Mercurial > sdl-ios-xcode
diff include/SDL_timer.h @ 0:74212992fb08
Initial revision
author | Sam Lantinga <slouken@lokigames.com> |
---|---|
date | Thu, 26 Apr 2001 16:45:43 +0000 |
parents | |
children | b8688cfdc232 |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/include/SDL_timer.h Thu Apr 26 16:45:43 2001 +0000 @@ -0,0 +1,118 @@ +/* + SDL - Simple DirectMedia Layer + Copyright (C) 1997, 1998, 1999, 2000, 2001 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@devolution.com +*/ + +#ifdef SAVE_RCSID +static char rcsid = + "@(#) $Id$"; +#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 __cplusplus +extern "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 SDL_GetTicks(void); + +/* Wait a specified number of milliseconds before returning */ +extern DECLSPEC void SDL_Delay(Uint32 ms); + +/* Function prototype for the timer callback function */ +typedef Uint32 (*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. + */ +extern DECLSPEC int 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 (*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 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 SDL_RemoveTimer(SDL_TimerID t); + +/* Ends C function definitions when using C++ */ +#ifdef __cplusplus +} +#endif +#include "close_code.h" + +#endif /* _SDL_timer_h */