iphone - autoreleasing a CGContextRef ??

Question

I have this method

-(CGContextRef) createPDFContext:(CGRect)inMediaBox path:(CFStringRef) path
{

   // bla bla
   // at some point I have

   CGContextRef myOutContext = CGPDFContextCreate (dataConsumer, &inMediaBox, NULL);

   // and then I have to return the value
    return myOutContext;
}

The problem is that myOutContext was not released and will leak.

if I put a CGContextRelease (myOutContext) before the return, then the reference will arrive invalid at the caller...

How do I solve that? Doing return [myOutContext autorelease]; will not work, as I suspected and tested.

thanks.

Answer 1

Because your method has "Create" in its name, it's expected that the caller will be responsible for releasing the object. See http://developer.apple.com/library/ios/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029.

---

Update: Because this is a method and not a function, you should change it to start with "new" as described at http://developer.apple.com/library/ios/documentation/cocoa/Conceptual/MemoryMgmt/Articles/mmObjectOwnership.html#//apple_ref/doc/uid/20000043-SW1.

Answer 2

You need to follow memory conventions. Your method has the word "create" in it, which means that whoever calls that method is responsible for calling CGContextRelease on it when they are done with it. If you don't like that idea, then you need to find some way of knowing when the caller is done with it.