Documentation/userspace-api/media/dvb/fe-read-status.rst

Source file repositories/reference/linux-study-clean/Documentation/userspace-api/media/dvb/fe-read-status.rst

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Linux kernel
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Documentation/userspace-api/media/dvb/fe-read-status.rst
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.rst
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1438 bytes
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63
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Detected Declarations

Annotated Snippet

.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
.. c:namespace:: DTV.fe

.. _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:macro:: FE_READ_STATUS

``int ioctl(int fd, FE_READ_STATUS, unsigned int *status)``

Arguments
=========

``fd``
    File descriptor returned by :c:func:`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.

Annotation

Implementation Notes