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From: Robert Dewar <robert_dewar@my-deja.com>
Subject: Re: Subverting 'Access for Sub-programs
Date: 1999/08/14
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In article <37B2D220.9CAAD611@gandalf.atm.fh-luebeck.de>,
  "Dmitry A. Kazakov" <dmitry@gandalf.atm.fh-luebeck.de> wrote:
> 2. Otherwise (when used locally) it should be passed by
reference,
> which would lift all unnecessary (in this case) limitations of
'access.
> The same way you pass a variable.


Passing something by reference is completely equivalent to
passing it by pointer at the calling sequence level, and if
you are calling a C program, it could not care whether you
pass an array as an IN parameter, or pass a pointer to an
array. The same is true of procedures. Passing a procedure
by reference to foreign code would be identical to passing
it by pointer. Yes, if you are only talking about ada-to-ada
there is some protection (although I really think that the
scheme proposed by the design team in mapping document 2
is a lot neater, and you should review that thoroughly before
making your own suggestions).

But in practice call back programming VERY often involves
interfacing to external code, in which case passing by
reference vs passing by pointer is identical.


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