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From: ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe)
Newsgroups: comp.lang.c,comp.lang.fortran,comp.unix.questions
Subject: Re: Calling C from FORTRAN under Unix
Message-ID: <5826@goanna.cs.rmit.oz.au>
Date: 20 May 91 05:23:14 GMT
References: <5343@dftsrv.gsfc.nasa.gov> <1991May17.023941.18053@zoo.toronto.edu> <5348@dftsrv.gsfc.nasa.gov>
Followup-To: comp.lang.fortran
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 18

In article <5348@dftsrv.gsfc.nasa.gov>, packer@amarna.gsfc.nasa.gov (Charles Packer) writes:
> In fact, everybody said that =their= systems' C compiler put an
> underscore =following= the routine name, and therefore I should
> write the calling Fortran code to CALL subr_.

That is back to front.  On many UNIX systems, it is the *Fortran*
compiler which adds '_' as a suffix (and either _both_ C and Fortran
add '_' at the beginning (usually BSD) or _neither_ do (usually Sys V)).
So when a C function calls a Fortran 'SUBR' C uses the name 'subr_',
and a C function can be called *from* Fortran only if the C function
name has no capital letters and ends with '_'.  So C would call the
function 'subr_()' and Fortran would 'CALL SUBR'.

However, there are lots of different UNIX Fortran compilers out there,
so it isn't enough to say which hardware and operating system; you have
to say whose Fortran compiler as well.
-- 
There is no such thing as a balanced ecology; ecosystems are chaotic.