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From: tkammeye@sdcsvax@ucsd.edu (Thomas E. Kammeyer)
Newsgroups: comp.parallel
Subject: Re: A Linda Question
Summary: Definition of out() for linda
Keywords: linda, parallel computation, tuple space, shared memory
Message-ID: <12486@hubcap.clemson.edu>
Date: 6 Jan 91 18:06:25 GMT
References: <12439@hubcap.clemson.edu>
Sender: fpst@hubcap.clemson.edu
Followup-To: <12439@hubcap.clemson.edu>
Organization: CSE Dept., U.C. San Diego
Lines: 34
Approved: parallel@hubcap.clemson.edu

In article <12439@hubcap.clemson.edu> snykanen@cs.Helsinki.FI (Silja Nykanen) writes:
>We would like to know if there is an exact definition for 
>the out-operation of Linda. 
 ...
>There are not any guarantees that
>the inp-operation would succeed in the following example:
>
>out("T");
>inp("T");
>

My version of the "C-linda Reference Manual" says: (section 3.4, page 19)
	"A given tuple is evaluated and then added to tuple space with
	the out() operation.  Once the tuple has been added, the executing
	process continues immediately."
In human language:  The all of the arguments to out() are evaluated by the
process calling out() and then out() waits until it has finished adding
the completed tuple to the tuple space before continuing (note the relative
clause at the beginning of the second sentence of my quote.  If your example
used eval() in place of out, then of course the inp()'s success would depend
completely 'pon whether process scheduling happened to run the process
before the process which was forked to do the eval().  Hope this is helpful,
and correct.  If you lack a recent reference manual, and cannot
acquire one, send e-mail and I'll be glad to help track down the relevant
source.

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>From the fevered brain of: Thomas E. Kammeyer
Disclaimer:  My opinions are mine alone... in particular they in no way
are meant to be taken as policy or opinion of those I work for
or of the University of California in general.  If my facts turn out to
be wrong, I will not be held responsible; I reserve the right to my fallibility
and thus my humanity.  Check my facts if you desire absolute certitude.
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