ios importing contacts by modified date

I want to import contacts in to my application regularly and instead of pulling them all in and开发者_运维百科 then updating by a local diff I would prefer to just get the contacts that changed data in the last 6 hours.

Any ideas?

You should use kABPersonModificationDateProperty property from ABPerson record.

http://developer.apple.com/library/ios/documentation/AddressBook/Reference/ABPersonRef_iPhoneOS/Reference/reference.html#//apple_ref/doc/c_ref/kABPersonModificationDateProperty