In glibc library (on linux) pthread_t is defined as:typedef unsigned long int pthread_t;But python thread module interprets this value as signed long. Reproduce:>>> import thread>>> thread.get_ident()In some cases it returns negative value.Checked in python 2.4, 2.5, 2.6Proposal:In my opinion code that cast value returned by pthread_self() should bechanged (see:Python/thread_pthread.h).Other possibility is to change only returned value by get_identfunction. In this case it should use PyLong_FromUnsignedLong (see:Modules/threadmodule.c).Background:logging module uses 'thread.get_ident()' to save thread_id in logs. Ifthe same application uses some C library that also writes in log filesome info with thread_id, in some situations this numbers are diffrent.This complicate logs analyze.

Can a C guru comment on this please.

Well, the issue is that signedness differs depending on the platform. Under Windows, thread ids are signed (DWORD). Satisfying all cases would complicate things quite a bit.

no, DWORD is a 32-bit unsigned integerhttp://msdn.microsoft.com/en-us/library/aa383751(VS.85).aspx

> no, DWORD is a 32-bit unsigned integer>http://msdn.microsoft.com/en-us/library/aa383751(VS.85).aspxOops, my bad.

Here is a patch, which made all thread id to be unsigned.

You could add a test for it.

On Linux, the following C program tells me that pthread_t is unsigned.---#include <pthread.h>#include <stdio.h>#define TYPE_IS_SIGNED(TYPE) ((TYPE)-1 < (TYPE)0)int main(){    printf("signed? %i\n", TYPE_IS_SIGNED(pthread_t));    return 0;}---So it's fair to modify threading.get_ident() to return an unsigned number.But I disagree to change stable Python versions, it may break applications.Oh, I wrote write_thread_id() inPython/traceback.c and this function already casts the thread identifier to an unsigned number ;-)

Here is updated patch. Added few tests.

> Here is updated patch. Added few tests.Cool. I sent a review.

Thank you Victor for your review. Here is updated patch.

New changesetaefa7ebf0ff0f73feee7ab24f4cdcb2014d83ee5 by Victor Stinner (Serhiy Storchaka) in branch 'master':bpo-6532: Make the thread id an unsigned integer. (#781)https://github.com/python/cpython/commit/aefa7ebf0ff0f73feee7ab24f4cdcb2014d83ee5