文章目录

• 1. 创建一个命名管道
• 2. 用命名管道实现server&client通信
• • 2.0 log.hpp打印日志信息
  • 2.1 comm.hpp(server.cc和client.cc共有文件)
  • 2.2 server.cc读取数据
  • 2.3 client.cc发送数据
  • 2.4 结果展示
• 3. 还可以多个进程接收

1. 创建一个命名管道

• 命名管道可以从命令行上创建，命令行方法是使用下面这个命令。

  $ mkfifo filename
  

  
  上图可见进程间通信成功。

• 命名管道也可以从程序里创建，相关函数有

  int mkfifo(const char *filename,mode_t mode);
  

  查手册：

  man 3 mkfifo
  

  

2. 用命名管道实现server&client通信

2.0 log.hpp打印日志信息

#ifndef _LOG_H_
#define _LOG_H_#include 
#include enum e
{Debug,Notice,Warning,Error
};const std::string msg[]{"Debug","Notice","Warning","Error"};std::ostream &log(std::string message, int level)
{std::cout << " | " << (unsigned)time(nullptr) << " | " << msg[level] << " | " << message;return std::cout;
}#endif

2.1 comm.hpp(server.cc和client.cc共有文件)

#ifndef _COMM_H_
#define _COMM_H#include 
#include 
#include 
#include 
#include 
#include using namespace std;#define MODE 0666
#define SIZE 128
string ipcpath = "./fifo.ioc";
#endif

2.2 server.cc读取数据

#include "comm.hpp"
#include "log.hpp"
int main()
{// 1. 创建管道文件if (mkfifo(ipcpath.c_str(), MODE) < 0){perror("mkfifo");exit(1);}log("创建管道文件成功", Debug) << " step 1" << endl;// 2. 正常的文件操作int fd = open(ipcpath.c_str(), O_RDONLY);if (fd < 0){perror("open");exit(2);}log("打开管道文件成功", Debug) << " step 2" << endl;// 3. 编写正常代码char buffer[SIZE];while (true){ssize_t s = read(fd, buffer, sizeof(buffer) - 1);if (s > 0){cout << "[" << getpid() << "]"<< "client say " << buffer << endl;}else if (s == 0){// end of filecerr << "[" << getpid() << "]"<< "read end of file, client quit, server quit too!" << endl;break;}else{// read errorperror("read");exit(3);break;}}// 4. 关闭文件close(fd);log("关闭管道文件成功", Debug) << " step 3" << endl;unlink(ipcpath.c_str()); //通信完毕，就删除文件log("删除管道文件成功", Debug) << " step 4" << endl;return 0;
}

2.3 client.cc发送数据

#include "comm.hpp"int main()
{// 1. 获取管道文件int fd = open(ipcpath.c_str(), O_WRONLY);if (fd < 0){perror("open");exit(1);}// 2. ipc过程string buffer;while (true){cout << "请输入一行信息 :> ";getline(cin, buffer);write(fd, buffer.c_str(), buffer.size());}// 3. 关闭close(fd);return 0;
}

2.4 结果展示

3. 还可以多个进程接收

• client.cc

#include "comm.hpp"
#include "log.hpp"
#include 
static void getMessag(int fd)
{char buffer[SIZE];while (true){ssize_t s = read(fd, buffer, sizeof(buffer) - 1);if (s > 0){cout << "[" << getpid() << "]"<< "client say " << buffer << endl;}else if (s == 0){// end of filecerr << "[" << getpid() << "]"<< "read end of file, client quit, server quit too!" << endl;break;}else{// read errorperror("read");exit(3);break;}}
}
int main()
{// 1. 创建管道文件if (mkfifo(ipcpath.c_str(), MODE) < 0){perror("mkfifo");exit(1);}log("创建管道文件成功", Debug) << " step 1" << endl;// 2. 正常的文件操作int fd = open(ipcpath.c_str(), O_RDONLY);if (fd < 0){perror("open");exit(2);}log("打开管道文件成功", Debug) << " step 2" << endl;for (int i = 0; i < 3; i++){pid_t id = fork();if (id == 0){// 3. 编写正常代码getMessag(fd);exit(0);}}for (int i = 0; i < 3; i++){waitpid(-1, nullptr, 0);}// 4. 关闭文件close(fd);log("关闭管道文件成功", Debug) << " step 3" << endl;unlink(ipcpath.c_str()); //通信完毕，就删除文件log("删除管道文件成功", Debug) << " step 4" << endl;return 0;
}