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From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: file locking in Ada
Date: 1997/03/29
Message-ID: <dewar.859696916@merv>#1/1
X-Deja-AN: 229388488
References: <333BB430.BF8@aston.ac.uk> <5hglog$lf8@top.mitre.org>
 <dewar.859565840@merv> <E7tuD6.4n7@world.std.com>
Organization: New York University
Newsgroups: comp.lang.ada
Date: 1997-03-29T00:00:00+00:00
List-Id: <comp.lang.ada>


Bob Duff said

<<Where does the RM allow implementations to not bother with parallel
protected function calls?  I know that the intent of the language
designers was to allow both -- one function locks out another, or one
function allows another to run in parallel.  But I don't see where the
RM says so.  It seems possible to write code that detects the difference
-- it might deadlock if a function grabs read/write access, when it
would not deadlock if it only grabs read-only access.  What am I
missing?>>

How can you deadlock without doing a potentially blocking operation
Yes, if protected objects were orthogonal abstraction mechanisms, one
could certainly tell, but given the severe restrictions that are placed
on them, I don't see how you could possibly tell with a functional test.