[New-bugs-announce] [issue23652] ifdef uses of EPOLLxxx macros so we can compile on systems that don't have them

[Matt Frank]

New submission from Matt Frank:

With the LSB (Linux Standard Base) headers for libc Modules/selectmodule.c fails to compile because we have code that uses EPOLLRDNORM, EPOLLRDBAND, EPOLLWRNORM and EPOLLMSG without first checking that they are defined.

The patch wraps the five uses of PyModule_AddIntMacro in #ifdefs, following exactly the same pattern that is used for the POLLRDNORM, POLLRDBAND, POLLWRNORM, POLLMSG macros 30 lines earlier in selectmodule.c.

The only documentation I can find for these five macros from Linux is (a) in the Python documentation for the select module!  (https://docs.python.org/3.4/library/select.html#edge-and-level-trigger-polling-epoll-objects) and (b) on this StackOverflow answer: http://stackoverflow.com/a/27143672/2209313.

They are not described on http://man7.org/linux/man-pages/man2/epoll_ctl.2.html (where the rest of the EPOLL macros are defined), nor at http://linux.die.net/man/4/epoll.  As explained by the StackOverflow answer they actually are described (indirectly) by http://man7.org/linux/man-pages/man2/poll.2.html.

Nor are these macros in the Linux Foundation's LSB database: http://www.linuxbase.org/navigator/browse/headgroup.php?cmd=list-byheadgroup&HGid=1398.

Obviously almost all modern Linuxes have these macros, so we should keep them, but we should also compile with the LSB headers (since compiling and linking against the LSB SDK (http://www.linuxfoundation.org/collaborate/workgroups/lsb/group) is one of the easiest ways to produce a Python binary that will actually run on most important supported Linux distros (e.g., RHEL 5).

http://man7.org/linux/man-pages/man7/epoll.7.html,

----------
components: Build
files: epoll-macros-patch.diff
keywords: patch
messages: 237984
nosy: WanderingLogic
priority: normal
severity: normal
status: open
title: ifdef uses of EPOLLxxx macros so we can compile on systems that don't have them
versions: Python 2.7, Python 3.5, Python 3.6
Added file: http://bugs.python.org/file38461/epoll-macros-patch.diff

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