source: trunk/external/sdl-1.2.15/include/SDL_timer.h @ 2214

Last change on this file since 2214 was 1586, checked in by sam, 9 years ago

build: update Windows SDL binaries to 1.2.15.

File size: 4.4 KB
Line 
1/*
2    SDL - Simple DirectMedia Layer
3    Copyright (C) 1997-2012 Sam Lantinga
4
5    This library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 2.1 of the License, or (at your option) any later version.
9
10    This library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Lesser General Public License for more details.
14
15    You should have received a copy of the GNU Lesser General Public
16    License along with this library; if not, write to the Free Software
17    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18
19    Sam Lantinga
20    slouken@libsdl.org
21*/
22
23#ifndef _SDL_timer_h
24#define _SDL_timer_h
25
26/** @file SDL_timer.h
27 *  Header for the SDL time management routines
28 */
29
30#include "SDL_stdinc.h"
31#include "SDL_error.h"
32
33#include "begin_code.h"
34/* Set up for C function definitions, even when using C++ */
35#ifdef __cplusplus
36extern "C" {
37#endif
38
39/** This is the OS scheduler timeslice, in milliseconds */
40#define SDL_TIMESLICE           10
41
42/** This is the maximum resolution of the SDL timer on all platforms */
43#define TIMER_RESOLUTION        10      /**< Experimentally determined */
44
45/**
46 * Get the number of milliseconds since the SDL library initialization.
47 * Note that this value wraps if the program runs for more than ~49 days.
48 */
49extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void);
50
51/** Wait a specified number of milliseconds before returning */
52extern DECLSPEC void SDLCALL SDL_Delay(Uint32 ms);
53
54/** Function prototype for the timer callback function */
55typedef Uint32 (SDLCALL *SDL_TimerCallback)(Uint32 interval);
56
57/**
58 * Set a callback to run after the specified number of milliseconds has
59 * elapsed. The callback function is passed the current timer interval
60 * and returns the next timer interval.  If the returned value is the
61 * same as the one passed in, the periodic alarm continues, otherwise a
62 * new alarm is scheduled.  If the callback returns 0, the periodic alarm
63 * is cancelled.
64 *
65 * To cancel a currently running timer, call SDL_SetTimer(0, NULL);
66 *
67 * The timer callback function may run in a different thread than your
68 * main code, and so shouldn't call any functions from within itself.
69 *
70 * The maximum resolution of this timer is 10 ms, which means that if
71 * you request a 16 ms timer, your callback will run approximately 20 ms
72 * later on an unloaded system.  If you wanted to set a flag signaling
73 * a frame update at 30 frames per second (every 33 ms), you might set a
74 * timer for 30 ms:
75 *   @code SDL_SetTimer((33/10)*10, flag_update); @endcode
76 *
77 * If you use this function, you need to pass SDL_INIT_TIMER to SDL_Init().
78 *
79 * Under UNIX, you should not use raise or use SIGALRM and this function
80 * in the same program, as it is implemented using setitimer().  You also
81 * should not use this function in multi-threaded applications as signals
82 * to multi-threaded apps have undefined behavior in some implementations.
83 *
84 * This function returns 0 if successful, or -1 if there was an error.
85 */
86extern DECLSPEC int SDLCALL SDL_SetTimer(Uint32 interval, SDL_TimerCallback callback);
87
88/** @name New timer API
89 * New timer API, supports multiple timers
90 * Written by Stephane Peter <megastep@lokigames.com>
91 */
92/*@{*/
93
94/**
95 * Function prototype for the new timer callback function.
96 * The callback function is passed the current timer interval and returns
97 * the next timer interval.  If the returned value is the same as the one
98 * passed in, the periodic alarm continues, otherwise a new alarm is
99 * scheduled.  If the callback returns 0, the periodic alarm is cancelled.
100 */
101typedef Uint32 (SDLCALL *SDL_NewTimerCallback)(Uint32 interval, void *param);
102
103/** Definition of the timer ID type */
104typedef struct _SDL_TimerID *SDL_TimerID;
105
106/** Add a new timer to the pool of timers already running.
107 *  Returns a timer ID, or NULL when an error occurs.
108 */
109extern DECLSPEC SDL_TimerID SDLCALL SDL_AddTimer(Uint32 interval, SDL_NewTimerCallback callback, void *param);
110
111/**
112 * Remove one of the multiple timers knowing its ID.
113 * Returns a boolean value indicating success.
114 */
115extern DECLSPEC SDL_bool SDLCALL SDL_RemoveTimer(SDL_TimerID t);
116
117/*@}*/
118
119/* Ends C function definitions when using C++ */
120#ifdef __cplusplus
121}
122#endif
123#include "close_code.h"
124
125#endif /* _SDL_timer_h */
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