C++11 concurrency bug since update 3 ?

Question

Hey,

I am using c++11 threading libraries with visual studio 2012 ( phone and windows 8 ) editions. Ever since I installed update 3 all my programs started crashing periodically. After few hours of investigating I came to the conclusion that connect bug 762560 is back. The forum doesn't allow me to post the actual link, but basically std::condition_variable::wait_for crashes at random moments. The following code reproduces it:

// Concurrency bug in Microsoft Visual C++ 2011

#include <mutex>
#include <thread>
#include <condition_variable>
#include <vector>

struct WaitForConditionInThreads
{
	std::mutex mutex;
	std::condition_variable condition;

	void run(int threads)
	{
		std::vector<std::thread> thread_pool(threads);
		for(auto & i : thread_pool)
			i = std::thread(&WaitForConditionInThreads::thread_fn, this);
		for(auto & i : thread_pool)
			i.join();
	}

	void thread_fn()
	{
		int count=100;
		std::unique_lock<std::mutex> lock(mutex);
		while(count--)
			condition.wait_for(lock, std::chrono::milliseconds(1));
		condition.notify_one();
	}
};

int main()
{
	WaitForConditionInThreads w;
	for(;;) w.run(16);
}

Can anyone confirm it? Also if that's the case whats the alternative? Good ol' WaitForSingleObject and similar can't be used in RT (right?) so what should I do? Revert to update 2?

Thanks.

Answer 1

Thanks Kenny,

It looks like this was already reported and will be fixed in VS 2013 (possibly already available in the preview): http://connect.microsoft.com/VisualStudio/feedback/details/792653/crash-in-runtime-library-msvcr110-dll

You can use WaitForSingleObjectEx in Windows Store apps. See the docs at http://msdn.microsoft.com/en-us/library/windows/apps/ms687036(v=vs.85).aspx

--Rob

Answer 2

Thanks Rob!

Didn't know 'Ex version of Win API functions can be used in RT/Phone, I guess that's the way to go ( well, that or Microsoft not breaking STL ). I can't understand how come it is decided the bug not to be fixed in visual studio 2012, spending several hundred bugs on a product you'd expect it to work. Oh well, I am using express version so I am not the one to complain here.

Thanks again for the Ex version hint.