C语言利用fork创建多进程服务端

一、概述

　　案例：利用for改造上一节的服务端程序，让其能够和多个客户端之间收发数据。Client端代码请参考上一篇

二、代码示例

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#include <iostream> #include <sys/socket.h> #include <netinet/in.h> #include <unistd.h>   #define PORT 8888 #define MESSAGE_LEN 1024 int main(int argc, char const *argv[]) {           int socket_fd,accept_fd;     int on= 1;     int ret =-1;     int backlog = 10;     pid_t pid;     struct sockaddr_in localaddr ,remoteaddr;     socket_fd = socket(AF_INET,SOCK_STREAM,0);       char in_buff[MESSAGE_LEN] = {0};     //如果socket创建失败就退出     if(socket_fd==-1){         std::cout<<"Failed to create socket!"<<std::endl;         exit(-1);     }       ret = setsockopt(         socket_fd,         SOL_SOCKET,         SO_REUSEADDR,         &on,         sizeof(on));     if(ret==-1){         std::cout<<"Failed 通setsocket options!"<<std::endl;         exit(-1);     }       localaddr.sin_family=AF_INET;     localaddr.sin_port = PORT;     localaddr.sin_addr.s_addr = INADDR_ANY;     bzero(&(localaddr.sin_zero),8);         ret = bind(socket_fd,         (struct sockaddr*)&localaddr,sizeof(struct sockaddr));     if(ret  ==-1){         std::cout<< "Failed to bind addr!"<<std::endl;         exit(-1);     }       ret = listen(socket_fd,backlog);     if(ret==-1){         std::cout<< "Failed to bind listen socket!"<<std::endl;         exit(-1);     }     for(;;){         socklen_t addr_len = sizeof(struct sockaddr);         accept_fd = accept(socket_fd,(struct sockaddr*)&remoteaddr,&addr_len);           pid = fork();         if(pid==0){//pid==0子进程             for(;;){                 ret=recv(accept_fd,(void*)in_buff,MESSAGE_LEN,0);                 if(ret==0){                     break;                 }                 std::cout << "recv:"<< in_buff<<std::endl;                 send(accept_fd,(void*)in_buff,MESSAGE_LEN,0);                               }             close(accept_fd);         }                     }     //关闭父进程     if(pid!=0){         close(socket_fd);     }           return 0; }