공간사랑

 int tcp_connect_timeo(const char *hostname, const char *service,int nsec)
{
     struct addrinfo hints, *res, *ressave;
     int  sock,n;

     bzero(&hints, sizeof(struct addrinfo));
     hints.ai_family = AF_UNSPEC;
     hints.ai_socktype = SOCK_STREAM;

     if( (n=getaddrinfo(hostname,service,&hints,&res)) != 0)
         return -1;
     ressave = res;
     do
     {  
         struct  sockaddr_in *ts;
         sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
         if(sock < 0)
             continue;

         ts = (struct sockaddr_in *) res->ai_addr;

         if(connect_nonb(sock, (struct sockaddr *)res->ai_addr, res->ai_addrlen,nsec) == 0)
             break;
         close(sock);
     }while( (res=res->ai_next) !=NULL);
     if( res == NULL)
         return -1;
     freeaddrinfo(ressave);
     return sock;
}


int connect_nonb(int sockfd, const struct sockaddr *saptr, int salen, int nsec)
{
    int             flags, n, error;
    socklen_t       len;
    fd_set          rset, wset;
    struct timeval  tval;

    flags = fcntl(sockfd, F_GETFL, 0);
    fcntl(sockfd, F_SETFL, flags | O_NONBLOCK);

    error = 0;
    if ( (n = connect(sockfd, (struct sockaddr *) saptr, salen)) < 0)
        if (errno != EINPROGRESS)
            return(-1);

    /* Do whatever we want while the connect is taking place. */

    if (n == 0)
        goto done;  /* connect completed immediately */

    FD_ZERO(&rset);
    FD_SET(sockfd, &rset);
    wset = rset;
    tval.tv_sec = nsec;
    tval.tv_usec = 0;

    if ( (n = select(sockfd+1, &rset, &wset, NULL,
                     nsec ? &tval : NULL)) == 0) {
        close(sockfd);      /* timeout */
        errno = ETIMEDOUT;
        return(-1);
    }

    if (FD_ISSET(sockfd, &rset) || FD_ISSET(sockfd, &wset)) {
        len = sizeof(error);
        if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &error, &len) < 0)
            return(-1);         /* Solaris pending error */
    } else
        err_quit("select error: sockfd not set");

done:
    fcntl(sockfd, F_SETFL, flags);  /* restore file status flags */
    if (error) {
        close(sockfd);      /* just in case */
        errno = error;
        return(-1);
    }
    return(0);
}