From:	Hans-Bernhard Broeker <broeker AT physik DOT rwth-aachen DOT de>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: selectively turning off function name mangling in C++
Date:	25 Apr 2001 10:49:58 GMT
Organization:	Aachen University of Technology (RWTH)
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Alistair_P SHILTON <apsh AT ecr DOT mu DOT oz DOT au> wrote:
> I was wondering if it is possible to tell gxx to not mangle the names of
> certain functions?  I've been trying to interface some of my C++ code with
> some fortran code I downloaded of the net.  g77 mangles its function names
> by adding _'s to start and finish (so foo becomes _foo_).  

Careful, there --- that's not the only effect. Fortran also adds
invisible parameters for multidimensional variable-sized array
arguments, and it passes all arguments by reference.  It also treats
strings in a wildly different way than the NUL-terminated variety used
by C and C++.

You may want to get your hands on the 'cfortran.h' package to help you
get around these pitfalls, while still keeping your own source code as
portable as possible.

> But gxx mangles the same function to _foo__*** (*** = annoying junk)
> - which stops the .o files from linking correctly!

Learn about the 

	extern "C"

qualifier of C++.  Note that even this won't let you blindly call C++
methods from Fortran: the "this" pointer will be missing, and it's
hard to find out when and how to add it in manually.

Calling other language functions from C++ is rather simple as long as
they have a C-compatible calling interface available. Calling C++
methods from other languages can be close to impossible without
extensive knowledge about internal C++ compiler details.

-- 
Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de)
Even if all the snow were burnt, ashes would remain.

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