C++ 使用lambda表达式作为函数参数

C++ 使用lambda表达式作为函数参数

1. 使用模板参数实现

#include 
#include 

#include 

volatile bool g_is_running = true;
volatile bool g_is_idle = false;

template <typename T, typename F>
int32_t EventLoop(const T& do_func, const F& do_idle) {
    while (g_is_running)
    {
        if (!g_is_idle)
        {
            int32_t ec = do_func();
            if (ec != 0)
            {
                break;
            }
        }
        else
        {
            do_idle();
        }
    }
    g_is_running = false;
    return 0;
}

int main(int argc, char ** argv) {
    std::cout << "Hello, World!" << std::endl;

    std::string language = "Rust";
    auto do_biz = [&]() { 
        std::cout << "Welcome to " << language << std::endl;
        sleep(1);
        return 0;
    };

    auto do_idle = []() { 
        usleep(1);
    };

    return EventLoop(do_biz, do_idle);
}

2. 使用std::function方式实现

#include 
#include 

#include 
#include 

volatile bool g_is_running = true;
volatile bool g_is_idle = false;


int32_t EventLoop(const std::function<int(void)>& do_func, const std::function<int(void)>& do_idle) {
    while (g_is_running)
    {
        if (!g_is_idle)
        {
            int32_t ec = do_func();
            if (ec != 0)
            {
                break;
            }
        }
        else
        {
            do_idle();
        }
    }
    g_is_running = false;
    return 0;
}

int main(int argc, char ** argv) {
    std::cout << "Hello, World!" << std::endl;

    std::string language = "Rust";
    auto do_biz = [&]() { 
        std::cout << "Welcome to " << language << std::endl;
        sleep(1);
        return 0;
    };

    auto do_idle = []() { 
        usleep(1);
        return 0;
    };

    return EventLoop(do_biz, do_idle);
}