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Linux_Drivers/linux_5.10/Documentation/userspace-api/media/dvb/dmx-munmap.rst
sam.xiang 5c7dd7acc3 [linux] create linux_5.10.4 from T-head official:
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.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
.. c:namespace:: DTV.dmx
.. _dmx-munmap:
************
DVB munmap()
************
Name
====
dmx-munmap - Unmap device memory
.. warning:: This API is still experimental.
Synopsis
========
.. code-block:: c
#include <unistd.h>
#include <sys/mman.h>
.. c:function:: int munmap( void *start, size_t length )
Arguments
=========
``start``
Address of the mapped buffer as returned by the
:c:func:`mmap()` function.
``length``
Length of the mapped buffer. This must be the same value as given to
:c:func:`mmap()`.
Description
===========
Unmaps a previously with the :c:func:`mmap()` function mapped
buffer and frees it, if possible.
Return Value
============
On success :c: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.