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From: Stephen Leake <stephen.a.leake.1@gsfc.nasa.gov>
Subject: Re: 'Read for pointers
Date: 2000/07/31
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"Pat Rogers" <progers@NOclasswideSPAM.com> writes:

> "Stephen Leake" <stephen.a.leake.1@gsfc.nasa.gov> wrote in message
> news:uaef1lxlw.fsf@gsfc.nasa.gov...
> > Suppose the user writes:
> >
> > My_Handle : Handle;
> >
> > (somehow, My_Handle is given some value)
> >
> > Read (Stream, My_Handle);
> >
> > The value of My_Handle is _not_ copied to Item at the procedure
> call.
> > That only happens for "in" or "in out" parameters, not "out"
> > parameters.
> 
> Have a look at RM 6.4.1{12,13} for a surprise.

I stand corrected. I guess the Ada designers were trying to prevent
garbage pointers. I think I'd prefer the standard "initialized to
null" behavior here, for consistency. 

I guess it's easy enough to remember that "out" is the same as "in
out" for access types, and composite types with discriminants.

On further thought, I can't think of a time when this behavior is
actively bad; it's just not what I thought the rules were.

-- 
-- Stephe