Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!jarthur!uci-ics!rfg
From: rfg@ics.uci.edu (Ronald Guilmette)
Newsgroups: comp.lang.c++
Subject: Re:  how do you define classes that refer to each other ???
Message-ID: <261087B8.2418@paris.ics.uci.edu>
Date: 28 Mar 90 09:45:28 GMT
References: <1990Mar26.115427.14031@newcastle.ac.uk>
Reply-To: rfg@ics.uci.edu (Ronald Guilmette)
Organization: UC Irvine Department of ICS
Lines: 45

In article <1990Mar26.115427.14031@newcastle.ac.uk> Lindsay.Marshall@newcastle.ac.uk (Lindsay F. Marshall) writes:
>Just to be awkward, can anybody suggest a legal way of doing the
>following :-
>
>	class B;
>
>	class A
>	{
>	public:
>	    A();
>
>	    void fa(void (*B::fb)());
>	};
>
>	class B
>	{
>	public:
>	    B();
>
>	    void fb(void (*A::fa)());
>	};
>
>CC 2.0 gives syntax errors when you try to do this...

As well it should.  It seems that you have the *'s in the wrong places.
Try using these function declarations instead:

	void fa(void (B::*fb)());

	void fb (void (A::*fa)());


>g++ 1.37.1 gives reasonable error messages.

I'd like to know how you define "reasonable". g++ certainly doesn't allow
such things, either when they are written with correct syntax or not.

When written incorrectly (as shown in your example) I have no idea what
g++ will say.

When written with correct syntax, g++ will probably just say "syntax error".

// Ron Guilmette (rfg@ics.uci.edu)
// C++ Entomologist
// Motto:  If it sticks, force it.  If it breaks, it needed replacing anyway.