1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2.. c:namespace:: V4L
3
4.. _func-munmap:
5
6*************
7V4L2 munmap()
8*************
9
10Name
11====
12
13v4l2-munmap - Unmap device memory
14
15Synopsis
16========
17
18.. code-block:: c
19
20    #include <unistd.h>
21    #include <sys/mman.h>
22
23.. c:function:: int munmap( void *start, size_t length )
24
25Arguments
26=========
27
28``start``
29    Address of the mapped buffer as returned by the
30    :c:func:`mmap()` function.
31
32``length``
33    Length of the mapped buffer. This must be the same value as given to
34    :c:func:`mmap()` and returned by the driver in the struct
35    :c:type:`v4l2_buffer` ``length`` field for the
36    single-planar API and in the struct
37    :c:type:`v4l2_plane` ``length`` field for the
38    multi-planar API.
39
40Description
41===========
42
43Unmaps a previously with the :c:func:`mmap()` function mapped
44buffer and frees it, if possible.
45
46Return Value
47============
48
49On success :c:func:`munmap()` returns 0, on failure -1 and the
50``errno`` variable is set appropriately:
51
52EINVAL
53    The ``start`` or ``length`` is incorrect, or no buffers have been
54    mapped yet.
55