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| >Video for Linux Two API Specification: Revision 0.24</TH |
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| ><H1 |
| ><A |
| NAME="VIDIOC-G-INPUT" |
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| >ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT</H1 |
| ><DIV |
| CLASS="REFNAMEDIV" |
| ><A |
| NAME="AEN11221" |
| ></A |
| ><H2 |
| >Name</H2 |
| >VIDIOC_G_INPUT, VIDIOC_S_INPUT -- Query or select the current video input</DIV |
| ><DIV |
| CLASS="REFSYNOPSISDIV" |
| ><A |
| NAME="AEN11225" |
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| ><H2 |
| >Synopsis</H2 |
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| ><A |
| NAME="AEN11226" |
| ></A |
| ><P |
| ><CODE |
| ><CODE |
| CLASS="FUNCDEF" |
| >int ioctl</CODE |
| >(int fd, int request, int *argp);</CODE |
| ></P |
| ><P |
| ></P |
| ></DIV |
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| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN11236" |
| ></A |
| ><H2 |
| >Arguments</H2 |
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| CLASS="VARIABLELIST" |
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| ><DT |
| ><CODE |
| CLASS="PARAMETER" |
| >fd</CODE |
| ></DT |
| ><DD |
| ><P |
| >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_G_INPUT, VIDIOC_S_INPUT</P |
| ></DD |
| ><DT |
| ><CODE |
| CLASS="PARAMETER" |
| >argp</CODE |
| ></DT |
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| ><A |
| NAME="AEN11256" |
| ></A |
| ><H2 |
| >Description</H2 |
| ><P |
| >To query the current video input applications call the |
| <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_G_INPUT</CODE |
| > ioctl with a pointer to an integer |
| where the driver stores the number of the input, as in the |
| struct <A |
| HREF="r8936.htm#V4L2-INPUT" |
| >v4l2_input</A |
| > <CODE |
| CLASS="STRUCTFIELD" |
| >index</CODE |
| > field. This ioctl will |
| fail only when there are no video inputs, returning |
| <SPAN |
| CLASS="ERRORCODE" |
| >EINVAL</SPAN |
| >.</P |
| ><P |
| >To select a video input applications store the number of the |
| desired input in an integer and call the |
| <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_INPUT</CODE |
| > ioctl with a pointer to this |
| integer. Side effects are possible. For example inputs may support |
| different video standards, so the driver may implicitly switch the |
| current standard. It is good practice to select an input before |
| querying or negotiating any other parameters.</P |
| ><P |
| >Information about video inputs is available using the |
| <A |
| HREF="r8936.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_ENUMINPUT</CODE |
| ></A |
| > ioctl.</P |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN11268" |
| ></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 |
| ><P |
| ></P |
| ><DIV |
| CLASS="VARIABLELIST" |
| ><DL |
| ><DT |
| ><SPAN |
| CLASS="ERRORCODE" |
| >EINVAL</SPAN |
| ></DT |
| ><DD |
| ><P |
| >The number of the video input is out of bounds, or |
| there are no video inputs at all and this ioctl is not |
| supported.</P |
| ></DD |
| ><DT |
| ><SPAN |
| CLASS="ERRORCODE" |
| >EBUSY</SPAN |
| ></DT |
| ><DD |
| ><P |
| >I/O is in progress, the input cannot be |
| switched.</P |
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