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SDL_AddTimer(3) 	       SDL API Reference	       SDL_AddTimer(3)


SDL_AddTimer - Add a timer which will call a callback after the speci- fied number of milliseconds has elapsed.


#include "SDL.h" SDL_TimerID SDL_AddTimer(Uint32 interval, SDL_NewTimerCallback call- back, void *param);


/* type definition for the "new" timer callback function */ typedef Uint32 (*SDL_NewTimerCallback)(Uint32 interval, void *param);


Adds a callback function to be run after the specified number of mil- liseconds has elapsed. The callback function is passed the current timer interval and the user supplied parameter from the SDL_AddTimer 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 con- tinues, otherwise a new alarm is scheduled. To cancel a currently running timer call SDL_RemoveTimer with the timer ID returned from SDL_AddTimer. 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 SDL_PushEvent, however. 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 SDL_INIT_TIMER to SDL_Init.


Returns an ID value for the added timer or NULL if there was an error.


my_timer_id = SDL_AddTimer((33/10)*10, my_callbackfunc, my_callback_param);


SDL_RemoveTimer, SDL_PushEvent SDL Tue 11 Sep 2001, 23:01 SDL_AddTimer(3)

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