annotate docs/man3/SDL_AddTimer.3 @ 4249:429c8dd3175d SDL-1.2

Fixed bug #713 Don't clamp the mouse coordinates to the video surface size, instead clamp them to the last known window size. This allows users to get the correct mouse coordinates even if they don't call SDL_SetVideoMode() in response to an SDL_VIDEORESIZE event (used as a hack to retain the OpenGL context on Windows and Linux after a window resize)
author Sam Lantinga <slouken@libsdl.org>
date Sun, 27 Sep 2009 05:18:43 +0000
parents 4e3b250c950e
children 1238da4a7112
rev   line source
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1 .TH "SDL_AddTimer" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference"
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2 .SH "NAME"
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3 SDL_AddTimer \- Add a timer which will call a callback after the specified number of milliseconds has elapsed\&.
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4 .SH "SYNOPSIS"
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5 .PP
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6 \fB#include "SDL\&.h"
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7 .sp
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8 \fBSDL_TimerID \fBSDL_AddTimer\fP\fR(\fBUint32 interval, SDL_NewTimerCallback callback, void *param\fR);
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9 .SH "CALLBACK"
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10 .PP
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11 .nf
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12 \f(CW/* type definition for the "new" timer callback function */
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13 typedef Uint32 (*SDL_NewTimerCallback)(Uint32 interval, void *param);\fR
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14 .fi
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15 .PP
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16 .SH "DESCRIPTION"
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17 .PP
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18 Adds a callback function to be run after the specified number of milliseconds has elapsed\&. The callback function is passed the current timer interval and the user supplied parameter from the \fBSDL_AddTimer\fP call and returns the next timer interval\&. If the returned value from the callback is the same as the one passed in, the periodic alarm continues, otherwise a new alarm is scheduled\&.
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19 .PP
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20 To cancel a currently running timer call \fISDL_RemoveTimer\fR with the timer ID returned from \fBSDL_AddTimer\fP\&.
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21 .PP
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22 The timer callback function may run in a different thread than your main program, and so shouldn\&'t call any functions from within itself\&. You may always call \fISDL_PushEvent\fR, however\&.
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23 .PP
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24 The granularity of the timer is platform-dependent, but you should count on it being at least 10 ms as this is the most common number\&. This means that if you request a 16 ms timer, your callback will run approximately 20 ms later on an unloaded system\&. If you wanted to set a flag signaling a frame update at 30 frames per second (every 33 ms), you might set a timer for 30 ms (see example below)\&. If you use this function, you need to pass \fBSDL_INIT_TIMER\fP to \fISDL_Init\fR\&.
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25 .SH "RETURN VALUE"
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26 .PP
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27 Returns an ID value for the added timer or \fBNULL\fR if there was an error\&.
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28 .SH "EXAMPLES"
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29 .PP
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30 .PP
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31 .nf
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32 \f(CWmy_timer_id = SDL_AddTimer((33/10)*10, my_callbackfunc, my_callback_param);\fR
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33 .fi
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34 .PP
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35 .SH "SEE ALSO"
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36 .PP
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37 \fI\fBSDL_RemoveTimer\fP\fR, \fI\fBSDL_PushEvent\fP\fR
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38 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01