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boostorg / thread

Boost.org thread module
http://boost.org/libs/thread
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is_mutex_type<recursive_mutex> is false if BOOST_NO_CXX11_SFINAE_EXPR is defined #370

Open jwakely opened 2 years ago

jwakely commented 2 years ago

This part of the old has_member_try_lock implementation fails to match recursive_mutex::try_lock() because it's noexcept:

https://github.com/boostorg/thread/blob/4abafccff4bdeb4b5ac516ff0c2bc7c0dad8bafb/include/boost/thread/lockable_traits.hpp#L143-L146

The bug is still there in the current code, but hidden by a35ffa3a83e6f74262d66feac66ef5b513c99745 which has a working version that is used by most compilers since Boost 1.69.0

A fix would be to add another partial specialization for noexcept functions:

#ifndef BOOST_NO_CXX11_NOEXCEPT
        template<typename U>
        static true_type has_member(bool (U::*)() noexcept);
#endif
jwakely commented 2 years ago

Demo of the bug in 1.66.0: https://godbolt.org/z/hnTrsceTv