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From: emery@gypsy.UUCP
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Subject: Re: Propagation of exceptions raised wit
Message-ID: <38000029@gypsy.UUCP>
Date: Fri, 6-Jun-86 16:57:00 EDT
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Posted: Fri Jun  6 16:57:00 1986
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Nf-From: gypsy!emery    Jun  6 16:57:00 1986
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Both Frank Prindle and Doug Bryan have reminded me that, should an
exception be raised during rendeveous, the exception is propogated to
BOTH tasks.  This is perfectly consistent with the notion that the
rendeveous code is run 'by both tasks'.  

However, exception propogation, once inside the two tasks, follows
the rule I cited, i.e. the exception is not propogated out of either
task.

Thanks, guys.  

On a related topic:  A command interpreter is one good example of 
a program that may be called to invoke other programs, which are
not known at compile time (see Tom Wheeler's article, cited in 
previous discussions.)  If you presume that all such 'programs' are
tasks, here's my design problem again:  How does a task report
failure to its parent.  One of the problems here is the task name
problem.  A task does not know its identity, therefore it cannot say
things like "I am task 36, and I aborted because of a fubar exception."
The standard way around this is to "christen" the task through an 
entry call, where the caller tells the task its name ("You are task 36").
It seems that a task identity scheme is a necessary condition for having
tasks report their failure.

				Dave Emery
				Princeton Research
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