Based on kernel version 6.8
. Page generated on 2024-03-11 21:26 EST
.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 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 <sys/poll.h> .. 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. |