1<refentry id="vidioc-enumaudio"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_ENUMAUDIO</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_ENUMAUDIO</refname> 9 <refpurpose>Enumerate audio inputs</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_audio *<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_ENUMAUDIO</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 input applications 52initialize the <structfield>index</structfield> field and zero out the 53<structfield>reserved</structfield> array of a &v4l2-audio; 54and call the <constant>VIDIOC_ENUMAUDIO</constant> ioctl with a pointer 55to 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 57inputs applications shall begin at index zero, incrementing by one 58until the driver returns <errorcode>EINVAL</errorcode>.</para> 59 60 <para>See <xref linkend="vidioc-g-audio" /> for a description of 61&v4l2-audio;.</para> 62 </refsect1> 63 64 <refsect1> 65 &return-value; 66 67 <variablelist> 68 <varlistentry> 69 <term><errorcode>EINVAL</errorcode></term> 70 <listitem> 71 <para>The number of the audio input is out of bounds, or 72there are no audio inputs at all and this ioctl is not 73supported.</para> 74 </listitem> 75 </varlistentry> 76 </variablelist> 77 </refsect1> 78</refentry> 79 80<!-- 81Local Variables: 82mode: sgml 83sgml-parent-document: "v4l2.sgml" 84indent-tabs-mode: nil 85End: 86--> 87