested for a result of \ 
dereferencing a directory iterator. (PR#55)
        Reworked current_path and read_symlink implementation to avoid \ 
possiblfilesystems. The functions now have an internal limit of the path size \ 
they will accept from the OS, which is currently 16 MiB.
        Increased the size of the internal buffer used by copy_file.
    Integer:
        Added Extended Euclidean Algorithm and Modular Multiplicative Inverse \ 
function. (Nick Thompson, PR#11)
    Log:
        New features:
            Added support for generating another log file name before collecting \ 
the file in the text file sink backend. This allows to combine appending to \ 
aexisting log file with timestamps and file counters in log filenames, and, \ 
consequently, file collection in general.
        See changelog for more details.
    Math:
        New features:
            Add Lanczos smoothing derivatives
            Move numols/ to boost/math/differentiation/finite_difference.hpp.
            Add mean, variance, skewness, kurtosis, median, Gini coefficient, \ 
and median absolute deviation to tools/univariate_statistics.hpp.
            Add correlation coefficients and covariand absolute Gini \ 
coefficient, Hoyer sparsity, oracle SNR, and the M[sub 2]M[sub 4] SNR estimator \ 
to tools/signal_statistics.hpp.
            Add total variation, l0, l1, l2, and sup norms, as well as \ 
corresponding distance functions to tools/norms.hpp.
   for polynomials, support complex coefficients, add .prime() and .integrate() \ 
methods.
            Add quadratic_roots to tools/roots.hpp.
            Add support for complex-valued functions to Newton's method in roots.hpp.
            Add Catmull-Rom inted mp_invoke to mp_invoke_q
        Added mp_similar
        Added mp_set_union, mp_set_intersection, mp_set_difference
        Added mp_not_fn
        Added mp_transform_first, mp_transform_second, mp_transform_third
        Added mp_filter
        Addedp_valid_q
        Added mp_back, mp_pop_back
    Multi-index Containers:
        size_type and difference_type are now defined as the allocator's \ 
same-named types. This will not make any difference in the vast majority of \ 
cases, but allows for some degreevia user-defined allocator types (see issue #17 \ 
for motivation). For the moment being, this change is not documented in the \ 
reference section (i.e., it has semi-official status).
        Maintenance work.
    Multiprecision:
        Fix various conversioncheck for compatibility with Boost.Optional.
        Prevent instantiation of std::numeric_limits on any old type when \ 
checking for convertibility. See #98.
        Update variable precision code to account for arbitrary precision \ 
integers. See #103.
    lization archives.
        Fix bug in fixed precision iostream formatting in mpf_float and \ 
mpfr_float. See #113.
        Add more overloads for special functions which are better handled \ 
natively by MPFR.
        Fixed bug in generic exp implementation wh.
        Fixed generic conversion from float to integer to avoid undefined \ 
behaviour. See #110.
    PolyCollection:
        Improved handling of stateful allocators and allocator propagation \ 
traits, after an error reported by Billy O'Neal (PR#9).
       ug with an internal cache structure.
    Spirit:
        Removed use of deprecated boost/detail/iterator.hpp header. PR#432
        X3
            Integer parsers should now handle user defined types. PR#429
            Note: The check_overflow trait defan \ 
std::numeric_limits<T>::is_bounded instead of \ 
boost::integer_traits<T>::is_integral.
            Removed sequence into plain parsing. Now it triggers a compile time \ 
error instead of silently parsing the the sequence and taking the last value as \ 
a resulte_rule instantiation with BOOST_SPIRIT_INSTANTIATE when:
                A rule has no attribute. PR#455
                An actual attribute is not of type a rule was declared with. \ 
PR#456 #457
            A huge thanks goes out to Xeverous for reporting    Fixed unneded \ 
attribute synthesization and no-transformation attribute reference pass-through \ 
in rules. #444 PR#449 PR#452
            Removed broken 1.0#INF parser. It was poorly documented and never \ 
worked. #415 PR#458 #8699
            The undocumenoved due to bugs PR#449 and to simplify attribute \ 
transformation. PR#460
            If you were using it to workaround bugs in attribute transformation \ 
- they should not be needed anymore as of this release.
