Generate a random alphanumeric string in Cocoa

Not exactly what you ask, but still useful:

[[NSProcessInfo processInfo] globallyUniqueString]

Sample output:

450FEA63-2286-4B49-8ACC-9822C7D4356B-1376-00000239A4AC4FD5

Here's a quick and dirty implementation. Hasn't been tested.

NSString *letters = @"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

-(NSString *) randomStringWithLength: (int) len {

    NSMutableString *randomString = [NSMutableString stringWithCapacity: len];

    for (int i=0; i<len; i++) {
         [randomString appendFormat: @"%C", [letters characterAtIndex: arc4random_uniform([letters length])]];
    }

    return randomString;
}