Mercurial > sdl-ios-xcode
view include/SDL_timer.h @ 388:4e9044b378fd
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author | Sam Lantinga <slouken@libsdl.org> |
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date | Sat, 01 Jun 2002 19:51:08 +0000 |
parents | 9154ec9ca3d2 |
children | b8d311d90021 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 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_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 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. */ 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 */