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Diffstat (limited to 'Documentation/DocBook/v4l/media-func-open.xml')
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diff --git a/Documentation/DocBook/v4l/media-func-open.xml b/Documentation/DocBook/v4l/media-func-open.xml new file mode 100644 index 000000000000..f7df034dc9ed --- /dev/null +++ b/Documentation/DocBook/v4l/media-func-open.xml | |||
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1 | <refentry id="media-func-open"> | ||
2 | <refmeta> | ||
3 | <refentrytitle>media open()</refentrytitle> | ||
4 | &manvol; | ||
5 | </refmeta> | ||
6 | |||
7 | <refnamediv> | ||
8 | <refname>media-open</refname> | ||
9 | <refpurpose>Open a media device</refpurpose> | ||
10 | </refnamediv> | ||
11 | |||
12 | <refsynopsisdiv> | ||
13 | <funcsynopsis> | ||
14 | <funcsynopsisinfo>#include <fcntl.h></funcsynopsisinfo> | ||
15 | <funcprototype> | ||
16 | <funcdef>int <function>open</function></funcdef> | ||
17 | <paramdef>const char *<parameter>device_name</parameter></paramdef> | ||
18 | <paramdef>int <parameter>flags</parameter></paramdef> | ||
19 | </funcprototype> | ||
20 | </funcsynopsis> | ||
21 | </refsynopsisdiv> | ||
22 | |||
23 | <refsect1> | ||
24 | <title>Arguments</title> | ||
25 | |||
26 | <variablelist> | ||
27 | <varlistentry> | ||
28 | <term><parameter>device_name</parameter></term> | ||
29 | <listitem> | ||
30 | <para>Device to be opened.</para> | ||
31 | </listitem> | ||
32 | </varlistentry> | ||
33 | <varlistentry> | ||
34 | <term><parameter>flags</parameter></term> | ||
35 | <listitem> | ||
36 | <para>Open flags. Access mode must be either <constant>O_RDONLY</constant> | ||
37 | or <constant>O_RDWR</constant>. Other flags have no effect.</para> | ||
38 | </listitem> | ||
39 | </varlistentry> | ||
40 | </variablelist> | ||
41 | </refsect1> | ||
42 | <refsect1> | ||
43 | <title>Description</title> | ||
44 | <para>To open a media device applications call <function>open()</function> | ||
45 | with the desired device name. The function has no side effects; the device | ||
46 | configuration remain unchanged.</para> | ||
47 | <para>When the device is opened in read-only mode, attemps to modify its | ||
48 | configuration will result in an error, and <varname>errno</varname> will be | ||
49 | set to <errorcode>EBADF</errorcode>.</para> | ||
50 | </refsect1> | ||
51 | <refsect1> | ||
52 | <title>Return Value</title> | ||
53 | |||
54 | <para><function>open</function> returns the new file descriptor on success. | ||
55 | On error, -1 is returned, and <varname>errno</varname> is set appropriately. | ||
56 | Possible error codes are:</para> | ||
57 | |||
58 | <variablelist> | ||
59 | <varlistentry> | ||
60 | <term><errorcode>EACCES</errorcode></term> | ||
61 | <listitem> | ||
62 | <para>The requested access to the file is not allowed.</para> | ||
63 | </listitem> | ||
64 | </varlistentry> | ||
65 | <varlistentry> | ||
66 | <term><errorcode>EMFILE</errorcode></term> | ||
67 | <listitem> | ||
68 | <para>The process already has the maximum number of files open. | ||
69 | </para> | ||
70 | </listitem> | ||
71 | </varlistentry> | ||
72 | <varlistentry> | ||
73 | <term><errorcode>ENFILE</errorcode></term> | ||
74 | <listitem> | ||
75 | <para>The system limit on the total number of open files has been | ||
76 | reached.</para> | ||
77 | </listitem> | ||
78 | </varlistentry> | ||
79 | <varlistentry> | ||
80 | <term><errorcode>ENOMEM</errorcode></term> | ||
81 | <listitem> | ||
82 | <para>Insufficient kernel memory was available.</para> | ||
83 | </listitem> | ||
84 | </varlistentry> | ||
85 | <varlistentry> | ||
86 | <term><errorcode>ENXIO</errorcode></term> | ||
87 | <listitem> | ||
88 | <para>No device corresponding to this device special file exists. | ||
89 | </para> | ||
90 | </listitem> | ||
91 | </varlistentry> | ||
92 | </variablelist> | ||
93 | </refsect1> | ||
94 | </refentry> | ||