NAME¶

SDL_AddTimer - Call a callback function at a future time.

SYNOPSIS¶

#include "SDL3/SDL.h"

SDL_TimerID SDL_AddTimer(Uint32 interval,
                         SDL_TimerCallback callback,
                         void *param);

DESCRIPTION¶

If you use this function, you must pass SDL_INIT_TIMER to SDL_Init ().

The callback function is passed the current timer interval and the user supplied parameter from the SDL_AddTimer () call and should return the next timer interval. If the value returned from the callback is 0, the timer is canceled.

The callback is run on a separate thread.

Timers take into account the amount of time it took to execute the callback. For example, if the callback took 250 ms to execute and returned 1000 (ms), the timer would only wait another 750 ms before its next iteration.

Timing may be inexact due to OS scheduling. Be sure to note the current time with SDL_GetTicksNS () or

SDL_GetPerformanceCounter () in case your callback needs to adjust for variances.

FUNCTION PARAMETERS¶

interval

the timer delay, in milliseconds, passed to callback

callback

the SDL_TimerCallback
function to call when the specified interval elapses

param

a pointer that is passed to callback

RETURN VALUE¶

Returns a timer ID or 0 if an error occurs; call

SDL_GetError () for more information.

AVAILABILITY¶

This function is available since SDL 3.0.0.

SEE ALSO¶

SDL_RemoveTimer(3)