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     64 ><H1
     65 ><A
     66 NAME="SDLSETTIMER"
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     68 >SDL_SetTimer</H1
     69 ><DIV
     70 CLASS="REFNAMEDIV"
     71 ><A
     72 NAME="AEN8557"
     73 ></A
     74 ><H2
     75 >Name</H2
     76 >SDL_SetTimer&nbsp;--&nbsp;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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