Re: Right way to initialize python embedded in a multi-threaded application
Hi, Maybe you already fixed the issue, but for the record, I've got the same problem and finally it turned out that I was calling PyEval_InitThreads twice and also after fixing that, I also had to move the call to PyEval_ReleaseLock(); at the end of the entire initialization (not just after PyEval_initThreads). The key thing there is to follow: at initialization thread Py_Initialize (); PyEval_InitThreads(); /* now call here to initialize all python code by loading external files or internal module loading (i.e. Py_InitModule3) */ /* ..and now, once no more Python C/API call is required, release the GIL so other threads can come into play */ PyEval_ReleaseLock (); and now, from other threads, use /* wait til gil acquired */ state = PyGILState_Ensure(); /* your code */ /* release GIL */ PyGILState_Release (state); Hope it helps, Cheers! I'm embedding python in a multi-threaded C application. I've taken care to wrap every call to the Python C API with gstate = PyGILState_Ensure(); // call python code PyGILState_Release(gstate); But I'm stumped with what to do in the initialization. Right after the call to Py_IsInitialized() I've added a call: PyEval_InitThreads(); The docs say that this function leaves the GIL locked when it returns. I do some more initializations like importing modules and then I call PyEval_ReleaseLock(); This seems to cause a problem since not long after a call to PyGILState_Release(gstate) that's made in a different thread crashes. with Fatal Python error: This thread state must be current when releasing If I don't do the call to PyEval_ReleaseLock() in the main thread right after initialization, the GIL seems to be released after the first PyGILState_Ensure() - PyGILState_Release() pair. So what am I doing wrong here? What is the correct way of initializing a multi-threaded application? -- http://mail.python.org/mailman/listinfo/python-list
Re: Right way to initialize python embedded in a multi-threaded application
Just clarify there's no problem about calling twice to PyEval_InitThreads () as indicated by Python's doc. Hi, Maybe you already fixed the issue, but for the record, I've got the same problem and finally it turned out that I was calling PyEval_InitThreads twice and also after fixing that, I also had to move the call to PyEval_ReleaseLock(); at the end of the entire initialization (not just after PyEval_initThreads). The key thing there is to follow: at initialization thread Py_Initialize (); PyEval_InitThreads(); /* now call here to initialize all python code by loading external files or internal module loading (i.e. Py_InitModule3) */ /* ..and now, once no more Python C/API call is required, release the GIL so other threads can come into play */ PyEval_ReleaseLock (); and now, from other threads, use /* wait til gil acquired */ state = PyGILState_Ensure(); /* your code */ /* release GIL */ PyGILState_Release (state); Hope it helps, Cheers! I'm embedding python in a multi-threaded C application. I've taken care to wrap every call to the Python C API with gstate = PyGILState_Ensure(); // call python code PyGILState_Release(gstate); But I'm stumped with what to do in the initialization. Right after the call to Py_IsInitialized() I've added a call: PyEval_InitThreads(); The docs say that this function leaves the GIL locked when it returns. I do some more initializations like importing modules and then I call PyEval_ReleaseLock(); This seems to cause a problem since not long after a call to PyGILState_Release(gstate) that's made in a different thread crashes. with Fatal Python error: This thread state must be current when releasing If I don't do the call to PyEval_ReleaseLock() in the main thread right after initialization, the GIL seems to be released after the first PyGILState_Ensure() - PyGILState_Release() pair. So what am I doing wrong here? What is the correct way of initializing a multi-threaded application? -- http://mail.python.org/mailman/listinfo/python-list
Right way to initialize python embedded in a multi-threaded application
I'm embedding python in a multi-threaded C application. I've taken care to wrap every call to the Python C API with gstate = PyGILState_Ensure(); // call python code PyGILState_Release(gstate); But I'm stumped with what to do in the initialization. Right after the call to Py_IsInitialized() I've added a call: PyEval_InitThreads(); The docs say that this function leaves the GIL locked when it returns. I do some more initializations like importing modules and then I call PyEval_ReleaseLock(); This seems to cause a problem since not long after a call to PyGILState_Release(gstate) that's made in a different thread crashes. with Fatal Python error: This thread state must be current when releasing If I don't do the call to PyEval_ReleaseLock() in the main thread right after initialization, the GIL seems to be released after the first PyGILState_Ensure() - PyGILState_Release() pair. So what am I doing wrong here? What is the correct way of initializing a multi-threaded application? -- http://mail.python.org/mailman/listinfo/python-list
Re: Right way to initialize python embedded in a multi-threaded application
On 17/05/2012 10:08 PM, shooshx wrote: I'm embedding python in a multi-threaded C application. I've taken care to wrap every call to the Python C API with gstate = PyGILState_Ensure(); // call python code PyGILState_Release(gstate); But I'm stumped with what to do in the initialization. Right after the call to Py_IsInitialized() I've added a call: PyEval_InitThreads(); The docs say that this function leaves the GIL locked when it returns. I do some more initializations like importing modules and then I call PyEval_ReleaseLock(); This seems to cause a problem since not long after a call to PyGILState_Release(gstate) that's made in a different thread crashes. with Fatal Python error: This thread state must be current when releasing If I don't do the call to PyEval_ReleaseLock() in the main thread right after initialization, the GIL seems to be released after the first PyGILState_Ensure() - PyGILState_Release() pair. So what am I doing wrong here? What is the correct way of initializing a multi-threaded application? Try replacing the PyEval_ReleaseLock() call with PyEval_SaveThread(); - that works for pythoncom, which has the same basic requirement - see http://pywin32.hg.sourceforge.net/hgweb/pywin32/pywin32/raw-file/b8c62cf04c5a/com/win32com/src/dllmain.cpp for how it works. HTH, Mark -- http://mail.python.org/mailman/listinfo/python-list
