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     40 >Video for Linux Two API Specification: Revision 0.24</TH
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     72 ><A
     73 NAME="FUNC-MUNMAP"
     74 ></A
     75 >V4L2 munmap()</H1
     76 ><DIV
     77 CLASS="REFNAMEDIV"
     78 ><A
     79 NAME="AEN14041"
     80 ></A
     81 ><H2
     82 >Name</H2
     83 >v4l2-munmap&nbsp;--&nbsp;Unmap device memory</DIV
     84 ><DIV
     85 CLASS="REFSYNOPSISDIV"
     86 ><A
     87 NAME="AEN14044"
     88 ></A
     89 ><H2
     90 >Synopsis</H2
     91 ><DIV
     92 CLASS="FUNCSYNOPSIS"
     93 ><P
     94 ></P
     95 ><A
     96 NAME="AEN14045"
     97 ></A
     98 ><PRE
     99 CLASS="FUNCSYNOPSISINFO"
    100 >#include &lt;unistd.h&gt;
    101 #include &lt;sys/mman.h&gt;</PRE
    102 ><P
    103 ><CODE
    104 ><CODE
    105 CLASS="FUNCDEF"
    106 >int munmap</CODE
    107 >(void *start, size_t length);</CODE
    108 ></P
    109 ><P
    110 ></P
    111 ></DIV
    112 ></DIV
    113 ><DIV
    114 CLASS="REFSECT1"
    115 ><A
    116 NAME="AEN14054"
    117 ></A
    118 ><H2
    119 >Arguments</H2
    120 ><P
    121 ></P
    122 ><DIV
    123 CLASS="VARIABLELIST"
    124 ><DL
    125 ><DT
    126 ><CODE
    127 CLASS="PARAMETER"
    128 >start</CODE
    129 ></DT
    130 ><DD
    131 ><P
    132 >Address of the mapped buffer as returned by the
    133 <A
    134 HREF="r13889.htm"
    135 ><CODE
    136 CLASS="FUNCTION"
    137 >mmap()</CODE
    138 ></A
    139 > function.</P
    140 ></DD
    141 ><DT
    142 ><CODE
    143 CLASS="PARAMETER"
    144 >length</CODE
    145 ></DT
    146 ><DD
    147 ><P
    148 >Length of the mapped buffer. This must be the same
    149 value as given to <CODE
    150 CLASS="FUNCTION"
    151 >mmap()</CODE
    152 > and returned by the
    153 driver in the struct&nbsp;<A
    154 HREF="x5953.htm#V4L2-BUFFER"
    155 >v4l2_buffer</A
    156 > <CODE
    157 CLASS="STRUCTFIELD"
    158 >length</CODE
    159 >
    160 field.</P
    161 ></DD
    162 ></DL
    163 ></DIV
    164 ></DIV
    165 ><DIV
    166 CLASS="REFSECT1"
    167 ><A
    168 NAME="AEN14072"
    169 ></A
    170 ><H2
    171 >Description</H2
    172 ><P
    173 >Unmaps a previously with the <A
    174 HREF="r13889.htm"
    175 ><CODE
    176 CLASS="FUNCTION"
    177 >mmap()</CODE
    178 ></A
    179 > function mapped
    180 buffer and frees it, if possible. </P
    181 ></DIV
    182 ><DIV
    183 CLASS="REFSECT1"
    184 ><A
    185 NAME="AEN14077"
    186 ></A
    187 ><H2
    188 >Return Value</H2
    189 ><P
    190 >On success <CODE
    191 CLASS="FUNCTION"
    192 >munmap()</CODE
    193 > returns 0, on
    194 failure -1 and the <CODE
    195 CLASS="VARNAME"
    196 >errno</CODE
    197 > variable is set
    198 appropriately:</P
    199 ><P
    200 ></P
    201 ><DIV
    202 CLASS="VARIABLELIST"
    203 ><DL
    204 ><DT
    205 ><SPAN
    206 CLASS="ERRORCODE"
    207 >EINVAL</SPAN
    208 ></DT
    209 ><DD
    210 ><P
    211 >The <CODE
    212 CLASS="PARAMETER"
    213 >start</CODE
    214 > or
    215 <CODE
    216 CLASS="PARAMETER"
    217 >length</CODE
    218 > is incorrect, or no buffers have been
    219 mapped yet.</P
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