64 lines
1.5 KiB
ReStructuredText
64 lines
1.5 KiB
ReStructuredText
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
|
|
.. c:namespace:: CEC
|
|
|
|
.. _cec-func-ioctl:
|
|
|
|
***********
|
|
cec ioctl()
|
|
***********
|
|
|
|
Name
|
|
====
|
|
|
|
cec-ioctl - Control a cec device
|
|
|
|
Synopsis
|
|
========
|
|
|
|
.. code-block:: c
|
|
|
|
#include <sys/ioctl.h>
|
|
|
|
``int ioctl(int fd, int request, void *argp)``
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``fd``
|
|
File descriptor returned by :c:func:`open()`.
|
|
|
|
``request``
|
|
CEC ioctl request code as defined in the cec.h header file, for
|
|
example :ref:`CEC_ADAP_G_CAPS <CEC_ADAP_G_CAPS>`.
|
|
|
|
``argp``
|
|
Pointer to a request-specific structure.
|
|
|
|
Description
|
|
===========
|
|
|
|
The :c:func:`ioctl()` function manipulates cec device parameters. The
|
|
argument ``fd`` must be an open file descriptor.
|
|
|
|
The ioctl ``request`` code specifies the cec 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 cec ioctl requests and
|
|
their parameters are located in the cec.h header file. All cec ioctl
|
|
requests, their respective function and parameters are specified in
|
|
:ref:`cec-user-func`.
|
|
|
|
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
|
|
descriptions.
|
|
|
|
When an ioctl that takes an output or read/write parameter fails, the
|
|
parameter remains unmodified.
|