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From: "Nick Roberts" <nick.roberts@acm.org>
Newsgroups: comp.lang.ada
Subject: Re: GtkAda Problem
Date: Sun, 18 Jul 2004 15:17:11 +0100
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On 18 Jul 2004 12:29:51 +0100, Simon Wright <simon@pushface.org> wrote:

> Unrestricted_Access

Aha! Thank you, Simon.

It occurs to me that possibly a better approach would be to declare a  
library package which interfaces to some external subsystem (e.g. GTK or  
Win32) as a generic package (even if it has no generic parameters).

This way, the user can instantiate the package at the appropriate level  
(e.g. immediately in the declarative region of the main subprogram), and  
then use 'Access on subprograms at this level to provide values for  
access-to-subprogram types declared in the package (e.g. for callbacks).

It wouldn't be perfect, but it would actually provide a level (sorry ;-)  
of protection against accidentally calling back a subprogram in an inner  
scope that was no longer active, which is what the standard's restrictions  
on 'Access are intended to do.

I'll have a look at my copy of the AARM to see if I can work out whether  
this would work.

I've just discovered that Windows XP is now displaying the task bar 'low'  
(so that half of it disappears). It's not the monitor. Amazing. Microsoft  
seem to have a /genius/ for bugs!

-- 
Nick Roberts