NSString hash with same value across releases of iOS (not OS X)?

问题

The documentation for NSString hash (even the iOS documentation) contains this instruction:

You should not rely on this property having the same hash value across releases of OS X.

Do we know whether the property can be assumed to have the same value across releases of iOS (as opposed to OS X)?

And do we know why it may vary for OS X? (Is this e.g. for allowing Apple to switch from, say, MD5 to another hash function at some point?)

回答1:

We can not rely on NSString hash. Take a look at :

Why is [NSString hash] device dependent?

http://www.abakia.de/blog/2012/12/05/nsstring-hash-is-bad/

来源：https://stackoverflow.com/questions/28301891/nsstring-hash-with-same-value-across-releases-of-ios-not-os-x