I need to generate a UUID string in some code with ARC enabled.
After doing some research, this is what I came up with:
CFUUIDRef uuid = CFUUIDCreate(NULL); NSString *uuidStr = (__bridge_transfer NSString *)CFUUIDCreateString(NULL, uuid); CFRelease(uuid);
Am I correctly using __bridge_transfer
to avoid leaking any objects under ARC?
Looks fine to me. This is what I use (available as a gist)
- (NSString *)uuidString { // Returns a UUID CFUUIDRef uuid = CFUUIDCreate(kCFAllocatorDefault); NSString *uuidString = (__bridge_transfer NSString *)CFUUIDCreateString(kCFAllocatorDefault, uuid); CFRelease(uuid); return uuidString; }
Edited to add
If you are on OS X 10.8 or iOS 6 you can use the new NSUUID class to generate a string UUID, without having to go to Core Foundation:
NSString *uuidString = [[NSUUID UUID] UUIDString]; // Generates: 7E60066C-C7F3-438A-95B1-DDE8634E1072
But mostly, if you just want to generate a unique string for a file or directory name then you can use NSProcessInfo
's globallyUniqueString
method like:
NSString *uuidString = [[NSProcessInfo processInfo] globallyUniqueString]; // generates 56341C6E-35A7-4C97-9C5E-7AC79673EAB2-539-000001F95B327819
It's not a formal UUID, but it is unique for your network and your process and is a good choice for a lot of cases.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With