Version 1.77.0
August 11th, 2021 14:25 GMT
Documentation
New Libraries
- Describe:
- A C++14 reflection
library, from Peter Dimov. Provides macros for describing enumerators and
struct/class members, and primitives for querying this information.
- Lambda2:
- A C++14, dependency-free,
single header lambda library, from Peter Dimov. Allows simple function
objects to be constructed via expressions such as _1
+ 5,
_1 %
2 == 0, _1
> _2,
or _1 ==
' ' || _1 == '\t'.
Updated Libraries
-
Any:
-
Added
boost::anys::basic_any - a data type with customizable
Small Object Optimization whose instances can hold instances of any
type that satisfies ValueType requirements (many thanks to Ruslan
Arutyunyan @rarutyun). If you are not sure that you really need it,
then use boost::any instead.
-
Started using GithubActions CI for additional testing
-
Asio:
-
Added support for cancellation of individual asynchronous operations.
-
Added the
associator
trait, used to generically forward associators.
-
Changed all asynchronous operations implemented in Asio to invoke
their completion handlers as rvalue references.
-
Added support for asynchronous operations with multiple completion
signatures.
-
Added
operator&&
and operator||
for awaitable<>,
to allow coroutines to be trivially awaited in parallel.
-
Added the
experimental::as_tuple
completion token adapter.
-
Added the
experimental::append
completion token adapter.
-
Added the
experimental::prepend
completion token adapter.
-
Added the
experimental::deferred
completion token, whicih allows deferred execution of asynchronous
operations.
-
Added the
experimental::parallel_group
class and experimental::make_parallel_group
function.
-
Added
experimental::promise,
which allows eager execution and synchronisation of asynchronous
operations.
-
Added the
experimental::coro
class template, a C++20 coroutine primitive with the ability to combine
both asynchronous waiting (co_await)
and yielding (co_yield).
-
Added move assignment to
ssl::stream<>.
-
Changed
co_spawn
to dispatch the coroutine's
initial step to the executor.
-
Enabled additional optimisations for
any_executor
and any_io_executor
when used with asynchronous operations.
-
Added the
nodiscard
attribute to awaitable<>.
-
Increased the number of cached slots in the default recycling allocator.
-
Changed the default allocator behaviour to respect alignment requirements,
to support over-aligned types.
-
Ensured the result strings are always initialised in reverse name
resolution.
-
Fixed recursive template instantiation issues in
use_awaitable_t::executor_with_default.
-
Fixed the
any_io_executor
equality operators to correctly return a result based on the target
executor.
-
Fixed
strand<>
to avoid using a potentially moved-from executor.
-
Ensured gcc tests are not used for clang
when detecting compiler features.
-
Disabled coroutines support for the clang shipped
with MSVC.
-
Fixed compatibility with recent LibreSSL when
OPENSSL_NO_SSL_INTERN
is defined.
-
Fixed
posix::basic_stream_descriptor move operations
to work with non-defaulted executors.
-
Consult the Revision
History for further details.
-
Atomic:
-
Added
make_atomic_ref
and make_ipc_atomic_ref
factory functions for constructing atomic reference objects.
-
Added C++17 template argument deduction guides for
atomic_ref and ipc_atomic_ref
to allow omitting template arguments when they can be deduced from
constructor arguments.
-
Beast:
-
This maintenance update brings minor bug fixes and updated 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.
-
Conversion:
-
boost::implicit_cast is now constexpr (#25).
-
Fixed broken links (PR#23).
-
Started using GithubActions CI for additional testing
-
Core:
-
boost/core/uncaught_exceptions.hpp has been modified for compatibility
with Mac OS 10.4 and older. (PR#92)
-
DLL:
-
More runtime checks for malformed ELFs in
boost::dll::library_info
-
In
boost::dll::library_info use info from .dynsym
ELF section if .symtab
is empty or missing
-
List protected ELF symbols in
boost::dll::library_info
as they are available for import (#50)
-
Remove unneeded convert from
wchar_t
to char on POSIX environment, thanks to Vladislav Shchapov (PR#49)
-
Started using GithubAction CI for additional testing
-
Filesystem:
-
Introducing Boost.Filesystem v4.
This new version of the library removes all deprecated features of
v3 and also makes a number of breaking API changes intended to make
Boost.Filesystem more compatible with std::filesystem introduced
in C++17. The differences are described in the release notes and
documentation using v3 and v4 tags and are also summarised in a separate
section. Users can select Boost.Filesystem version by defining
BOOST_FILESYSTEM_VERSION macro
to either 3 or 4 when compiling their code. There is no need to separately
compile Boost.Filesystem for each library version - a single binary
supports both v3 and v4. Users should avoid using both v3 and v4
in the same application as this can lead to subtle bugs. Currently,
v3 is the default. In a future release v4 will become the default,
and eventually v3 will be removed. v4 is functional, but it is still
a work in progress and there may be breaking API changes in the future.
