Implementation inheritance

[ERDI Gergo <cactus cactus rulez org>]

Loaded with enthusiasm after hearing about Murray's success with ORBit/C++
and the Hello World demo, I jumped on it to play with it.

The first thing I wanted to figure out was how implementation inheritance
works. So I created a Hello2 interface that extends Hello with a new "foo"
method. Without looking at any CORBA docs, the obvious thing to do was:

class Hello_impl: public POA_hellomodule::Hello
{
public:
	virtual char* helloWorld (const char* greeting) throw (CORBA::SystemException);
};

class Hello2_impl: public POA_hellomodule::Hello2,
		   public Hello_impl
{
public:
	void foo () throw (CORBA::SystemException);
};

This didn't quite work:

server.cc: In function `int main(int, char**)':
server.cc:25: cannot declare variable `servant' to be of type `hellomodule::Hello2_impl'
server.cc:25:   because the following virtual functions are abstract:
generated/helloworld-cpp-skels.hh:62: 	virtual char* POA_hellomodule::Hello::helloWorld(const char*)

server.cc:26: request for member `_this' is ambiguous
generated/helloworld-cpp-skels.hh:51: candidates are: _orbitcpp::stub::hellomodule::Hello* POA_hellomodule::Hello::_this()
generated/helloworld-cpp-skels.hh:109:                _orbitcpp::stub::hellomodule::Hello2* POA_hellomodule::Hello2::_this()

So, I thought, yeah right, I'm duplicating POA_hellomodule::Hello in
Hello2_impl since POA_hellomodule::Hello2 is inherited from it.

After playing around with every combination of virtual inheritance, I
decided to look for 'canonical' answers on the Web. However, the pages
I've found all boiled down to my initial solution.

So I guess the above code should work, in which case it is ORBit's fault.
If it's not, I'd like to hear how you do implementation inheritance.

-- 
   .--= ULLA! =---------------------.   `We are not here to give users what
   \     http://cactus.rulez.org     \   they want'  -- RMS, at GUADEC 2001
    `---= cactus cactus rulez org =---'
As a computer, I find your faith in technology amusing.