Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!indri!nic.MR.NET!umn-d-ub!umn-cs!ns!logajan
From: logajan@ns.UUCP (John Logajan)
Newsgroups: comp.sys.atari.st
Subject: GFA BASIC Bug (or feature?)
Message-ID: <1217@ns.UUCP>
Date: 21 Mar 89 17:47:43 GMT
Organization: Network Systems Corp. Mpls MN
Lines: 24

Thanks entirely to Hans-Ch. Eckert of Berlin, West Germany for solving
this "problem" I had with GFA Basic!

To wit: GFA BASIC apparently moves valid strings around when it does
garbage collection.  Thus if you poke, or otherwise put, a machine
language routine in a string, it will from time to time, be moved
around.  Eckert's fix is to get the new VARPTR(X$) value *EVERY* time
the machine language routine is called.

My accidental fix (because I didn't understand the problem) was to move
the machine language routine into an integer array. (Gee, I hope they
don't do garbage collections on arrays????)

GFA Basic Programming rule #978

1.) Either get the new pointer before each call to a machine-language
    "string" or
2.) Place the mach-lang routine in a "fixed" location.  (I would have
    said in an integer array, but I have just raised doubts in my own
    mind whether such arrays can be counted on not to hop around.)

-- 
- John M. Logajan @ Network Systems; 7600 Boone Ave; Brooklyn Park, MN 55428  -
- ...rutgers!umn-cs!ns!logajan / logajan@ns.network.com / john@logajan.mn.org -