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Based on kernel version 3.16. Page generated on 2014-08-06 21:38 EST.

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>
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