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.. -*- coding: utf-8; mode: rst -*-
.. _func-munmap:
*************
V4L2 munmap()
*************
Name
====
v4l2-munmap - Unmap device memory
Synopsis
========
.. code-block:: c
#include <unistd.h>
#include <sys/mman.h>
.. cpp:function:: int munmap( void *start, size_t length )
Arguments
=========
``start``
Address of the mapped buffer as returned by the
:ref:`mmap() <func-mmap>` function.
``length``
Length of the mapped buffer. This must be the same value as given to
:ref:`mmap() <func-mmap>` and returned by the driver in the struct
:ref:`v4l2_buffer <v4l2-buffer>` ``length`` field for the
single-planar API and in the struct
:ref:`v4l2_plane <v4l2-plane>` ``length`` field for the
multi-planar API.
Description
===========
Unmaps a previously with the :ref:`mmap() <func-mmap>` function mapped
buffer and frees it, if possible.
Return Value
============
On success :ref:`munmap() <func-munmap>` returns 0, on failure -1 and the
``errno`` variable is set appropriately:
EINVAL
The ``start`` or ``length`` is incorrect, or no buffers have been
mapped yet.
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