view docs/man3/SDL_AddTimer.3 @ 3950:9d9e15ab1697 SDL-1.2

Check if yasm supports a nasm-specific syntax we use (it doesn't in 0.5.0, which is still common in Linux distros, and does in 0.6.0). Disable it if we don't, attempting to fallback to using nasm. Thanks to Mike Frysinger for the patch. Fixes Bugzilla #393.
author Ryan C. Gordon <icculus@icculus.org>
date Mon, 04 Jun 2007 11:06:48 +0000
parents e5bc29de3f0a
children 546f7c1eb755
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.TH "SDL_AddTimer" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_AddTimer\- Add a timer which will call a callback after the specified number of milliseconds has elapsed\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBSDL_TimerID \fBSDL_AddTimer\fP\fR(\fBUint32 interval, SDL_NewTimerCallback callback, void *param\fR);
.SH "CALLBACK"
.PP
.nf
\f(CW/* type definition for the "new" timer callback function */
typedef Uint32 (*SDL_NewTimerCallback)(Uint32 interval, void *param);\fR
.fi
.PP
.SH "DESCRIPTION"
.PP
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 \fBSDL_AddTimer\fP 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 continues, otherwise a new alarm is scheduled\&.
.PP
To cancel a currently running timer call \fISDL_RemoveTimer\fR with the timer ID returned from \fBSDL_AddTimer\fP\&.
.PP
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 \fISDL_PushEvent\fR, however\&.
.PP
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 \fBSDL_INIT_TIMER\fP to \fISDL_Init\fR\&.
.SH "RETURN VALUE"
.PP
Returns an ID value for the added timer or \fBNULL\fR if there was an error\&.
.SH "EXAMPLES"
.PP
.PP
.nf
\f(CWmy_timer_id = SDL_AddTimer((33/10)*10, my_callbackfunc, my_callback_param);\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_RemoveTimer\fP\fR, \fI\fBSDL_PushEvent\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01