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+.. 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.