linux/linux-5.4.31/Documentation/media/uapi/dvb/fe-read-status.rst

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.. 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/media/uapi/fdl-appendix.rst.
..
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
.. _FE_READ_STATUS:
********************
ioctl FE_READ_STATUS
********************
Name
====
FE_READ_STATUS - Returns status information about the front-end. This call only requires - read-only access to the device
Synopsis
========
.. c:function:: int ioctl( int fd, FE_READ_STATUS, unsigned int *status )
:name: FE_READ_STATUS
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <frontend_f_open>`.
``status``
pointer to a bitmask integer filled with the values defined by enum
:c:type:`fe_status`.
Description
===========
All Digital TV frontend devices support the ``FE_READ_STATUS`` ioctl. It is
used to check about the locking status of the frontend after being
tuned. The ioctl takes a pointer to an integer where the status will be
written.
.. note::
The size of status is actually sizeof(enum fe_status), with
varies according with the architecture. This needs to be fixed in the
future.
int fe_status
=============
The fe_status parameter is used to indicate the current state and/or
state changes of the frontend hardware. It is produced using the enum
:c:type:`fe_status` values on a bitmask
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.