[deliverable/linux.git] / Documentation / linux_tv / media / v4l / media-func-open.rst

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

.. _media-func-open:

************
media open()
************

*man media-open(2)*

Open a media device


Synopsis
========

.. code-block:: c

    #include <fcntl.h>


.. c:function:: int open( const char *device_name, int flags )

Arguments
=========

``device_name``
    Device to be opened.

``flags``
    Open flags. Access mode must be either ``O_RDONLY`` or ``O_RDWR``.
    Other flags have no effect.


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

To open a media device applications call :c:func:`open()` with the
desired device name. The function has no side effects; the device
configuration remain unchanged.

When the device is opened in read-only mode, attempts to modify its
configuration will result in an error, and ``errno`` will be set to
EBADF.


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

:c:func:`open()` returns the new file descriptor on success. On error,
-1 is returned, and ``errno`` is set appropriately. Possible error codes
are:

EACCES
    The requested access to the file is not allowed.

EMFILE
    The process already has the maximum number of files open.

ENFILE
    The system limit on the total number of open files has been reached.

ENOMEM
    Insufficient kernel memory was available.

ENXIO
    No device corresponding to this device special file exists.


.. ------------------------------------------------------------------------------
.. This file was automatically converted from DocBook-XML with the dbxml
.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
.. from the linux kernel, refer to:
..
.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
.. ------------------------------------------------------------------------------
Commit	Line	Data
5377d91f MH	1	.. -- coding: utf-8; mode: rst --
	2
	3	.. _media-func-open:
	4
	5	************
	6	media open()
	7	************
	8
	9	man media-open(2)
	10
	11	Open a media device
	12
	13
	14	Synopsis
	15	========
	16
	17	.. code-block:: c
	18
	19	#include <fcntl.h>
	20
	21
	22	.. c:function:: int open( const char *device_name, int flags )
	23
	24	Arguments
	25	=========
	26
	27	``device_name``
	28	Device to be opened.
	29
	30	``flags``
	31	Open flags. Access mode must be either ``O_RDONLY`` or ``O_RDWR``.
	32	Other flags have no effect.
	33
	34
	35	Description
	36	===========
	37
	38	To open a media device applications call :c:func:`open()` with the
	39	desired device name. The function has no side effects; the device
	40	configuration remain unchanged.
	41
	42	When the device is opened in read-only mode, attempts to modify its
	43	configuration will result in an error, and ``errno`` will be set to
	44	EBADF.
	45
	46
	47	Return Value
	48	============
	49
	50	:c:func:`open()` returns the new file descriptor on success. On error,
	51	-1 is returned, and ``errno`` is set appropriately. Possible error codes
	52	are:
	53
	54	EACCES
	55	The requested access to the file is not allowed.
	56
	57	EMFILE
	58	The process already has the maximum number of files open.
	59
	60	ENFILE
	61	The system limit on the total number of open files has been reached.
	62
	63	ENOMEM
	64	Insufficient kernel memory was available.
65
66	ENXIO
67	No device corresponding to this device special file exists.
68
69
70	.. ------------------------------------------------------------------------------
71	.. This file was automatically converted from DocBook-XML with the dbxml
72	.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
73	.. from the linux kernel, refer to:
74	..
75	.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
76	.. ------------------------------------------------------------------------------