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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada,comp.lang.fortran,comp.lang.pl1
Subject: Re: Checking for Undefined
Date: Thu, 25 May 2006 23:02:24 +0100
Organization: Pushface
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Date: 2006-05-25T23:02:24+01:00
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Gordon Sande <g.sande@worldnet.att.net> writes:

> I am getting the impression from the silence of the cross postings
> that undefined checking has only shown up in Fortran systems.  The
> exception is Salford who also have it for their C but one also seems
> to notice that their C and Fortran seem to share a lot of features.

The pro version of GNAT (I don't know about the FSF version) has
optional initialization with out-of-range values and checking even in
places where it normally would be omitted because the compiler would
assume it had already done the checks. This only works if there _are_
out-of-range values, so Integer can't be checked. Normally the
recommendation is to define types appropriate to the application, so
checks are possible.

My current project is using an older compiler which is imperfect in
this area, so we don't use this feature, but compiler warnings such as
'X may be used before initialization' are very valuable.