tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2.. c:namespace:: DTV.dmx
3
4.. _dmx_fopen:
5
6=======================
7Digital TV demux open()
8=======================
9
10Name
11----
12
13Digital TV demux open()
14
15Synopsis
16--------
17
18.. c:function:: int open(const char *deviceName, int flags)
19
20Arguments
21---------
22
23``name``
24 Name of specific Digital TV demux device.
25
26``flags``
27 A bit-wise OR of the following flags:
28
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35
36 -
37 - ``O_RDONLY``
38 - read-only access
39
40 -
41 - ``O_RDWR``
42 - read/write access
43
44 -
45 - ``O_NONBLOCK``
46 - open in non-blocking mode
47 (blocking mode is the default)
48
49Description
50-----------
51
52This system call, used with a device name of ``/dev/dvb/adapter?/demux?``,
53allocates a new filter and returns a handle which can be used for
54subsequent control of that filter. This call has to be made for each
55filter to be used, i.e. every returned file descriptor is a reference to
56a single filter. ``/dev/dvb/adapter?/dvr?`` is a logical device to be used
57for retrieving Transport Streams for digital video recording. When
58reading from this device a transport stream containing the packets from
59all PES filters set in the corresponding demux device
60(``/dev/dvb/adapter?/demux?``) having the output set to ``DMX_OUT_TS_TAP``.
61A recorded Transport Stream is replayed by writing to this device.
62
63The significance of blocking or non-blocking mode is described in the
64documentation for functions where there is a difference. It does not
65affect the semantics of the ``open()`` call itself. A device opened
66in blocking mode can later be put into non-blocking mode (and vice versa)
67using the ``F_SETFL`` command of the fcntl system call.
68
69Return Value
70------------
71
72On success 0 is returned.
73
74On error -1 is returned, and the ``errno`` variable is set
75appropriately.
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83
84 - - ``EMFILE``
85 - "Too many open files", i.e. no more filters available.
86
87The generic error codes are described at the
88:ref:`Generic Error Codes <gen-errors>` chapter.