-
v4:
path::filename,
path::stem and path::extension
no longer consider root name or root directory of the path as a filename
if the path only consists of those components. For example, on Windows
path("C:").filename()
used to return "C:" and path("C:\\").filename() used to return "\" and
both will return an empty path now. (#88, #194)
-
v4:
path::stem
and path::extension no longer treat a filename
that starts with a dot and has no other dots as an extension. Filenames
starting with a dot are commonly treated as filenames with an empty
extension. The leading dot is used to indicate a hidden file on most
UNIX-like systems. (#88)
-
New: Improved support for various
path prefixes on Windows. Added support for local device prefix ("\\.\")
and experimental support for NT path prefix ("\??\"). The
prefixes will be included in the root name of a path. Note that using
the prefixes with Boost.Filesystem v3 can lead to surprising results
(e.g.
path("\\\\.\\").stem()
== "\\\\").
It is recommended to use the prefixes only with Boost.Filesystem
v4.
-
Reworked
path::lexically_normal implementation
to eliminate some cases of duplicate dot (".") elements
in the normalized paths.
-
New: Added runtime detection of
the
statx and getrandom system calls on Linux.
This can be useful if the syscall is present at compile time but
fails with ENOSYS
at run time (for example, in Docker containers that restrict the
syscall, even if available on the host). (#172)
-
New: Added support for disabling
usage of various system APIs at library build time. This can be useful
when a certain API is detected as present by the library configuration
scripts but must not be used for some reason (for example, when runtime
detection does not work on the target system). See the description
of configuration macros in the library documentationfor for more
details.
-
New: Added
copy_options::synchronize_data
and copy_options::synchronize
options for the copy_file
operation. These options allow to synchronize the written data and
attributes with the permanent storage. These options are expensive
in terms of performance, but allow to ensure reliability of the copied
data. Note that copy_file
performed implicit data synchronization on POSIX systems since Boost.Filesystem
1.74.0. This release adds support for more platforms and disables
data synchronization by default while allowing the caller to explicitly
request it. (#186)
-
Added handling of
EINTR
error code on POSIX systems for some system calls issued internally.
In particular, EINTR
could have been ignored on close,
which on HP-UX would result in a leaked file descriptor.
-
In the
copy_file
implementations based on Linux sendfile
and copy_file_range
system calls, added handling of error codes indicating that a particular
filesystem does not support the system call and fall back to the
generic read/write loop. This should fix copy_file failing on eCryptFS
and possibly other filesystems. (#184)
-
The
copy_file_range
system call is now used since Linux kernel 4.5, whereas previously
it was only enabled since 5.3. The copy_file
implementation will fall back to sendfile
or read/write loop if copy_file_range
fails to copy a given file across filesystems.
-
The
copy_file implementations
based on Linux sendfile
and copy_file_range
system calls will not be used on filesystems that are known to contain
files with generated content. These system calls are incompatible
with such files, and copying them would result in zero-sized files.
The generic read/write loop will be used instead.
Currently, the blacklisted filesystems are: procfs, sysfs, tracefs
and debugfs.
-
In the
copy_file
implementation based on read/write loop, increased the maximum
size of the buffer used for temporary storage and take into account
the target filesystem block size for more optimal performance.
-
On Windows CE, calling
current_path
to obtain the current path for a process will now fail with an error
instead of returning successfully with a root path. This platform
does not support current directory. Changing the current path was
already failing similarly in previous releases of Boost.Filesystem.
-
In
canonical, fixed
the check for a symlink referencing a directory above root, if an
earlier symlink was resolved to an absolute path with a different
root from the original path.
-
In
canonical, added
a limit for the maximum number of symlinks that can be resolved during
the call. The limit is currently at least 40 symlinks.
-
On Windows,
canonical
and weakly_canonical
will now use path::preferred_separator
for the root directory separator in the resulting paths. This fixes
"file not found" errors caused by Windows API not handling
generic separators in UNC paths and paths that start with the Win32
filesystem prefix ("\\?\"). (#87, #187)
-
New: Added
weakly_canonical
overloads taking base
path as an argument.
-
On Windows,
weakly_canonical
no longer fails with an error if the input path contains elements
that do not exist in the filesystem but are cancelled by a subsequent
dot-dot ("..") element. For example, weakly_canonical("C:\\a\\..") would previously fail if "C:\a"
directory did not exist. (#201)
-
In
read_symlink on
Windows, corrected reparse point handling. The operation would return
an empty path for some mount points (for example, created by Box cloud storage driver) and
directory junction points that had empty print names. The new implementation
now parses substitute name of the reparse point and attempts to reconstruct
a Win32 path from it. (#187)
-
On Windows, file streams provided in
boost/filesystem/fstream.hpp
will use wide character paths on libc++ versions 7.0 and higher,
when the standard library supports opening files with wide character
paths. (#181)
-
On Windows, creating symlinks should no longer require elevated privileges,
if Windows is configured in Developer
mode.
-
With some compilers, global objects used internally in Boost.Filesystem
are now destroyed after user's global destructors are called. This
allows to call Boost.Filesystem methods during the program termination
stage. In particular, this concerns the path locale that is used
for character code conversion and can be installed by calling
path::imbue. The supported compilers
include MSVC, GCC and Clang, as well as other compilers that support
customizing program initialization order through #pragma
section (for MSVC-compatible
compilers) or __attribute__
((init_priority)) (for GCC-compatible compilers).
