[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>


.. c:function:: ssize_t write( int fd, void *buf, size_t count )
    :name: lirc-write

Arguments
=========

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

``buf``
    Buffer with data to be written

``count``
    Number of bytes at the buffer

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
	1	.. -- coding: utf-8; mode: rst --
	2
	3	.. _lirc-write:
	4
	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	.. c:function:: ssize_t write( int fd, void *buf, size_t count )
	24	:name: lirc-write
	25
	26	Arguments
	27	=========
	28
	29	``fd``
	30	File descriptor returned by ``open()``.
	31
	32	``buf``
	33	Buffer with data to be written
	34
	35	``count``
	36	Number of bytes at the buffer
	37
	38	Description
	39	===========
	40
	41	:ref:`write() <lirc-write>` writes up to ``count`` bytes to the device
	42	referenced by the file descriptor ``fd`` from the buffer starting at
	43	``buf``.
	44
	45	The data written to the chardev is a pulse/space sequence of integer
	46	values. Pulses and spaces are only marked implicitly by their position.
	47	The data must start and end with a pulse, therefore, the data must
	48	always include an uneven number of samples. The write function must
	49	block until the data has been transmitted by the hardware. If more data
	50	is provided than the hardware can send, the driver returns ``EINVAL``.
	51
	52
	53	Return Value
	54	============
	55
	56	On success, the number of bytes read is returned. It is not an error if
	57	this number is smaller than the number of bytes requested, or the amount
	58	of data required for one frame. On error, -1 is returned, and the ``errno``
	59	variable is set appropriately. The generic error codes are described at the
	60	:ref:`Generic Error Codes <gen-errors>` chapter.