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| >Video for Linux Two API Specification: Revision 0.24</TH |
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| ><H1 |
| ><A |
| NAME="VIDIOC-G-FREQUENCY" |
| ></A |
| >ioctl VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY</H1 |
| ><DIV |
| CLASS="REFNAMEDIV" |
| ><A |
| NAME="AEN11098" |
| ></A |
| ><H2 |
| >Name</H2 |
| >VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY -- Get or set tuner or modulator radio |
| frequency</DIV |
| ><DIV |
| CLASS="REFSYNOPSISDIV" |
| ><A |
| NAME="AEN11102" |
| ></A |
| ><H2 |
| >Synopsis</H2 |
| ><DIV |
| CLASS="FUNCSYNOPSIS" |
| ><P |
| ></P |
| ><A |
| NAME="AEN11103" |
| ></A |
| ><P |
| ><CODE |
| ><CODE |
| CLASS="FUNCDEF" |
| >int ioctl</CODE |
| >(int fd, int request, struct v4l2_frequency |
| *argp);</CODE |
| ></P |
| ><P |
| ></P |
| ></DIV |
| ><DIV |
| CLASS="FUNCSYNOPSIS" |
| ><P |
| ></P |
| ><A |
| NAME="AEN11113" |
| ></A |
| ><P |
| ><CODE |
| ><CODE |
| CLASS="FUNCDEF" |
| >int ioctl</CODE |
| >(int fd, int request, const struct v4l2_frequency |
| *argp);</CODE |
| ></P |
| ><P |
| ></P |
| ></DIV |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN11123" |
| ></A |
| ><H2 |
| >Arguments</H2 |
| ><P |
| ></P |
| ><DIV |
| CLASS="VARIABLELIST" |
| ><DL |
| ><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_FREQUENCY, VIDIOC_S_FREQUENCY</P |
| ></DD |
| ><DT |
| ><CODE |
| CLASS="PARAMETER" |
| >argp</CODE |
| ></DT |
| ><DD |
| ><P |
| ></P |
| ></DD |
| ></DL |
| ></DIV |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN11143" |
| ></A |
| ><H2 |
| >Description</H2 |
| ><P |
| >To get the current tuner or modulator radio frequency |
| applications set the <CODE |
| CLASS="STRUCTFIELD" |
| >tuner</CODE |
| > field of a |
| struct <A |
| HREF="r11094.htm#V4L2-FREQUENCY" |
| >v4l2_frequency</A |
| > to the respective tuner or modulator number (only |
| input devices have tuners, only output devices have modulators), zero |
| out the <CODE |
| CLASS="STRUCTFIELD" |
| >reserved</CODE |
| > array and |
| call the <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_G_FREQUENCY</CODE |
| > ioctl with a pointer |
| to this structure. The driver stores the current frequency in the |
| <CODE |
| CLASS="STRUCTFIELD" |
| >frequency</CODE |
| > field.</P |
| ><P |
| >To change the current tuner or modulator radio frequency |
| applications initialize the <CODE |
| CLASS="STRUCTFIELD" |
| >tuner</CODE |
| >, |
| <CODE |
| CLASS="STRUCTFIELD" |
| >type</CODE |
| > and |
| <CODE |
| CLASS="STRUCTFIELD" |
| >frequency</CODE |
| > fields, and the |
| <CODE |
| CLASS="STRUCTFIELD" |
| >reserved</CODE |
| > array of a struct <A |
| HREF="r11094.htm#V4L2-FREQUENCY" |
| >v4l2_frequency</A |
| > and |
| call the <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_FREQUENCY</CODE |
| > ioctl with a pointer |
| to this structure. When the requested frequency is not possible the |
| driver assumes the closest possible value. However |
