I am trying to run a python programme embedded from C++. I want to run the same python code concurrently in several threads. I read the manual on embedding, especially chapter 8, and searched for relevant info on google all afternoon, but I can't get this to work. What am I doing wrong? I use python2.4 and vc++7 (.net). The first thread seems to work okay, the 2nd thread crashes, but the exception information is not very useful: (An unhandled exception of type 'System.NullReferenceException' occurred in pyembed_test.exe
Additional information: Object reference not set to an instance of an object.) Here is a simplified example, it is heavily based on this article: http://www.codeproject.com/cpp/embedpython_1.asp #include <afxwin.h> #include <Python.h> #include <Windows.h> #include <process.h> #define USE_AFX 0 #if USE_AFX UINT MyThread(LPVOID lpParam) #else void MyThread(void* lpParam) #endif { Py_Initialize(); //#if 0 // PyEval_InitThreads(); PyThreadState *mainthreadstate = PyThreadState_Get(); PyInterpreterState *maininterpreterstate = mainthreadstate->interp; PyThreadState *mythreadstate = PyThreadState_New(maininterpreterstate); PyEval_ReleaseLock(); PyEval_AcquireLock(); PyThreadState *tmpstate = PyThreadState_Swap(mythreadstate); //#endif int* num = (int *)lpParam; int ret = 0; ret = PyRun_SimpleString("x = []"); ret = PyRun_SimpleString("for i in range(10):\n x.append(i)"); char cmd[100]; sprintf(cmd, "f = open('test%d.txt', 'w')", *num); ret = PyRun_SimpleString(cmd); ret = PyRun_SimpleString("f.write('%s' % x.__str__())"); ret = PyRun_SimpleString("f.close()"); //#if 0 PyThreadState_Swap(tmpstate); PyEval_ReleaseLock(); PyThreadState_Clear(mythreadstate); PyThreadState_Delete(mythreadstate); //#endif Py_Finalize(); #if USE_AFX return 0; #else _endthread(); #endif } class CMyWinApp : public CWinApp { public: CMyWinApp() { } BOOL InitInstance() { int num0 = 0, num1 = 1; HANDLE hnd0, hnd1; #if USE_AFX CWinThread* pThread0 = AfxBeginThread(MyThread, &num0); hnd0 = pThread0->m_hThread; CWinThread* pThread1 = AfxBeginThread(MyThread, &num1); hnd1 = pThread1->m_hThread; #else hnd0 = (HANDLE) _beginthread(MyThread, 0, &num0); hnd1 = (HANDLE) _beginthread(MyThread, 0, &num1); #endif // wait for the worker thread to terminate. WaitForSingleObject(hnd0, INFINITE); WaitForSingleObject(hnd1, INFINITE); return TRUE; }; }; CMyWinApp app; -- http://mail.python.org/mailman/listinfo/python-list
