object-c selector

gistfile1.txt

//定义
SEL class_func;

//赋值
@interface foo
   -(int)add:int val;
@end
class_func = @selector(add:int);

//执行
SEL变量的执行.用performSelecor方法来执行.
[对象　performSelector:SEL变量　withObject:参数1　withObject:参数2];