引用自 stackoverflow
So this works. That being said, I would be very uncomfortable relying on this in a project of mine. If that variable gets released before you scan its address, who knows what you're going to get. In that respect, I guess that breaks the "ARC compatible" criterion because who knows when that reference will get released which makes this very dangerous. Also, type safety is totally out the window.
Method 1:
NSString *pointer = @"test";
NSString *address = [NSString stringWithFormat:@"%p",pointer];
NSString *retrievedObject;
sscanf([address cStringUsingEncoding:NSUTF8StringEncoding], "%p", &retrievedObject);
Method 2:
/// this requires a "0x" formatted hex string
ptr = [ptr hasPrefix:@"0x"] ? ptr : [@"0x" stringByAppendingString:ptr];
uintptr_t hex = strtoull(ptr.UTF8String, NULL, 0);
id gotcha = (__bridge id)(void *)hex;
