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.. -*- coding: utf-8; mode: rst -*-

.. _lirc_ioctl:

************
LIRC ioctl()
************


Name
====

LIRC ioctl - Sends a I/O control command to a LIRC device

Synopsis
========

.. cpp:function:: int ioctl( int fd, int request, struct v4l2_capability *argp )


Arguments
=========

``fd``
    File descriptor returned by ``open()``.

``request``
    The type of I/O control that will be used. See table :ref:`lirc-request`
    for details.

``argp``
    Arguments for the I/O control. They're specific to each request.


The LIRC device's ioctl definition is bound by the ioctl function
definition of struct file_operations, leaving us with an unsigned int
for the ioctl command and an unsigned long for the arg. For the purposes
of ioctl portability across 32-bit and 64-bit, these values are capped
to their 32-bit sizes.

The ioctls can be used to change specific hardware settings.
In general each driver should have a default set of settings. The driver
implementation is expected to re-apply the default settings when the
device is closed by user-space, so that every application opening the
device can rely on working with the default settings initially.

.. _lirc-request:

.. _LIRC_SET_SEND_MODE:
.. _LIRC_SET_REC_MODE:

``LIRC_SET_{SEND,REC}_MODE``

    Set send/receive mode. Largely obsolete for send, as only
    ``LIRC_MODE_PULSE`` is supported.

.. _LIRC_SET_REC_TIMEOUT:

``LIRC_SET_REC_TIMEOUT``

    Sets the integer value for IR inactivity timeout (cf.
    ``LIRC_GET_MIN_TIMEOUT`` and ``LIRC_GET_MAX_TIMEOUT).`` A value of 0
    (if supported by the hardware) disables all hardware timeouts and
    data should be reported as soon as possible. If the exact value
    cannot be set, then the next possible value _greater_ than the
    given value should be set.

.. _LIRC_SET_REC_TIMEOUT_REPORTS:

``LIRC_SET_REC_TIMEOUT_REPORTS``

    Enable (1) or disable (0) timeout reports in ``LIRC_MODE_MODE2.`` By
    default, timeout reports should be turned off.


.. _LIRC_SET_MEASURE_CARRIER_MODE:
.. _lirc-mode2-frequency:

``LIRC_SET_MEASURE_CARRIER_MODE``

    Enable (1)/disable (0) measure mode. If enabled, from the next key
    press on, the driver will send ``LIRC_MODE2_FREQUENCY`` packets. By
    default this should be turned off.

.. _LIRC_SET_WIDEBAND_RECEIVER:

``LIRC_SET_WIDEBAND_RECEIVER``

    Some receivers are equipped with special wide band receiver which is
    intended to be used to learn output of existing remote. Calling that
    ioctl with (1) will enable it, and with (0) disable it. This might
    be useful of receivers that have otherwise narrow band receiver that
    prevents them to be used with some remotes. Wide band receiver might
    also be more precise On the other hand its disadvantage it usually
    reduced range of reception.

    .. note:: Wide band receiver might be
       implictly enabled if you enable carrier reports. In that case it
       will be disabled as soon as you disable carrier reports. Trying to
       disable wide band receiver while carrier reports are active will do
       nothing.


.. _lirc_dev_errors:

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.