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From: geert@fozzie.sun3.iaf.nl (Geert Bosch)
Subject: Re: Java vs Ada 95 (Was Re: Once again,
 Ada absent from DoD SBIR solicitation)
Date: 1996/11/16
Message-ID: <56kt98$6at@fozzie.sun3.iaf.nl>#1/1
X-Deja-AN: 196982085
references: <325BC3B3.41C6@hso.link.com>
 <EACHUS.96Nov1103759@spectre.mitre.org>  <E07Dwq.5L@world.std.com>
 <55gkch$gg6@fozzie.sun3.iaf.nl>  <E0B6CL.84r@world.std.com>
 <dewar.847053681@merv>  <1996Nov4.072757.1@eisner>
 <EACHUS.96Nov4182340@spectre.mitre.org> <dewar.848026322@merv>
organization: La Calandre Infortunee
newsgroups: comp.lang.ada
Date: 1996-11-16T00:00:00+00:00
List-Id: <comp.lang.ada>


Robert Dewar wrote:
  "If you are using reference counts for unbounded strings, then it is
   indeed the case that the code manipulating these refrence counts is
   highly likely to be erroneous (wrt the reference counts as shared
   variables), if there is any sharing of string values between tasks."

   [example deleted]

  "Well this program execution may be erroneous, which is at least to
   me a bit of a surprise."

It is a suprise, because the user of the Unbounded_String package
would not expect that the package body contains code that may lead to
erroneous execution. 

A correct and efficient implementation of the Unbounded_String package
is easy if the system provides Test_And_Increment and
Decrement_And_Test, where the Test tests wether the value is zero.
Both of these primitives can be implemented easily using Test_And_Set.
-- 
E-Mail: geert@sun3.iaf.nl