objective c - Why NSNotFound isn't -1 but NSIntegerMax

Question

NSNotFound is defined as NSIntegerMax, which has different values on 32-bit and 64-bit, this brings a lot of inconvenience for persistent and distributed env. Why not define it as -1?

PS, In ObjC and Cocoa, some indexOf... methods returns NSNotFound but some returns -1, is there a reason these results are inconsistent.

Answer 1

This note from the docs is probably relevant:

Special Considerations

Prior to Mac OS X v10.5, NSNotFound was defined as 0x7fffffff. For 32-bit systems, this was effectively the same as NSIntegerMax. To support 64-bit environments, NSNotFound is now formally defined as NSIntegerMax. This means, however, that the value is different in 32-bit and 64-bit environments.