Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!island!lars
From: lars@island.COM (Lars Nyman)
Newsgroups: comp.sys.mac.programmer
Subject: virtual base class problems
Message-ID: <3552@island.COM>
Date: 5 Feb 91 01:57:22 GMT
Organization: Island Graphics, Marin County, California
Lines: 44


The following code using a virtual base class causes CFront to complain
(Sun C++ 2.0, and MPW C++ 3.1, both which are based on CFront 2.0).

IS this indeed a CFront bug, and does anybody know if it is fixed/will be fixed
in later versions of CFront (> 2.0) ?

// -------------------------------------------------
//#define INHERIT public
#define INHERIT virtual public

class TOne
{
 public:
    virtual void foo() {};
};

class TTwo : virtual public TOne
{
 public:
    void foo() {};
};

class TThree : INHERIT TTwo {};
class TFour  : INHERIT TThree {};
class TFive  : public TFour {};
class TSix   : public TFive {};
class TSeven : public TSix
{
 public:
    void bar() { foo(); };
};

//----------------------------------

CC foo-bug.cc
CC  foo-bug.cc:
"foo-bug.cc", line 24: error: ambiguous TTwo::foo() and TOne::foo() (different s
ub-objects)
"foo-bug.cc", line 24: error: ambiguous TTwo::foo() and TOne::foo() (different s
ub-objects)
"foo-bug.cc", line 24: error: ambiguous TTwo::foo() and TOne::foo() (different s
ub-objects)
3 errors