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From: gijs@mbase97.xs4all.nl (Maarten Landzaat)
Newsgroups: comp.lang.ada
Message-ID: <H.eg.yfQlZ_ydPoc@mbase97.xs4all.nl>
Organization: M-BASE
Subject: delay duration'last: problems?
Reply-To: gijs@mbase97.xs4all.nl
X-Software: HERMES GUS 1.10 Rev. May 17 1993
Date: Sun, 16 Oct 1994 18:03:54 +0200
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Date: 1994-10-16T18:03:54+02:00
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Hi,

Our current project (DEC Ada on VAX/VMS) yielded a generic timer,
which does a "delay duration'last" when there's no work to do,
or when the callback is to be called a long time ahead in the future.

More of these timers run concurrently. Each timer is one task, with
a queue of wake-up times.

Now after those 36.4 (or something) hours, we get ACCess VIOlations.
A simple put_line after the delay is not executed.

Changing duration'last to 1 hour or 24 hours does NOT present these
problems. 

The delay is in a select statement like this:

select
	accept boo;
or	
	accept baa;
or
 	delay time_to_wait;
	do_callback;
	determine(time_to_wait);  -- if queue's empty: duration'last
end select;


Can anybody tell me why the access violations may occur?

Thanks very much!
-- 
Maarten Landzaat (gijs@mbase97.xs4all.nl)
Amsterdam, Double bass, Fender Jazz Bass, Atari ST, Roland Sound Canvas.
Listen to M-BASE music!