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authorMauro Carvalho Chehab2016-07-27 10:45:04 -0300
committerMauro Carvalho Chehab2016-07-27 10:45:04 -0300
commit85538b1ad145c67198cb55d02de14ba269cc323d (patch)
tree409fca93b357839b8c89b7099f2888c087694b64 /Documentation/media/uapi/rc/lirc-read.rst
parent9c1958fc326a0a0a533ec8e86ea6fa30977207de (diff)
parentd271d3d9b333c94cd54a12fa506e17772a04617c (diff)
Merge branch 'topic/docs-next' into v4l_for_linus
* topic/docs-next: (322 commits) [media] cx23885-cardlist.rst: add a new card [media] doc-rst: add some needed escape codes [media] doc-rst: kapi: use :c:func: instead of :cpp:func doc-rst: kernel-doc: fix a change introduced by mistake [media] v4l2-ioctl.h add debug info for struct v4l2_ioctl_ops [media] dvb_ringbuffer.h: some documentation improvements [media] v4l2-ctrls.h: fully document the header file [media] doc-rst: Fix some typedef ugly warnings [media] doc-rst: reorganize the kAPI v4l2 chapters [media] rename v4l2-framework.rst to v4l2-intro.rst [media] move V4L2 clocks to a separate .rst file [media] v4l2-fh.rst: add cross references and markups [media] v4l2-fh.rst: add fh contents from v4l2-framework.rst [media] v4l2-fh.h: add documentation for it [media] v4l2-event.rst: add cross-references and markups [media] v4l2-event.h: document all functions [media] v4l2-event.rst: add text from v4l2-framework.rst [media] v4l2-framework.rst: remove videobuf quick chapter [media] v4l2-dev: add cross-references and improve markup [media] doc-rst: move v4l2-dev doc to a separate file ...
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _lirc-read:
+
+***********
+LIRC read()
+***********
+
+Name
+====
+
+lirc-read - Read from a LIRC device
+
+
+Synopsis
+========
+
+.. code-block:: c
+
+ #include <unistd.h>
+
+
+.. cpp:function:: ssize_t read( int fd, void *buf, size_t count )
+
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by ``open()``.
+
+``buf``
+``count``
+
+
+Description
+===========
+
+:ref:`read() <lirc-read>` attempts to read up to ``count`` bytes from file
+descriptor ``fd`` into the buffer starting at ``buf``. If ``count`` is zero,
+:ref:`read() <lirc-read>` returns zero and has no other results. If ``count``
+is greater than ``SSIZE_MAX``, the result is unspecified.
+
+The lircd userspace daemon reads raw IR data from the LIRC chardev. The
+exact format of the data depends on what modes a driver supports, and
+what mode has been selected. lircd obtains supported modes and sets the
+active mode via the ioctl interface, detailed at :ref:`lirc_func`.
+The generally preferred mode for receive is
+:ref:`LIRC_MODE_MODE2 <lirc-mode-mode2>`, in which packets containing an
+int value describing an IR signal are read from the chardev.
+
+See also
+`http://www.lirc.org/html/technical.html <http://www.lirc.org/html/technical.html>`__
+for more info.
+
+Return Value
+============
+
+On success, the number of bytes read is returned. It is not an error if
+this number is smaller than the number of bytes requested, or the amount
+of data required for one frame. On error, -1 is returned, and the ``errno``
+variable is set appropriately.