• 局部變量：

returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...};

• 屬性：

@property (nonatomic, copy, nullability) returnType (^blockName)(parameterTypes);

• 方法參數(shù)：

-(void)someMethodThatTakesABlock:(returnType (^nullability)(parameterTypes))blockName;

• 方法調(diào)用參數(shù)：

[someObject someMethodThatTakesABlock:^returnType (parameters) {...}];

• typedef：

typedef returnType (^TypeName)(parameterTypes);TypeName blockName = ^returnType(parameters) {...};