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 &lt;fcntl.h&gt;</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>
95