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From: tuck@jason.cs.unc.edu (Russ Tuck)
Newsgroups: comp.lang.c++
Subject: Re: virt base c'tor -- my error or CC bug?
Keywords: CC, cfront, 2.0, multiple inheritance, virtual base class
Message-ID: <11594@thorin.cs.unc.edu>
Date: 23 Jan 90 00:36:52 GMT
References: <11582@thorin.cs.unc.edu>
Sender: news@thorin.cs.unc.edu
Reply-To: tuck@jason.cs.unc.edu (Russ Tuck)
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Organization: University Of North Carolina, Chapel Hill
Lines: 37

In article <11582@thorin.cs.unc.edu> tuck@jason.cs.unc.edu (Russ Tuck) writes:
>I think I've found a bug ...
>Here's a trivial example program showing this case.
>
>  class V { public: V(int); };
>
>  class A : public virtual V { public: A(); };
>
>  A::A() : V(1) {}
>
>  V v(1);
>  A a;
>
>CC (cfront 2.0, running on any of Sun4, DEC 3100, VAX 785) gives these 
>error messages when compiling the above code .....

I've found what appears to be a good work-around to this problem:
adding a private default constructor to class V.  This gets rid of the
error messages, but should not change V's public or protected interfaces
because the added c'tor is private.  Here's the revised code.

class V { private: V(); public: V(int); };

class A : public virtual V { public: A(); };

A::A() : V(1) {}

V v(1);
A a;

CC (cfront 2.0) compiles this without giving errors or warnings.
(Of course, it won't link without defining V's methods.)
 
Russ Tuck		               tuck@cs.unc.edu
UNC Dept. of Computer Science          ...!mcnc!unc!tuck
CB 3175, Sitterson Hall
Chapel Hill, NC 27599-3175, USA        (919) 962-1755 or 962-1700