Based on kernel version 4.7.2. Page generated on 2016-08-22 22:45 EST.
1 <refentry id="vidioc-enumaudioout"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_ENUMAUDOUT</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_ENUMAUDOUT</refname> 9 <refpurpose>Enumerate audio outputs</refpurpose> 10 </refnamediv> 11 12 <refsynopsisdiv> 13 <funcsynopsis> 14 <funcprototype> 15 <funcdef>int <function>ioctl</function></funcdef> 16 <paramdef>int <parameter>fd</parameter></paramdef> 17 <paramdef>int <parameter>request</parameter></paramdef> 18 <paramdef>struct v4l2_audioout *<parameter>argp</parameter></paramdef> 19 </funcprototype> 20 </funcsynopsis> 21 </refsynopsisdiv> 22 23 <refsect1> 24 <title>Arguments</title> 25 26 <variablelist> 27 <varlistentry> 28 <term><parameter>fd</parameter></term> 29 <listitem> 30 <para>&fd;</para> 31 </listitem> 32 </varlistentry> 33 <varlistentry> 34 <term><parameter>request</parameter></term> 35 <listitem> 36 <para>VIDIOC_ENUMAUDOUT</para> 37 </listitem> 38 </varlistentry> 39 <varlistentry> 40 <term><parameter>argp</parameter></term> 41 <listitem> 42 <para></para> 43 </listitem> 44 </varlistentry> 45 </variablelist> 46 </refsect1> 47 48 <refsect1> 49 <title>Description</title> 50 51 <para>To query the attributes of an audio output applications 52 initialize the <structfield>index</structfield> field and zero out the 53 <structfield>reserved</structfield> array of a &v4l2-audioout; and 54 call the <constant>VIDIOC_G_AUDOUT</constant> ioctl with a pointer 55 to this structure. Drivers fill the rest of the structure or return an 56 &EINVAL; when the index is out of bounds. To enumerate all audio 57 outputs applications shall begin at index zero, incrementing by one 58 until the driver returns <errorcode>EINVAL</errorcode>.</para> 59 60 <para>Note connectors on a TV card to loop back the received audio 61 signal to a sound card are not audio outputs in this sense.</para> 62 63 <para>See <xref linkend="vidioc-g-audioout" /> for a description of 64 &v4l2-audioout;.</para> 65 </refsect1> 66 67 <refsect1> 68 &return-value; 69 70 <variablelist> 71 <varlistentry> 72 <term><errorcode>EINVAL</errorcode></term> 73 <listitem> 74 <para>The number of the audio output is out of bounds.</para> 75 </listitem> 76 </varlistentry> 77 </variablelist> 78 </refsect1> 79 </refentry>
