感谢您的帮助——这个问题的变体已经被问过很多次,但我还没有找到完整的答案。我正在使用 MS MFC 类将嵌入式 Python 3.4.2 添加到用 C++ 编写的现有模拟器工具中。该应用程序是多线程的,以便用户可以执行Python脚本并与模拟器系统交互。
怎样才能成功退出呢?
我是否以正确的顺序使用 GIL 和线程状态命令?
我是否提前结束了Python解释器线程并破坏了Python线程合并机制?
我的问题是,当我调用 Py_Finalize 时,它调用 wait_for_thread_shutdown,然后调用 PyThreadState_Get,并遇到致命错误“PyThreadState_Get:没有当前线程”。根据检测到致命错误的点,它似乎与多线程嵌入式 Python 应用程序末尾的线程合并有关。
我已经浓缩了我的代码以使其更加清晰并消除了任何看起来不相关的内容。如果我走得太远或不够远,我深表歉意。主线程初始化并完成Python。
BOOL CSimApp::InitInstance()
{
...
// Initialize command table for appl. object and for documents
int iReturn = PyImport_AppendInittab("sim", &PyInit_SimApp);
iReturn = PyImport_AppendInittab("sim_doc", &PyInit_SimDoc);
// Initialize Python and prepar to create threads
_pHInstance = new CPyInstance();
...
}
int CSimApp::ExitInstance()
{
...
if (_pHInstance) {
delete _pHInstance;
_pHInstance = NULL;
}
...
}
我使用实用程序类来创建 Python 实例 (CPyInstance) 并管理 Python GIL (ACQUIRE_PY_GIL)。当应用程序初始化时,还会创建 CPyInstance 的实例。 CPyInstance 类初始化并完成 Python 线程管理。 Python 全局锁管理是通过 ACQUIRE_PY_GIL 和 RELEASE_PY_GIL 结构完成的。
class CPyInstance
{
public:
CPyInstance();
~CPyInstance();
static PyThreadState * mainThreadState;
};
inline CPyInstance::CPyInstance()
{
mainThreadState = NULL;
Py_Initialize();
PyEval_InitThreads();
mainThreadState = PyThreadState_Get();
PyEval_ReleaseLock();
}
inline CPyInstance::~CPyInstance()
{
Py_Finalize();
}
static CPyInstance *_pHInstance = NULL;
int PyExit()
{
if (_pHInstance) {
delete _pHInstance;
_pHInstance = NULL;
}
return 0;
}
struct ACQUIRE_PY_GIL {
PyGILState_STATE state;
ACQUIRE_PY_GIL() { state = PyGILState_Ensure(); }
~ACQUIRE_PY_GIL() { PyGILState_Release(state); }
};
struct RELEASE_PY_GIL {
PyThreadState *state;
RELEASE_PY_GIL() { state = PyEval_SaveThread(); }
~RELEASE_PY_GIL() { PyEval_RestoreThread(state); }
};
Python 解释器线程是为了响应 CMainFrame 窗口处理的 Windows 消息而创建的。 Python 线程和解释器响应用户命令而运行。当用户完成解释器 (Control-Z) 时,解释器退出,线程清除并删除 Python 线程状态,然后线程自行终止。
void CMainFrame::OnOpenPythonInterpreter()
{
// Create PyThread thread
m_pPyThread = (CPyThread*)AfxBeginThread(RUNTIME_CLASS(CPyThread),
THREAD_PRIORITY_BELOW_NORMAL,0, CREATE_SUSPENDED);
CMainFrame* mf = (CMainFrame*)theApp.m_pMainWnd;
m_pPyThread->SetOwner(this,((CWnd*)mf)->GetSafeHwnd());
m_pPyThread->CreateLocks(&m_PyThreadEvent,&m_PyThreadBusyMutex);
m_pPyThread->ResumeThread();
}
CPyThread类实际上调用了Python解释器。当解释器返回时,GIL 被释放,Python 线程状态被清除和删除。线程响应 PostQuitMessage 而终止。
int CPyThread::Run()
{
PyEval_AcquireLock();
PyInterpreterState * mainInterpreterState = CPyInstance::mainThreadState->interp;
PyThreadState * myThreadState = PyThreadState_New(mainInterpreterState);
PyEval_ReleaseLock();
try {
ACQUIRE_PY_GIL lock;
FILE* fp1 = stdin;
char *filename = "Embedded";
PyRun_InteractiveLoop(fp1, filename);
} catch(const std::exception &e) {
safe_cout << "Exception in PyRun_InteractiveLoop: " << e.what() << "\n";
} catch(...) {
std::cout << "Exception in Python code: UNKNOWN\n";
}
PyThreadState_Clear(myThreadState);
PyThreadState_Delete(myThreadState);
::PostQuitMessage(0);
return 0;
}
int CPyThread::ExitInstance()
{
return CWinThread::ExitInstance();
}
根据“user4815162342”的建议,我修改了 ~CPyInstance() 析构函数以在调用 Py_Finalize() 之前获取 GIL。现在我的应用程序似乎可以正常退出,谢谢。
inline CPyInstance::~CPyInstance()
{
try {
PyGILState_STATE state = PyGILState_Ensure();
Py_Finalize();
} catch(const std::exception &e) {
safe_cout << "Exception in ~CPyInstance(): " << e.what() << "\n";
} catch(...) {
std::cout << "Exception in Python code: UNKNOWN\n";
}
}