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From: Stephen Leake <Stephen.A.Leake@nasa.gov>
Newsgroups: comp.lang.ada
Subject: Re: new_line in a put_line
Date: 05 Dec 2002 09:19:18 -0500
Organization: NASA Goddard Space Flight Center (skates.gsfc.nasa.gov)
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"Grein, Christoph" <christoph.grein@eurocopter.com> writes:

> > > >>    procedure Put_Line (Text : String) is
> > > >>       Get_It : Lock (Write_Mutex'Access);
> > > >>    begin
> > > >>       Ada.Text_IO.Put_Line (Text);
> > > >>    end Put_Line;
> > > >
> > > >Something inside me rebels at using side-effects from a declaration
> > > >like that. 
> > > 
> > > Right, right. It is also my opinion [there was a thread regarding this
> > > subject in c.l.a] that using unused (:-)) objects probably indicates a
> > > design problem. 
> > 
> > That's what pragma Unreferenced (in GNAT) is for; it documents that
> > the object is declared only for the hidden effects of Initialize and
> > Finalize.
> > 
> > Assuming Lock is a controlled type, that releases the lock in
> > Finalize, this is an excellent design.
> 
> This should only be necessary 

It's not "necessary" in any case. It does avoid a warning from GNAT,
and it informs the reader. That's what I meant by "documents".

> for objects of not limited controlled types. As I said, limited
> controlled objects must not be optimized away.

Yes, the reader could lookup the type of the variable and realized it
is limited controlled. Unreferenced is quicker and clearer.

-- 
-- Stephe