C++11 std::mutex in Visual Studio 2012 deadlock when locked from DllMain()

Question

I am seeing a deadlock with std::mutex when the mutex is locked from DllMain() Below is a minimal DLL test case that exhibits the problem for me. M

Answer 1

It seems that using QueueUserAPC() to queue initialization is always executed before main() but out of the dreaded loader lock. This looks like a solution to my problem.

EDIT 1

After some testing it seems that the APC method works if I queue the APC from DllMain() but it does not work if I queue the APC from a ctor of a static global instance of a class. IOW, using the APC is not uniformly usable across all possible combinations of compilers and build modes for me.

Answer 2

Check the Best Practices for Creating DLLs document:

You should never perform the following tasks from within DllMain:

• Call LoadLibrary or LoadLibraryEx (either directly or indirectly). This can cause a deadlock or a crash.
• Synchronize with other threads. This can cause a deadlock.