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| 5131 | clevermous | 1 | |
| 2 | > |
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| 3 | > |
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| 4 | >Audio Examples |
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| 5 | > |
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| 6 | NAME="GENERATOR" |
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| 7 | CONTENT="Modular DocBook HTML Stylesheet Version 1.64 |
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| 8 | "> |
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| 9 | REL="HOME" |
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| 10 | TITLE="SDL Library Documentation" |
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| 11 | HREF="index.html"> |
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| 12 | REL="UP" |
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| 13 | TITLE="Examples" |
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| 14 | HREF="guideexamples.html"> |
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| 15 | REL="PREVIOUS" |
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| 16 | TITLE="Event Examples" |
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| 17 | HREF="guideeventexamples.html"> |
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| 18 | REL="NEXT" |
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| 19 | TITLE="CDROM Examples" |
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| 20 | HREF="guidecdromexamples.html"> |
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| 21 | > |
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| 22 | CLASS="SECT1" |
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| 23 | BGCOLOR="#FFF8DC" |
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| 24 | TEXT="#000000" |
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| 25 | LINK="#0000ee" |
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| 26 | VLINK="#551a8b" |
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| 27 | ALINK="#ff0000" |
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| 28 | > |
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| 29 | CLASS="NAVHEADER" |
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| 30 | > |
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| 31 | WIDTH="100%" |
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| 32 | BORDER="0" |
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| 33 | CELLPADDING="0" |
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| 34 | CELLSPACING="0" |
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| 35 | > |
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| 36 | > |
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| 37 | COLSPAN="3" |
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| 38 | ALIGN="center" |
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| 39 | >SDL Library Documentation |
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| 40 | > |
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| 41 | > |
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| 42 | > |
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| 43 | WIDTH="10%" |
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| 44 | ALIGN="left" |
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| 45 | VALIGN="bottom" |
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| 46 | > |
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| 47 | HREF="guideeventexamples.html" |
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| 48 | >Prev |
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| 49 | > |
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| 50 | > |
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| 51 | WIDTH="80%" |
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| 52 | ALIGN="center" |
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| 53 | VALIGN="bottom" |
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| 54 | >Chapter 4. Examples |
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| 55 | > |
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| 56 | WIDTH="10%" |
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| 57 | ALIGN="right" |
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| 58 | VALIGN="bottom" |
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| 59 | > |
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| 60 | HREF="guidecdromexamples.html" |
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| 61 | >Next |
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| 62 | > |
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| 63 | > |
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| 64 | > |
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| 65 | > |
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| 66 | ALIGN="LEFT" |
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| 67 | WIDTH="100%"> |
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| 68 | > |
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| 69 | CLASS="SECT1" |
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| 70 | > |
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| 71 | CLASS="SECT1" |
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| 72 | > |
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| 73 | NAME="GUIDEAUDIOEXAMPLES" |
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| 74 | >Audio Examples |
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| 75 | > |
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| 76 | > |
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| 77 | > |
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| 78 | > |
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| 79 | CLASS="SECT2" |
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| 80 | > |
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| 81 | CLASS="SECT2" |
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| 82 | > |
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| 83 | NAME="AEN382" |
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| 84 | >Opening the audio device |
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| 85 | > |
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| 86 | > |
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| 87 | > |
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| 88 | CLASS="PROGRAMLISTING" |
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| 89 | > SDL_AudioSpec wanted; |
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| 90 | extern void fill_audio(void *udata, Uint8 *stream, int len); |
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| 91 | |||
| 92 | /* Set the audio format */ |
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| 93 | wanted.freq = 22050; |
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| 94 | wanted.format = AUDIO_S16; |
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| 95 | wanted.channels = 2; /* 1 = mono, 2 = stereo */ |
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| 96 | wanted.samples = 1024; /* Good low-latency value for callback */ |
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| 97 | wanted.callback = fill_audio; |
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| 98 | wanted.userdata = NULL; |
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| 99 | |||
| 100 | /* Open the audio device, forcing the desired format */ |
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| 101 | if ( SDL_OpenAudio(&wanted, NULL) < 0 ) { |
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| 102 | fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError()); |
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| 103 | return(-1); |
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| 104 | } |
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| 105 | return(0); |
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| 106 | > |
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| 107 | > |
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| 108 | > |
