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Diffstat (limited to 'Documentation/media/uapi/v4l/func-open.rst')
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diff --git a/Documentation/media/uapi/v4l/func-open.rst b/Documentation/media/uapi/v4l/func-open.rst deleted file mode 100644 index a3d149ce6635..000000000000 --- a/Documentation/media/uapi/v4l/func-open.rst +++ /dev/null @@ -1,90 +0,0 @@ -.. 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/media/uapi/fdl-appendix.rst. -.. -.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections - -.. _func-open: - -*********** -V4L2 open() -*********** - -Name -==== - -v4l2-open - Open a V4L2 device - - -Synopsis -======== - -.. code-block:: c - - #include <fcntl.h> - - -.. c:function:: int open( const char *device_name, int flags ) - :name: v4l2-open - -Arguments -========= - -``device_name`` - Device to be opened. - -``flags`` - Open flags. Access mode must be ``O_RDWR``. This is just a - technicality, input devices still support only reading and output - devices only writing. - - When the ``O_NONBLOCK`` flag is given, the :ref:`read() <func-read>` - function and the :ref:`VIDIOC_DQBUF <VIDIOC_QBUF>` ioctl will - return the ``EAGAIN`` error code when no data is available or no - buffer is in the driver outgoing queue, otherwise these functions - block until data becomes available. All V4L2 drivers exchanging data - with applications must support the ``O_NONBLOCK`` flag. - - Other flags have no effect. - - -Description -=========== - -To open a V4L2 device applications call :ref:`open() <func-open>` with the -desired device name. This function has no side effects; all data format -parameters, current input or output, control values or other properties -remain unchanged. At the first :ref:`open() <func-open>` call after loading the -driver they will be reset to default values, drivers are never in an -undefined state. - - -Return Value -============ - -On success :ref:`open() <func-open>` returns the new file descriptor. On error --1 is returned, and the ``errno`` variable is set appropriately. -Possible error codes are: - -EACCES - The caller has no permission to access the device. - -EBUSY - The driver does not support multiple opens and the device is already - in use. - -ENXIO - No device corresponding to this device special file exists. - -ENOMEM - Not enough kernel memory was available to complete the request. - -EMFILE - The process already has the maximum number of files open. - -ENFILE - The limit on the total number of files open on the system has been - reached. |