Hi! I think I've found the bug, but I need to confirm this behavior.
My findings is that if you use PyEval_InitThreads(), it is crucial to release the GIL with PyEval_ReleaseThread() afterwards. The API docs states that you can release the GIL with PyEval_ReleaseLock() or PyEval_ReleaseThread() AFAICS. http://docs.python.org/api/threads.html under docs of void PyEval_InitThreads(). However, if I do use PyEval_ReleaseLock() it will crash shortly after with "Fatal Python error: ceval: tstate mix-up" in a multithreaded C environment. If I use PyEval_ReleaseThread() to release the GIL, my app seems stable. I release the GIL like this: PyThreadState *pts = PyGILState_GetThisThreadState(); PyEval_ReleaseThread(pts); Now, is this a feature or expected behavior in python (i.e. unclear API documentation), or is this a bug in python itself? Regards, Svein PS: For reference I did something like this in pseudo-code: Py_Initialize(); PyEval_InitThreads(); other_py_inits(); // Load py modules, etc. PyEval_ReleaseLock(); // <-- MAKES THE APP UNSTABLE create_c_thread(); PyGILState_STATE gstate; gstate = PyGILState_Ensure(); call_py_function_main(); // Py main() wont return PyGILState_Release(gstate); And the "main" of the C thread function looks like this: while(1) { PyGILState_STATE gstate; gstate = PyGILState_Ensure(); call_py_function_send(); PyGILState_Release(gstate); } -- http://mail.python.org/mailman/listinfo/python-list
