NSString retainCount is 2147483647

Question

Possible Duplicates:
NSString retain Count
Objective C NSString* property retain count oddity
When to use -retainCount ?

Why does this code show the retain value greater than 1? And why is it 2147483647?

NSString *data22 = [[NSString alloc] initWithString:@"fsdfsfsdf"];

int a = [data22 retainCount];
NSLog(@"retain count 1== %d  ====" ,a);

The output of the above code is

 retain count 1== 2147483647  ====

Answer 1

It is 2147483647 because you looked. Don't look and it will be the value you expect.

Seriously. Don't call retainCount. Not ever. It is useless.

Why it is such a ridiculous number is because of an implementation detail. @"..." is a constant string. NSString can recognize constant strings and decides that your particular code has no need of a second space consuming copy of a constant immutable string and, thus, returns the already existing constant string.

I.e. a singleton. Of a class whose instances are only ever created by the compiler. For which retain/release/autorelease/retainCount are utterly devoid of meaning.

As for why it is 2147483647, a picture is worth a thousand words. Or, in this case, 31 set bits.