Mercurial > sdl-ios-xcode
annotate docs/html/sdladdtimer.html @ 211:0cc95f442f3a
If we're looking at the /dev/input event devices, and we found
at least one, then we don't want to look at the input joystick
devices, since they're built on top of devices that we've already
seen, so we're done.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Mon, 22 Oct 2001 21:34:50 +0000 |
| parents | e5bc29de3f0a |
| children | 355632dca928 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_AddTimer</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
|
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.64 |
| 0 | 8 "><LINK |
| 9 REL="HOME" | |
| 10 TITLE="SDL Library Documentation" | |
| 11 HREF="index.html"><LINK | |
| 12 REL="UP" | |
| 13 TITLE="Time" | |
| 14 HREF="time.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="SDL_Delay" | |
| 17 HREF="sdldelay.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_RemoveTimer" | |
| 20 HREF="sdlremovetimer.html"></HEAD | |
| 21 ><BODY | |
| 22 CLASS="REFENTRY" | |
| 23 BGCOLOR="#FFF8DC" | |
| 24 TEXT="#000000" | |
| 25 LINK="#0000ee" | |
| 26 VLINK="#551a8b" | |
| 27 ALINK="#ff0000" | |
| 28 ><DIV | |
| 29 CLASS="NAVHEADER" | |
| 30 ><TABLE | |
| 31 WIDTH="100%" | |
| 32 BORDER="0" | |
| 33 CELLPADDING="0" | |
| 34 CELLSPACING="0" | |
| 35 ><TR | |
| 36 ><TH | |
| 37 COLSPAN="3" | |
| 38 ALIGN="center" | |
| 39 >SDL Library Documentation</TH | |
| 40 ></TR | |
| 41 ><TR | |
| 42 ><TD | |
| 43 WIDTH="10%" | |
| 44 ALIGN="left" | |
| 45 VALIGN="bottom" | |
| 46 ><A | |
| 47 HREF="sdldelay.html" | |
| 48 >Prev</A | |
| 49 ></TD | |
| 50 ><TD | |
| 51 WIDTH="80%" | |
| 52 ALIGN="center" | |
| 53 VALIGN="bottom" | |
| 54 ></TD | |
| 55 ><TD | |
| 56 WIDTH="10%" | |
| 57 ALIGN="right" | |
| 58 VALIGN="bottom" | |
| 59 ><A | |
| 60 HREF="sdlremovetimer.html" | |
| 61 >Next</A | |
| 62 ></TD | |
| 63 ></TR | |
| 64 ></TABLE | |
| 65 ><HR | |
| 66 ALIGN="LEFT" | |
| 67 WIDTH="100%"></DIV | |
| 68 ><H1 | |
| 69 ><A | |
| 70 NAME="SDLADDTIMER" | |
| 71 >SDL_AddTimer</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN8094" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_AddTimer -- Add a timer which will call a callback after the specified number of milliseconds has | |
| 81 elapsed.</DIV | |
| 82 ><DIV | |
| 83 CLASS="REFSYNOPSISDIV" | |
| 84 ><A | |
|
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85 NAME="AEN8097" |
| 0 | 86 ></A |
| 87 ><H2 | |
| 88 >Synopsis</H2 | |
| 89 ><DIV | |
| 90 CLASS="FUNCSYNOPSIS" | |
| 91 ><A | |
|
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92 NAME="AEN8098" |
| 0 | 93 ></A |
| 94 ><P | |
| 95 ></P | |
| 96 ><PRE | |
| 97 CLASS="FUNCSYNOPSISINFO" | |
| 98 >#include "SDL.h"</PRE | |
| 99 ><P | |
| 100 ><CODE | |
| 101 ><CODE | |
| 102 CLASS="FUNCDEF" | |
| 103 >SDL_TimerID <B | |
| 104 CLASS="FSFUNC" | |
| 105 >SDL_AddTimer</B | |
| 106 ></CODE | |
| 107 >(Uint32 interval, SDL_NewTimerCallback callback, void *param);</CODE | |
| 108 ></P | |
| 109 ><P | |
| 110 ></P | |
| 111 ></DIV | |
| 112 ></DIV | |
| 113 ><DIV | |
| 114 CLASS="REFSECT1" | |
| 115 ><A | |
| 116 NAME="SDLNEWTIMERCALLBACK" | |
| 117 ></A | |
| 118 ><H2 | |
| 119 >Callback</H2 | |
| 120 ><PRE | |
| 121 CLASS="PROGRAMLISTING" | |
| 122 >/* type definition for the "new" timer callback function */ | |
| 123 typedef Uint32 (*SDL_NewTimerCallback)(Uint32 interval, void *param);</PRE | |
| 124 ></DIV | |
| 125 ><DIV | |
| 126 CLASS="REFSECT1" | |
| 127 ><A | |
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128 NAME="AEN8107" |
| 0 | 129 ></A |
| 130 ><H2 | |
| 131 >Description</H2 | |
| 132 ><P | |
| 133 >Adds a callback function to be run after the specified number of | |
| 134 milliseconds has elapsed. The callback function is passed the current | |
| 135 timer interval and the user supplied parameter from the | |
| 136 <TT | |
| 137 CLASS="FUNCTION" | |
| 138 >SDL_AddTimer</TT | |
| 139 > call and returns the next timer | |
| 140 interval. If the returned value from the callback is the same as the one | |
| 141 passed in, the periodic alarm continues, otherwise a new alarm is | |
| 142 scheduled.</P | |
| 143 ><P | |
| 144 >To cancel a currently running timer call | |
| 145 <A | |
| 146 HREF="sdlremovetimer.html" | |
| 147 >SDL_RemoveTimer</A | |
| 148 > with the | |
| 149 timer ID returned from | |
