1 .. SPDX-License-Identifier: GFDL-1.1-no-invari
2 .. c:namespace:: V4L
3
4 .. _func-ioctl:
5
6 ************
7 V4L2 ioctl()
8 ************
9
10 Name
11 ====
12
13 v4l2-ioctl - Program a V4L2 device
14
15 Synopsis
16 ========
17
18 .. code-block:: c
19
20 #include <sys/ioctl.h>
21
22 ``int ioctl(int fd, int request, void *argp)``
23
24 Arguments
25 =========
26
27 ``fd``
28 File descriptor returned by :c:func:`open(
29
30 ``request``
31 V4L2 ioctl request code as defined in the
32 file, for example VIDIOC_QUERYCAP.
33
34 ``argp``
35 Pointer to a function parameter, usually a
36
37 Description
38 ===========
39
40 The :ref:`ioctl() <func-ioctl>` function is us
41 argument ``fd`` must be an open file descripto
42 has encoded in it whether the argument is an i
43 parameter, and the size of the argument ``argp
44 defines specifying V4L2 ioctl requests are loc
45 ``videodev2.h`` header file. Applications shou
46 include the version in the kernel sources on t
47 All V4L2 ioctl requests, their respective func
48 specified in :ref:`user-func`.
49
50 Return Value
51 ============
52
53 On success 0 is returned, on error -1 and the
54 appropriately. The generic error codes are des
55 :ref:`Generic Error Codes <gen-errors>` chapte
56
57 When an ioctl that takes an output or read/wri
58 parameter remains unmodified.
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