potential ARC retain cycle with C++ helper classes?

Question

I am integrating a C++ library to an iOS app (Objective C) which uses abstract classes to implement an event-handler pattern.

In order to receive the events, I need to implement a C++ class. Unless I'm missing something, I've been implementing C++ classes to implement the abstract interfaces, and then keeping an instance to the Objective-C class, so I can call selectors on it.

Here's an example

@implementation MYClass : NSObject
{
    CppHelper * _helper;
}

- (id)init
{
    if(self = [super init])
    {
        _helper = new CppHelper(self);
    }
}

- (void)dealloc
{
    delete _helper;
}

@end

...

class CppHelper : public AbstractLibraryInterface
{
private:
    MYClass * _parent;
public:
    CppHelper(MYClass * objCParent)
        : _parent(objCParent)
    { }

    onEvent()
    {
        [_parent handleEvent];
    }
};

My question is, does passing self via the C++ constructor create a strong ARC reference, such that my ObjC classes will be holding onto themselves?

Would using __bridge void* and storing the ObjC class as void* alleviate this problem? The lifetime of the C++ class is meant to be tied to the parent ObjC class.

Thanks!

Answer 1

Yes, yours self is retained in CppHelper constructor. I don't love ARC for making simple pointers strong. You can define __weak MYClass * _parent; to avoid retain cycle.

Also why not use abstract interfaces of objective-C: @protocol `s?