ifdef uses of EPOLLxxx macros so we can compile on systems that don't have them

[WanderingLogic]

BPO	23652
Nosy	@zware
Files	epoll-macros-patch.diff: Patch to wrap uses of unusual EPOLLxxx macros in ifdefs

^{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 = None
closed_at = <Date 2015-08-02.02:39:58.132>
created_at = <Date 2015-03-12.20:41:46.794>
labels = ['build']
title = "ifdef uses of EPOLLxxx macros so we can compile on systems that don't have them"
updated_at = <Date 2015-08-02.02:40:31.203>
user = 'https://bugs.python.org/WanderingLogic'

bugs.python.org fields:

activity = <Date 2015-08-02.02:40:31.203>
actor = 'zach.ware'
assignee = 'none'
closed = True
closed_date = <Date 2015-08-02.02:39:58.132>
closer = 'python-dev'
components = ['Build']
creation = <Date 2015-03-12.20:41:46.794>
creator = 'WanderingLogic'
dependencies = []
files = ['38461']
hgrepos = []
issue_num = 23652
keywords = ['patch']
message_count = 4.0
messages = ['237984', '247733', '247850', '247851']
nosy_count = 4.0
nosy_names = ['neologix', 'python-dev', 'zach.ware', 'WanderingLogic']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'compile error'
url = 'https://bugs.python.org/issue23652'
versions = ['Python 2.7', 'Python 3.4', 'Python 3.5', 'Python 3.6']

[WanderingLogic]

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,

[zware]

Looks good to me.

[python-dev]

New changeset e38470b49d3c by Zachary Ware in branch '2.7':
Issue bpo-23652: Make the select module compile against LSB headers.
https://hg.python.org/cpython/rev/e38470b49d3c

New changeset c18a18b65a49 by Zachary Ware in branch '3.4':
Issue bpo-23652: Make the select module compile against LSB headers.
https://hg.python.org/cpython/rev/c18a18b65a49

New changeset a99f17c752d8 by Zachary Ware in branch '3.5':
Issue bpo-23652: Merge with 3.4
https://hg.python.org/cpython/rev/a99f17c752d8

New changeset c7273b46980c by Zachary Ware in branch 'default':
Closes bpo-23652: Merge with 3.5
https://hg.python.org/cpython/rev/c7273b46980c

[zware]

Thanks for the patch!