Mercurial > sdl-ios-xcode
view docs/man3/SDL_AddTimer.3 @ 1303:52b5afd7ecee
Date: Tue, 05 Jul 2005 21:43:26 +1000
From: Sean Childs
Subject: [SDL] Compiling SDL 1.2.8 with the free Borland compiler
When compiling SDL 1.2.8 with the free Borland compiler, I received this
error (there is a similar error that occurs in
src\video\windx5\sdl_dx5events.c):
Error E2342 ..\..\src\video\windib\sdl_dibevents.c 189: Type mismatch in
parameter 'lpPrevWndFunc' (wanted 'int (__stdcall *)()', got 'long
(__stdcall *)(void *,unsigned int,unsigned int,long)') in function
DIB_HandleMessage
I checked the MSDN library at:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/
windowsuserinterface/windowing/windowprocedures/windowprocedurereference/wind
owprocedurefunctions/callwindowproc.asp
and it had this to say:
If STRICT is not defined, the lpPrevWndFunc parameter has the data type
FARPROC. The FARPROC type is declared as follows:
int (FAR WINAPI * FARPROC) ()
In C, the FARPROC declaration indicates a callback function that has an
unspecified parameter list. In C++, however, the empty parameter list in
the declaration indicates that a function has no parameters. This subtle
distinction can break careless code. Following is one way to handle this
situation:
#ifdef STRICT
WNDPROC MyWindowProcedure
#else
FARPROC MyWindowProcedure
#endif
...
lResult = CallWindowProc(MyWindowProcedure, ...)
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Tue, 31 Jan 2006 15:30:42 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
line wrap: on
line source
.TH "SDL_AddTimer" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_AddTimer\- Add a timer which will call a callback after the specified number of milliseconds has elapsed\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBSDL_TimerID \fBSDL_AddTimer\fP\fR(\fBUint32 interval, SDL_NewTimerCallback callback, void *param\fR); .SH "CALLBACK" .PP .nf \f(CW/* type definition for the "new" timer callback function */ typedef Uint32 (*SDL_NewTimerCallback)(Uint32 interval, void *param);\fR .fi .PP .SH "DESCRIPTION" .PP Adds a callback function to be run after the specified number of milliseconds has elapsed\&. The callback function is passed the current timer interval and the user supplied parameter from the \fBSDL_AddTimer\fP call and returns the next timer interval\&. If the returned value from the callback is the same as the one passed in, the periodic alarm continues, otherwise a new alarm is scheduled\&. .PP To cancel a currently running timer call \fISDL_RemoveTimer\fR with the timer ID returned from \fBSDL_AddTimer\fP\&. .PP The timer callback function may run in a different thread than your main program, and so shouldn\&'t call any functions from within itself\&. You may always call \fISDL_PushEvent\fR, however\&. .PP The granularity of the timer is platform-dependent, but you should count on it being at least 10 ms as this is the most common number\&. This 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 (see example below)\&. If you use this function, you need to pass \fBSDL_INIT_TIMER\fP to \fISDL_Init\fR\&. .SH "RETURN VALUE" .PP Returns an ID value for the added timer or \fBNULL\fR if there was an error\&. .SH "EXAMPLES" .PP .PP .nf \f(CWmy_timer_id = SDL_AddTimer((33/10)*10, my_callbackfunc, my_callback_param);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_RemoveTimer\fP\fR, \fI\fBSDL_PushEvent\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01