/*    SDL - Simple DirectMedia Layer    Copyright (C) 1997-2004 Sam Lantinga    This library is free software; you can redistribute it and/or    modify it under the terms of the GNU Library General Public    License as published by the Free Software Foundation; either    version 2 of the License, or (at your option) any later version.    This library is distributed in the hope that it will be useful,    but WITHOUT ANY WARRANTY; without even the implied warranty of    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU    Library General Public License for more details.    You should have received a copy of the GNU Library General Public    License along with this library; if not, write to the Free    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA    Sam Lantinga    slouken@libsdl.org*/#ifdef SAVE_RCSIDstatic char rcsid = "@(#) $Id: SDL_timer.h,v 1.7 2005/01/13 23:24:56 slouken Exp $";#endif#ifndef _SDL_timer_h#define _SDL_timer_h/* Header for the SDL time management routines */#include "SDL_main.h"#include "SDL_types.h"#include "begin_code.h"/* Set up for C function definitions, even when using C++ */#ifdef __cplusplusextern "C" {#endif/* This is the OS scheduler timeslice, in milliseconds */#define SDL_TIMESLICE		10/* This is the maximum resolution of the SDL timer on all platforms */#define TIMER_RESOLUTION	10	/* Experimentally determined *//* Get the number of milliseconds since the SDL library initialization. * Note that this value wraps if the program runs for more than ~49 days. */ extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void);/* Wait a specified number of milliseconds before returning */extern DECLSPEC void SDLCALL SDL_Delay(Uint32 ms);/* Function prototype for the timer callback function */typedef Uint32 (SDLCALL *SDL_TimerCallback)(Uint32 interval);/* 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.  If the callback returns 0, the periodic alarm * is cancelled. * * To cancel a currently running timer, call SDL_SetTimer(0, NULL); * * The timer callback function may run in a different thread than your * main code, and so shouldn't call any functions from within itself. * * 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: *   SDL_SetTimer((33/10)*10, flag_update); * * If you use this function, you need to pass SDL_INIT_TIMER to SDL_Init(). * * Under UNIX, you should not use raise or use SIGALRM and this function * in the same program, as it is implemented using setitimer().  You also * should not use this function in multi-threaded applications as signals * to multi-threaded apps have undefined behavior in some implementations. * * This function returns 0 if successful, or -1 if there was an error. */extern DECLSPEC int SDLCALL SDL_SetTimer(Uint32 interval, SDL_TimerCallback callback);/* New timer API, supports multiple timers * Written by Stephane Peter <megastep@lokigames.com> *//* Function prototype for the new timer callback function. * 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.  If the callback returns 0, the periodic alarm is cancelled. */typedef Uint32 (SDLCALL *SDL_NewTimerCallback)(Uint32 interval, void *param);/* Definition of the timer ID type */typedef struct _SDL_TimerID *SDL_TimerID;/* Add a new timer to the pool of timers already running.   Returns a timer ID, or NULL when an error occurs. */extern DECLSPEC SDL_TimerID SDLCALL SDL_AddTimer(Uint32 interval, SDL_NewTimerCallback callback, void *param);/* Remove one of the multiple timers knowing its ID. * Returns a boolean value indicating success. */extern DECLSPEC SDL_bool SDLCALL SDL_RemoveTimer(SDL_TimerID t);/* Ends C function definitions when using C++ */#ifdef __cplusplus}#endif#include "close_code.h"#endif /* _SDL_timer_h */