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| >Video for Linux Two API Specification: Revision 0.24</TH |
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| NAME="FUNC-MUNMAP" |
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| >V4L2 munmap()</H1 |
| ><DIV |
| CLASS="REFNAMEDIV" |
| ><A |
| NAME="AEN14041" |
| ></A |
| ><H2 |
| >Name</H2 |
| >v4l2-munmap -- Unmap device memory</DIV |
| ><DIV |
| CLASS="REFSYNOPSISDIV" |
| ><A |
| NAME="AEN14044" |
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| >Synopsis</H2 |
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| ><PRE |
| CLASS="FUNCSYNOPSISINFO" |
| >#include <unistd.h> |
| #include <sys/mman.h></PRE |
| ><P |
| ><CODE |
| ><CODE |
| CLASS="FUNCDEF" |
| >int munmap</CODE |
| >(void *start, size_t length);</CODE |
| ></P |
| ><P |
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| CLASS="REFSECT1" |
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| NAME="AEN14054" |
| ></A |
| ><H2 |
| >Arguments</H2 |
| ><P |
| ></P |
| ><DIV |
| CLASS="VARIABLELIST" |
| ><DL |
| ><DT |
| ><CODE |
| CLASS="PARAMETER" |
| >start</CODE |
| ></DT |
| ><DD |
| ><P |
| >Address of the mapped buffer as returned by the |
| <A |
| HREF="r13889.htm" |
| ><CODE |
| CLASS="FUNCTION" |
| >mmap()</CODE |
| ></A |
| > function.</P |
| ></DD |
| ><DT |
| ><CODE |
| CLASS="PARAMETER" |
| >length</CODE |
| ></DT |
| ><DD |
| ><P |
| >Length of the mapped buffer. This must be the same |
| value as given to <CODE |
| CLASS="FUNCTION" |
| >mmap()</CODE |
| > and returned by the |
| driver in the struct <A |
| HREF="x5953.htm#V4L2-BUFFER" |
| >v4l2_buffer</A |
| > <CODE |
| CLASS="STRUCTFIELD" |
| >length</CODE |
| > |
| field.</P |
| ></DD |
| ></DL |
| ></DIV |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN14072" |
| ></A |
| ><H2 |
| >Description</H2 |
| ><P |
| >Unmaps a previously with the <A |
| HREF="r13889.htm" |
| ><CODE |
| CLASS="FUNCTION" |
| >mmap()</CODE |
| ></A |
| > function mapped |
| buffer and frees it, if possible. </P |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN14077" |
| ></A |
| ><H2 |
| >Return Value</H2 |
| ><P |
| >On success <CODE |
| CLASS="FUNCTION" |
| >munmap()</CODE |
| > returns 0, on |
| failure -1 and the <CODE |
| CLASS="VARNAME" |
| >errno</CODE |
| > variable is set |
| appropriately:</P |
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| ></P |
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| >EINVAL</SPAN |
| ></DT |
| ><DD |
| ><P |
| >The <CODE |
| CLASS="PARAMETER" |
| >start</CODE |
| > or |
| <CODE |
| CLASS="PARAMETER" |
| >length</CODE |
| > is incorrect, or no buffers have been |
| mapped yet.</P |
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