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From: mcf@tardis.trl.OZ.AU (Michael Flower)
Newsgroups: comp.lang.c++
Subject: Virtual function problem.
Keywords: C++ virtual function
Message-ID: <3472@trlluna.trl.oz>
Date: 8 May 91 05:12:40 GMT
Sender: news@trlluna.trl.oz
Lines: 32


I have come across something that appears strange.

If I compile the following with the AT&T 2.1 C++ compiler:

class A {
	virtual void	fn(char);	// 1
	virtual void	fn(char *);	// 2
};

class B : public A {
	void	fn(int);
};

main() {}

in the following way, I get.

"t.c", line 7: warning:  B::fn() hides virtual A::fn()
"t.c", line 7: warning:  B::fn() hides virtual A::fn()

Of course B::fn() hides A::fn(). That is why I wrote it! After all A::fn() is
virtual.

If I change the order of lines 1 and 2 (in class A), the problem goes away.
Admittedly it is only a warning, but I don't like warnings, they often spell
trouble. Is this an anomally?

Michael Flower
Artificial Intelligence Systems         Email:     m.flower@trl.oz.au
Telecom Research Laboratories           Voice:     +61 3 541 6179
Melbourne, AUSTRALIA                    Fax:       +61 3 543 8863