/*+
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    SDL - Simple DirectMedia Layer+
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    Copyright (C) 1997-2004 Sam Lantinga+
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+
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    This library is free software; you can redistribute it and/or+
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    modify it under the terms of the GNU Library General Public+
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    License as published by the Free Software Foundation; either+
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    version 2 of the License, or (at your option) any later version.+
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+
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    This library is distributed in the hope that it will be useful,+
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    but WITHOUT ANY WARRANTY; without even the implied warranty of+
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU+
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    Library General Public License for more details.+
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+
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    You should have received a copy of the GNU Library General Public+
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    License along with this library; if not, write to the Free+
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    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA+
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+
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    Sam Lantinga+
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    slouken@libsdl.org+
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*/+
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+
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#ifdef SAVE_RCSID+
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static char rcsid =+
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 "@(#) $Id$";+
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#endif+
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+
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#include <windows.h>+
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#include <mmsystem.h>+
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+
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#include "SDL_timer.h"+
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#include "SDL_timer_c.h"+
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#include "SDL_error.h"+
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+
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#ifdef _WIN32_WCE+
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#define USE_GETTICKCOUNT+
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#define USE_SETTIMER+
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#endif+
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+
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#define TIME_WRAP_VALUE	(~(DWORD)0)+
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+
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/* The first (low-resolution) ticks value of the application */+
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static DWORD start;+
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+
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#ifndef USE_GETTICKCOUNT+
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/* Store if a high-resolution performance counter exists on the system */+
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static BOOL hires_timer_available;+
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/* The first high-resolution ticks value of the application */+
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static LARGE_INTEGER hires_start_ticks;+
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/* The number of ticks per second of the high-resolution performance counter */+
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static LARGE_INTEGER hires_ticks_per_second;+
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#endif+
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+
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void SDL_StartTicks(void)+
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{+
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	/* Set first ticks value */+
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#ifdef USE_GETTICKCOUNT+
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	start = GetTickCount();+
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#else+
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#if 0 /* Apparently there are problems with QPC on Win2K */+
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	if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE)+
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	{+
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		hires_timer_available = TRUE;+
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		QueryPerformanceCounter(&hires_start_ticks);+
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	}+
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	else+
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#endif+
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	{+
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		hires_timer_available = FALSE;+
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		timeBeginPeriod(1);		/* use 1 ms timer precision */+
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		start = timeGetTime();+
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	}+
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#endif+
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}+
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+
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Uint32 SDL_GetTicks(void)+
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{+
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	DWORD now, ticks;+
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#ifndef USE_GETTICKCOUNT+
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	LARGE_INTEGER hires_now;+
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#endif+
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+
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#ifdef USE_GETTICKCOUNT+
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	now = GetTickCount();+
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#else+
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	if (hires_timer_available)+
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	{+
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		QueryPerformanceCounter(&hires_now);+
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+
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		hires_now.QuadPart -= hires_start_ticks.QuadPart;+
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		hires_now.QuadPart *= 1000;+
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		hires_now.QuadPart /= hires_ticks_per_second.QuadPart;+
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+
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		return (DWORD)hires_now.QuadPart;+
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	}+
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	else+
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	{+
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		now = timeGetTime();+
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	}+
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#endif+
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+
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	if ( now < start ) {+
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		ticks = (TIME_WRAP_VALUE-start) + now;+
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	} else {+
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		ticks = (now - start);+
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	}+
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	return(ticks);+
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}+
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+
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void SDL_Delay(Uint32 ms)+
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{+
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	Sleep(ms);+
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}+
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+
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#ifdef USE_SETTIMER+
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+
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static UINT WIN_timer;+
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+
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int SDL_SYS_TimerInit(void)+
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{+
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	return(0);+
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}+
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+
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void SDL_SYS_TimerQuit(void)+
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{+
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	return;+
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}+
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+
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/* Forward declaration because this is called by the timer callback */+
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int SDL_SYS_StartTimer(void);+
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+
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static VOID CALLBACK TimerCallbackProc(HWND hwnd, UINT uMsg, UINT idEvent, DWORD dwTime)+
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{+
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	Uint32 ms;+
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+
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	ms = SDL_alarm_callback(SDL_alarm_interval);+
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	if ( ms != SDL_alarm_interval ) {+
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		KillTimer(NULL, idEvent);+
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		if ( ms ) {+
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			SDL_alarm_interval = ROUND_RESOLUTION(ms);+
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			SDL_SYS_StartTimer();+
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		} else {+
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			SDL_alarm_interval = 0;+
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		}+
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	}+
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}+
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+
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int SDL_SYS_StartTimer(void)+
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{+
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	int retval;+
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+
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	WIN_timer = SetTimer(NULL, 0, SDL_alarm_interval, TimerCallbackProc);+
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	if ( WIN_timer ) {+
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		retval = 0;+
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	} else {+
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		retval = -1;+
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	}+
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	return retval;+
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}+
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+
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void SDL_SYS_StopTimer(void)+
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{+
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	if ( WIN_timer ) {+
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		KillTimer(NULL, WIN_timer);+
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		WIN_timer = 0;+
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	}+
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}+
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+
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#else /* !USE_SETTIMER */+
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+
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/* Data to handle a single periodic alarm */+
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static UINT timerID = 0;+
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+
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static void CALLBACK HandleAlarm(UINT uID,  UINT uMsg, DWORD dwUser,+
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						DWORD dw1, DWORD dw2)+
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{+
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	SDL_ThreadedTimerCheck();+
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}+
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+
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+
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int SDL_SYS_TimerInit(void)+
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{+
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	MMRESULT result;+
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+
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	/* Set timer resolution */+
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	result = timeBeginPeriod(TIMER_RESOLUTION);+
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	if ( result != TIMERR_NOERROR ) {+
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		SDL_SetError("Warning: Can't set %d ms timer resolution",+
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							TIMER_RESOLUTION);+
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	}+
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	/* Allow 10 ms of drift so we don't chew on CPU */+
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	timerID = timeSetEvent(TIMER_RESOLUTION,1,HandleAlarm,0,TIME_PERIODIC);+
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	if ( ! timerID ) {+
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		SDL_SetError("timeSetEvent() failed");+
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		return(-1);+
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	}+
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	return(SDL_SetTimerThreaded(1));+
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}+
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+
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void SDL_SYS_TimerQuit(void)+
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{+
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	if ( timerID ) {+
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		timeKillEvent(timerID);+
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	}+
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	timeEndPeriod(TIMER_RESOLUTION);+
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}+
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+
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int SDL_SYS_StartTimer(void)+
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{+
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	SDL_SetError("Internal logic error: Win32 uses threaded timer");+
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	return(-1);+
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}+
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+
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void SDL_SYS_StopTimer(void)+
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{+
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	return;+
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}+
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+
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#endif /* USE_SETTIMER */+
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