cfDictionaryValue回调保留/释放?

id / NSObject 什么?有 kCFTypeDictionaryValueCallBacks 但它们只适用于“CFType派生对象”。我不相信NSObjects是CFType,所以我写了这些:

const void *valueRetainCallBack(CFAllocatorRef allocator, const void *ptr)
{
    id o = (id)ptr;
    [o retain];

    return o;
}

void valueReleaseCallBack(CFAllocatorRef allocator, const void *ptr)
{
    id o = (id)ptr;
    [o release];
}