importing fortran routines to GNAT

["Pasi J. Hakala" <pjh@msslac.mssl.ucl.ac.uk>]

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Hi!

I'm a sworn FORTRAN-programmer finally trying to learn a more
advanced language (ADA). Now, I still have lots of fortran
subroutines that I want to use, but somehow all the information
on how to do that in GNAT (3.05 I think) doesn't seem to apply
to me... :( 
      I've attached two files to this message: amain.adb is a
very simple main program that calls subsum.f (an even more simple
fortran subroutine). Now, HOW CAN I MAKE THE ADA MAIN
PROGRAM TO SEE THE SUBROUTINE???!!!
   Here's what I've done (This is under OS/2 with g77, gcc 2.7... and
emx 0.9c):
      - gcc -c amain.adb   (no complaints)
      - g77 -c subsum.f    (no complaints)
      - gnatbind amain.ali  (no complaints) 
      - gnatlink amain.ali subsum.o  
         which results in 'cannot find object _subsum etc....

    So can please someone help a poor astronomer on a way from 
    fortran to ADA....or otherwise I'll stick to fortran for
     another Hubble-time......

                   Cheers, Pasi

[-- Attachment #2: amain.adb --]
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with Text_Io; use Text_Io;
with Interfaces.Fortran; use Interfaces.Fortran;

procedure Amain is

   package Int_Io is new Integer_IO (Integer); use Int_Io;
   package Flt_Io is new Float_IO (Float); use Flt_Io;

   procedure subsum(In1 : in Real; In2 : in Real ; Outsum : out Real);
   pragma import(Fortran,subsum);

   i1,i2,ou : Real;

begin
   ou:=0.0;
   i1:=1.0;
   i2:=2.0;
--
--      Call the imported fortran routine
--
   subsum(i1,i2,ou);
   New_Line;
   Put(Float(ou));
end; 
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[-- Attachment #3: subsum.f --]
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        SUBROUTINE SUBSUM(IN1,IN2,OUT)
        REAL IN1,IN2,OUT
C
        OUT=IN1+IN2
        RETURN
        END
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