gh-108765: Python.h no longer includes <unistd.h> #108783
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I merged my PR. If it causes too many trouble in 3rd party C extensions (require to update too many C extensions before Python 3.13 beta1), I can make this change conditional only in the limited C API version 3.13, as I did for other headers in I consider that |
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breaks signalmodule.c |
Would you mind to elaborate your comment "a little bit"? What is broken? Is it a build issue? On which Python version? On which OS (name, version) and compiler (name, version)? |
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signalmodule.c calls pause() and alarm() (under #ifdef HAVE_{PAUSE,ALARM} guards), which are defined in unistd.h On the Python version where you deleted unistd.h from Python.h, of course. |
Hum, in fact, <unistd.h> is included indirectly by pycore_pythread.h. But well, I wrote PR #111402 to make it extra clear. |
Which is not necessarily included when signalmodule.c is compiled ... it wasn't in my build. (Which I've abandoned ... I never actually intended to build the top of tree.)
Seems like the right thing to do. |
You didn't reply to my question about OS and compiler... Also, pycore_pythread.h was modified recently. |
This fixes the following compilation error with Python 3.13.0a1:
```
c-ext/backend_c.c:275:13: error: implicit declaration of function ‘sysconf’; did you mean ‘sscanf’? [-Werror=implicit-function-declaration]
275 | count = sysconf(_SC_NPROCESSORS_ONLN);
| ^~~~~~~
| sscanf
```
According to https://docs.python.org/3.13/whatsnew/3.13.html:
Python.h no longer includes the <unistd.h> standard header file.
If needed, it should now be included explicitly.
For example, it provides the functions: read(), write(), close(), isatty(), lseek(), getpid(), getcwd(), sysconf() and getpagesize().
As a consequence, _POSIX_SEMAPHORES and _POSIX_THREADS macros are no longer defined by Python.h.
The HAVE_UNISTD_H and HAVE_PTHREAD_H macros defined by Python.h can be used to decide if <unistd.h> and <pthread.h> header files can be included.
See python/cpython#108783 .
This fixes the following compilation error with Python 3.13.0a1:
```
c-ext/backend_c.c:275:13: error: implicit declaration of function ‘sysconf’; did you mean ‘sscanf’? [-Werror=implicit-function-declaration]
275 | count = sysconf(_SC_NPROCESSORS_ONLN);
| ^~~~~~~
| sscanf
```
According to https://docs.python.org/3.13/whatsnew/3.13.html:
Python.h no longer includes the <unistd.h> standard header file.
If needed, it should now be included explicitly.
For example, it provides the functions: read(), write(), close(), isatty(), lseek(), getpid(), getcwd(), sysconf() and getpagesize().
As a consequence, _POSIX_SEMAPHORES and _POSIX_THREADS macros are no longer defined by Python.h.
The HAVE_UNISTD_H and HAVE_PTHREAD_H macros defined by Python.h can be used to decide if <unistd.h> and <pthread.h> header files can be included.
See python/cpython#108783 .
📚 Documentation preview 📚: https://cpython-previews--108783.org.readthedocs.build/