Path: utzoo!attcan!uunet!cme-durer!libes
From: libes@cme-durer.ARPA (Don Libes)
Newsgroups: comp.lang.c
Subject: Re: implementing Dijkstra's guarded commands
Keywords: in a serial environment, parallel to come
Message-ID: <516@muffin.cme-durer.ARPA>
Date: 16 Jul 88 18:38:22 GMT
References: <515@muffin.cme-durer.ARPA> <8044@alice.UUCP>
Organization: National Bureau of Standards, Gaithersburg, MD
Lines: 23

In article <8044@alice.UUCP>, ark@alice.UUCP writes:
> Dijkstra's guarded commands don't really allow for parallel
> [ example deleted ]
> Where's the parallelism?

You can execute the guards in parallel, as long as they don't have
side-effects.  I noted this in the last paragraph of my posting, but I
guess you missed it.  I'll repeat it:

In article <515@muffin.cme-durer.ARPA>, I wrote:
> parallel execution of guards containing functions with side-effects
> would be awful.  (Fortunately, I don't believe I have to worry about
> that particular problem.)

In fact, I have never seen anyone using guards WITH side-effects.  I
think it is commonly understood that one of the benefits of Dijkstra's
guarded commands is that the obvious nondeterminism makes it easy to
speed up on a parallel machine.

I have already received several elegant solutions to my question.  I
will post the best shortly.

Don Libes          cme-durer.arpa      ...!uunet!cme-durer!libes