当我从与 python 调用不同的 C 线程调用 C-API 的 Py_Finalize() 时,我收到错误输出。
我看到的错误是:
Exception ignored in: <module 'threading' from 'C:\\Python34-32\\Lib\\threading.py'>
Traceback (most recent call last):
File "C:\Python34-32\Lib\threading.py", line 1289, in _shutdown
assert tlock.locked()
AssertionError:
这只发生在 Python 3.X 中(使用 3.4.2 测试),在 Python 2.7 中完全相同的代码没有任何问题。
下面是一个最小的示例,显示使用 C 线程时会发生这种情况,但当所有事情都发生在单个 C 线程上时则不会:
#include <iostream>
#include <fstream>
#include <thread>
#include <cassert>
#include <Python.h>
void make_file()
{
std::fstream file("my_test.py", std::ios::out);
file <<
"import threading\n" <<
"def my_function():\n" <<
" pass\n" ;
file.close();
}
void exec()
{
PyGILState_STATE gstate = PyGILState_Ensure();
PyObject* pdict = PyDict_New();
PyDict_SetItemString(pdict, "__builtins__", PyEval_GetBuiltins());
PyRun_String("import my_test", Py_file_input, pdict, pdict);
PyRun_String("my_test.my_function()", Py_file_input, pdict, pdict);
assert(!PyErr_Occurred());
PyGILState_Release(gstate);
}
void basic()
{
std::cout << "--Starting Basic--" << std::endl;
Py_Initialize();
PyEval_InitThreads();
PyThreadState* threadState = PyEval_SaveThread();
exec();
PyEval_RestoreThread(threadState);
Py_Finalize();
std::cout << "--Basic Complete--" << std::endl;
}
void with_thread()
{
std::cout << "--Starting With Thread--" << std::endl;
Py_Initialize();
PyEval_InitThreads();
PyThreadState* threadState = PyEval_SaveThread();
std::thread t(exec);
t.join();
PyEval_RestoreThread(threadState);
Py_Finalize();
std::cout << "--With Thread Complete--" << std::endl;
}
int main(int argc, char* argv[])
{
make_file();
basic();
with_thread();
return 0;
}
output
--Starting Basic--
--Basic Complete--
--Starting With Thread--
Exception ignored in: <module 'threading' from 'C:\\Python34-32\\Lib\\threading.py'>
Traceback (most recent call last):
File "C:\Python34-32\Lib\threading.py", line 1289, in _shutdown
assert tlock.locked()
AssertionError:
--With Thread Complete--
main 中 basic()/with_thread() 调用的顺序并不重要,我什至可以多次包含这些行而不会产生任何影响,每个 with_thread() 调用都会导致错误输出。
Edit :
使 threadState 全局化,然后将 exec 更改为:
void exec()
{
//PyGILState_STATE gstate = PyGILState_Ensure();
PyEval_RestoreThread(threadState);
PyObject* pdict = PyDict_New();
PyDict_SetItemString(pdict, "__builtins__", PyEval_GetBuiltins());
PyRun_String("import my_test", Py_file_input, pdict, pdict);
PyRun_String("my_test.my_function()", Py_file_input, pdict, pdict);
assert(!PyErr_Occurred());
//PyGILState_Release(gstate);
threadState = PyEval_SaveThread();
}
导致错误消失,但是我有一个全局值,我需要在我的库的用户之间进行协调(在我的实际代码中, exec() 函数可以由任何人编写,并且我有更多的初始化内容跑步)。关于如何使 GIL 抓取像原始示例一样更加隔离,同时保持线程兼容性,有什么见解吗?