android_kernel_xiaomi_sm8450/Documentation/linux_tv/media/dvb/fe-get-property.rst

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

.. _FE_GET_PROPERTY:

**************************************
ioctl FE_SET_PROPERTY, FE_GET_PROPERTY
**************************************

*man FE_SET_PROPERTY(2)*

FE_GET_PROPERTY
FE_SET_PROPERTY sets one or more frontend properties.
FE_GET_PROPERTY returns one or more frontend properties.


Synopsis
========

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

Arguments
=========

``fd``
    File descriptor returned by :ref:`open() <frontend_f_open>`.

``request``
    FE_SET_PROPERTY, FE_GET_PROPERTY

``argp``
    pointer to struct :ref:`dtv_properties <dtv-properties>`


Description
===========

All DVB frontend devices support the ``FE_SET_PROPERTY`` and
``FE_GET_PROPERTY`` ioctls. The supported properties and statistics
depends on the delivery system and on the device:

-  ``FE_SET_PROPERTY:``

   -  This ioctl is used to set one or more frontend properties.

   -  This is the basic command to request the frontend to tune into
      some frequency and to start decoding the digital TV signal.

   -  This call requires read/write access to the device.

   -  At return, the values are updated to reflect the actual parameters
      used.

-  ``FE_GET_PROPERTY:``

   -  This ioctl is used to get properties and statistics from the
      frontend.

   -  No properties are changed, and statistics aren't reset.

   -  This call only requires read-only access to the device.

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.