ObjectiveC Syntax for Specifying Protocol Name in Method Argument

Question

What's the ObjectiveC syntax for specifying a protocol as an argument in a method?

Say I have 2 protocols, MyProtocol and MyProtocolCB:

@protocol MyProtocolCB <NSObject>
- (void) func;
@end

@protocol MyProtocol <NSObject>
- (void) register:(MyProtocolCB*) cb;
@end

I'm receiving this syntax error: error: expected type-specifier before 'MyProtocolCB'

Vladimir · Accepted Answer · 2010-04-20 14:53:42Z

51

Try:

- (void) register:(NSObject<MyProtocol>*) cb;

answered Apr 20, 2010 at 14:53

Vladimir

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2 Comments

You also might use more generic id<MyProtocol> instead of NSObject<MyProtocol>*, especially if MyProtocol already extends NSObject protocol

@iPhone beginner: it's not exactly the same. some methods in the NSObject class are not in the NSObject protocol

AFTAB MUHAMMED KHAN · Accepted Answer · 2018-07-10 13:51:29Z

0

use id instead of NSObject as you already know id is the instance type or generic type so if you use id it will help you in big perspective.

- (void) register:(id<MyProtocol>*) sender;

answered Jul 10, 2018 at 13:51

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