system."+" renaming using GNAT

system."+" renaming using GNAT

[Oliver Hilgendorf]

The following statement

      function "+" (Left : in System.Address; Right : in Integer)
return System.Address renames system."+"; 

works fine using the Rational Ada compiler (for Solaris) . It doesn't
work with GNAT (for NT) since "+" is not defined in its package
system.

How can I make it work?

Oliver

Re: system."+" renaming using GNAT

[David C. Hoos, Sr.]

Oliver Hilgendorf wrote in message <369bb27b.18027210@news.nacamar.de>...
>The following statement
>
>      function "+" (Left : in System.Address; Right : in Integer)
>return System.Address renames system."+";
>
>works fine using the Rational Ada compiler (for Solaris) . It doesn't
>work with GNAT (for NT) since "+" is not defined in its package
>system.
>
>How can I make it work?
>

The package System.Storage_Elements has the following function:
function "+"(Left : Address; Right : Storage_Offset)
  return Address;

If you change your code to read:
      function "+" (Left : in System.Address; Right : in Integer)
return System.Address is
  use System.Storage_Elements;
begin
  return Left + Storage_Offset (Right);
end "+";

You should do just fine.

David C. Hoos, Sr.

Re: system."+" renaming using GNAT

[Tucker Taft]

Oliver Hilgendorf (news@hilgendorf.de) wrote:

: The following statement

:       function "+" (Left : in System.Address; Right : in Integer)
: return System.Address renames system."+"; 

: works fine using the Rational Ada compiler (for Solaris) . It doesn't
: work with GNAT (for NT) since "+" is not defined in its package
: system.

: How can I make it work?

Ada 95 defines a "+" between Address and an integer type
in the package System.Storage_Elements.  The integer type
is System.Storage_Elements.Storage_Offset.  Hence,
don't make it a rename; instead, implement it portably as follows:

  with System.Storage_Elements;
   ...
    function "+"(Left : in System.Address; Right : in Integer)
    return System.Address is
    begin
       return System.Storage_Elements."+"(Left, System.Storage_Offset(Right));
    end "+";
    

: Oliver


--
-Tucker Taft   stt@averstar.com   http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions  (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.)   Burlington, MA  USA