1 .. SPDX-License-Identifier: GPL-2.0 OR GFDL-1. 1 .. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
2 .. c:namespace:: MC 2 .. c:namespace:: MC
3 3
4 .. _request-func-ioctl: 4 .. _request-func-ioctl:
5 5
6 *************** 6 ***************
7 request ioctl() 7 request ioctl()
8 *************** 8 ***************
9 9
10 Name 10 Name
11 ==== 11 ====
12 12
13 request-ioctl - Control a request file descrip 13 request-ioctl - Control a request file descriptor
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 cmd, void *argp)`` 22 ``int ioctl(int fd, int cmd, void *argp)``
23 23
24 Arguments 24 Arguments
25 ========= 25 =========
26 26
27 ``fd`` 27 ``fd``
28 File descriptor returned by :ref:`MEDIA_IO 28 File descriptor returned by :ref:`MEDIA_IOC_REQUEST_ALLOC`.
29 29
30 ``cmd`` 30 ``cmd``
31 The request ioctl command code as defined 31 The request ioctl command code as defined in the media.h header file, for
32 example :ref:`MEDIA_REQUEST_IOC_QUEUE`. 32 example :ref:`MEDIA_REQUEST_IOC_QUEUE`.
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() <request-func-ioctl>` functi 40 The :ref:`ioctl() <request-func-ioctl>` function manipulates request
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 ``cmd`` code specifies the request f 43 The ioctl ``cmd`` code specifies the request 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 r 47 Macros and structures definitions specifying request ioctl commands and
48 their parameters are located in the media.h he 48 their parameters are located in the media.h header file. All request ioctl
49 commands, their respective function and parame 49 commands, 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 Command-specific error codes are listed in the 59 Command-specific error codes are listed in the individual command
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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