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From: Ludovic Brenta <ludovic@ludovic-brenta.org>
Newsgroups: comp.lang.ada
Subject: Re: Use aggregates (Was: Allocation question)
Date: Mon, 11 May 2009 05:16:02 -0700 (PDT)
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Date: 2009-05-11T05:16:02-07:00
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Jacob Sparre Andersen wrote on comp.lang.ada:
> Olivier Scalbert wrote:
> > procedure Fill(Image: in out Image_T; Color: Color_T) is
> > begin
> > =A0 =A0 =A0 for x in Image'range(1) loop
> > =A0 =A0 =A0 =A0 =A0 for y in Image'range(2) loop
> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 Image(x,y) :=3D Color;
> > =A0 =A0 =A0 =A0 =A0 end loop;
> > =A0 =A0 =A0 end loop;
> > end Fill;
>
> I would sugges that you rather wrote this:
>
> =A0 =A0Image :=3D (others =3D> (others =3D> Color));
>
> It is a more precise expression of what (I guess) you want done, and
> thus it gives the compiler more precise information to work with.

This is not always a good idea. On some targets, GNAT places the
aggregate on the stack and this can raise a Storage_Error. In avionics
programs, I remember replacing aggregates with loops for this reason.

--
Ludovic Brenta.