I'm getting an error output when I call the C-API's Py_Finalize() from a
different C-thread than I made a python call on.
The error I'm seeing is:
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:
Here's a minimal example that shows it happening when a C-thread is used, but
not when everything happens on a single c-thread:
----------main.cpp--------------
#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;
}
----------main.cpp--------------
----------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--
----------output----------
The order of the basic()/with_thread() calls in main does not matter, I can
even include those lines multiple times with no affect, each with_thread() call
results in the error output.
Thanks,
Tom Kent
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