-
Geometry:
-
Improvements
-
PR#812 Umbrella strategies for distance and comparable_distance
(undocumented for now).
-
PR#840 Umbrella strategies for various algorithms
(undocumented for now).
-
PR#850 Introduced DynamicGeometry and GeometryCollection
concepts and support in some algorithms (undocumented for now).
-
PR#855 Various improvements related to strategies.
Default strategies are now included with algorithms.
-
Solved issues
-
#865 Exception thrown in rtree serialization.
-
#439 Invalid box spherical area computation.
-
#838 Invalid result of union_().
-
#851 Invalid geographic disjoint segment/box result.
-
#861 Invalid result of intersection().
-
Bugfixes
-
PR#832 Fixed box spherical and geographic area computation.
-
PR#853 Fixed geographic disjoint segment/box.
-
PR#866 Fixed serialization of rtree containing lesser
number of elements in root node than minimum.
-
PR#886 Fixed knn rtree query bug causing it to be
slow for big k.
-
Various fixes in set operations and buffer.
-
JSON:
-
value_to supports
TupleLike types.
-
value_to and value_from support std::array and similar types.
-
Implicit conversion operator from
string
to std::string_view.
-
std::hash specializations for json types.
-
Fixed allocation errors in
object
and key_value_pair.
-
Fixed crash when constructing
array
from a pair of iterators that form an empty range.
-
LexicalCast:
-
Fixed assignment to an int of a floating point value that is out
of representable range for int.
-
Started using GithubActions CI for additional testing
-
Log:
-
Fixed compilation for riscv32 target. (PR#150)
-
Mp11:
-
Added
mp_intersperse,
mp_split, mp_join
-
Multi-index Containers:
-
Nowide:
-
Allow for usage of
iostream
classes before main
(best effort, works for most environments)
-
Fix initialization of
rdbuf
in cin/cout/cerr for redirected input/output
-
Fix corner case in
cin::unget() after using putback()
-
Fix possibly delayed
close
of filebuf after
move assignment
-
Improve performance of
utf8_codecvt
-
PFR:
-
A MurMur Hash based implementation of hash_combine() is now used
to reduce collisions count and improve quality of
boost::pfr::hash_value()
-
Visual Studio 2017 now supported in C++14 mode (thanks to Denis Mikhailov
aka @denzor200)
-
Issues found by inspect tool were fixed
-
Fixed some warnings, including removal of extra semicolons in include/boost/pfr/detail/fields_count.hpp
(#72)
-
Added a compile time assert for inherited types (thanks to Denis
Mikhailov aka @denzor200)
-
Reflection of aggregates with non movable fields is now possible
if guaranteed copy elision is on
-
Fixed spelling issues
-
Started using GithubActions CI for additional testing
-
PropertyTree:
-
This is a maintenance release.
-
Extend compiler coverage in CI.
-
Fix Boost compatibility for CMakeLists.txt.
-
System:
-
The conversion operator from
error_category
to std::error_category has been improved
and no longer requires <map>
or <mutex>.
-
The comparison operators of
error_category
are now inline friends instead of member functions (a side effect
of the previous change.)
-
error_condition now
defers calling generic_category() to avoid instantiating the object
until it's actually needed.
-
error_condition::failed and error_condition::message
have been undeprecated, and operator
bool()
now once again returns failed().
-
The system category now doesn't call
generic_category(), to avoid instantiating the object.
-
The return value of
default_error_condition
changes in some cases into an error_condition
from the generic category, instead of from the system category. This
happens on POSIX when the input error_code
is from the system category and does not correspond to any errc_t value.
-
The interoperability of
error_code
and std::error_code has been improved substantially.
It is now possible to construct boost::system::error_code
from std::error_code, and it's possible to
pass boost::system::error_code to functions taking
std::error_code&.
-
A stream insertion operator for
error_condition
has been added.
-
Uuid:
-
Added
to_chars for
writing uuid strings without allocating (PR#116)
Updated Tools
Compilers Tested
Boost's primary test compilers are:
-
Linux:
-
Clang: 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 12.0.0
-
Clang, C++11: 3.4, 11.0.0
-
Clang, C++14: 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 5.0, 12.0.0
-
Clang, C++17: 6.0.1, 7.0.0, 8.0.0, 9.0.0, 10.0.0, 11.0.0, 12.0.0
-
Clang, C++20: 11.0.0, 12.0.0, 13.0.0
-
GCC: 4.6.3, 11
-
GCC, C++11: 4.7.3, 4.8.5, 11
-
GCC, C++14: 5.4.0, 6.4.0, 7.3.0, 8.0.1, 9.1.0, 11
-
GCC, C++17: 7.3.0, 8.0.1, 9.1.0, 11
-
GCC, C++20: 8.0.1, 9.1.0, 10, 11
-
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
Acknowledgements
Marshall Clow, Michael Caisse and Glen Fernandes managed this release.
