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SDL_AddTimer(3) 	       SDL API Reference	       SDL_AddTimer(3)


NAME

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


SYNOPSIS

       #include "SDL.h"

       SDL_TimerID SDL_AddTimer(Uint32	interval,  SDL_NewTimerCallback  call-
       back, void *param);


CALLBACK

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


DESCRIPTION

       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.


RETURN VALUE

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


EXAMPLES

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


SEE ALSO

       SDL_RemoveTimer, SDL_PushEvent

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

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