epoll_wait man page error

[Angelo Borsotti]

man epoll_wait states:

EINTR The call was interrupted by a signal handler before any of the
              requested events occurred or the timeout expired; see signal(7).

However, epoll_wait does not return EINTR when the timeout expires, it
simply returns 0 as number of file descriptors, and errno = 0.
This is the correct behaviour (otherwise there would be no way to tell
a signal interruption from a timeout one).

[Brian Murray (brian-murray)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This bug did not have a package associated with it, which is important for ensuring that it gets looked at by the proper developers. You can learn more about finding the right package at https://wiki.ubuntu.com/Bugs/FindRightPackage. I have classified this bug as a bug in manpages.

When reporting bugs in the future please use apport, either via the appropriate application's "Help -> Report a Problem" menu or using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[Michael Kerrisk (mtk-manpages)]

I belive the problem here is a misreading of the English text.

I changed the text slightly in upstream 3.41 from

EINTR The call was interrupted by a signal handler before any of the
              requested events occurred or the timeout expired; see signal(7).

to

EINTR The call was interrupted by a signal handler before either any of the
              requested events occurred or the timeout expired; see signal(7).

[Angelo Borsotti (angelo-borsotti)]

Hi Michael.

the correct text should be:

EINTR The call was interrupted by a signal handler before any of the
             requested events occurred; see signal(7).

The issue is that EINTR is not returned when the timeout expires, but only
when one of the events occur.

-Angelo

[Stéphane Aulery (lkppo)]

This bug have been fixed by 2 commits (manpages 3.57):

- https://git.kernel.org/cgit/docs/man-pages/man-pages.git/commit/man2/epoll_wait.2?id=8d8eb2f0c8442b74b850e460a8281ac9e19633cb
- https://git.kernel.org/cgit/docs/man-pages/man-pages.git/commit/man2/epoll_wait.2?id=db6f9ec8076036b0ee5c49963dd8b52ce61da321