There was a lot of work done on that in the C11 release with updates to the memory model and thread.h. I have heard some criticisms of thread.h APIs which could

There was a lot of work done on that in the C11 release with updates to the memory model and thread.h. I have heard some criticisms of thread.h APIs which could be addressed, such as the ability to specify stack size. There are C++2x proposals to add a green thread/goroutine style mechanism. I'm not convinced that it's something which belongs in the C core language or C standard library though.