[Bug libstdc++/108836] std::mutex disappears in single-threaded libstdc++ builds

[pdimov at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108836

--- Comment #4 from Peter Dimov  ---
A compromise between no mutex at all, and a mutex that is silently a no-op,
could be a no-op mutex with [[deprecated]] members, although the atomic_flag is
probably better.

[Bug libstdc++/108836] std::mutex disappears in single-threaded libstdc++ builds

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108836

--- Comment #3 from Jonathan Wakely  ---
Whatever we do it won't help them, as they're using libstdc++ headers from gcc
6.3

It's possible to have a gcc build that has limited support for threading, but
not enough to support C++11 std::mutex, std::thread etc and in such cases it
would be odd to have a no-op mutex. Another option might be to provide a very
dumb mutex using atomic_flag for a spin lock.

[Bug libstdc++/108836] std::mutex disappears in single-threaded libstdc++ builds

[pdimov at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108836

--- Comment #2 from Peter Dimov  ---
That's good to hear, but I don't think the issue is specific to mingw32. The
other report, https://github.com/boostorg/system/issues/92, was about "B
PLC", whatever this means. :-)

[Bug libstdc++/108836] std::mutex disappears in single-threaded libstdc++ builds

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108836

--- Comment #1 from Andrew Pinski  ---
mingw32 is no longer defaults to a single threaded and std::mutex is supported
there on the trunk for GCC 13