Xref: utzoo comp.lang.c++:7946 gnu.g++:888
Path: utzoo!utgpu!watserv1!watmath!uunet!mcsun!ukc!edcastle!ecsv38
From: ecsv38@castle.ed.ac.uk (S Manoharan)
Newsgroups: comp.lang.c++,gnu.g++
Subject: Virtual functions under cfront 1.21 and g++ 1.37.1
Message-ID: <4566@castle.ed.ac.uk>
Date: 7 Jun 90 17:53:01 GMT
Reply-To: ecsv38@castle.ed.ac.uk (S Manoharan)
Organization: Dept of Computer Science, University of Edinburgh
Lines: 67


Consider the following code:

#include <stream.h>

class A {
private:
   int x;
protected:
   virtual void printx()        { cout << x << "\n"; }
public:
   A(int x1)                    { x = x1; }
   void hello()                 { printx(); }
};

class B: public A {
protected:
   virtual void printx()        { cout << "gee, naa\n"; }
public:
   B(int x1) : (x1)             { }
   void greet()                 { printx(); }
};

class C: public B {
protected:
   virtual void printx(int x)   { cout << x << "\n"; }
public:
   C(int x1) : (x1)             { }
   void bye()                   { printx(3); }
};  // line 27

int main()
{
   A a(2); B b(4); C c(8);

   a.hello();
   b.greet();
   c.bye();

   return 0;
}

----
<<cfront 1.2.1 2/16/87>> produces the error:

"prot.c", line 27: error: virtual C::printx() type mismatch: 
void C::(int ) and void B::()

----
g++ version 1.37.1 compiles fine and produces this result:
2
gee, naa
3
----

I then moved the virtuals to the public area. I had the same error
under cfront. And same result under g++.

What is my code supposed to do? Is this a bug in g++?

Thanks.

-- 
S. Manoharan               Janet: sam@uk.ac.ed.lfcs
Dept of Computer Science   Uucp : ..!mcsun!ukc!edcastle!lfcs!sam
University of Edinburgh    Arpa : sam%lfcs.ed.ac.uk@nsfnet-relay.ac.uk
Edinburgh EH9 3JZ    UK.   Voice: 667 8323(home) 667 1018x2708(office)