How to use nonnull and nullable Objective-C keywords in block-based API method

Question

Consider the following method

- (void)methodWithArg:(NSString *)arg1 andArg:(NSString *)arg2 completionHandler:(void (^)(NSArray *results, NSError *error))co         


        

Answer 1

You can also do like this:

- (id __nullable)methodWithArg:(NSString * __nullable)arg1
                        andArg:(NSString * __nonnull)arg2
             completionHandler:(void (^ __nonnull)(NSArray * __nonnull results, NSError * __nullable error))completionHandler;

It only depends which syntax you like more.