When I ran the code in #6869 (msg95444) on py3k, I noticed
Fatal Python error occurs.

# Actually, I need to copy created executable file into
# PC/VC6 directoly where python32_d.dll exists. Otherwise,
# the error "encoding.utf-8 was not found" occured even if
# PC/VC6 was added to environment variable PATH. But probably
# it is another issue.

E:\python-dev\py3k\PC\VC6>foo
--- 0 ---
[34859 refs]
--- 1 ---
Fatal Python error: drop_gil: wrong thread state

... And here is stacktrace.

_NMSG_WRITE(int 10) line 221
abort() line 44 + 7 bytes
Py_FatalError(const char * 0x1e371878) line 2109
drop_gil(_ts * 0x00920d90) line 321 + 10 bytes
PyEval_SaveThread() line 424 + 6 bytes
0012ff30()
PyCFunction_Call(_object * 0x00b99378, _object * 0x00afcc40, _object * 0x00000000) line 89 + 9 bytes
PyObject_Call(_object * 0x00b99378, _object * 0x00afcc40, _object * 0x00000000) line 2149 + 15 bytes
call_function_tail(_object * 0x00b99378, _object * 0x00afcc40) line 2181 + 15 bytes
_PyObject_CallMethod_SizeT(_object * 0x00bf6838, char * 0x1e332898, char * 0x00000000) line 2297 + 13 bytes
io_open(_object * 0x00c17f78, _object * 0x00ae0f88, _object * 0x00000000) line 423 + 16 bytes
PyCFunction_Call(_object * 0x00b0cab8, _object * 0x00ae0f88, _object * 0x00000000) line 84 + 15 bytes
PyObject_Call(_object * 0x00b0cab8, _object * 0x00ae0f88, _object * 0x00000000) line 2149 + 15 bytes
call_function_tail(_object * 0x00b0cab8, _object * 0x00ae0f88) line 2181 + 15 bytes
PyObject_CallMethod(_object * 0x00bf6138, char * 0x1e3d6abc, char * 0x1e3d6ab4) line 2258 + 13 bytes
create_stdio(_object * 0x00bf6138, int 0, int 0, char * 0x1e3d6968, char * 0x00000000, char * 0x00000000) line 808 + 48 bytes
initstdio() line 931 + 28 bytes
Py_InitializeEx(int 1) line 303 + 5 bytes
Py_Initialize() line 314 + 7 bytes
main() line 10 + 8 bytes
mainCRTStartup() line 206 + 25 bytes
KERNEL32! 77e789d5()

Because first run succeeded, Py_Finalize might not do enough
work to reset thread state, I guess.

I didn't try this on other platforms. (thread_nt.h was used here)