This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
SDL_timer.h
1
2
/*
SDL - Simple DirectMedia Layer
3
Copyright (C) 1997-2006 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
11
12
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
13
Lesser General Public License for more details.
15
16
17
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19
Sam Lantinga
20
slouken@libsdl.org
21
22
23
24
25
*/
#ifndef _SDL_timer_h
#define _SDL_timer_h
26
27
28
29
30
/**
* \file SDL_timer.h
*
* Header for the SDL time management routines
*/
32
#include "SDL_stdinc.h"
33
#include "SDL_error.h"
34
35
36
37
#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
38
/* *INDENT-OFF* */
39
extern "C" {
40
/* *INDENT-ON* */
41
42
43
44
45
46
#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 */
47
#define TIMER_RESOLUTION 10 /* Experimentally determined */
48
49
50
/* Get the number of milliseconds since the SDL library initialization.
* Note that this value wraps if the program runs for more than ~49 days.
52
extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void);
53
54
/* Wait a specified number of milliseconds before returning */
55
extern DECLSPEC void SDLCALL SDL_Delay(Uint32 ms);
56
57
/* Function prototype for the timer callback function */
58
typedef Uint32(SDLCALL * SDL_TimerCallback) (Uint32 interval);
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
/* 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.
85
86
*
* This function returns 0 if successful, or -1 if there was an error.
87
*/
88
89
extern DECLSPEC int SDLCALL SDL_SetTimer(Uint32 interval,
SDL_TimerCallback callback);
90
91
92
93
94
95
96
97
98
99
100
/* 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.
*/
101
typedef Uint32(SDLCALL * SDL_NewTimerCallback) (Uint32 interval, void *param);
102
103
104
105
106
107
108
/* 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.
*/
109
110
111
extern DECLSPEC SDL_TimerID SDLCALL SDL_AddTimer(Uint32 interval,
SDL_NewTimerCallback
callback, void *param);
112
113
114
115
/* Remove one of the multiple timers knowing its ID.
* Returns a boolean value indicating success.
*/
116
extern DECLSPEC SDL_bool SDLCALL SDL_RemoveTimer(SDL_TimerID t);
117
118
119
/* Ends C function definitions when using C++ */
#ifdef __cplusplus
120
/* *INDENT-OFF* */
121
}
122
/* *INDENT-ON* */
123
124
125
126
#endif
#include "close_code.h"
#endif /* _SDL_timer_h */
127
128
/* vi: set ts=4 sw=4 expandtab: */