hostent *tent = gethostbyname(host_name);
//转换成IP地址
in_addr ip_addr;
memmove(&ip_addr,tent->h_addr_list[0],4);

//绑定端口号和ip
sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port   = htons(3050);      //默认设置的端口号
addr.sin_addr   = ip_addr;
if( bind(socket_server,(sockaddr *)&addr,sizeof(sockaddr)) )
{
    AfxMessageBox("绑定端口号和ip出错");
    return;
}