How to generate a unique identifier?

Question

I need to generate some int value that would never repeat (at least theoretically). I know there is arc4random() fnc but I'm not sure how to use it with some current date or smth :(

Answer 1

This returns a unique key very similar to UUID generated in MySQL.

+ (NSString *)uuid
{
    CFUUIDRef uuidRef = CFUUIDCreate(NULL);
    CFStringRef uuidStringRef = CFUUIDCreateString(NULL, uuidRef);
    CFRelease(uuidRef);
    return [(NSString *)uuidStringRef autorelease];
}

ARC version:

+ (NSString *)uuid
{
    CFUUIDRef uuidRef = CFUUIDCreate(NULL);
    CFStringRef uuidStringRef = CFUUIDCreateString(NULL, uuidRef);
    CFRelease(uuidRef);
    return (__bridge_transfer NSString *)uuidStringRef;
}