Use PAGE_SIZE macro instead of getpagesize() for macOS.

[doneria-anjali]

For issue 1791 (#1791)

[kainjow]

@doneria-anjali Can you try just adding #include <unistd.h>? getpagesize() should still be available AFAIK.

[kainjow]

I confirmed the include is all you need with this little hack:

echo "#include <unistd.h>" > /tmp/test.h
CFLAGS="-include /tmp/test.h" pip install psutil

[doneria-anjali]

Thanks for the help @kainjow. The installation works. But when I am trying to use the psutil module from python code, it throws error:

File "/Library/Python/2.7/site-packages/psutil/__init__.py", line 159, in <module>
    from . import _psosx as _psplatform
  File "/Library/Python/2.7/site-packages/psutil/_psosx.py", line 15, in <module>
    from . import _psutil_osx as cext
ImportError: dynamic module does not define init function (init_psutil_osx)

After googling up, it looks like psutil is built using python3 but I am trying to call it from python2. Is that the issue? If yes, how can it be worked around because I cannot migrate my script to py3 (not yet).

Without this little hack, it gives error. Shall I change the use of PAGE_SIZE to something else that works both compile time and runtime?

[doneria-anjali]

A friendly ping to follow up on this pull request. Thanks!

[giampaolo]

Hello. I currently don't have an OSX box to test against, but this error:

ImportError: dynamic module does not define init function (init_psutil_osx)

...seems unrelated by the introduction of #include <unistd.h>. Are you sure you didn't change something else or you accidentally messed up psutil installation? In this case (messed up psutil installation) I suggest to run make uninstall (a couple of times) and make clean first, then retry.
It seems to me using #include <unistd.h> + getpagesize() should be the way to go, because:

1. it is documented by Apple:
   https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/getpagesize.3.html
2. it is being used by cPython's resource.getpagesize(): https://github.com/python/cpython/blob/master/Modules/resource.c#L309-L325
3. in the unlikely event the OS/user changes the default page size, getpagesize() syscall is supposed to return an updated result, while PAGE_SIZE macro will not

Hope this helps.

[giampaolo]

In this case (messed up psutil installation) I suggest to run make uninstall (a couple of times) and make clean first, then retry.

Note: the Makefile uses python3 by default, so if you're on python 2 you actually want this instead:

make uninstall PYTHON=python
make uninstall PYTHON=python
make clean PYTHON=python

[ThiagoIze]

I can also confirm that adding #include <unistd.h> fixes the build. Can we have that committed please?

[giampaolo]

I proceeded by adding #include <unistd.h>. If this didn't work please reopen #1791.