[deliverable/linux.git] / Documentation / linux_tv / media / dvb / fe-read-signal-strength.rst

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

.. _FE_READ_SIGNAL_STRENGTH:

***********************
FE_READ_SIGNAL_STRENGTH
***********************

NAME
====

FE_READ_SIGNAL_STRENGTH

SYNOPSIS
========

.. c:function:: int ioctl( int fd, int request = FE_READ_SIGNAL_STRENGTH, uint16_t *strength)


ARGUMENTS
=========

.. flat-table::
    :header-rows:  0
    :stub-columns: 0


    -  .. row 1

       -  int fd

       -  File descriptor returned by a previous call to open().

    -  .. row 2

       -  int request

       -  Equals
	  :ref:`FE_READ_SIGNAL_STRENGTH`
	  for this command.

    -  .. row 3

       -  uint16_t \*strength

       -  The signal strength value is stored into \*strength.


DESCRIPTION
===========

This ioctl call returns the signal strength value for the signal
currently received by the front-end. For this command, read-only access
to the device is sufficient.


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.
Commit	Line	Data
	1	.. -- coding: utf-8; mode: rst --
	2
	3	.. _FE_READ_SIGNAL_STRENGTH:
	4
	5	***********************
	6	FE_READ_SIGNAL_STRENGTH
	7	***********************
	8
	9	NAME
	10	====
	11
	12	FE_READ_SIGNAL_STRENGTH
	13
	14	SYNOPSIS
	15	========
	16
	17	.. c:function:: int ioctl( int fd, int request = FE_READ_SIGNAL_STRENGTH, uint16_t *strength)
	18
	19
	20	ARGUMENTS
	21	=========
	22
	23	.. flat-table::
	24	:header-rows: 0
	25	:stub-columns: 0
	26
	27
	28	- .. row 1
	29
	30	- int fd
	31
	32	- File descriptor returned by a previous call to open().
	33
	34	- .. row 2
	35
	36	- int request
	37
	38	- Equals
	39	:ref:`FE_READ_SIGNAL_STRENGTH`
	40	for this command.
	41
	42	- .. row 3
	43
	44	- uint16_t \*strength
	45
	46	- The signal strength value is stored into \*strength.
	47
	48
	49	DESCRIPTION
	50	===========
	51
	52	This ioctl call returns the signal strength value for the signal
	53	currently received by the front-end. For this command, read-only access
	54	to the device is sufficient.
	55
	56
	57	RETURN VALUE
	58	============
	59
	60	On success 0 is returned, on error -1 and the ``errno`` variable is set
	61	appropriately. The generic error codes are described at the
	62	:ref:`Generic Error Codes <gen-errors>` chapter.