Request authorization to Address Book

This code use for accessing address book

 ABAddressBookRef addressBookRef = ABAddressBookCreateWithOptions(NULL, NULL);  
 // Check address book permission is given or not   
  if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusNotDetermined)  
 {  
      ABAddressBookRequestAccessWithCompletion(addressBookRef, ^(bool granted, CFErrorRef error)  
     {  
          //the address book permission is given  
          //do your code for address book  
     });  
 }  
  else if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusAuthorized)  
 {  
          //if you have already permission for address book  
          //do your code for address book  
 }  
  else {  
     // The user has previously denied access  
     // Send an alert telling user to change privacy setting in settings app  
 }