int Open_clientfd_ts(char *hostname, int port)
{
    int clientfd;
    struct sockaddr_in serveraddr;
    struct hostent hostent, *hp = &hostent;
    struct hostent *temp_hp;


    if ((clientfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
	return -1; /* check errno for cause of error */

	/*lock-and-copy for thread safety*/
    P(&mutex); /* lock P(&mutex) */
    temp_hp = gethostbyname(hostname);
    if (temp_hp != NULL)
        hostent = *temp_hp; /* copy */
    V(&mutex); /*V(&mutex)*/


	 /* Fill in the server's IP address and port */
    if ((hp = gethostbyname(hostname)) == NULL)
	return -2; /* check h_errno for cause of error */
    bzero((char *) &serveraddr, sizeof(serveraddr));
    serveraddr.sin_family = AF_INET;
    bcopy((char *)hp->h_addr_list[0],
	  (char *)&serveraddr.sin_addr.s_addr, hp->h_length);
    serveraddr.sin_port = htons(port);

    /* Establish a connection with the server */
    if (connect(clientfd, (SA *) &serveraddr, sizeof(serveraddr)) < 0)
	return -1;
    return clientfd;
}