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linux-next/Documentation/media/uapi/dvb/ca-fopen.rst
Mauro Carvalho Chehab 699f19e3f1 media: dvb uAPI docs: Prefer use "Digital TV instead of "DVB"
The usage of the term "DVB" at the dvb API docs is confusing,
as, right now, it can refer to either the European digital TV
standard or to the subsystem.

So, prefer calling it as "Digital TV" on most places, to avoid
ambiguity.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-09-05 06:18:03 -04:00

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.. -*- coding: utf-8; mode: rst -*-
.. _ca_fopen:
====================
Digital TV CA open()
====================
Name
----
Digital TV CA open()
Synopsis
--------
.. c:function:: int open(const char *name, int flags)
:name: dvb-ca-open
Arguments
---------
``name``
Name of specific Digital TV CA device.
``flags``
A bit-wise OR of the following flags:
.. flat-table::
:header-rows: 0
:stub-columns: 0
-
- O_RDONLY
- read-only access
-
- O_RDWR
- read/write access
-
- O_NONBLOCK
- open in non-blocking mode
(blocking mode is the default)
Description
-----------
This system call opens a named ca device (e.g. ``/dev/dvb/adapter?/ca?``)
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 CA Device in O_RDWR mode. All other attempts to open
the device in this mode will fail, and an error code will be returned.
Return Value
------------
On success 0 is returned.
On error -1 is returned, and the ``errno`` variable is set
appropriately.
Generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.