Description

YvesDup

opened on Jun 5, 2026

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Bug report

Bug description:

Working from this #130913 PR, I recently needed to add this line #include <sys/sysctl.h> // sysctlbyname in a header file.

From CI, the check-c-globals.py tools failed with this message:

..... ..... /home/runner/work/cpython/cpython/Modules/_multiprocessing/semaphore_macosx.h:5:10: fatal error: sys/sysctl.h: No such file or directory
    5 | #include <sys/sysctl.h>  // sysctlbyname
      |          ^~~~~~~~~~~~~~
compilation terminated.
# requested file: </home/runner/work/cpython/cpython/Modules/_multiprocessing/semaphore_macosx.h>

See https://github.com/python/cpython/actions/runs/26958247530/job/79541476456?pr=130913#step:11:39 for complete logs

cc @ericsnowcurrently (As suggested in the documentation:)

CPython versions tested on:

3.16

Operating systems tested on:

macOS

Linked PRs

• gh-150948: Exclude macOS semaphore header from c-analyzer #151777

Activity

1. YvesDup

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Jun 5, 2026
2. StanFromIreland commented on Jun 5, 2026

   

   StanFromIreland

   on Jun 5, 2026 · Hidden as off-topic

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3. StanFromIreland

   added

   infraCI, GitHub Actions, buildbots, Dependabot, etc.CI, GitHub Actions, buildbots, Dependabot, etc.

   on Jun 5, 2026
4. YvesDup commented on Jun 5, 2026

   

   YvesDup

   on Jun 5, 2026

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   Occasionally the tool is unable to parse updated code.
   If this happens then add the file to the "EXCLUDED" list
   in Tools/c-analyzer/cpython/_parser.py and create a new
   issue for fixing the tool (and CC ericsnowcurrently
   on the issue).

   I guess if the PR is approved, this new file will be noted as excluded from the tool run.
5. YvesDup commented on Jun 5, 2026

   

   YvesDup

   on Jun 5, 2026

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   I added in Tools/c-analyzer/cpython/_parser.py the file that raises the error.

   # XXX Handle these.
   EXCLUDED = format_conf_lines([
       # macOS
       'Modules/_scproxy.c',              # SystemConfiguration/SystemConfiguration.h
       'Modules/_multiprocessing/semaphore_macosx.h',              # <sys/sysctl.h>
   
       # Windows
   

   I created a new branch with the change into the Tools/c-analyzer/cpython/_parser.py file but the "Check for unsupported C global variables" test is disabled - see https://github.com/YvesDup/cpython/actions/runs/27023166717/job/79756266970
6. zainnadeem786 commented on Jun 20, 2026

   

   zainnadeem786

   on Jun 20, 2026

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   Hi @StanFromIreland @YvesDup ,

   I'd like to work on this issue.

   I investigated the c-analyzer path and it appears that Modules/_multiprocessing/semaphore_macosx.h is being picked up by the analyzer through the generic Modules/**/*.h scan, but preprocessing fails on non-macOS CI because of the #include <sys/sysctl.h> dependency.

   From what I found, the existing approach for files that cannot be parsed cross-platform is to add them to the EXCLUDED list in Tools/c-analyzer/cpython/_parser.py. Similar platform-specific exclusions already exist for _scproxy.c, _winapi.c, and other OS-specific files.

   I plan to submit a small PR that adds Modules/_multiprocessing/semaphore_macosx.h to the macOS exclusion list, which appears to be consistent with the current c-analyzer guidance and existing exclusions.

   Please let me know if there is a preferred alternative approach.
7. StanFromIreland commented on Jun 20, 2026

   

   StanFromIreland

   on Jun 20, 2026

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   I'm sorry but I closed your PR, it is not necessary. Such changes should be done in #130913 instead.
8. zainnadeem786 commented on Jun 20, 2026

   

   zainnadeem786

   on Jun 20, 2026

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   @StanFromIreland Understood, thank you for the clarification. I'll follow up in #130913 instead.
9. YvesDup commented on Jun 21, 2026

   

   YvesDup

   on Jun 21, 2026 · Hidden as off-topic

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10. StanFromIreland commented on Jun 21, 2026

    

    StanFromIreland

    on Jun 21, 2026

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    Sorry @YvesDup, I'm not familiar with macOS things and I don't have access to a machine to test.
11. YvesDup commented on Jun 22, 2026

    

    YvesDup

    on Jun 22, 2026 · Hidden as off-topic

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12. YvesDup commented on Jun 22, 2026

    

    YvesDup

    on Jun 22, 2026

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    I confirm that this part of code is dedicated to macOS platform. The c-analyzer tool runs on linux where the <sys/sysctl.h> header has been deprecated for some time and no longer exists.
    So I think it makes sense to add semaphore_macosx.h into the file Tools/c-analyzer/cpython/_parser.py, as suggested below.
    I wish this is the right way to go about it.
    This modification will be add to the #130913 PR.
13. YvesDup commented on Jun 22, 2026

    

    YvesDup

    on Jun 22, 2026

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    I will close this issue as completed. No objection ?
14. StanFromIreland commented on Jun 22, 2026

    

    StanFromIreland

    on Jun 22, 2026

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    Since we don't need any action here, I agree we can close.

    Reacted by Duprat
15. StanFromIreland

    closed this as not plannedon Jun 22, 2026
16. YvesDup commented on Jun 22, 2026

    

    YvesDup

    on Jun 22, 2026

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    @StanFromIreland thank you for adding macOS team as #130913 reviewers

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