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From: hbaker@netcom.com (Henry Baker)
Subject: Re: Depending on passing mechanism
Date: 1997/10/14
Message-ID: <hbaker-1410971205270001@10.0.2.1>#1/1
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References: <x2hgal3jxa.fsf@moon.inf.fu-berlin.de> <dewar.876842858@merv>
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Newsgroups: comp.lang.ada
Date: 1997-10-14T00:00:00+00:00
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In article <dewar.876842858@merv>, dewar@merv.cs.nyu.edu (Robert Dewar) wrote:

> <<In Ada, compilers may choose to pass certain types either by reference
> or by copy (see RM95 6.2).  This allows for greater efficiency (bit
> arrays may be passed in registers, etc.), but under some
> circumstances, this can change program semantics (RM95 6.2(12)).
> >>
> 
> No, this cannot change program semantics, since the semantics is formally
> non-deterministic (that is a change in Ada 95). Yes, it may change program
> behavior, but program behavior is occasionally non-deterministic in Ada,
> and this is one of those cases.

It should be comforting to you when your Boeing 777 crashes that its Ada code
met the standard....

This is another one of those cases that give standards bodies such a
bad name -- the behavior is well-defined as 'non-deterministic', but
non-functional.