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From: bane@parcvax.Xerox.COM (John R. Bane)
Newsgroups: comp.sys.atari.st
Subject: Lattice 3.04 Bug - structure passing by value
Message-ID: <390@parcvax.Xerox.COM>
Date: Sat, 25-Jul-87 03:34:34 EDT
Article-I.D.: parcvax.390
Posted: Sat Jul 25 03:34:34 1987
Date-Received: Sun, 26-Jul-87 00:42:16 EDT
Reply-To: bane@parcvax.xerox.com.UUCP (John R. Bane)
Organization: Xerox PARC
Lines: 28
Keywords: Small structures lose

The following program should print "1234"; when compiled by Lattice 3.04,
it prints "3434".  The problem only occurs with structures smaller than
four bytes; what happens is that the code in the caller and the code in
the callee disagree on the alignment of the structure within the 4-byte
area the caller copies the structure into. It took me two evenings to
track this one down; thanks, Lattice!

/* this is a test of structure passing */
struct bogus {unsigned char a,b;};

main () {
	struct bogus b1,b2;
	b1.a = 1; b1.b = 2; b2.a = 3; b2.b = 4;
	subr(b1, b2);
        }

subr(b1,b2) struct bogus b1,b2; {
	printf("%d%d%d%d\n", b1.a, b1.b, b2.a, b2.b);
}

Despite this lossage, the 3.04 upgrade is well worth getting, for the
debugger (semi-symbolic), window-and-mouse editor, Kuma resource editor,
and make program.  I have no opinion on Lattice vs the others if you
aren't just getting the upgrade.
-- 
	Rene P.S. Bane
	bane.pa@xerox.ARPA
	...!parcvax!bane.UUCP