| <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_FREQUENCY</CODE |
| > is a write-only ioctl, it does |
| not return the actual new frequency.</P |
| ><DIV |
| CLASS="TABLE" |
| ><A |
| NAME="V4L2-FREQUENCY" |
| ></A |
| ><P |
| ><B |
| >Table 1. struct <CODE |
| CLASS="STRUCTNAME" |
| >v4l2_frequency</CODE |
| ></B |
| ></P |
| ><TABLE |
| BORDER="0" |
| FRAME="void" |
| WIDTH="100%" |
| CLASS="CALSTABLE" |
| ><COL |
| WIDTH="25%" |
| TITLE="C1"><COL |
| WIDTH="25%" |
| TITLE="C2"><COL |
| WIDTH="50%" |
| TITLE="C3"><TBODY |
| VALIGN="TOP" |
| ><TR |
| ><TD |
| >__u32</TD |
| ><TD |
| ><CODE |
| CLASS="STRUCTFIELD" |
| >tuner</CODE |
| ></TD |
| ><TD |
| >The tuner or modulator index number. This is the |
| same value as in the struct <A |
| HREF="r8936.htm#V4L2-INPUT" |
| >v4l2_input</A |
| > <CODE |
| CLASS="STRUCTFIELD" |
| >tuner</CODE |
| > |
| field and the struct <A |
| HREF="r12342.htm#V4L2-TUNER" |
| >v4l2_tuner</A |
| > <CODE |
| CLASS="STRUCTFIELD" |
| >index</CODE |
| > field, or |
| the struct <A |
| HREF="r9149.htm#V4L2-OUTPUT" |
| >v4l2_output</A |
| > <CODE |
| CLASS="STRUCTFIELD" |
| >modulator</CODE |
| > field and the |
| struct <A |
| HREF="r11430.htm#V4L2-MODULATOR" |
| >v4l2_modulator</A |
| > <CODE |
| CLASS="STRUCTFIELD" |
| >index</CODE |
| > field.</TD |
| ></TR |
| ><TR |
| ><TD |
| >enum <A |
| HREF="r12342.htm#V4L2-TUNER-TYPE" |
| >v4l2_tuner_type</A |
| ></TD |
| ><TD |
| ><CODE |
| CLASS="STRUCTFIELD" |
| >type</CODE |
| ></TD |
| ><TD |
| >The tuner type. This is the same value as in the |
| struct <A |
| HREF="r12342.htm#V4L2-TUNER" |
| >v4l2_tuner</A |
| > <CODE |
| CLASS="STRUCTFIELD" |
| >type</CODE |
| > field. The field is not |
| applicable to modulators, i. e. ignored by drivers.</TD |
| ></TR |
| ><TR |
| ><TD |
| >__u32</TD |
| ><TD |
| ><CODE |
| CLASS="STRUCTFIELD" |
| >frequency</CODE |
| ></TD |
| ><TD |
| >Tuning frequency in units of 62.5 kHz, or if the |
| struct <A |
| HREF="r12342.htm#V4L2-TUNER" |
| >v4l2_tuner</A |
| > or struct <A |
| HREF="r11430.htm#V4L2-MODULATOR" |
| >v4l2_modulator</A |
| > <CODE |
| CLASS="STRUCTFIELD" |
| >capabilities</CODE |
| > flag |
| <CODE |
| CLASS="CONSTANT" |
| >V4L2_TUNER_CAP_LOW</CODE |
| > is set, in units of 62.5 |
| Hz.</TD |
| ></TR |
| ><TR |
| ><TD |
| >__u32</TD |
| ><TD |
| ><CODE |
| CLASS="STRUCTFIELD" |
| >reserved</CODE |
| >[8];</TD |
| ><TD |
| >Reserved for future extensions. Drivers and |
| applications must set the array to zero.</TD |
| ></TR |
| ></TBODY |
| ></TABLE |
| ></DIV |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN11203" |
| ></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 <CODE |
| CLASS="STRUCTFIELD" |
| >tuner</CODE |
| > index is out of |
| bounds or the value in the <CODE |
| CLASS="STRUCTFIELD" |
| >type</CODE |
| > field is |
| wrong.</P |
| ></DD |
| ></DL |
| ></DIV |
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| VIDIOC_TRY_FMT</TD |
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