SDL_AddTimer(3) SDL API Reference SDL_AddTimer(3)NAME
SDL_AddTimer- Add a timer which will call a callback after
the specified number of milliseconds has elapsed.
SYNOPSIS
#include "SDL.h"
SDL_TimerID SDL_AddTimer(Uint32 interval, SDL_NewTimer-
Callback callback, 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 milliseconds 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 contin-
ues, 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 func-
tions 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)
