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From: limes%ouroborous@Sun.COM (Greg Limes)
Newsgroups: comp.lang.c
Subject: Re: compilers and linkers
Message-ID: <33890@sun.uucp>
Date: Fri, 13-Nov-87 19:34:29 EST
Article-I.D.: sun.33890
Posted: Fri Nov 13 19:34:29 1987
Date-Received: Sun, 15-Nov-87 12:02:23 EST
References: <2522@calmasd.GE.COM>
Sender: news@sun.uucp
Reply-To: limes@sun.UUCP (Greg Limes)
Organization: Sun Microsystems, Mountain View
Lines: 39

In article <2522@calmasd.GE.COM> pal@calmasd.GE.COM (Peter Lawrence) writes:
>... C global names get an underscore prepended to them ...
>... FORTRAN global names get an underscore appended to them.
>how does one link C and or FORTRAN with Pascal?

Peter, if C and FORTRAN globals did not get slightly different names,
one might be tempted to assume that they used the same calling and
storage conventions. In at least one FORTRAN compiler that I know of,
parameters are passed by address to subroutines. Thus, if you call a
FORTRAN subroutine from a C program, you have to pass pointers.
Likewise, if your C routine is called by a FORTRAN routine, what you
get is pointers to the FORTRAN parameters. Note that, in this case,
the interface conversion burden is entirely on the C language.

Thus, a C function callable by FORTRAN would be declared

	int
	foo_ (barp, bazp)
		int	*barp;
		int	*bazp;
	{
	}

and would be called from fortran as:

	CALL _FOO (IBAR, IBAZ)

Note the careful modification of the name "foo" so that each
can talk to the other; the assembler thinks they are both
using the global symbol "_foo_".

** You will probably have to contact a guru about your particular
C, FORTRAN, and Pascal implementations. Be sure to ask him about
nice things like naming of routines, calling sequences, return
values, and so on.

-- Greg [are we there yet?] Limes (limes@sun.com)

DISCLAIMER: If I spoke for SUN, who would speak for me?