c++ 知识点 std::function 使用

这是c++11新添加的,头文件#include <functional>

官方说明：

Class template 

std::function

 is a general-purpose polymorphic function wrapper. Instances of 

std::function

 can store, copy, and invoke any Callable target -- functions, lambda expressions, bind expressions, or other function objects, as well as pointers to member functions and pointers to data members.

The stored callable object is called the target of 

std::function

. If a 

std::function

 contains no target, it is called empty. Invoking the target of an empty 

std::function

 results in std::bad_