mirror of https://gitee.com/openkylin/linux.git
87 lines
2.2 KiB
XML
87 lines
2.2 KiB
XML
<refentry id="vidioc-enumaudio">
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<refmeta>
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<refentrytitle>ioctl VIDIOC_ENUMAUDIO</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname>VIDIOC_ENUMAUDIO</refname>
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<refpurpose>Enumerate audio inputs</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcprototype>
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<funcdef>int <function>ioctl</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>int <parameter>request</parameter></paramdef>
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<paramdef>struct v4l2_audio *<parameter>argp</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Arguments</title>
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<variablelist>
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<varlistentry>
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<term><parameter>fd</parameter></term>
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<listitem>
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<para>&fd;</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>request</parameter></term>
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<listitem>
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<para>VIDIOC_ENUMAUDIO</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>argp</parameter></term>
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<listitem>
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<para></para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Description</title>
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<para>To query the attributes of an audio input applications
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initialize the <structfield>index</structfield> field and zero out the
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<structfield>reserved</structfield> array of a &v4l2-audio;
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and call the <constant>VIDIOC_ENUMAUDIO</constant> ioctl with a pointer
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to this structure. Drivers fill the rest of the structure or return an
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&EINVAL; when the index is out of bounds. To enumerate all audio
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inputs applications shall begin at index zero, incrementing by one
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until the driver returns <errorcode>EINVAL</errorcode>.</para>
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<para>See <xref linkend="vidioc-g-audio" /> for a description of
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&v4l2-audio;.</para>
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</refsect1>
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<refsect1>
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&return-value;
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<variablelist>
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<varlistentry>
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<term><errorcode>EINVAL</errorcode></term>
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<listitem>
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<para>The number of the audio input is out of bounds, or
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there are no audio inputs at all and this ioctl is not
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supported.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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</refentry>
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<!--
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Local Variables:
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mode: sgml
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sgml-parent-document: "v4l2.sgml"
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indent-tabs-mode: nil
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End:
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-->
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