OpenCloudOS-Kernel/Documentation/media/uapi/dvb/video-fopen.rst

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.. -*- coding: utf-8; mode: rst -*-
.. _video_fopen:
================
dvb video open()
================
Name
----
dvb video open()
Synopsis
--------
.. cpp:function:: int open(const char *deviceName, int flags)
Arguments
---------
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- const char \*deviceName
- Name of specific video device.
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- int flags
- A bit-wise OR of the following flags:
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-
- O_RDONLY read-only access
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-
- O_RDWR read/write access
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-
- O_NONBLOCK open in non-blocking mode
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-
- (blocking mode is the default)
Description
-----------
This system call opens a named video device (e.g.
/dev/dvb/adapter0/video0) for subsequent use.
When an open() call has succeeded, the device will be ready for use. The
significance of blocking or non-blocking mode is described in the
documentation for functions where there is a difference. It does not
affect the semantics of the open() call itself. A device opened in
blocking mode can later be put into non-blocking mode (and vice versa)
using the F_SETFL command of the fcntl system call. This is a standard
system call, documented in the Linux manual page for fcntl. Only one
user can open the Video Device in O_RDWR mode. All other attempts to
open the device in this mode will fail, and an error-code will be
returned. If the Video Device is opened in O_RDONLY mode, the only
ioctl call that can be used is VIDEO_GET_STATUS. All other call will
return an error code.
Return Value
------------
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- ``ENODEV``
- Device driver not loaded/available.
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- ``EINTERNAL``
- Internal error.
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- ``EBUSY``
- Device or resource busy.
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- ``EINVAL``
- Invalid argument.