iOS 获取全局唯一标示符

NSString *identifier = [[NSProcessInfo processInfo] globallyUniqueString];

NSLog(@"identifier1 ====== %@",identifier);

identifier = [[NSProcessInfo processInfo] globallyUniqueString];

NSLog(@"identifier2 ====== %@",identifier);

identifier = [[NSProcessInfo processInfo] globallyUniqueString];

NSLog(@"identifier3 ====== %@",identifier);

identifier = [[NSProcessInfo processInfo] globallyUniqueString];

NSLog(@"identifier4 ====== %@",identifier);