使用nanomsg库实现多进程之间通信

概述：

       之前下载并安装了nanomsg库，接下来就是看看怎么使用啦。首先是看看如何实现进程间的通信吧。

实例demo：

#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <nanomsg/pair.h>
#include <nanomsg/bus.h>
#include <nanomsg/nn.h>

/*
PAIR - simple one-to-one communication
BUS - simple many-to-many communication
REQREP - allows to build clusters of stateless services to process user requests
PUBSUB - distributes messages to large sets of interested subscribers
PIPELINE - aggregates messages from multiple sources and load balances them among many destinations
SURVEY - allows to query state of multiple applications in a single go
*/
/*
INPROC - transport within a process (between threads, modules etc.) 线程
IPC - transport between processes on a single machine   进程
TCP - network transport via TCP  网络TCP
WS - websockets over TCP   websockets TCP
*/

//ipc:// 标识用于多进程通信,后面的sky_test是我自己命名，可以随意命名
char *url = "ipc://sky_test";

int server_sock_init(int *sock)
{
  *sock = nn_socket (AF_SP, NN_PAIR);
  if (*sock < 0) {
    printf("create server sock failed\r\n");
    return 1;
  }
  if (nn_bind(*sock, url) < 0) {
    printf("bind server sock failed\r\n");
    return 1;
  }
  printf("server socket init success...\r\n");
  return 0;
}

int client_sock_init(int *sock)
{
  *sock = nn_socket (AF_SP, NN_PAIR);
  if (*sock < 0) {
    printf("create server sock failed\r\n");
    return 1;
  }
  if (nn_connect(*sock, url) < 0) {
    printf("bind server sock failed\r\n");
    return 1;
  }
  printf("client socket init success...\r\n");
  return 0;
}

void child_process_test()
{
  int c_sock;
  char *tx_msg = "Hello Main Process";
  if (0 != client_sock_init(&c_sock)) {
    return;
  }
  while (1) {
    //发送信息到主进程客户端
    while (1) {
      size_t len = strlen (tx_msg) + 1;
      if (nn_send(c_sock, tx_msg, len, 0) < 0) {
        printf("Thread Send Msg Failed\r\n");
        usleep(500000);
        continue;
      }
      break;
    }
    while (1) {
      //接收主进程客户端信息
      char *rx_msg = NULL;
      int result = nn_recv(c_sock, &rx_msg, NN_MSG,NN_DONTWAIT);
      if (result > 0) {
        printf("Child Process Recieve: %s\r\n", rx_msg);
        nn_freemsg (rx_msg);
        break;
      }
      usleep(200000);
    }
  }
}

void main_process_test()
{
  int s_sock;
  char *tx_msg = "Hi Child Process Test";
  if (0 != server_sock_init(&s_sock)) {
    return;
  }
  sleep(1);
  while (1) {
    while (1) {
      //接收子进程客户端信息
      char *rx_msg = NULL;
      int result = nn_recv(s_sock, &rx_msg, NN_MSG,NN_DONTWAIT);
      if (result > 0) {
        printf("Main Recieve: %s\r\n", rx_msg);
        nn_freemsg (rx_msg);
        break;
      }
      usleep(200000);
    }
    //发送信息到子进程客户端
    while (1) {
      size_t len = strlen (tx_msg) + 1;
      if (nn_send(s_sock, tx_msg, len, 0) < 0) {
        printf("Main Send Msg Failed\r\n");
        usleep(500000);
        continue;
      }
      break;
    }
  }
}

int main()
{
  pid_t fpid;
  fpid = fork();
  if (fpid < 0) {
    printf("fork failed\r\n");
    return 1;
  } else if (fpid == 0) {
    //子进程
    child_process_test();
  } else {
    //主进程
    main_process_test();
  }
  return 0;
}

编译运行：

//我的c文件名称nanomsg_ipc.c,编译时记得加上-lnanomsg
gcc -o nanomsg_ipc nanomsg_ipc.c -lnanomsg

运行结果：

总结：

        这样，我们就实现了多进程之间通信，这对于多进程编程来说，传输数据就非常方便了，对于实际编程过程中会有很大的帮助。