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1.. -*- coding: utf-8; mode: rst -*-
2
3.. _lirc-read:
4
5***********
6LIRC read()
7***********
8
9Name
10====
11
12lirc-read - Read from a LIRC device
13
14
15Synopsis
16========
17
18.. code-block:: c
19
20    #include <unistd.h>
21
22
23.. c:function:: ssize_t read( int fd, void *buf, size_t count )
24    :name: lirc-read
25
26
27Arguments
28=========
29
30``fd``
31    File descriptor returned by ``open()``.
32
33``buf``
34   Buffer to be filled
35
36``count``
37   Max number of bytes to read
38
39Description
40===========
41
42:ref:`read() <lirc-read>` attempts to read up to ``count`` bytes from file
43descriptor ``fd`` into the buffer starting at ``buf``.  If ``count`` is zero,
44:ref:`read() <lirc-read>` returns zero and has no other results. If ``count``
45is greater than ``SSIZE_MAX``, the result is unspecified.
46
47The exact format of the data depends on what :ref:`lirc_modes` a driver
48uses. Use :ref:`lirc_get_features` to get the supported mode.
49
50The generally preferred mode for receive is
51:ref:`LIRC_MODE_MODE2 <lirc-mode-mode2>`,
52in which packets containing an int value describing an IR signal are
53read from the chardev.
54
55Return Value
56============
57
58On success, the number of bytes read is returned. It is not an error if
59this number is smaller than the number of bytes requested, or the amount
60of data required for one frame.  On error, -1 is returned, and the ``errno``
61variable is set appropriately.
62