[fpc-pascal] Re: KeyPressed

[Tomas Hajny]

Date sent:      	Mon, 22 Aug 2005 21:45:05 +0200 (CEST)
From:           	Michael Van Canneyt <michael at freepascal.org>
To:             	FPC-Pascal users discussions <fpc-pascal at lists.freepascal.org>
Subject:        	Re: [fpc-pascal] Re:  KeyPressed
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> > Some, perhaps....I ran into this problem when I was still compiling
> > the program as a pure Pascal program.  (I had the interfaces to
> > other languages commented out.)
> > 
> > I'm using: CRT, IO, DOS, Video, Printer, Graph, and Drivers.  
> 
> This is the problem. You can't use the Drivers, CRT and Video unit
> together. Each of them tries to catch keystrokes, and they will
> randomly receive them. (depending on thread usage).
> 
> You should use only Video or only CRT or only Drivers 
> (though it can be that drivers and video work together)
> 
> > It's only one or
> > two modules that need Video, Printer, Graph and Drivers (not
> > necessarily the same ones).  But, of course when it all gets linked
> > together, you only need one reference to cause trouble, right?
> > 
> > And I don't care about multi-platform, so the C library DLL looks
> > kind of like the way to go.
> 
> It will still cause problems, because the C library also will
> interfere with the Video and CRT units...
> 
> It's planned to base the CRT unit on the video unit (so they would
> work together), but until now no-one had time.

Yes - it's specifically Crt plus Drivers (which in turn uses Keyboard 
and Mouse units), which interfere. Crt should be rewritten to use 
unit Keyboard for ReadKey and KeyPressed implementation - this should 
probably resolve most of the problems. The other part (Crt accessing 
console independently of the Video unit) isn't good design, but 
shouldn't be causing your problems.

Tomas