Ownership of returned quartz objects

Question

I recently asked about auto-implementation of a return quartz object: Auto-advertising for CGMutablePathRef?

Dave DeLong answered my question that there is no auto advertising for quartz (or any NS foundation objects), and I have to use the Create Rule . However, the naming convention in the document reads:

Core Foundation naming conventions, in particular the use of the word "create", apply only to C functions that return Core Foundation objects. The naming conventions for Objective-C methods are determined by Cocoa conventions, whether the method returns a Core Foundation or Cocoa object.

In this account, since my function is a message in a C object, it seems incorrect to call it createSomething. I still want to return this object. What is the best way to approach this? Should I use Get Rule and then for the calling box to explicitly save it? But this is not part of the Cocoa agreement. What is the right way to handle this?

Answer 1

Normally, you should return an auto-implemented object from the Objective-C method, which returns a new object. It's easy enough to do this with Core Foundation objects. For example, take this base class method:

+ (CFURLRef)appleWebsiteURL
{
    CFURLRef url = CFURLCreateWithString(NULL,CFSTR("http://apple.com"),NULL);
    return (CFURLRef)[NSMakeCollectable(url) autorelease];
}

, , . iPhone, :

return (CFURLRef)[(NSObject*)url autorelease];