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thread.get_ident() should return unsigned value #50781

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sargo mannequin opened this issue Jul 21, 2009 · 12 comments
Closed

thread.get_ident() should return unsigned value #50781

sargo mannequin opened this issue Jul 21, 2009 · 12 comments
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3.7 extension-modules type-bug

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@sargo
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Mannequin

@sargo sargo mannequin commented Jul 21, 2009

BPO 6532
Nosy @gpshead, @amauryfa, @pitrou, @vstinner, @rnk, @serhiy-storchaka
PRs
  • #781
  • Files
  • thread_id_unsigned.patch
  • thread_id_unsigned_3.patch
  • thread_id_unsigned_4.patch
  • Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = 'https://github.com/serhiy-storchaka'
    closed_at = <Date 2017-03-24.17:22:55.071>
    created_at = <Date 2009-07-21.14:25:21.052>
    labels = ['extension-modules', 'type-bug', '3.7']
    title = 'thread.get_ident() should return unsigned value'
    updated_at = <Date 2017-03-24.17:22:55.070>
    user = 'https://bugs.python.org/sargo'

    bugs.python.org fields:

    activity = <Date 2017-03-24.17:22:55.070>
    actor = 'serhiy.storchaka'
    assignee = 'serhiy.storchaka'
    closed = True
    closed_date = <Date 2017-03-24.17:22:55.071>
    closer = 'serhiy.storchaka'
    components = ['Extension Modules']
    creation = <Date 2009-07-21.14:25:21.052>
    creator = 'sargo'
    dependencies = []
    files = ['28976', '38167', '38168']
    hgrepos = []
    issue_num = 6532
    keywords = ['patch']
    message_count = 12.0
    messages = ['90761', '112303', '125442', '125443', '125445', '181526', '181548', '236157', '236165', '236166', '236169', '290096']
    nosy_count = 7.0
    nosy_names = ['gregory.p.smith', 'amaury.forgeotdarc', 'pitrou', 'vstinner', 'rnk', 'sargo', 'serhiy.storchaka']
    pr_nums = ['781']
    priority = 'normal'
    resolution = 'fixed'
    stage = 'resolved'
    status = 'closed'
    superseder = None
    type = 'behavior'
    url = 'https://bugs.python.org/issue6532'
    versions = ['Python 3.7']

    @sargo
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    @sargo sargo mannequin commented Jul 21, 2009

    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, 2.6

    Proposal:
    In my opinion code that cast value returned by pthread_self() should be
    changed (see: Python/thread_pthread.h).

    Other possibility is to change only returned value by get_ident
    function. 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. If
    the same application uses some C library that also writes in log file
    some info with thread_id, in some situations this numbers are diffrent.
    This complicate logs analyze.

    @sargo sargo mannequin added the stdlib label Jul 21, 2009
    @BreamoreBoy
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    @BreamoreBoy BreamoreBoy mannequin commented Aug 1, 2010

    Can a C guru comment on this please.

    @BreamoreBoy BreamoreBoy mannequin added extension-modules type-bug and removed stdlib labels Aug 1, 2010
    @pitrou
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    @pitrou pitrou commented Jan 5, 2011

    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.

    @amauryfa
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    @amauryfa amauryfa commented Jan 5, 2011

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

    @pitrou
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    @pitrou pitrou commented Jan 5, 2011

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

    Oops, my bad.

    @serhiy-storchaka
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    @serhiy-storchaka serhiy-storchaka commented Feb 6, 2013

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

    @pitrou
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    @pitrou pitrou commented Feb 6, 2013

    You could add a test for it.

    @vstinner
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    @vstinner vstinner commented Feb 17, 2015

    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() in Python/traceback.c and this function already casts the thread identifier to an unsigned number ;-)

    @serhiy-storchaka
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    @serhiy-storchaka serhiy-storchaka commented Feb 18, 2015

    Here is updated patch. Added few tests.

    @vstinner
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    @vstinner vstinner commented Feb 18, 2015

    Here is updated patch. Added few tests.

    Cool. I sent a review.

    @serhiy-storchaka
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    @serhiy-storchaka serhiy-storchaka commented Feb 18, 2015

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

    @vstinner
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    @vstinner vstinner commented Mar 24, 2017

    New changeset aefa7eb by Victor Stinner (Serhiy Storchaka) in branch 'master':
    bpo-6532: Make the thread id an unsigned integer. (#781)
    aefa7eb

    @serhiy-storchaka serhiy-storchaka self-assigned this Mar 24, 2017
    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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