TCP echo server demo

#include "unp.h"int main(int argc, char *argv[]){int listenfd, connfd;pid_t childpid;socklen_t clilen;struct sockaddr_in cliaddr, servaddr;  //一般是程序员填写sockaddr_in 然后转化成sockaddr类型传到内核listenfd = Socket(AF_INET, SOCK_STREAM, 0);     //用制定的协议创建一个socket，AF_INET表示ipv4，SOCK_STREAM表示TCPbzero(&servaddr, sizeof(servaddr));           //将服务器地址结构体清零servaddr.sin_family = AF_INET;               servaddr.sin_addr.s.addr = htonl(INADDR_ANY);   servaddr.sin_port = htons(SERV_PORT);Bind(listenfd, (SA*) &servaddr, sizeof(servaddr);Listen(listenfd, LISTENQ);while(1){connfd = fork();if(0 == connfd){Close(listenfd);str_echo(connfd);exit(0)}Close(connfd);}return 0;}