STINNER Victor added the comment: > The complication is that the return values of spawn*() etc are process > handles (cast to intptr_t), not pids:
I opened this issue because of a compiler warning in os.waitpid(). On Windows, the C function _cwait() is used and it expects a intptr_t ("handle to the process to wait on") and returns a intptr_t ("returns the handle of the specified process").... But os.waitpid() uses PyLong_FromPid() to convert the C intptr_t to a Python int, which may loose most significant bits (sizeof(void*) > sizeof(int) on Windows x64). I see that PC/pyconfig.h defines "typedef int pid_t;". Because intptr_t is bigger than int, using intptr_t is compatible with pid_t, at least for PyLong_FromPid(). It may be a problem in the other direction: PyLong_AsPid(). Python code using Windows HANDLE is not consistent. Sometimes, intptr_t is used, sometimes long is used. Examples: - msvcrt.open_osfhandle() parses an handle with "l" (long) format, whereas it should uses a wider type. - msvcrt.get_osfhandle() uses PyLong_FromVoidPtr() to convert an C Py_intptr_t to a Python int, with the following comment: /* technically 'handle' is not a pointer, but a integer as large as a pointer, Python's *VoidPtr interface is the most appropriate here */ -- @sbt: Would you like to have a strict separation between UNIX-like pid (pid_t) and Windows process identifier (HANDLE)? Can we consider that HANDLE is a pointer? Or can we consider that HANDLE is intptr_t or intmax_t? See the issue #17870 which proposes an API to handle intmax_t. If we want to be more explicit, we should add functions to handle the C HANDLE type. Example: - PyLong_FromHandle(): C HANDLE to Python int - PyLong_AsHandle(): Python int to C HANDLE - "P" format (or another letter): PyArg_Parse*() format ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue17931> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com