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From: rmartin@clear.com (Bob Martin)
Newsgroups: comp.lang.c++
Subject: Re: Bug in Sun C++ 2.0
Message-ID: <1991Mar23.023706.21574@clear.com>
Date: 23 Mar 91 02:37:06 GMT
References: <1991Mar21.022309.15355@clear.com>
Organization: Clear Communications, Inc.
Lines: 89


			Bug in Sun CFont 2.0
			--------------------
			 Sun Ref# 696308
			 Called in by Robert Martin.

Abstract
	In a class with overloaded member function of the form:
		
		Add(type, ...);

	Only the first two declarations are recognized.  
	Subsequent declarations do not seem to work if called
	with variable arguments.

Example

	class X
	{
	public:
		X::X() {}
		void Add(int, ...) {};
		void Add(long, ...) {};
		void Add(double, ...) {};
	};

	main()
	{
		X x;

		x.Add(1, 1);
		x.Add(1L, 2);
	/*###16 [cc] error: ambiguous argument for X::Add(): 
		void X::(int ... ) and void X::(long ... )%%%*/
	/*###16 [cc] warning: double passed as int%%%*/
		x.Add(1.2, 3); // fails.

		x.Add(1);
		x.Add(1L);
		x.Add(1.2); // works.
	} 


	But if you swap the declarations around a bit.


	class X
	{
	public:
		X::X() {}
		void Add(double, ...) {}; // now double is first.
		void Add(int, ...) {};
		void Add(long, ...) {};
	};

	main()
	{
		X x;

		x.Add(1, 1);
	/*###15 [cc] error: ambiguous argument for X::Add(): 
	void X::(double ... ) and void X::(int ... )%%%*/
		x.Add(1L, 2); // now it doesn't like longs.  
		x.Add(1.2, 3); 

		x.Add(1);
		x.Add(1L); // but this it can handle.
		x.Add(1.2); 
	} 

So I conclude that the compiler is having trouble matching
the signatures of member functions if those member functions are
called with variable arguments.  

***********

Sun has acknowledged that this is indeed a bug, and that it has been
fixed in version 2.1.


+-Robert C. Martin-----+:RRR:::CCC:M:::::M:| Nobody is responsible for |
| rmartin@clear.com    |:R::R:C::::M:M:M:M:| my words but me.  I want  |
| uunet!clrcom!rmartin |:RRR::C::::M::M::M:| all the credit, and all   |
+----------------------+:R::R::CCC:M:::::M:| the blame.  So there.     |
-- 
+-Robert C. Martin-----+:RRR:::CCC:M:::::M:| Nobody is responsible for |
| rmartin@clear.com    |:R::R:C::::M:M:M:M:| my words but me.  I want  |
| uunet!clrcom!rmartin |:RRR::C::::M::M::M:| all the credit, and all   |
+----------------------+:R::R::CCC:M:::::M:| the blame.  So there.     |