Conference star::wizards

1692.0. "Closed: how to link the C++ and FORTRAN?" by STAR::JKEENAN () Fri Mar 21 1997 13:38

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Name: Steve Frost
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CPU Architecture: Alpha
Version: v 6.2
Questions: 

Probably a dumb question and I'm sure it's some simple qualifier or option but ...

When trying to call a Fortran (V6.1-386) routine from
a C++ (V5.3-005) main, we get an unresolved reference during the link (LINK version A11-20) of "subroutine__XV".  

For example:

    C++ main of HELLO
    FORTRAN sub HELLOWORLD
    LINK HELLO,HELLOWORLD

%LINK-W-NUDFSYMS, 1 undefined symbol:
%LINK-I-UDFSYM,  HELLOWORLD__XV 
%LINK-W-USEUNDEF, undefined symbol HELLOWORLD__XV referenced 

If instead:

   C++ main of HELLO
   C++ sub HELLOWORLD
   LINK HELLO, HELLOWORLD

then no problem as the HELLOWORLD.OBJ created by C++ has the HELLOWORLD__XV symbol, the OBJ created by FORTRAN doesn't.

How do we successfully link the C++ and FORTRAN?

Thanks.

The C++ compiler is "name mangling" the Fortran routine name.  To prevent it
from doing this, you must declare the name using

	extern "C"

Please see the DEC C++ manuals for more information on this and mixed-language
programming.