std :: function learning

Using std :: function bindings

The following source content from the "in-depth application C ++ 11 code optimization and engineering application" 1.5.2 callable wrapper --std :: function

std :: function is callable wrapper. It is a template class can accommodate all calls except class member objects (function) of the pointer. Template by specifying its parameters, which can be treated in a uniform way function , function objects , function pointers , and allows saving and delay execution thereof.

#include <iostream>
#include <functional>
using namespace std;

// 普通函数
void func(void)
{
    cout << __FUNCTION__ << endl;
}

// 静态函数
struct Foo
{
    static int foo_func(int a)
    {
        cout << __FUNCTION__ << "(" << a << ")->:";
        return a;
    }
};

// 仿函数
struct Bar
{
    int operator()(int a)
    {
        std::cout << __FUNCTION__ << "(" << a << ") ->: ";
        return a;
    }
};

int main()
{
    // 绑定一个普通函数
    std::function<void(void)> fr1 = func;
    fr1();

    // 绑定一个类的静态成员函数
    std::function<int(int)> fr2 = Foo::foo_func;
    std::cout << fr2(123) << std::endl;

    // 绑定一个仿函数
    Bar bar;
    fr2 = bar;
    std::cout << fr2(234) << std::endl;
    return 0;
}