From: ts <decoux@...>
Date: 2001-09-01T02:15:18+09:00
Subject: [ruby-talk:20634] Re: Calling class member functions from C++

>>>>> "B" == =?ISO-8859-1?Q?Bernhard Gl=FCck?= <jglueck@vol.at> writes:

[...]
B> class SpaceShip < Mesh 

B> 	def OnDoSomething ( dummy )
	
B> 		Log("Just a dummy log output")
B> 	end

B> end

B> m = SpaceShip.new()
B> AddToGame( m )

[...]

B> Of particular interest should be the  obj->linkScriptClass call where
B> the self VALUE is stored.... shouldn't the self VALUE be a handle to
B> the SpaceShip class
B> instance when used in the code above ?

 Well difficult to reply without seeing completely the code. Apparently the
self VALUE is SpaceShip

B> 		static VALUE cname##New( VALUE self ) \
B> 		{ \
B> 			ObjectPtr * inst = new ObjectPtr(); \
B> 			*inst = Factory()->CreateObject(#cname); \
B> 			VALUE t = Data_Wrap_Struct(self,0,SE_DELETE(cname##Delete),inst); \
B> 			rb_obj_call_init(t, 0, NULL); \
B> 			Object * obj = inst->Get(); \
obj-> LinkScriptClass( self ); \
B> 			return t; \
B> 		} \
 

B> And when I try to call the SpaceShip method it crashes all the time, I
B> am doing so
		
B> 		In the upper cases m_msg contains "DoSomething"
B> 		and val is the VALUE stored in the above procedure ( the C++ Ruby
B> "Constructor" )

 if `val' is `self' of the above procedure then it's SpaceShip

B> 		String callString = "On";
B> 		callString += m_msg;
		
B> 		// Generated for the method
B> 		ID callId = rb_intern( callString );

B> 		// Now create the parameter array for the call...
B> 		Array<VALUE> args;

B> 		// And make the script call
B> 		rb_funcall2_protect( val,callId,args.Size(),args.Begin() );

 Here you are calling the class method SpaceShift::OnDoSomething and not
the instance method SpaceShift#OnDoSomething



Guy Decoux