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From: "Juan Carlos =?iso-8859-1?Q?D=EDaz=20Mart=EDn?=" <juancarl@unex.es>
Subject: Imported Monolitic Monitor
Date: 1999/03/05
Message-ID: <36E014CD.55717933@unex.es>#1/1
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Organization: Universidad de Extremadura
X-Server-Date: 5 Mar 1999 17:33:02 GMT
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Newsgroups: comp.lang.ada
Date: 1999-03-05T17:33:02+00:00
List-Id: <comp.lang.ada>

Let's be the C procedures in a module that share global data

 a
 b
 c

and I make a C library with them. This library will be used by a
multitasked Ada95 application by the pragma Import

Tasks T, Q and R may invoke a, b or c in a concurrent, uncontrolled way.
Isn't it? I'm interested in a, b and c to be executed in mutual
exclusion to preserve global data integrity. The question is: How do I
do it in Ada95?
I've thought in a protected object, such as:

protected Monitor is
  procedure a;
  procedure b;
  procedure c;
end Monitor;

The object could be used:

with Monitor;
procedure P is
begin
  ...
  a; b; c;
  ...
end P;

task T is      task Q is     task R is
begin          begin         begin
  P;             P;            P;
end;           end;          end;

Does this way guarantee mutual exclusion of a, b and c??? Any ideas??

Thanks in advance
Juan Carlos