| 150 <TT | |
| 151 CLASS="FUNCTION" | |
| 152 >SDL_AddTimer</TT | |
| 153 >.</P | |
| 154 ><P | |
| 155 >The timer callback function may run in a different thread than your | |
|
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156 main program, and so shouldn't call any functions from within itself. |
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157 You may always call <A |
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158 HREF="sdlpushevent.html" |
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159 >SDL_PushEvent</A |
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160 >, however.</P |
| 0 | 161 ><P |
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162 >The granularity of the timer is platform-dependent, but you should count |
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163 on it being at least 10 ms as this is the most common number. |
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164 This means that if |
| 0 | 165 you request a 16 ms timer, your callback will run approximately 20 ms |
| 166 later on an unloaded system. If you wanted to set a flag signaling | |
| 167 a frame update at 30 frames per second (every 33 ms), you might set a | |
| 168 timer for 30 ms (see example below). | |
| 169 | |
| 170 If you use this function, you need to pass <TT | |
| 171 CLASS="LITERAL" | |
| 172 >SDL_INIT_TIMER</TT | |
| 173 > | |
| 174 to <A | |
| 175 HREF="sdlinit.html" | |
| 176 >SDL_Init</A | |
| 177 >.</P | |
| 178 ></DIV | |
| 179 ><DIV | |
| 180 CLASS="REFSECT1" | |
| 181 ><A | |
|
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182 NAME="AEN8119" |
| 0 | 183 ></A |
| 184 ><H2 | |
| 185 >Return Value</H2 | |
| 186 ><P | |
| 187 >Returns an ID value for the added timer or | |
| 188 <SPAN | |
| 189 CLASS="RETURNVALUE" | |
| 190 >NULL</SPAN | |
| 191 > if there was an error.</P | |
| 192 ></DIV | |
| 193 ><DIV | |
| 194 CLASS="REFSECT1" | |
| 195 ><A | |
|
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196 NAME="AEN8123" |
| 0 | 197 ></A |
| 198 ><H2 | |
| 199 >Examples</H2 | |
| 200 ><P | |
| 201 ><PRE | |
| 202 CLASS="PROGRAMLISTING" | |
| 203 >my_timer_id = SDL_AddTimer((33/10)*10, my_callbackfunc, my_callback_param);</PRE | |
| 204 ></P | |
| 205 ></DIV | |
| 206 ><DIV | |
| 207 CLASS="REFSECT1" | |
| 208 ><A | |
|
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209 NAME="AEN8127" |
| 0 | 210 ></A |
| 211 ><H2 | |
| 212 >See Also</H2 | |
| 213 ><P | |
| 214 ><A | |
| 215 HREF="sdlremovetimer.html" | |
| 216 ><TT | |
| 217 CLASS="FUNCTION" | |
| 218 >SDL_RemoveTimer</TT | |
| 219 ></A | |
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220 >, |
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221 <A |
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222 HREF="sdlpushevent.html" |
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223 ><TT |
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224 CLASS="FUNCTION" |
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225 >SDL_PushEvent</TT |
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226 ></A |
| 0 | 227 ></P |
| 228 ></DIV | |
| 229 ><DIV | |
| 230 CLASS="NAVFOOTER" | |
| 231 ><HR | |
| 232 ALIGN="LEFT" | |
| 233 WIDTH="100%"><TABLE | |
| 234 WIDTH="100%" | |
| 235 BORDER="0" | |
| 236 CELLPADDING="0" | |
| 237 CELLSPACING="0" | |
| 238 ><TR | |
| 239 ><TD | |
| 240 WIDTH="33%" | |
| 241 ALIGN="left" | |
| 242 VALIGN="top" | |
| 243 ><A | |
| 244 HREF="sdldelay.html" | |
| 245 >Prev</A | |
| 246 ></TD | |
| 247 ><TD | |
| 248 WIDTH="34%" | |
| 249 ALIGN="center" | |
| 250 VALIGN="top" | |
| 251 ><A | |
| 252 HREF="index.html" | |
| 253 >Home</A | |
| 254 ></TD | |
| 255 ><TD | |
| 256 WIDTH="33%" | |
| 257 ALIGN="right" | |
| 258 VALIGN="top" | |
| 259 ><A | |
| 260 HREF="sdlremovetimer.html" | |
| 261 >Next</A | |
| 262 ></TD | |
| 263 ></TR | |
| 264 ><TR | |
| 265 ><TD | |
| 266 WIDTH="33%" | |
| 267 ALIGN="left" | |
| 268 VALIGN="top" | |
| 269 >SDL_Delay</TD | |
| 270 ><TD | |
| 271 WIDTH="34%" | |
| 272 ALIGN="center" | |
| 273 VALIGN="top" | |
| 274 ><A | |
| 275 HREF="time.html" | |
| 276 >Up</A | |
| 277 ></TD | |
| 278 ><TD | |
| 279 WIDTH="33%" | |
| 280 ALIGN="right" | |
| 281 VALIGN="top" | |
| 282 >SDL_RemoveTimer</TD | |
| 283 ></TR | |
| 284 ></TABLE | |
| 285 ></DIV | |
| 286 ></BODY | |
| 287 ></HTML | |
| 288 > |