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From: gas@cs.nott.ac.uk (Alan Shepherd)
Newsgroups: comp.lang.c++
Subject: Mixing C with C++
Message-ID: <1991Apr22.064847.16929@cs.nott.ac.uk>
Date: 22 Apr 91 06:48:47 GMT
Reply-To: gas@cs.nott.ac.uk ()
Organization: Nottingham University
Lines: 26

About a week ago I posted an article asking for help with a problem I
was having with making C++ functions (not methods) callable from C++.

I've had quite a response so I thought other people might be
interested in the necessary details.  The first thing to do is to
declare your C++ function to have C linkage (even though you compile
it with C++) e.g.

extern "C" void aC++Fn();

void aC++Fn()
{
	cout << "A C++ Function" << endl;
}

This is the easy bit.  The second step involves linking using C++ and
not C.  Most of my replies pointed this out, but I had done this and
still encountered problems (sorry for not pointing this out before).
The crucial step is that the file with main() needs to be compiled
using C++ even if it is in a c file.  Thanks to those people who
pointed this out.

I felt a bit of an idiot when I realised the solution, but several of
my replies missed this too, so I don't feel quite so bad....:-)

Alan Shepherd