Re: Pure, Storage_Size and Unchecked_Conversion

[Georg Bauhaus <rm.tsoh+bauhaus@maps.futureapps.de>]

On Sat, 2007-07-07 at 17:24 -0700, Y.Tomino wrote:

> with Ada.Unchecked_Conversion;
> package Pure_SS_Unc is
>    pragma Pure;
>    type T is access Integer;
>    for T'Storage_Size use 0;
>    function F1 (X : Integer) return T;
>    function F2 is new Ada.Unchecked_Conversion (Integer, T);
> end Pure_SS_Unc;
> 
> [...]
> pure_ss_unc.ads:7:58: named access types not allowed in pure unit

The message should really apply to the declaration of T.
T is a named access type. If you remove all lines referring
to U_C, the compiler might say something like


GNAT 4.1.2 (Ubuntu 4.1.2-0ubuntu4)
Copyright 1992-2005 Free Software Foundation, Inc.

Compiling: pure_ss_unc.ads (source file time stamp: 2007-07-08 09:44:14)

     4.    type T is access Integer;
                |
        >>> named access type not allowed in pure unit

 8 lines: 1 error


Just guessing what your package is supposed to achieve,
have you considered using System.Address_To_Access_Conversions?