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| 109 | CLASS="SECT2" |
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| 110 | > |
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| 111 | CLASS="SECT2" |
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| 112 | > |
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| 113 | NAME="AEN386" |
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| 114 | >Playing audio |
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| 115 | > |
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| 116 | > |
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| 117 | > |
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| 118 | CLASS="PROGRAMLISTING" |
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| 119 | > static Uint8 *audio_chunk; |
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| 120 | static Uint32 audio_len; |
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| 121 | static Uint8 *audio_pos; |
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| 122 | |||
| 123 | /* The audio function callback takes the following parameters: |
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| 124 | stream: A pointer to the audio buffer to be filled |
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| 125 | len: The length (in bytes) of the audio buffer |
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| 126 | */ |
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| 127 | void fill_audio(void *udata, Uint8 *stream, int len) |
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| 128 | { |
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| 129 | /* Only play if we have data left */ |
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| 130 | if ( audio_len == 0 ) |
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| 131 | return; |
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| 132 | |||
| 133 | /* Mix as much data as possible */ |
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| 134 | len = ( len > audio_len ? audio_len : len ); |
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| 135 | SDL_MixAudio(stream, audio_pos, len, SDL_MIX_MAXVOLUME) |
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| 136 | audio_pos += len; |
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| 137 | audio_len -= len; |
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| 138 | } |
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| 139 | |||
| 140 | /* Load the audio data ... */ |
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| 141 | |||
| 142 | ;;;;; |
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| 143 | |||
| 144 | audio_pos = audio_chunk; |
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| 145 | |||
| 146 | /* Let the callback function play the audio chunk */ |
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| 147 | SDL_PauseAudio(0); |
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| 148 | |||
| 149 | /* Do some processing */ |
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| 150 | |||
| 151 | ;;;;; |
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| 152 | |||
| 153 | /* Wait for sound to complete */ |
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| 154 | while ( audio_len > 0 ) { |
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| 155 | SDL_Delay(100); /* Sleep 1/10 second */ |
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| 156 | } |
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| 157 | SDL_CloseAudio(); |
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| 158 | > |
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| 159 | > |
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| 160 | > |
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| 161 | > |
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| 162 | CLASS="NAVFOOTER" |
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| 163 | > |
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| 164 | ALIGN="LEFT" |
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| 165 | WIDTH="100%"> |
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| 166 | WIDTH="100%" |
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| 167 | BORDER="0" |
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| 168 | CELLPADDING="0" |
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| 169 | CELLSPACING="0" |
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| 170 | > |
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| 171 | > |
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| 172 | WIDTH="33%" |
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| 173 | ALIGN="left" |
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| 174 | VALIGN="top" |
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| 175 | > |
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| 176 | HREF="guideeventexamples.html" |
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| 177 | >Prev |
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| 178 | > |
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| 179 | > |
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| 180 | WIDTH="34%" |
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| 181 | ALIGN="center" |
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| 182 | VALIGN="top" |
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| 183 | > |
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| 184 | HREF="index.html" |
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| 185 | >Home |
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| 186 | > |
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| 187 | > |
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| 188 | WIDTH="33%" |
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| 189 | ALIGN="right" |
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| 190 | VALIGN="top" |
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| 191 | > |
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| 192 | HREF="guidecdromexamples.html" |
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| 193 | >Next |
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| 194 | > |
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| 195 | > |
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| 196 | > |
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| 197 | > |
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| 198 | WIDTH="33%" |
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| 199 | ALIGN="left" |
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| 200 | VALIGN="top" |
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| 201 | >Event Examples |
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| 202 | > |
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| 203 | WIDTH="34%" |
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| 204 | ALIGN="center" |
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| 205 | VALIGN="top" |
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| 206 | > |
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| 207 | HREF="guideexamples.html" |
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| 208 | >Up |
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| 209 | > |
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| 210 | > |
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| 211 | WIDTH="33%" |
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| 212 | ALIGN="right" |
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| 213 | VALIGN="top" |
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| 214 | >CDROM Examples |
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| 215 | > |
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| 216 | > |
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| 217 | > |
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| 218 | > |
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| 219 | > |
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| 220 | > |