xlock.cpp: Should _Lock_at_thread_exit_mutex() be noexcept?

[StephanTLavavej]

_Lock_at_thread_exit_mutex() and _Unlock_at_thread_exit_mutex() are separately compiled, but aren't used outside the STL's DLL (or static LIB):

STL/stl/src/xlock.cpp

Lines 123 to 129 in f9b1dcc

	extern "C" void _Lock_at_thread_exit_mutex() { // lock the at-thread-exit mutex
	_Mtxlock(&mtx[_LOCK_AT_THREAD_EXIT]);
	}
	extern "C" void _Unlock_at_thread_exit_mutex() { // unlock the at-thread-exit mutex
	_Mtxunlock(&mtx[_LOCK_AT_THREAD_EXIT]);
	}

STL/stl/src/xnotify.cpp

Lines 31 to 34 in f9b1dcc

	_EXTERN_C
	void _Lock_at_thread_exit_mutex();
	void _Unlock_at_thread_exit_mutex();

Since they aren't exported, I believe that it would be safe (i.e. binary-compatible) to mark them as noexcept, and give them C++ linkage.

It's also possible that there's no point in doing so; because they're extern "C" and we compile with /EHsc, they should already be treated as noexcept.

[BillyONeal]

No, they should be deleted :)

[StephanTLavavej]

For vNext, or can that be done in v19?

[BillyONeal]

If they aren't exported should be doable in v19.

[StephanTLavavej]

What would deletion involve? (i.e. what additional code would be necessary to replace this mechanism?)

[BillyONeal]

Would probably hook it into the existing locale lock system. Even just moving this stuff into the one .cpp where it's currently used would be an improvement.

[StephanTLavavej]

#4106 actually made them noexcept.