.. Permission is granted to copy, distribute and/or modify this
.. document under the terms of the GNU Free Documentation License,
.. Version 1.1 or any later version published by the Free Software
.. Foundation, with no Invariant Sections, no Front-Cover Texts
.. and no Back-Cover Texts. A copy of the license is included at
.. Documentation/userspace-api/media/fdl-appendix.rst.
..
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections

.. _FE_GET_PROPERTY:

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

Name
====

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


Synopsis
========

.. c:function:: int ioctl( int fd, FE_GET_PROPERTY, struct dtv_properties *argp )
    :name: FE_GET_PROPERTY

.. c:function:: int ioctl( int fd, FE_SET_PROPERTY, struct dtv_properties *argp )
    :name: FE_SET_PROPERTY


Arguments
=========

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

``argp``
    Pointer to struct :c:type:`dtv_properties`.


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

All Digital TV 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.

.. note::

   At return, the values aren't updated to reflect the actual
   parameters used. If the actual parameters are needed, an explicit
   call to ``FE_GET_PROPERTY`` is needed.

-  ``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 is returned, and the ``errno`` variable is set
appropriately.

Generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.