| 1 | <HTML |
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| 3 | ><TITLE |
| 4 | >SDL_SetTimer</TITLE |
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| 7 | CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
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| 13 | TITLE="Time" |
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| 16 | TITLE="SDL_RemoveTimer" |
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| 37 | >SDL Library Documentation</TH |
| 38 | ></TR |
| 39 | ><TR |
| 40 | ><TD |
| 41 | WIDTH="10%" |
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| 43 | VALIGN="bottom" |
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| 45 | HREF="sdlremovetimer.html" |
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| 61 | ><HR |
| 62 | ALIGN="LEFT" |
| 63 | WIDTH="100%"></DIV |
| 64 | ><H1 |
| 65 | ><A |
| 66 | NAME="SDLSETTIMER" |
| 67 | ></A |
| 68 | >SDL_SetTimer</H1 |
| 69 | ><DIV |
| 70 | CLASS="REFNAMEDIV" |
| 71 | ><A |
| 72 | NAME="AEN8557" |
| 73 | ></A |
| 74 | ><H2 |
| 75 | >Name</H2 |
| 76 | >SDL_SetTimer -- Set a callback to run after the specified number of milliseconds has |
| 77 | elapsed.</DIV |
| 78 | ><DIV |
| 79 | CLASS="REFSYNOPSISDIV" |
| 80 | ><A |
| 81 | NAME="AEN8560" |
| 82 | ></A |
| 83 | ><H2 |
| 84 | >Synopsis</H2 |
| 85 | ><DIV |
| 86 | CLASS="FUNCSYNOPSIS" |
| 87 | ><A |
| 88 | NAME="AEN8561" |
| 89 | ></A |
| 90 | ><P |
| 91 | ></P |
| 92 | ><PRE |
| 93 | CLASS="FUNCSYNOPSISINFO" |
| 94 | >#include "SDL.h"</PRE |
| 95 | ><P |
| 96 | ><CODE |
| 97 | ><CODE |
| 98 | CLASS="FUNCDEF" |
| 99 | >int <B |
| 100 | CLASS="FSFUNC" |
| 101 | >SDL_SetTimer</B |
| 102 | ></CODE |
| 103 | >(Uint32 interval, SDL_TimerCallback callback);</CODE |
| 104 | ></P |
| 105 | ><P |
| 106 | ></P |
| 107 | ></DIV |
| 108 | ></DIV |
| 109 | ><DIV |
| 110 | CLASS="REFSECT1" |
| 111 | ><A |
| 112 | NAME="SDLTIMERCALLBACK" |
| 113 | ></A |
| 114 | ><H2 |
| 115 | >Callback</H2 |
| 116 | ><P |
| 117 | >/* Function prototype for the timer callback function */ |
| 118 | typedef Uint32 (*SDL_TimerCallback)(Uint32 interval);</P |
| 119 | ></DIV |
| 120 | ><DIV |
| 121 | CLASS="REFSECT1" |
| 122 | ><A |
| 123 | NAME="AEN8570" |
| 124 | ></A |
| 125 | ><H2 |
| 126 | >Description</H2 |
| 127 | ><P |
| 128 | >Set a callback to run after the specified number of milliseconds has |
| 129 | elapsed. The callback function is passed the current timer interval |
| 130 | and returns the next timer interval. If the returned value is the |
| 131 | same as the one passed in, the periodic alarm continues, otherwise a |
| 132 | new alarm is scheduled.</P |
| 133 | ><P |
| 134 | >To cancel a currently running timer, call |
| 135 | <TT |
| 136 | CLASS="FUNCTION" |
| 137 | >SDL_SetTimer(0, NULL);</TT |
| 138 | ></P |
| 139 | ><P |
| 140 | >The timer callback function may run in a different thread than your |
| 141 | main constant, and so shouldn't call any functions from within itself.</P |
| 142 | ><P |
| 143 | >The maximum resolution of this timer is 10 ms, which means that if |
| 144 | you request a 16 ms timer, your callback will run approximately 20 ms |
| 145 | later on an unloaded system. If you wanted to set a flag signaling |
| 146 | a frame update at 30 frames per second (every 33 ms), you might set a |
| 147 | timer for 30 ms (see example below).</P |
| 148 | ><P |
| 149 | >If you use this function, you need to pass <TT |
| 150 | CLASS="LITERAL" |
| 151 | >SDL_INIT_TIMER</TT |
| 152 | > |
| 153 | to <TT |
| 154 | CLASS="FUNCTION" |
| 155 | >SDL_Init()</TT |
| 156 | >.</P |
| 157 | ><DIV |
| 158 | CLASS="NOTE" |
| 159 | ><BLOCKQUOTE |
| 160 | CLASS="NOTE" |
| 161 | ><P |
| 162 | ><B |
| 163 | >Note: </B |
| 164 | >This function is kept for compatibility but has been superseded |
| 165 | by the new timer functions |
| 166 | <A |
| 167 | HREF="sdladdtimer.html" |
| 168 | >SDL_AddTimer</A |
| 169 | > and |
| 170 | <A |
| 171 | HREF="sdlremovetimer.html" |
| 172 | >SDL_RemoveTimer</A |
| 173 | > which support |
| 174 | multiple timers.</P |
| 175 | ></BLOCKQUOTE |
| 176 | ></DIV |
| 177 | ></DIV |
| 178 | ><DIV |
| 179 | CLASS="REFSECT1" |
| 180 | ><A |
| 181 | NAME="AEN8584" |
| 182 | ></A |
| 183 | ><H2 |
| 184 | >Examples</H2 |
| 185 | ><P |
| 186 | ><PRE |
| 187 | CLASS="PROGRAMLISTING" |
| 188 | >SDL_SetTimer((33/10)*10, my_callback);</PRE |
| 189 | ></P |
| 190 | ></DIV |
| 191 | ><DIV |
| 192 | CLASS="REFSECT1" |
| 193 | ><A |
| 194 | NAME="AEN8588" |
| 195 | ></A |
| 196 | ><H2 |
| 197 | >See Also</H2 |
| 198 | ><P |
| 199 | ><A |
| 200 | HREF="sdladdtimer.html" |
| 201 | ><TT |
| 202 | CLASS="FUNCTION" |
| 203 | >SDL_AddTimer</TT |
| 204 | ></A |
| 205 | ></P |
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| 247 | >SDL_RemoveTimer</TD |
| 248 | ><TD |
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