Message 71135 - Python tracker
in Lib/ctypes/__init__.py the wstring_at and string_at functions are declared with CFUNCTYPE. This means that in Modules/_ctypes/callproc.c when the functions are invoked, Py_UNBLOCK_THREADS and Py_BLOCK_THREADS surround the call. But string_at and wstring_at call PyString_FromString and PyUnicode_FromWideChar, respectively. The solution (I think) is to declare the functions with PYFUNCTYPE instead, so that callproc.c doesn't release the GIL when calling them.