Documentation/userspace-api/media/dvb/fe-read-snr.rst
Source file repositories/reference/linux-study-clean/Documentation/userspace-api/media/dvb/fe-read-snr.rst
File Facts
- System
- Linux kernel
- Corpus path
Documentation/userspace-api/media/dvb/fe-read-snr.rst- Extension
.rst- Size
- 852 bytes
- Lines
- 50
- 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.
- Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
Dependency Surface
- No C-style include directives detected by the generator.
Detected Declarations
- No top-level syscall, struct, function, initcall, or export declaration detected by the generator.
Annotated Snippet
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
.. c:namespace:: DTV.fe
.. _FE_READ_SNR:
***********
FE_READ_SNR
***********
Name
====
FE_READ_SNR
.. attention:: This ioctl is deprecated.
Synopsis
========
.. c:macro:: FE_READ_SNR
``int ioctl(int fd, FE_READ_SNR, int16_t *snr)``
Arguments
=========
``fd``
File descriptor returned by :c:func:`open()`.
``snr``
The signal-to-noise ratio is stored into \*snr.
Description
===========
This ioctl call returns the signal-to-noise ratio 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.Annotation
- Atlas domain: Support Tooling And Documentation / Documentation.
- Implementation status: atlas-only.
Implementation Notes
- This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
- Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
- Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.