linux/Documentation/userspace-api/media/dvb/audio-fwrite.rst
Mauro Carvalho Chehab 54f38fcae5 media: docs: move uAPI book to userspace-api/media
Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee38 ("docs: Create a user-space API guide").

As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.

Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-14 10:31:49 +02:00

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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/userspace-api/media/fdl-appendix.rst.
..
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
.. _audio_fwrite:
=========================
Digital TV audio write()
=========================
Name
----
Digital TV audio write()
.. attention:: This ioctl is deprecated
Synopsis
--------
.. c:function:: size_t write(int fd, const void *buf, size_t count)
:name: dvb-audio-write
Arguments
---------
.. flat-table::
:header-rows: 0
:stub-columns: 0
- .. row 1
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- void \*buf
- Pointer to the buffer containing the PES data.
- .. row 3
- size_t count
- Size of buf.
Description
-----------
This system call can only be used if AUDIO_SOURCE_MEMORY is selected
in the ioctl call AUDIO_SELECT_SOURCE. The data provided shall be in
PES format. If O_NONBLOCK is not specified the function will block
until buffer space is available. The amount of data to be transferred is
implied by count.
Return Value
------------
.. flat-table::
:header-rows: 0
:stub-columns: 0
- .. row 1
- ``EPERM``
- Mode AUDIO_SOURCE_MEMORY not selected.
- .. row 2
- ``ENOMEM``
- Attempted to write more data than the internal buffer can hold.
- .. row 3
- ``EBADF``
- fd is not a valid open file descriptor.