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From: chrisj@cup.portal.com
Newsgroups: comp.lang.modula2
Subject: Logitech 3.0 alignment problem
Message-ID: <867@cup.portal.com>
Date: Mon, 5-Oct-87 20:54:46 EDT
Article-I.D.: cup.867
Posted: Mon Oct  5 20:54:46 1987
Date-Received: Sat, 10-Oct-87 13:01:51 EDT
Organization: The Portal System (TM)
Lines: 21
XPortal-User-Id: 1.1001.2041


WARNING: Logitech's version 3.0 compiler aligns fields slightly differently
than previous versions did.  A client of mine recompiled a module for a bug
fix, linked the output with a bunch of 2.0-compiled stuff, and found that
some of his fields were mispositioned by one byte if he compiled the module
with the Align flag turned ON, and others were off by one if he compiled with
it OFF.  Recompiling the whole suite of modules with 3.0 doesn't solve the
problem, since 100 or so customers in the field have data files with the old
field alignment in them.  Yucc!

(Personally, I usually declare the slack bytes in my records explicitly, but
we've all got 20-20 hindsight.)

Sorry that I cannot tell you the details of the record declaration in which
field offsets changed.  The client will notify Logitech of his problem, and
I will post further details when I understand the exact nature of the
compiler changes.

Christopher T. Jewell    | UUCP:       chrisj@cup.portal.com
3900 Moorpark Ave, #42   | or  :       ucbvax!sun!portal!chrisj
San Jose, CA, USA, 95117 | CompuServe: 72415,1757
                         | Musus     : Chris Jewell