From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- .../userspace-api/media/cec/cec-func-poll.rst | 74 ++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 Documentation/userspace-api/media/cec/cec-func-poll.rst (limited to 'Documentation/userspace-api/media/cec/cec-func-poll.rst') diff --git a/Documentation/userspace-api/media/cec/cec-func-poll.rst b/Documentation/userspace-api/media/cec/cec-func-poll.rst new file mode 100644 index 000000000..980bbfc0b --- /dev/null +++ b/Documentation/userspace-api/media/cec/cec-func-poll.rst @@ -0,0 +1,74 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: CEC + +.. _cec-func-poll: + +********** +cec poll() +********** + +Name +==== + +cec-poll - Wait for some event on a file descriptor + +Synopsis +======== + +.. code-block:: c + + #include + +.. c:function:: int poll( struct pollfd *ufds, unsigned int nfds, int timeout ) + +Arguments +========= + +``ufds`` + List of FD events to be watched + +``nfds`` + Number of FD events at the \*ufds array + +``timeout`` + Timeout to wait for events + +Description +=========== + +With the :c:func:`poll()` function applications can wait for CEC +events. + +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). CEC devices set the ``POLLIN`` and ``POLLRDNORM`` flags in +the ``revents`` field if there are messages in the receive queue. If the +transmit queue has room for new messages, the ``POLLOUT`` and +``POLLWRNORM`` flags are set. If there are events in the event queue, +then the ``POLLPRI`` flag is set. When the function times out it returns +a value of zero, on failure it returns -1 and the ``errno`` variable is +set appropriately. + +For more details see the :c:func:`poll()` manual page. + +Return Value +============ + +On success, :c:func:`poll()` returns the number 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. -- cgit v1.2.3