Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
74 lines
1.7 KiB
ReStructuredText
74 lines
1.7 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
|
|
.. c:namespace:: MC
|
|
|
|
.. _request-func-poll:
|
|
|
|
**************
|
|
request poll()
|
|
**************
|
|
|
|
Name
|
|
====
|
|
|
|
request-poll - Wait for some event on a file descriptor
|
|
|
|
Synopsis
|
|
========
|
|
|
|
.. code-block:: c
|
|
|
|
#include <sys/poll.h>
|
|
|
|
.. c:function:: int poll( struct pollfd *ufds, unsigned int nfds, int timeout )
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``ufds``
|
|
List of file descriptor events to be watched
|
|
|
|
``nfds``
|
|
Number of file descriptor events at the \*ufds array
|
|
|
|
``timeout``
|
|
Timeout to wait for events
|
|
|
|
Description
|
|
===========
|
|
|
|
With the :c:func:`poll()` function applications can wait
|
|
for a request to complete.
|
|
|
|
On success :c:func:`poll()` returns the number of file
|
|
descriptors that have been selected (that is, file descriptors for which the
|
|
``revents`` field of the respective struct :c:type:`pollfd`
|
|
is non-zero). Request file descriptor set the ``POLLPRI`` flag in ``revents``
|
|
when the request was completed. When the function times out it returns
|
|
a value of zero, on failure it returns -1 and the ``errno`` variable is
|
|
set appropriately.
|
|
|
|
Attempting to poll for a request that is not yet queued will
|
|
set the ``POLLERR`` flag in ``revents``.
|
|
|
|
Return Value
|
|
============
|
|
|
|
On success, :c:func:`poll()` returns the number of
|
|
structures which have non-zero ``revents`` fields, or zero if the call
|
|
timed out. On error -1 is returned, and the ``errno`` variable is set
|
|
appropriately:
|
|
|
|
``EBADF``
|
|
One or more of the ``ufds`` members specify an invalid file
|
|
descriptor.
|
|
|
|
``EFAULT``
|
|
``ufds`` references an inaccessible memory area.
|
|
|
|
``EINTR``
|
|
The call was interrupted by a signal.
|
|
|
|
``EINVAL``
|
|
The ``nfds`` value exceeds the ``RLIMIT_NOFILE`` value. Use
|
|
``getrlimit()`` to obtain this value.
|