.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
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.. c:namespace:: V4L
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.. _func-munmap:
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*************
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V4L2 munmap()
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*************
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Name
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====
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v4l2-munmap - Unmap device memory
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Synopsis
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========
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.. code-block:: c
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#include <unistd.h>
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#include <sys/mman.h>
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.. c:function:: int munmap( void *start, size_t length )
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Arguments
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=========
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``start``
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Address of the mapped buffer as returned by the
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:c:func:`mmap()` function.
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``length``
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Length of the mapped buffer. This must be the same value as given to
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:c:func:`mmap()` and returned by the driver in the struct
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:c:type:`v4l2_buffer` ``length`` field for the
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single-planar API and in the struct
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:c:type:`v4l2_plane` ``length`` field for the
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multi-planar API.
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Description
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===========
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Unmaps a previously with the :c:func:`mmap()` function mapped
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buffer and frees it, if possible.
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Return Value
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============
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On success :c:func:`munmap()` returns 0, on failure -1 and the
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``errno`` variable is set appropriately:
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EINVAL
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The ``start`` or ``length`` is incorrect, or no buffers have been
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mapped yet.
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