summaryrefslogtreecommitdiff
path: root/Documentation/userspace-api/media/dvb/ca-fopen.rst
blob: 9ca4bd1d8d5ff0a839dd88fb218ebc11af0b477d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later

.. _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:

.. tabularcolumns:: |p{2.5cm}|p{15.0cm}|

.. flat-table::
    :header-rows:  0
    :stub-columns: 0
    :widths: 1 16

    -  - ``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.