Nirvana

Noooo...not "Come As You Are," Nirvana, but the calm state of being, peace of mind, Nirvana.

My bafflement in my last post, as to why the Objective-C doc said this,

Objective-C++ similarly strives to allow C++ class instances to serve as instance variables. This is possible as long as the C++ class in question (along with all of its superclasses) does not have any virtual member functions defined. If any virtual member functions are present, the C++ class may not serve as an Objective-C instance variable.

And, I was able to do this...

Class Foo
{
public:
Foo(){};

private:
virtual LookImAVirtualFunc(void){};
};


@interface Bar : NSObject
{
@private
Foo* foo;
}

Clearly Foo is a C++ class with a virtual function, and Bar is an Objective-C class with an instance to Foo, but the doc said. And, here's my gaff...the doc is *correct.* Objective-C class cannot have an instance to a C++ class that has virtual functions. However, an Objective-C class can have a *pointer* to a C++ class that has virtual functions. In my test I had a *pointer* and that is why it works.

If I had,

@interface Bar : NSObject
{
@private
Foo foo; // ERROR
}

which is the instance to the class. So, you can have a C++ class that has virtual functions as instance variables inside an Objective-C class, you just have to declare them as pointers.

Ahhh...serenity.



Thanks to Andre' Pang, Kai, and Uli Kusterer for answering my question on the obj-language@lists.apple.com.