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From: tmoran@acm.org
Newsgroups: comp.lang.ada
Subject: Re: Variant Record Component
References: <3E5F8B38.EE7AE76F@boeing.com>
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Date: 2003-02-28T18:18:53+00:00
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> based on the message header, a particular structure is frozen.  Now I
> pass the message object to a decode function that is looking for
> particular message fields.  Well, surprise surprise, we occasionally
> raise Constraint_Error because the field in question is not present.
  Could you show what you mean?  What is "frozen"?  Are you getting a
Constraint_Error because of errors in the data (a field is out of range,
for instance), or because the program referenced msg.b when the
discriminant/case statement said there was no field "b"?  In the latter
case, it sounds like the symptom is the attempt to reference msg.b, but the
problem is erroneously thinking this message is of the subtype with a "b".