| 1 | .TH "SDL_SetTimer" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
| 2 | .SH "NAME" |
| 3 | SDL_SetTimer \- Set a callback to run after the specified number of milliseconds has elapsed\&. |
| 4 | .SH "SYNOPSIS" |
| 5 | .PP |
| 6 | \fB#include "SDL\&.h" |
| 7 | .sp |
| 8 | \fBint \fBSDL_SetTimer\fP\fR(\fBUint32 interval, SDL_TimerCallback callback\fR); |
| 9 | .SH "CALLBACK" |
| 10 | .PP |
| 11 | /* Function prototype for the timer callback function */ typedef Uint32 (*SDL_TimerCallback)(Uint32 interval); |
| 12 | .SH "DESCRIPTION" |
| 13 | .PP |
| 14 | Set a callback to run after the specified number of milliseconds has elapsed\&. The callback function is passed the current timer interval and returns the next timer interval\&. If the returned value is the same as the one passed in, the periodic alarm continues, otherwise a new alarm is scheduled\&. |
| 15 | .PP |
| 16 | To cancel a currently running timer, call \fBSDL_SetTimer(0, NULL);\fP |
| 17 | .PP |
| 18 | The timer callback function may run in a different thread than your main constant, and so shouldn\&'t call any functions from within itself\&. |
| 19 | .PP |
| 20 | The maximum resolution of this timer is 10 ms, which 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)\&. |
| 21 | .PP |
| 22 | If you use this function, you need to pass \fBSDL_INIT_TIMER\fP to \fBSDL_Init()\fP\&. |
| 23 | .PP |
| 24 | .RS |
| 25 | \fBNote: |
| 26 | .PP |
| 27 | This function is kept for compatibility but has been superseded by the new timer functions \fISDL_AddTimer\fR and \fISDL_RemoveTimer\fR which support multiple timers\&. |
| 28 | .RE |
| 29 | .SH "EXAMPLES" |
| 30 | .PP |
| 31 | .PP |
| 32 | .nf |
| 33 | \f(CWSDL_SetTimer((33/10)*10, my_callback);\fR |
| 34 | .fi |
| 35 | .PP |
| 36 | .SH "SEE ALSO" |
| 37 | .PP |
| 38 | \fI\fBSDL_AddTimer\fP\fR |
| 39 | .\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01 |