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| >Video for Linux Two API Specification: Revision 0.24</TH |
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| ><H1 |
| ><A |
| NAME="VIDIOC-ENUMAUDIO" |
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| >ioctl VIDIOC_ENUMAUDIO</H1 |
| ><DIV |
| CLASS="REFNAMEDIV" |
| ><A |
| NAME="AEN8246" |
| ></A |
| ><H2 |
| >Name</H2 |
| >VIDIOC_ENUMAUDIO -- Enumerate audio inputs</DIV |
| ><DIV |
| CLASS="REFSYNOPSISDIV" |
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| NAME="AEN8249" |
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| ><H2 |
| >Synopsis</H2 |
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| ><CODE |
| ><CODE |
| CLASS="FUNCDEF" |
| >int ioctl</CODE |
| >(int fd, int request, struct v4l2_audio *argp);</CODE |
| ></P |
| ><P |
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| >Arguments</H2 |
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| ><CODE |
| CLASS="PARAMETER" |
| >fd</CODE |
| ></DT |
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| >File descriptor returned by <A |
| HREF="r14090.htm" |
| ><CODE |
| CLASS="FUNCTION" |
| >open()</CODE |
| ></A |
| >.</P |
| ></DD |
| ><DT |
| ><CODE |
| CLASS="PARAMETER" |
| >request</CODE |
| ></DT |
| ><DD |
| ><P |
| >VIDIOC_ENUMAUDIO</P |
| ></DD |
| ><DT |
| ><CODE |
| CLASS="PARAMETER" |
| >argp</CODE |
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| ><A |
| NAME="AEN8280" |
| ></A |
| ><H2 |
| >Description</H2 |
| ><P |
| >To query the attributes of an audio input applications |
| initialize the <CODE |
| CLASS="STRUCTFIELD" |
| >index</CODE |
| > field and zero out the |
| <CODE |
| CLASS="STRUCTFIELD" |
| >reserved</CODE |
| > array of a struct <A |
| HREF="r9539.htm#V4L2-AUDIO" |
| >v4l2_audio</A |
| > |
| and call the <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_ENUMAUDIO</CODE |
| > ioctl with a pointer |
| to this structure. Drivers fill the rest of the structure or return an |
| <SPAN |
| CLASS="ERRORCODE" |
| >EINVAL</SPAN |
| > error code when the index is out of bounds. To enumerate all audio |
| inputs applications shall begin at index zero, incrementing by one |
| until the driver returns <SPAN |
| CLASS="ERRORCODE" |
| >EINVAL</SPAN |
| >.</P |
| ><P |
| >See <A |
| HREF="r9539.htm" |
| >ioctl VIDIOC_G_AUDIO, VIDIOC_S_AUDIO(2)</A |
| > for a description of |
| struct <A |
| HREF="r9539.htm#V4L2-AUDIO" |
| >v4l2_audio</A |
| >.</P |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
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| NAME="AEN8292" |
| ></A |
| ><H2 |
| >Return Value</H2 |
| ><P |
| >On success <SPAN |
| CLASS="RETURNVALUE" |
| >0</SPAN |
| > is returned, on error <SPAN |
| CLASS="RETURNVALUE" |
| >-1</SPAN |
| > and the <CODE |
| CLASS="VARNAME" |
| >errno</CODE |
| > variable is set appropriately:</P |
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| ><DT |
| ><SPAN |
| CLASS="ERRORCODE" |
| >EINVAL</SPAN |
| ></DT |
| ><DD |
| ><P |
| >The number of the audio input is out of bounds, or |
| there are no audio inputs at all and this ioctl is not |
| supported.</P |
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