Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!amdcad!ames!ll-xn!husc6!endor!singer
From: singer@endor.harvard.edu (Rich Siegel)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Overflow Checking from within Pasca
Message-ID: <429@husc6.harvard.edu>
Date: 4 Oct 88 11:36:01 GMT
References: <4276@polyslo.CalPoly.EDU> <900006@zaphod>
Sender: news@husc6.harvard.edu
Reply-To: singer@endor.UUCP (Rich Siegel)
Organization: Symantec/THINK Technologies, Bedford, MA
Lines: 36

In article <900006@zaphod> liberte@zaphod.ncsa.uiuc.edu writes:
>This all works.  But there is one final problem.  You cannot assign the
>value 32768 back into an integer variable.  I have no solution to this
>problem other than turning overflow checking off.  But unfortunately, I
>discovered that I cannot turn off this overflow checking, even if I
>turn it off for the whole project.  Is this a bug?

	Overflow checking checks for integer overflow during computations,
not during assignments. If you want to assign a large unsigned value
to an integer variable, turn off the "R" compile option, or use {$R-}.

>In my case, I can check for this illegal value while it is still
>longint and subtract one before taking the LoWord.  But this is
>an ugly hack, and LSP is broken when it comes to unsigned integers.

	No, Lightspeed Pascal is *not* "broken" when it comes to
unsigned integer. Pascal simply has no provisions for supporting
unsigned arithmetic, as C does. In any pascal, the only way to work
with unsigned values is to disable overflow and range checking.

>Dan LaLiberte

		--Rich




Rich Siegel
Staff Software Developer
THINK Technologies Division, Symantec Corp.
Internet: singer@endor.harvard.edu
UUCP: ..harvard!endor!singer
Phone: (617) 275-4800 x305

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or policies of Symantec Corporation or its employees.