_endthreadex(0) hangs

Question

I have some code which I did not originally create that uses _beginthreadex and _endthreadex. For some reason, when it calls _endthreadex(0), the call just hangs and never returns. Any ideas as to what would normally cause this call to hang?

Answer 1

_endthreadex ends the thread, so it can't return. That's the whole point of calling it.

EDIT: It's a bit unusual to call _endthreadex, normally you just let the thread start procedure return and the runtime calls _endthreadex for you. You may need to explain a bit more, what you are trying to do before we can help.

Answer 2

Ok....well, endthreadex gets called in the deconstructor of my class via "delete classinstance"...and that deconstructor call never returns...so the whole thing hangs

Answer 3

Are you mistakenly calling _endthreadex() to attempt to end a thread from the main thread?

The function _endthreadex() is meant to be called inside the thread that you want to terminate to report a return value, and for the proper "recovery of resources allocated for the thread." You shouldn't need to call it in a destructor from the main thread. You could, in a destructor, signal to the thread via an event (see SetEvent, called from the main thread) that the thread should exit as soon as possible, and then the thread that is exiting as its last statement would call _endthreadex().

Calling _endthreadex() in your main thread would cause the process to hang, because you've terminated your main thread, but you would still have the original thread you wanted to terminate still running.