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00004 <title>Vorbisfile - datatype - ov_callbacks</title>
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00011 <td><p class=tiny>Vorbisfile documentation</p></td>
00012 <td align=right><p class=tiny>vorbisfile version 1.68 - 20030307</p></td>
00013 </tr>
00014 </table>
00015
00016 <h1>ov_callbacks</h1>
00017
00018 <p><i>declared in "vorbis/codec.h"</i></p>
00019
00020 <p>
00021 The ov_callbacks structure contains file manipulation function prototypes necessary for opening, closing, seeking, and location.
00022
00023 <p>
00024 The ov_callbacks structure does not need to be user-defined if you are
00025 working with stdio-based file manipulation; the <a
00026 href="ov_open.html">ov_open()</a> call provides default callbacks for
00027 stdio. ov_callbacks are defined and passed to <a
00028 href="ov_open_callbacks.html">ov_open_callbacks()</a> when
00029 implementing non-stdio based stream manipulation (such as playback
00030 from a memory buffer).
00031 <p>
00032
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00036 <pre><b>typedef struct {
00037 size_t (*read_func) (void *ptr, size_t size, size_t nmemb, void *datasource);
00038 int (*seek_func) (void *datasource, ogg_int64_t offset, int whence);
00039 int (*close_func) (void *datasource);
00040 long (*tell_func) (void *datasource);
00041 } ov_callbacks;</b></pre>
00042 </td>
00043 </tr>
00044 </table>
00045
00046 <h3>Relevant Struct Members</h3>
00047 <dl>
00048 <dt><i>read_func</i></dt>
00049 <dd>Pointer to custom data reading function.</dd>
00050 <dt><i>seek_func</i></dt>
00051 <dd>Pointer to custom data seeking function. If the data source is not seekable (or the application wants the data source to be treated as unseekable at all times), the provided seek callback should always return -1 (failure).</dd>
00052 <dt><i>close_func</i></dt>
00053 <dd>Pointer to custom data source closure function.</dd>
00054 <dt><i>tell_func</i></dt>
00055 <dd>Pointer to custom data location function.</dd>
00056 </dl>
00057
00058 <p>
00059
00060 See <a href="callbacks.html">the callbacks and non-stdio I/O document</a> for more
00061 detailed information on required behavior of the various callback
00062 functions.<p>
00063
00064 <br><br>
00065 <hr noshade>
00066 <table border=0 width=100%>
00067 <tr valign=top>
00068 <td><p class=tiny>copyright © 2003 Xiph.org</p></td>
00069 <td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a></p></td>
00070 </tr><tr>
00071 <td><p class=tiny>Vorbisfile documentation</p></td>
00072 <td align=right><p class=tiny>vorbisfile version 1.68 - 20030307</p></td>
00073 </tr>
00074 </table>
00075
00076 </body>
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