#include <iostream>
#include <cstring>
#include <cerrno>
#include <sys/wait.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#define IPC_PATH "./.fifo" // 命名文件路径

using std::cerr;
using std::cout;
using std::endl;

int main() {
    umask(0);
    if (mkfifo(IPC_PATH, 0666) != 0) {
        cerr << "mkfifo error" << endl;
        return 1;
    }

    int pipeFd = open(IPC_PATH, O_RDONLY);
    if (pipeFd < 0) {
        cerr << "open error" << endl;
        return 2;
    }

    cout << "命名管道文件, 已创建, 已打开" << endl;

    char buffer[1024];
    while (true) {
        cout << "阻塞" << endl;
        ssize_t ret = read(pipeFd, buffer, sizeof(buffer) - 1);
        cout << "阻塞结束" << endl;
        buffer[ret] = 0;

        if (ret == 0) {
            cout << "\n客户端(写入端)退出了, 我也退出吧";
            break;
        }
        else if (ret > 0) {
            cout << "客户端 -> 服务器 # " << buffer << endl;
        }
        else {
            cout << "read error: " << strerror(errno) << endl;
            break;
        }
    }

    close(pipeFd);
    cout << "\n服务端退出……" << endl;
    unlink(IPC_PATH);

    return 0;
}

#include <cstdio>
#include <cstring>
#include <fcntl.h>
#include <iostream>
#include <sys/stat.h>
#include <sys/wait.h>
#include <unistd.h>

#define IPC_PATH "./.fifo" // 命名文件路径

using std::cerr;
using std::cout;
using std::endl;

int main() {
    int pipeFd = open(IPC_PATH, O_WRONLY); // 只写打开命名管道, 不参与创建
    if (pipeFd < 0) {
        cerr << "open fifo error" << endl;
        return 1;
    }

    char line[1024]; // 用于接收命令行的信息
    while (true) {
        printf("请输入消息 $ ");
        fflush(stdout); // printf没有刷新stdout, 所以手动刷新
        memset(line, 0, sizeof(line));
        if (fgets(line, sizeof(line), stdin) != nullptr) {
            // 由于fgets 会接收 回车, 所以将 line的最后一位有效字符设置为 '\0'
            line[strlen(line) - 1] = '\0';
            // 向命名管道写入信息
            write(pipeFd, line, strlen(line));
            
            if (strcmp(line, "quit") == 0)
                break;
        }
        else {
            break;
        }
    }
    close(pipeFd);
    cout << "客户端(写入端)退出啦" << endl;

    return 0;
}

int fcntl(int fd, int cmd, ... /* arg */ );

#ifndef __UTIL_HPP__
#define __UTIL_HPP__

#include <fcntl.h>
#include <unistd.h>

#include <iostream>

namespace Util {
    // 对文件描述符设置非阻塞 的函数
    bool setNoBlock(int fd) {
        // 获取文件描述符的 原有属性
        int flag = fcntl(fd, F_GETFL);
        if (flag == -1) {
            return false;
        }

        // 设置文件描述符属性
        fcntl(fd, F_SETFL, flag | O_NONBLOCK);

        return true;
    }
}  // namespace Util

#endif

#include <unistd.h>

#include <cstdio>
#include <cstring>
#include <functional>
#include <iostream>
#include <string>
#include <vector>

#include "util.hpp"

using func_t = std::function<void()>;

int main() {
    std::vector<func_t> funcs;
    funcs.push_back([]() {
        std::cout << "other task1 is running" << std::endl;
    });
    funcs.push_back([]() {
        std::cout << "other task2 is running" << std::endl;
    });
    funcs.push_back([]() {
        std::cout << "other task3 is running" << std::endl;
    });

    Util::setNoBlock(0);

    char buffer[1024] = { 0 };
    while (true) {
        int n = scanf("%s", buffer);
        if (n == -1) {
            std::cout << "errno: " << errno << ", desc: " << std::strerror(errno) << std::endl;
            for (const auto &f : funcs)
                f();
        }
        else
            std::cout << "some data: " << buffer << std::endl;

        sleep(1);
    }

    return 0;
}

int select(int nfds, 
           fd_set *restrict readfds,
           fd_set *restrict writefds,
           fd_set *restrict exceptfds,
           struct timeval *restrict timeout);