Re: Possible compiler bug with this simple program

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

Jeff Carter writes:
> Ada needs to know what the lower bound of this array parameter is, and
> apparently your compiler is getting it wrong. Using a constrained array type
> with a lower bound of zero and an upper bound as large or larger than can occur
> would be the best choice for this situation.

I would actually use a local, constrained array type of exactly the
required length:

procedure Ada_Callback (Length : in Natural; Array_Address : in
System.Address);
pragma Convention (C, Ada_Callback);

procedure Ada_Callback (Length : in Natural; Array_Address : in
System.Address) is
   type Constrained_Array_Subtype is array (1 .. Length) of
Long_Float;
   X : Constrained_Array_Subtype;
   for X'Address use Array_Address;
   pragma Import (Ada, X); -- disable default initialization
begin
   ...
end Ada_Callback;

I know using System.Address may seem unholy at first sight but this
implementation is explicit about what it does -- dangerous things with
an address received from the unsafe "external world" outside the
control of the compiler.

Comments?

--
Ludovic Brenta.