From: Dead_and_gone <alaric AT novia DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Help: What causes screen flash problem in Allegro 2.0?
Date: Mon, 06 Jan 1997 08:33:34 -0600
Organization: Novia Internetworking <> 33.6kbps dialup; 402/390-2NET
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To: djgpp AT delorie DOT com
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Alaric Dailey wrote:
> 
> radams AT mail DOT diac DOT com wrote:
> : void flip_page() {
> :       if (active_page==page1) {
> :               scroll_screen(0,0);
> :               active_page=page2;
> :               inactive_page=page1;
> :       }
> :       else {
> :               scroll_screen(0,SCREEN_H);
> :               active_page=page1;
> :               inactive_page=page2;
> :       }
> : }
> :
> does scroll_screen() wait for a vertical retrace if not that is probably
> your problem, otherwise I don't know let me ponder and I will try to come
> up with something else.
ok I feel pretty STUPID after re-reading the original message I you nee
to add these two lines to your code to make it wait till the end of the 
verical retrace-

while (!(inportb(0x3DA)&0x08));
while ((inportb(0x3DA)&0x08));

-Alaric Dailey