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From: gijs@mbase97.xs4all.nl (Maarten Landzaat)
Subject: DEC Ada problem
Date: Wed, 19 Oct 1994 21:15:36 +0200
Date: 1994-10-19T21:15:36+02:00	[thread overview]
Message-ID: <H.eg.tnw9lXPi0eA@mbase97.xs4all.nl> (raw)

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 set;
	....
or      
        accept reset;
	....
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!
-- 
Maarten Landzaat (gijs@mbase97.xs4all.nl)
Amsterdam, Double bass, Fender Jazz Bass, Atari ST, Roland Sound Canvas.
Listen to M-BASE music!



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