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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 | 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 | /* Header for the SDL time management routines */ | |
27 | ||
28 | #include "SDL_stdinc.h" | |
29 | #include "SDL_error.h" | |
30 | ||
31 | #include "begin_code.h" | |
32 | /* Set up for C function definitions, even when using C++ */ | |
33 | #ifdef __cplusplus | |
34 | extern "C" { | |
35 | #endif | |
36 | ||
37 | /* This is the OS scheduler timeslice, in milliseconds */ | |
38 | #define SDL_TIMESLICE 10 | |
39 | ||
40 | /* This is the maximum resolution of the SDL timer on all platforms */ | |
41 | #define TIMER_RESOLUTION 10 /* Experimentally determined */ | |
42 | ||
43 | /* Get the number of milliseconds since the SDL library initialization. | |
44 | * Note that this value wraps if the program runs for more than ~49 days. | |
45 | */ | |
46 | extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void); | |
47 | ||
48 | /* Wait a specified number of milliseconds before returning */ | |
49 | extern DECLSPEC void SDLCALL SDL_Delay(Uint32 ms); | |
50 | ||
51 | /* Function prototype for the timer callback function */ | |
52 | typedef Uint32 (SDLCALL *SDL_TimerCallback)(Uint32 interval); | |
53 | ||
54 | /* Set a callback to run after the specified number of milliseconds has | |
55 | * elapsed. The callback function is passed the current timer interval | |
56 | * and returns the next timer interval. If the returned value is the | |
57 | * same as the one passed in, the periodic alarm continues, otherwise a | |
58 | * new alarm is scheduled. If the callback returns 0, the periodic alarm | |
59 | * is cancelled. | |
60 | * | |
61 | * To cancel a currently running timer, call SDL_SetTimer(0, NULL); | |
62 | * | |
63 | * The timer callback function may run in a different thread than your | |
64 | * main code, and so shouldn't call any functions from within itself. | |
65 | * | |
66 | * The maximum resolution of this timer is 10 ms, which means that if | |
67 | * you request a 16 ms timer, your callback will run approximately 20 ms | |
68 | * later on an unloaded system. If you wanted to set a flag signaling | |
69 | * a frame update at 30 frames per second (every 33 ms), you might set a | |
70 | * timer for 30 ms: | |
71 | * SDL_SetTimer((33/10)*10, flag_update); | |
72 | * | |
73 | * If you use this function, you need to pass SDL_INIT_TIMER to SDL_Init(). | |
74 | * | |
75 | * Under UNIX, you should not use raise or use SIGALRM and this function | |
76 | * in the same program, as it is implemented using setitimer(). You also | |
77 | * should not use this function in multi-threaded applications as signals | |
78 | * to multi-threaded apps have undefined behavior in some implementations. | |
79 | * | |
80 | * This function returns 0 if successful, or -1 if there was an error. | |
81 | */ | |
82 | extern DECLSPEC int SDLCALL SDL_SetTimer(Uint32 interval, SDL_TimerCallback callback); | |
83 | ||
84 | /* New timer API, supports multiple timers | |
85 | * Written by Stephane Peter <megastep@lokigames.com> | |
86 | */ | |
87 | ||
88 | /* Function prototype for the new timer callback function. | |
89 | * The callback function is passed the current timer interval and returns | |
90 | * the next timer interval. If the returned value is the same as the one | |
91 | * passed in, the periodic alarm continues, otherwise a new alarm is | |
92 | * scheduled. If the callback returns 0, the periodic alarm is cancelled. | |
93 | */ | |
94 | typedef Uint32 (SDLCALL *SDL_NewTimerCallback)(Uint32 interval, void *param); | |
95 | ||
96 | /* Definition of the timer ID type */ | |
97 | typedef struct _SDL_TimerID *SDL_TimerID; | |
98 | ||
99 | /* Add a new timer to the pool of timers already running. | |
100 | Returns a timer ID, or NULL when an error occurs. | |
101 | */ | |
102 | extern DECLSPEC SDL_TimerID SDLCALL SDL_AddTimer(Uint32 interval, SDL_NewTimerCallback callback, void *param); | |
103 | ||
104 | /* Remove one of the multiple timers knowing its ID. | |
105 | * Returns a boolean value indicating success. | |
106 | */ | |
107 | extern DECLSPEC SDL_bool SDLCALL SDL_RemoveTimer(SDL_TimerID t); | |
108 | ||
109 | /* Ends C function definitions when using C++ */ | |
110 | #ifdef __cplusplus | |
111 | } | |
112 | #endif | |
113 | #include "close_code.h" | |
114 | ||
115 | #endif /* _SDL_timer_h */ |