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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Container reqs
Date: 17 Oct 2001 07:02:04 +0100
Organization: Pushface
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References: <9qctpn$lil$1@news.huji.ac.il>
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Date: 2001-10-17T06:02:06+00:00
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Ted Dennison<dennison@telepath.com> writes:

> In article <9qhcd2$amt$1@news.huji.ac.il>, Ehud Lamm says...
> >
> >Jean-Marc Bourguet <jbourguet@free.fr> wrote in message
> >news:3BCC01B1.18C18C98@free.fr...
> >> I'm not for making a container "threadsafe"  to the point where
> >> several tasks may modify the container without providing their
> >> synchronisation.
> >> In my experience
> >>    * most containers are accessed only by one task
> >>    * for those who are not, an explicit synchronisation is needed for
> >> other
> >>      purpose as the container is not the only part member of the
> >> datastructure
> >>      which has to be modified atomically.
> >>
> >
> >I agree, that we should not attempt to  make everything protected.
> 
> I find myself having to implement small queues with controlled types a lot. :-(
> 
> This issue is why Booch also has tasksafe and non-tasksafe versions of
> everything.

This is still an open area. You can easily create Guarded versions of
things (well, those that don't have structural sharing), where the
user gets to Seize and Release. But Synchronized versions (where the
locking is internal) are more work, and also semantically challenging
for Iterators I think.