include/SDL_timer.h
changeset 0 74212992fb08
child 251 b8688cfdc232
--- /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 */