[Bug libstdc++/103382] condition_variable::wait() is not cancellable because it is marked noexcept
cvs-commit at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Thu Dec 9 23:27:23 GMT 2021
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103382
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:
https://gcc.gnu.org/g:9e18a25331fa25c3907249fede65a02c6817b06e
commit r12-5877-g9e18a25331fa25c3907249fede65a02c6817b06e
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Tue Dec 7 15:11:15 2021 +0000
libstdc++: Allow std::condition_variable waits to be cancelled [PR103382]
std::condition_variable::wait(unique_lock<mutex>&) is incorrectly marked
noexcept, which means that the __forced_unwind exception used by NPTL
cancellation will terminate the process. It should allow exceptions to
pass through, so that a thread can be cleanly cancelled when waiting on
a condition variable.
The new behaviour is exported as a new version of the symbol, to avoid
an ABI break for existing code linked to the non-throwing definition of
the function. Code linked against older releases will have a reference
to the @GLIBCXX_3.4.11 version, andcode compiled against the new
libstdc++ will get a reference to the @@GLIBCXX_3.4.30 version.
libstdc++-v3/ChangeLog:
PR libstdc++/103382
* config/abi/pre/gnu.ver (GLIBCXX_3.4.11): Do not export old
symbol if .symver renaming is supported.
(GLIBCXX_3.4.30): Export new symbol if .symver renaming is
supported.
* doc/xml/manual/evolution.xml: Document change.
* doc/html/manual/api.html: Regenerate.
* include/bits/std_mutex.h (__condvar::wait,
__condvar::wait_until):
Remove noexcept.
* include/std/condition_variable (condition_variable::wait):
Likewise.
* src/c++11/condition_variable.cc (condition_variable::wait):
Likewise.
* src/c++11/compatibility-condvar.cc (__nothrow_wait_cv::wait):
Define nothrow wrapper around std::condition_variable::wait and
export the old symbol as an alias to it.
* testsuite/30_threads/condition_variable/members/103382.cc: New
test.
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