[deliverable/linux.git] / Documentation / media / uapi / rc / lirc-write.rst

.. -*- coding: utf-8; mode: rst -*-

.. _lirc-write:

************
LIRC write()
************

Name
====

lirc-write - Write to a LIRC device


Synopsis
========

.. code-block:: c

    #include <unistd.h>


.. cpp:function:: ssize_t write( int fd, void *buf, size_t count )


Arguments
=========

``fd``
    File descriptor returned by ``open()``.

``buf``
``count``


Description
===========

:ref:`write() <lirc-write>` writes up to ``count`` bytes to the device
referenced by the file descriptor ``fd`` from the buffer starting at
``buf``.

The data written to the chardev is a pulse/space sequence of integer
values. Pulses and spaces are only marked implicitly by their position.
The data must start and end with a pulse, therefore, the data must
always include an uneven number of samples. The write function must
block until the data has been transmitted by the hardware. If more data
is provided than the hardware can send, the driver returns ``EINVAL``.


Return Value
============

On success, the number of bytes read is returned. It is not an error if
this number is smaller than the number of bytes requested, or the amount
of data required for one frame.  On error, -1 is returned, and the ``errno``
variable is set appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
Commit	Line	Data
5377d91f MH	1	.. -- coding: utf-8; mode: rst --
5377d91f MH	2
4ed030af	3	.. _lirc-write:
5377d91f	4
8a6ba5c0 MCC	5	************
	6	LIRC write()
	7	************
	8
	9	Name
	10	====
	11
	12	lirc-write - Write to a LIRC device
	13
	14
	15	Synopsis
	16	========
	17
	18	.. code-block:: c
	19
	20	#include <unistd.h>
	21
	22
	23	.. cpp:function:: ssize_t write( int fd, void *buf, size_t count )
	24
	25
	26	Arguments
	27	=========
	28
	29	``fd``
	30	File descriptor returned by ``open()``.
	31
	32	``buf``
	33	``count``
	34
	35
	36	Description
	37	===========
	38
4ed030af	39	:ref:`write() <lirc-write>` writes up to ``count`` bytes to the device
8a6ba5c0 MCC	40	referenced by the file descriptor ``fd`` from the buffer starting at
8a6ba5c0 MCC	41	``buf``.
5377d91f MH	42
	43	The data written to the chardev is a pulse/space sequence of integer
	44	values. Pulses and spaces are only marked implicitly by their position.
	45	The data must start and end with a pulse, therefore, the data must
	46	always include an uneven number of samples. The write function must
	47	block until the data has been transmitted by the hardware. If more data
cdb4af0f	48	is provided than the hardware can send, the driver returns ``EINVAL``.
8a6ba5c0 MCC	49
	50
	51	Return Value
	52	============
	53
	54	On success, the number of bytes read is returned. It is not an error if
	55	this number is smaller than the number of bytes requested, or the amount
	56	of data required for one frame. On error, -1 is returned, and the ``errno``
	57	variable is set appropriately. The generic error codes are described at the
	58	:ref:`Generic Error Codes <gen-errors>` chapter.