This repository has been archived by the owner on Feb 11, 2021.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) 1997-2009 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
27
28
29
* \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
#endif
43
44
45
/**
* This is the OS scheduler timeslice, in milliseconds.
*/
46
47
#define SDL_TIMESLICE 10
48
49
50
51
/**
* This is the maximum resolution of the SDL timer on all platforms.
*/
#define TIMER_RESOLUTION 10 /**< Experimentally determined */
53
54
55
56
/**
* Get the number of milliseconds since the SDL library initialization.
*
* Note that this value wraps if the program runs for more than ~49 days.
58
extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void);
60
61
62
/**
* Wait a specified number of milliseconds before returning.
*/
63
extern DECLSPEC void SDLCALL SDL_Delay(Uint32 ms);
65
66
67
/**
* Function prototype for the timer callback function.
*/
68
typedef Uint32(SDLCALL * SDL_TimerCallback) (Uint32 interval);
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
/**
* 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
* \code SDL_SetTimer(0, NULL); \endcode
*
* 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:
* \code
* SDL_SetTimer((33/10)*10, flag_update);
* \endcode
*
* 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.
*
* \return 0 if successful, or -1 if there was an error.
101
*/
102
103
extern DECLSPEC int SDLCALL SDL_SetTimer(Uint32 interval,
SDL_TimerCallback callback);
105
106
107
108
/**
* \name Peter timers
* New timer API, supports multiple timers
* Written by Stephane Peter <megastep@lokigames.com>
109
*/
110
/*@{*/
112
113
114
115
116
117
118
/**
* 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.
119
*/
120
typedef Uint32(SDLCALL * SDL_NewTimerCallback) (Uint32 interval, void *param);
122
123
124
/**
* Definition of the timer ID type.
*/
125
126
typedef struct _SDL_TimerID *SDL_TimerID;
127
128
129
/**
* Add a new timer to the pool of timers already running.
* \return A timer ID, or NULL when an error occurs.
130
*/
131
132
133
extern DECLSPEC SDL_TimerID SDLCALL SDL_AddTimer(Uint32 interval,
SDL_NewTimerCallback
callback, void *param);
135
136
137
/**
* Remove one of the multiple timers knowing its ID.
* \return A boolean value indicating success or failure.
138
*/
139
extern DECLSPEC SDL_bool SDLCALL SDL_RemoveTimer(SDL_TimerID t);
141
142
/*@}*//*Peter timers*/
143
144
/* Ends C function definitions when using C++ */
#ifdef __cplusplus
145
/* *INDENT-OFF* */
146
}
147
/* *INDENT-ON* */
148
149
150
151
#endif
#include "close_code.h"
#endif /* _SDL_timer_h */
152
153
/* vi: set ts=4 sw=4 expandtab: */