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linux-next/Documentation/userspace-api/media/dvb/fe-read-signal-strength.rst
Mauro Carvalho Chehab f9b2e8aa32 media: docs: make DVB documents more compatible with Sphinx 3.1+
Sphinx 3.x broke support for the cdomain.py extension, as the
c domain code was rewritten. Due to that, the c tags need to
be re-written, in order to use the new c domain notation.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-10-15 07:49:39 +02:00

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.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
.. c:namespace:: DTV.fe
.. _FE_READ_SIGNAL_STRENGTH:
***********************
FE_READ_SIGNAL_STRENGTH
***********************
Name
====
FE_READ_SIGNAL_STRENGTH
.. attention:: This ioctl is deprecated.
Synopsis
========
.. c:macro:: FE_READ_SIGNAL_STRENGTH
``int ioctl(int fd, FE_READ_SIGNAL_STRENGTH, uint16_t *strength)``
Arguments
=========
``fd``
File descriptor returned by :c:func:`open()`.
``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 is returned, and the ``errno`` variable is set
appropriately.
Generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.