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.. -*- coding: utf-8; mode: rst -*-
.. _media-func-ioctl:
media ioctl()
media-ioctl - Control a media device
.. code-block:: c
#include <sys/ioctl.h>
.. c:function:: int ioctl( int fd, int request, void *argp )
:name: mc-ioctl
File descriptor returned by :c:func:`open() <mc-open>`.
Media ioctl request code as defined in the media.h header file, for
Pointer to a request-specific structure.
The :ref:`ioctl() <media-func-ioctl>` function manipulates media device
parameters. The argument ``fd`` must be an open file descriptor.
The ioctl ``request`` code specifies the media function to be called. It
has encoded in it whether the argument is an input, output or read/write
parameter, and the size of the argument ``argp`` in bytes.
Macros and structures definitions specifying media ioctl requests and
their parameters are located in the media.h header file. All media ioctl
requests, their respective function and parameters are specified in
Return Value
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
Request-specific error codes are listed in the individual requests
When an ioctl that takes an output or read/write parameter fails, the
parameter remains unmodified.