aboutsummaryrefslogtreecommitdiff
path: root/Documentation/media/uapi/cec/cec-func-poll.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/media/uapi/cec/cec-func-poll.rst')
-rw-r--r--Documentation/media/uapi/cec/cec-func-poll.rst70
1 files changed, 70 insertions, 0 deletions
diff --git a/Documentation/media/uapi/cec/cec-func-poll.rst b/Documentation/media/uapi/cec/cec-func-poll.rst
new file mode 100644
index 000000000000..fcab65f6d6b8
--- /dev/null
+++ b/Documentation/media/uapi/cec/cec-func-poll.rst
@@ -0,0 +1,70 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _cec-func-poll:
+
+**********
+cec poll()
+**********
+
+Name
+====
+
+cec-poll - Wait for some event on a file descriptor
+
+
+Synopsis
+========
+
+.. code-block:: c
+
+ #include <sys/poll.h>
+
+
+.. cpp:function:: int poll( struct pollfd *ufds, unsigned int nfds, int timeout )
+
+Arguments
+=========
+
+
+Description
+===========
+
+.. note:: This documents the proposed CEC API. This API is not yet finalized
+ and is currently only available as a staging kernel module.
+
+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 :c:type:`struct pollfd` structure
+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 timed 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`` argument is greater than ``OPEN_MAX``.