1 .. SPDX-License-Identifier: GFDL-1.1-no-invari 1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2 .. c:namespace:: V4L 2 .. c:namespace:: V4L
3 3
4 .. _func-munmap: 4 .. _func-munmap:
5 5
6 ************* 6 *************
7 V4L2 munmap() 7 V4L2 munmap()
8 ************* 8 *************
9 9
10 Name 10 Name
11 ==== 11 ====
12 12
13 v4l2-munmap - Unmap device memory 13 v4l2-munmap - Unmap device memory
14 14
15 Synopsis 15 Synopsis
16 ======== 16 ========
17 17
18 .. code-block:: c 18 .. code-block:: c
19 19
20 #include <unistd.h> 20 #include <unistd.h>
21 #include <sys/mman.h> 21 #include <sys/mman.h>
22 22
23 .. c:function:: int munmap( void *start, size_ 23 .. c:function:: int munmap( void *start, size_t length )
24 24
25 Arguments 25 Arguments
26 ========= 26 =========
27 27
28 ``start`` 28 ``start``
29 Address of the mapped buffer as returned b 29 Address of the mapped buffer as returned by the
30 :c:func:`mmap()` function. 30 :c:func:`mmap()` function.
31 31
32 ``length`` 32 ``length``
33 Length of the mapped buffer. This must be 33 Length of the mapped buffer. This must be the same value as given to
34 :c:func:`mmap()` and returned by the drive 34 :c:func:`mmap()` and returned by the driver in the struct
35 :c:type:`v4l2_buffer` ``length`` field for 35 :c:type:`v4l2_buffer` ``length`` field for the
36 single-planar API and in the struct 36 single-planar API and in the struct
37 :c:type:`v4l2_plane` ``length`` field for 37 :c:type:`v4l2_plane` ``length`` field for the
38 multi-planar API. 38 multi-planar API.
39 39
40 Description 40 Description
41 =========== 41 ===========
42 42
43 Unmaps a previously with the :c:func:`mmap()` 43 Unmaps a previously with the :c:func:`mmap()` function mapped
44 buffer and frees it, if possible. 44 buffer and frees it, if possible.
45 45
46 Return Value 46 Return Value
47 ============ 47 ============
48 48
49 On success :c:func:`munmap()` returns 0, on fa 49 On success :c:func:`munmap()` returns 0, on failure -1 and the
50 ``errno`` variable is set appropriately: 50 ``errno`` variable is set appropriately:
51 51
52 EINVAL 52 EINVAL
53 The ``start`` or ``length`` is incorrect, 53 The ``start`` or ``length`` is incorrect, or no buffers have been
54 mapped yet. 54 mapped yet.
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