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From: "Ward Correll" <wardless AT hotmail DOT com>
To: cygwin AT sourceware DOT cygnus DOT com
Subject: Maybe a Bug in Cygwin in using Pointers to class fuctions
Date: Mon, 02 Aug 1999 16:52:14 EDT
Mime-Version: 1.0
Content-Type: text/plain; format=flowed

Maybe a bug in Cygwin! I think that this sorce code is correct in the Final 
ANSI\ISO standard on C++ so I think it could be cygwin. Please check it out 
for me in this simple code.

//Maybe a bug (in Cygwin) in using a pointer to a class fuction

#include <iostream.h>

class Mammal
{
public:
	Mammal():itsAge(1) {  }
	virtual ~Mammal() { }
	virtual void Speak() const = 0;
	virtual void Move() const = 0;
protected:
	int itsAge;
};

class Dog : public Mammal
{
public:
	void Speak()const { cout << "Woof!\n"; }
	void Move() const { cout << "Walking to heel...\n"; }
};


class Cat : public Mammal
{
public:
	void Speak()const { cout << "Meow!\n"; }
	void Move() const { cout << "slinking...\n"; }
};


class Horse : public Mammal
{
public:
	void Speak()const { cout << "Winnie!\n"; }
	void Move() const { cout << "Galloping...\n"; }
};


int main()
{
	void (Mammal::*pFunc)() const =0;
	Mammal* ptr =0;
	int Animal;
	int Method;
	bool fQuit = false;

	while (fQuit == false)
	{
		cout << "(0)Quit (1)dog (2)cat (3)horse: ";
		cin >> Animal;
		switch (Animal)
		{
		case 1:	ptr = new Dog; break;
		case 2: ptr = new Cat; break;
		case 3: ptr = new Horse; break;
		default: fQuit = true; break;
		}
		if (fQuit)
			break;

		cout << "(1)Speak  (2)Move: ";
		cin >> Method;
		switch (Method)
		{
		case 1: pFunc = Mammal::Speak; break;
		default: pFunc = Mammal::Move; break;
		}

		(ptr->*pFunc)();
		delete ptr;
	}
	return 0;
}

=========================OUTPUT FROM CYGWIN==========================
BASH.EXE-2.02$ c++ -o try try.cpp
test.cpp: In function `int main()':
test.cpp:66: assuming & on `Mammal::Speak'
test.cpp:67: assuming & on `Mammal::Move'
=====================================================================
I know I want the fuction pointer to assume on Mammal::Speak or Mammal::Move 
when meets some conditions as you see. But cygwin won't let me do that.  
Anyway to force compiling?

Thanks!!! if you gave it a try.



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