Mercurial > sdl-ios-xcode
view docs/html/sdlsettimer.html @ 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 | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_SetTimer</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Time" HREF="time.html"><LINK REL="PREVIOUS" TITLE="SDL_RemoveTimer" HREF="sdlremovetimer.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdlremovetimer.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" > </TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLSETTIMER" ></A >SDL_SetTimer</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN8557" ></A ><H2 >Name</H2 >SDL_SetTimer -- Set a callback to run after the specified number of milliseconds has elapsed.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN8560" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN8561" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_SetTimer</B ></CODE >(Uint32 interval, SDL_TimerCallback callback);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="SDLTIMERCALLBACK" ></A ><H2 >Callback</H2 ><P >/* Function prototype for the timer callback function */ typedef Uint32 (*SDL_TimerCallback)(Uint32 interval);</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8570" ></A ><H2 >Description</H2 ><P >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.</P ><P >To cancel a currently running timer, call <TT CLASS="FUNCTION" >SDL_SetTimer(0, NULL);</TT ></P ><P >The timer callback function may run in a different thread than your main constant, and so shouldn't call any functions from within itself.</P ><P >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 (see example below).</P ><P >If you use this function, you need to pass <TT CLASS="LITERAL" >SDL_INIT_TIMER</TT > to <TT CLASS="FUNCTION" >SDL_Init()</TT >.</P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B >This function is kept for compatibility but has been superseded by the new timer functions <A HREF="sdladdtimer.html" >SDL_AddTimer</A > and <A HREF="sdlremovetimer.html" >SDL_RemoveTimer</A > which support multiple timers.</P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8584" ></A ><H2 >Examples</H2 ><P ><PRE CLASS="PROGRAMLISTING" >SDL_SetTimer((33/10)*10, my_callback);</PRE ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8588" ></A ><H2 >See Also</H2 ><P ><A HREF="sdladdtimer.html" ><TT CLASS="FUNCTION" >SDL_AddTimer</TT ></A ></P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlremovetimer.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" > </TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_RemoveTimer</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="time.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" > </TD ></TR ></TABLE ></DIV ></BODY ></HTML >