            The integer value parser now respe10 value. PR#469
            Fixed underflow check for a (Min % Base) == 0 corner case. PR#469
            Fixed an output value on overflow of IgnoreOverflowDigits=true \ 
integer parser. PR#470
            Container attribute elements were copyied, but notial handling of \ 
references in transform_attribute was removed. PR#480
        V2
            Macro name collisions and namespace conflicts with Boost.Endian were \ 
fixed. PR#349 PR#482
            utree
                Fixed UB in tag getter due to left shi            Fixed \ 
double-conversion (spirit::string -> std::string -> spirit::string). \ 
PR#462
            Qi
                Added static asserts for rule skipper type problems. PR#427
                The check_overflow trait default implementation now \ 
reoost::integer_traits<T>::is_integral PR#429
                Integer parsers should now handle user defined types. PR#429
                Note: The check_overflow trait default implementation now relies \ 
on std::numeric_limits<T>::is_bounded instead of boosl.
                Removed broken 1.0#INF parser. It was poorly documented and \ 
never worked. #415 PR#458 #8699
                The undocumented make_attribute trait was merged into \ 
transform_attribute trait. PR#471
                The pre_transform, post_tility functions were removed in favor \ 
of directly using pre/post/fail of the transform trait. PR#467
                The integer value parser now respects \ 
std::numeric_limits<T>::digits10 value. PR#469
                Fixed underflow check for a (Min % B            Fixed an output \ 
value on overflow of IgnoreOverflowDigits=true integer parser. PR#470
                Special handling of references in transform_attribute was \ 
removed. PR#480
            Lex
                Fixed UB in default constructor of ken type. PR#420
        Classic:
            Fixed position_iterator forming reference to local when the \ 
underlying iterator dereference operator returns a non-reference type. PR#422 \ 
#9737
    Stacktrace:
        Build fix for iOS 32-bit ARM (many thanksng the fix PR#70)
        Fixed multiple typos, warnings and updated the docs.
    Test:
        Boost.test v3.10 see the Changes log for more details.
        Breaking changes:
            Boost.Test minimal.hpp is now showing a deprecation warning,
    omparison may fail tests that were silently not using the floating point \ 
comparison logic prior to this release,
            Internal API change to unit_test_log_formatter, see detailed change log,
        New feature:
            Floating point compariso non-floating point and arithmetic operands: \ 
expressions like BOOST_TEST(3.0001 == 3) now use floating point support of \ 
Boost.Test,
            Custom datasets are not required to declare the sample type field \ 
anymore,
            Extending template test riadic definition,
            Windows support for timed tests,
            Timed test on test-suites,
            Removed dependency to Boost.Timer,
            New macro BOOST_TEST_INFO_SCOPE for scoped context declaration,
            Improved BOOST_TE and pull requests:
            Trac tickets: #7397, #9434, #13106, #13418
            GitHub Issues: #133, #138, #141, #157, #160, #174, #176, #177, #180, \ 
#181, #194, #196, #198, #199, #202, #203, #204
            GitHub Pull Requests: PR#171, PR#172, PR PR#195, PR#195, PR#197, PR#205
    TypeIndex:
        Support for the GHS C++ compiler added (many thanks to Brandon \ 
Castellano for providing the patch PR#28)
        Optimized string and type comparisons (many thanks to Andrey Semashev \ 
for providing the-win compilation (many thanks to Peter Dimov for providing the \ 
patch PR#25)
        CI hardening.
    TypeTraits:
        Added is_bounded_array and is_unbounded_array (Glen Fernandes).
        Added copy_reference and copy_cv_ref (Glen Fernandes).
       /clr option.
        Misc compiler compatibility fixes.
    Variant:
        Many cleanups and internal improvements, many thanks to Nikita Kniazev \ 
(PR#55, PR#56, PR#57) and Louis Dionne (PR#51)
        CI hardening.
    uBlas:
        Addition of tensorassoy PR#65)
        Addition of basic OpenCL support (many thanks to Fady Essam PR#59)
        Integration of basic benchmark suite (many thanks to Stefan Seefeld PR#57)
        CI integration and hardening

Compilers Tested

Boost's primary test compileang: 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
        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, 6.0.17, 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:
, 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: 3.4.4.0, 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
    Fr
        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..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
        G9.4, 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, 9ang, 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 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