block

As a local variable:returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...};As a property:@property (nonatomic, copy) returnType (^blockName)(parameterTypes);As a method parameter:- (void)someMethodThatTakesABlock:(returnType (^)(parameterTypes))blockName;As an argument to a method call:[someObject someMethodThatTakesABlock:^returnType (parameters) {...}];As a typedef:typedef returnType (^TypeName)(parameterTypes);TypeName blockName = ^returnType(parameters) {...};