Re: Simpler Question (was Assigning to dereferenced null access variable)

[Vincent Marciante <marciant@li.net>]

Jean-Pierre Rosen wrote:
> 
> "Vincent Marciante" <marciant@li.net> a �crit dans le message news:3A0847ED.49AF@li.net...
> >[...]
> >     begin
> >         Null_Sequence.The_Characters(1..0) := Null_Characters;
> >         Put_Line("The Null_Characters assignment succeeded");
> >     exception
> >         when Constraint_Error =>
> >         Put_Line("The Null_Characters assignment caused
> > Constraint_Error");
> >         --OS/2 GNAT 3.12 raises Constraint_Error
> >     end;
> > end;
> Null_Sequence.The_Characters is a null pointer, there is no array to point to. This is what causes Constraint_Error, nothing to do
> with the assignment.
> 
> --
> ---------------------------------------------------------
>            J-P. Rosen (Rosen.Adalog@wanadoo.fr)
> Visit Adalog's web site at http://pro.wanadoo.fr/adalog

I thought that null_sequence.the_characters being a null pointer
should always cause constraint_error.   I will assume that you 
mean that the fact that no constraint_error ocurred in the first 
block (repeated below) indicates a compiler defect, so, I will send
a report to ACT.   Thanks.

    begin
        Null_Sequence.The_Characters(1..0) := Null_Characters(1..0);  
        Put_Line("The Null_Characters(1..0) assignment succeeded");
        --OS/2 GNAT 3.12 succeeds
    exception
        when Constraint_Error => 
        Put_Line("The Null_Characters(1..0) assignment caused Constraint_Error");
    end;