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From: Colin_Paul_Gloster@ACM.org (Colin Paul Gloster)
Subject: Re: Null Record is not always Null
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Date: 10 Oct 2002 14:16:51 GMT
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Date: 2002-10-10T14:16:51+00:00
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Peter Richtmyer posted different behavior on three compilers and said:
"Don't know if there is a "right" result, or is this one of 
those gray areas. Anybody?"

Well, though 13.12 re pragmas has:

"[..]

An implementation may place limitations on the values of the expression
that are supported, and limitations on the supported combinations of
restrictions. The
consequences of violating such limitations are implementation defined.

[..]",

a pragma should never stop a compilation.

As for the rest, clearly you were given suboptimal results for your
possibly wacky null record but compilers are allowed to ignore your
requests:

"[..]

[..] A representation or operational item that is not supported by the
implementation is illegal, [..]

[..]

An implementation may interpret aspects of representation in an
implementation-defined manner. An implementation may place
implementation-defined restrictions
on representation items. [..]" (13.1).

In 13.3 is "nonnegative" chosen to denote >0 or >=0?

"[..]

Size may be specified for stand-alone objects via an
attribute_definition_clause; the expression of such a clause shall be
static and its value nonnegative.

[..]"