Date: Fri, 06 Jan 1995 10:20:16 -0500 (CDT)
From: Aaron Ucko <UCKO AT VAX1 DOT ROCKHURST DOT EDU>
Subject: Re: Debugging graphics programs
To: perkel AT slice DOT etho DOT caltech DOT edu
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Organization: Rockhurst College; Kansas City, MO

>What are your suggestions about the best way to debug a graphics
>program?  gdb runs my program fine, but when a breakpoint is hit with
>the screen in a graphics mode I can't read the text printed by gdb.

The traditional method, I believe, is to redirect the debugger's output
--either to another (presumably monochrome) monitor or to your printer.

>Actually, if I could get what gdb tries to print to be visible, I could
>do my debugging with printfs (yuk, but it would help).  All I see are
>white squares on a black background.  It's as if the bios font is
>screwed up or some attribute bit is set wrong, but I can't figure out
>where.

The problem is that whatever routine is producing the `text' output
doesn't realize you're in graphics mode, so it tries to write directly
to video memory.

--- Aaron Ucko (ucko AT vax1 DOT rockhurst DOT edu; finger for PGP public key) -=- httyp!
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