Linux C Select() - multi input trace

fd_set set;
    FD_ZERO(&set);      /*clear set */
    FD_SET(fd, &set);   /*add fd into set */
    FD_CLR(fd, &set);   /*remove fd from set*/
    FD_ISSET(fd, &set); /*return true if fd is in set*/
------------------------------------------------------------------------
int maxfd = MAX (fd1, fd2)+1;

struct timeval tv;
tv.tv_usec = 0;
tv.tv_sec = 2;


while (1) {
     FD_SET(fd1, &readfs);  /* input 1*/
     FD_SET(fd2, &readfs);  /* input 2 */
     /* block until input becomes available */
     int rul = select(maxfd, &readfs, NULL, NULL,  &tv );


     if (FD_ISSET(fd1))         /* if input 1 has signal*/
       handle_input_from_source1();
     if (FD_ISSET(fd2))         /* if input 2 has signal */
       handle_input_from_source2();
/*
     if(rul == -1)
         return errorout;
     if(rul == 0)
        return timeout;
     
*/
   }