| 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 | 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 |
| 36 | extern "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 | */ |
| 49 | extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void); |
| 50 | |
| 51 | /** Wait a specified number of milliseconds before returning */ |
| 52 | extern DECLSPEC void SDLCALL SDL_Delay(Uint32 ms); |
| 53 | |
| 54 | /** Function prototype for the timer callback function */ |
| 55 | typedef 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 | */ |
| 86 | extern 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 | */ |
| 101 | typedef Uint32 (SDLCALL *SDL_NewTimerCallback)(Uint32 interval, void *param); |
| 102 | |
| 103 | /** Definition of the timer ID type */ |
| 104 | typedef 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 | */ |
| 109 | extern 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 | */ |
| 115 | extern 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 */ |