1 .. SPDX-License-Identifier: GFDL-1.1-no-invari 1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2 .. c:namespace:: MC 2 .. c:namespace:: MC
3 3
4 .. _media-func-ioctl: 4 .. _media-func-ioctl:
5 5
6 ************* 6 *************
7 media ioctl() 7 media ioctl()
8 ************* 8 *************
9 9
10 Name 10 Name
11 ==== 11 ====
12 12
13 media-ioctl - Control a media device 13 media-ioctl - Control a media device
14 14
15 Synopsis 15 Synopsis
16 ======== 16 ========
17 17
18 .. code-block:: c 18 .. code-block:: c
19 19
20 #include <sys/ioctl.h> 20 #include <sys/ioctl.h>
21 21
22 ``int ioctl(int fd, int request, void *argp)`` 22 ``int ioctl(int fd, int request, void *argp)``
23 23
24 Arguments 24 Arguments
25 ========= 25 =========
26 26
27 ``fd`` 27 ``fd``
28 File descriptor returned by :c:func:`open( 28 File descriptor returned by :c:func:`open()`.
29 29
30 ``request`` 30 ``request``
31 Media ioctl request code as defined in the 31 Media ioctl request code as defined in the media.h header file, for
32 example MEDIA_IOC_SETUP_LINK. 32 example MEDIA_IOC_SETUP_LINK.
33 33
34 ``argp`` 34 ``argp``
35 Pointer to a request-specific structure. 35 Pointer to a request-specific structure.
36 36
37 Description 37 Description
38 =========== 38 ===========
39 39
40 The :ref:`ioctl() <media-func-ioctl>` function 40 The :ref:`ioctl() <media-func-ioctl>` function manipulates media device
41 parameters. The argument ``fd`` must be an ope 41 parameters. The argument ``fd`` must be an open file descriptor.
42 42
43 The ioctl ``request`` code specifies the media 43 The ioctl ``request`` code specifies the media function to be called. It
44 has encoded in it whether the argument is an i 44 has encoded in it whether the argument is an input, output or read/write
45 parameter, and the size of the argument ``argp 45 parameter, and the size of the argument ``argp`` in bytes.
46 46
47 Macros and structures definitions specifying m 47 Macros and structures definitions specifying media ioctl requests and
48 their parameters are located in the media.h he 48 their parameters are located in the media.h header file. All media ioctl
49 requests, their respective function and parame 49 requests, their respective function and parameters are specified in
50 :ref:`media-user-func`. 50 :ref:`media-user-func`.
51 51
52 Return Value 52 Return Value
53 ============ 53 ============
54 54
55 On success 0 is returned, on error -1 and the 55 On success 0 is returned, on error -1 and the ``errno`` variable is set
56 appropriately. The generic error codes are des 56 appropriately. The generic error codes are described at the
57 :ref:`Generic Error Codes <gen-errors>` chapte 57 :ref:`Generic Error Codes <gen-errors>` chapter.
58 58
59 Request-specific error codes are listed in the 59 Request-specific error codes are listed in the individual requests
60 descriptions. 60 descriptions.
61 61
62 When an ioctl that takes an output or read/wri 62 When an ioctl that takes an output or read/write parameter fails, the
63 parameter remains unmodified. 63 parameter remains unmodified.
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