c 中的客户端只能连接到服务器一次答案

【问题标题】：Can only connect to Server once with Client in cc 中的客户端只能连接到服务器一次
【发布时间】：2018-10-02 22:33:54
【问题描述】：

我正在用 C 语言编写并创建一个服务器，该服务器一次接收来自多个不同客户端的连接。但是，第一次连接关闭后，服务器就无法再次连接了。

server.c:

#include <stdio.h>
#include <stdlib.h>

#include <sys/socket.h>
#include <sys/types.h>

#include <netinet/in.h>
#include <unistd.h>

int main() {
 while(1) {
  char server_message[256] = "You have reached the server!";

  //Create a socket
  int server_socket;
  server_socket = socket(AF_INET, SOCK_STREAM, 0);

  //Define the server address
  struct sockaddr_in server_address;
  server_address.sin_family = AF_INET;
  server_address.sin_port = htons(9002);
  server_address.sin_addr.s_addr = INADDR_ANY;

  //Bind the socket to the IP and port
  bind(server_socket, (struct sockaddr *) &server_address, 
  sizeof(server_address));

  //Listen for connections
  listen(server_socket, 5);

  //Accept the connection
  int client_socket = accept(server_socket, NULL, NULL);

  //Send message
  send(client_socket, server_message, sizeof(server_message), 0);

  //Close the socket
  close(server_socket);
  }
 return 0;
}

【问题讨论】：

标签： c sockets server client

【解决方案1】：

你正在循环创建一个服务器套接字，接受一个连接，处理它，然后关闭你的服务器套接字。最后一个动作将丢弃所有挂起的连接。您的循环应该在listen() 调用之后立即开始，并在关闭客户端套接字之后终止，并且在关闭服务器套接字之前。

您还忽略了socket(), bind(), listen(), accept(), send() 和close() 上的所有错误。不要那样做。

【讨论】：

【解决方案2】：

这样改代码（省略错误检查）：

int main() {

  //Create a socket
  int server_socket;
  server_socket = socket(AF_INET, SOCK_STREAM, 0);

  //Define the server address
  struct sockaddr_in server_address;
  server_address.sin_family = AF_INET;
  server_address.sin_port = htons(9002);
  server_address.sin_addr.s_addr = INADDR_ANY;

  //Bind the socket to the IP and port
  bind(server_socket, (struct sockaddr *) &server_address, 
  sizeof(server_address));

  //Listen for connections
  listen(server_socket, 5);

 while(1) {
  char server_message[256] = "You have reached the server!";

   //Accept the connection
   int client_socket = accept(server_socket, NULL, NULL);
   /*check some condition to exit from loop*/

   /*or send client to another thread for parallel programing*/

   //Send message
   send(client_socket, server_message, sizeof(server_message), 0);

   //Close the client socket
   close(client_socket);
  }

  close(server_socket);

 return 0;
}

在此代码服务器中，获取客户端后必须等待客户端完成它的工作，然后尝试接受新客户端，如果要并行，接受客户端和客户端中的数据传输，最好将客户端发送和接收放在另一个线程中。

【讨论】：