Re: Ada95 location information

[Stephen Leake <Stephen.Leake@gsfc.nasa.gov>]

dommo1234@my-deja.com writes:

> I'm writing a program in Ada95 and require that when exceptions are
> thrown, the location in the source code is included in the message, not
> just in the call stack display. I realise there's no pre-processor, but
> C and C++ compilers have special tags, eg. "__LINE__", and I wonder
> whether Ada compilers have anything silimar. Does anyone know of any
> way to obtain this information from the compiler at compile time?

I just use Ada.Exceptions.Raise_Exception, and include the full name
of the subprogram in the message:

package body Foo is
   procedure Bar is
   begin
      if Error then
         Ada.Exceptions.Raise_Exception
            (Something_Bad'identity,
             "Foo.Bar : file not found");
      end if;
  end Bar;
end Foo;

This is easy to do. Possibly not quite as easy as a preprocessor
macro, but typing the subprogram name also makes you think about what
else should be in the error message.

One problem with this approach is that Ada.Exceptions is _not_ labeled
with pragma Preelaborate, so you end up using pragma Elaborate_Body
instead, which is not as nice. I hope this will be fixed in an AI
soon.

-- Stephe