{

int server_sock = socket(AF_INET, SOCK_STREAM, 0);

struct sockaddr_in serv_addr;

int serv_addr_len = sizeof(serv_addr);

serv_addr.sin_family = AF_INET;

serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);

serv_addr.sin_port = htons(8123);

//将 inet_ntoa() 改用 inet_ntop() 这个现代方法，支持 IPV4 和 IPV6

//printf("bind in %s : %d\n", inet_ntoa(serv_addr.sin_addr), ntohs(serv_addr.sin_port));

//INET_ADDRSTRLEN 是标识 IPV4 地址展现字符串的大小常量,INET6_ADDRSTRLEN是 IPV6 的

char serv_ip[INET_ADDRSTRLEN];

if (inet_ntop(AF_INET, &serv_addr.sin_addr, serv_ip, sizeof(serv_ip)) == NULL) {

printf("inet_ntop error\n");

close(server_sock);

return 0;

}

printf("bind in %s : %d\n", serv_ip, ntohs(serv_addr.sin_port));

if (bind(server_sock, (struct sockaddr*)&serv_addr, serv_addr_len) < 0) {

printf("bind error\n");

return 0;

}

if (listen(server_sock, 1)) {

printf("listen error\n");

return 0;

}

char buf[1024];

while (1) {

struct sockaddr_in client_addr;

int client_addr_len = sizeof(client_addr);

printf("等待链接的到来\n");

int client_sock = accept( server_sock,

(struct sockaddr*)&client_addr,

(unsigned int *)&client_addr_len );

if (client_sock == -1) {

printf("accept error\n");

return 0;

}

printf("有新连接到来\n");

int n = recv(client_sock, buf, sizeof(buf), 0);

while (n > 0) {

if (send(client_sock, buf, sizeof(buf), 0) < 0) {

printf("send error\n");

return 0;

}

n = recv(client_sock, buf, sizeof(buf), 0);

}

close(client_sock);

printf("连接离开\n");

}

close(server_sock);

return 0;

}