Whats this difference between [[NSUUID new] UUIDString] & CFUUIDRef

Question

Can Anyone let me know what is the difference between creating the Unique Id by these two implementations give below

1)

  CFUUIDRef cfuuid = CFUUIDCreate(kCFAllocatorDefault);
    NSString *udidString = (NSString*)CFBridgingRelease(CFUUIDCreateString(kCFAllocatorDefault, cfuuid));

2) NSString *guid = [[NSUUID new] UUIDString];

Which one is more reliable as I am working on app from IOS 8 and above.

score 2 · Accepted Answer · answered Nov 03 '15 at 06:27

2

You can find details on NSHipster's uuid-udid-unique-identifier post.

In the interest of not posting 'link only' answer here are excerpts form the same article:

NSUUID was added to Foundation in iOS 6 as a way to easily create UUIDs.

If your app targets iOS 5 or earlier, however, you have to settle for Core Foundation functions on CFUUIDRef

To sum up, although both return a valid UUID, go ahead and use NSUUID as its easier.

answered Nov 03 '15 at 06:27

Swapnil Luktuke

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Thanks for your quick response, shall use the same:) – codelover Nov 04 '15 at 06:37

score 1 · Answer 2 · answered Nov 03 '15 at 06:24

1

NSUUID was added to Foundation in iOS 6 as a way to easily create UUIDs.

CFUUIDRef is a Core Foundation function. If your app targets iOS 5 or earlier, you should go with this.

So, for iOS 8 and above, you should use NSUUID for the sake of simplicity and convenience.

answered Nov 03 '15 at 06:24

Abhinav

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Thanks for your quick response, shall use the same:) – codelover Nov 04 '15 at 06:37
Always happy to help :). Could you please accept this answer. – Abhinav Nov 04 '15 at 06:41

score 1 · Answer 3 · answered Nov 03 '15 at 07:30

Very simple

1.If your app targets iOS 5 or below iOS 5,it belongs to CoreFoundation also you need to set

CFUUIDRef uuid = CFUUIDCreate(NULL);
NSString *UUID = CFUUIDCreateString(NULL, uuid);

2.If you app targets iOS6 or above iOS 6,it belongs to Foundation also you need to set

NSString *UUID = [[NSUUID UUID] UUIDString];

Whats this difference between [[NSUUID new] UUIDString] & CFUUIDRef

3 Answers3