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From: budd@fog.cs.orst.edu (Tim Budd)
Newsgroups: comp.lang.c++
Subject: private inheritance in G++ 1.39
Message-ID: <1991Jun27.163527.25117@lynx.CS.ORST.EDU>
Date: 27 Jun 91 16:35:27 GMT
Sender: @lynx.CS.ORST.EDU
Organization: Computer Science Department, Oregon State Univ.
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Originator: budd@fog.CS.ORST.EDU
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We've recently upgraded our g++ from 1.37 to 1.39.  I have some code that
used to work that now gives errors.  So now I'm wondering if it is g++ 1.39
that is at fault or if my reading of ARM 11.2 and 11.3 is wrong.
The problem involes private inheritance.  Now it makes sense that when you
inherit privately from a base class that defines a destructor you need to
also make the destructor public in the subclass.  The following example
worked fine in 1.37, but complains about *both* the declarations now.
(error message is ``type Two is derived from private One'' - a most
uninformative error message since it tells me exactly what I already knew
and what I wanted in any case.

class One {
public:
	one() {printf("in one \n"); }
	~One() {}
};

class Two : private One {
public:
	two() { printf("in two\n"); }
	One::~One;
};

class Three : public Two {
public:
	three() { printf("in three\n"); }
};

main() {
Two x2;
Three x3;
}