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1 | .. -*- coding: utf-8; mode: rst -*- |
2 | ||
3 | .. _func-munmap: | |
4 | ||
5 | ************* | |
6 | V4L2 munmap() | |
7 | ************* | |
8 | ||
15e7d615 | 9 | Name |
586027ce | 10 | ==== |
5377d91f | 11 | |
586027ce | 12 | v4l2-munmap - Unmap device memory |
5377d91f | 13 | |
15e7d615 MCC |
14 | |
15 | Synopsis | |
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16 | ======== |
17 | ||
18 | .. code-block:: c | |
19 | ||
20 | #include <unistd.h> | |
21 | #include <sys/mman.h> | |
22 | ||
23 | ||
b7e67f6c | 24 | .. cpp:function:: int munmap( void *start, size_t length ) |
5377d91f | 25 | |
586027ce | 26 | |
15e7d615 | 27 | Arguments |
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28 | ========= |
29 | ||
30 | ``start`` | |
31 | Address of the mapped buffer as returned by the | |
32 | :ref:`mmap() <func-mmap>` function. | |
33 | ||
34 | ``length`` | |
35 | Length of the mapped buffer. This must be the same value as given to | |
760c7010 | 36 | :ref:`mmap() <func-mmap>` and returned by the driver in the struct |
5377d91f MH |
37 | :ref:`v4l2_buffer <v4l2-buffer>` ``length`` field for the |
38 | single-planar API and in the struct | |
39 | :ref:`v4l2_plane <v4l2-plane>` ``length`` field for the | |
40 | multi-planar API. | |
41 | ||
42 | ||
15e7d615 | 43 | Description |
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44 | =========== |
45 | ||
46 | Unmaps a previously with the :ref:`mmap() <func-mmap>` function mapped | |
47 | buffer and frees it, if possible. | |
48 | ||
49 | ||
15e7d615 | 50 | Return Value |
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51 | ============ |
52 | ||
760c7010 | 53 | On success :ref:`munmap() <func-munmap>` returns 0, on failure -1 and the |
5377d91f MH |
54 | ``errno`` variable is set appropriately: |
55 | ||
56 | EINVAL | |
57 | The ``start`` or ``length`` is incorrect, or no buffers have been | |
58 | mapped yet. |