From: ts <decoux@...>
Date: 2001-09-04T14:29:13+09:00
Subject: [ruby-talk:20839] Re: Calling member methods from C++

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

B> If i Make OnFire a class method everything works as expected.. However
B> I need to call instance methods....

 If you look at your first message [ruby-talk:20588] "Calling class member
 functions from C++", you'll find


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


 `self' is the class,  `t' is the instance

 You are storing the *class* when you write

       obj->LinkScriptClass( self );

 I suspect, but not really sure that in these lines

                String callString = "On";
                callString += m_msg;

                // Generated for the method
                ID callId = rb_intern( callString );

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

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

 that `val' is the value that you have stored in cname##New, this mean that
 `val' is the *class* and not the instance.

 When you call

     rb_funcall2(val, ...);

 you are calling a class method, because `val' is the *class*

 In cname##New just store the instance rather than the class.

p.s.:
 I don't know your source but probably you don't need to store the
 instance. 


Guy Decoux