/*
         *      usleep(delay)  --
         *
         *      Possible usleep replacement. Delay in microseconds.
         *      Another possiblity is to use poll(2). On Solaris
         *      2.x, select is just a wrapper for poll, so you
         *      are better off using it directly.  If you use,
         *      poll, note that it uses millisecond resolution,
         *      and is not affected by the O_NDELAY and O_NONBLOCK 
         *      flags.
         *
         *      Note that using nanosleep has portability implications,
         *      even across different versions of Solaris 2.x. In
         *      particular, only Solaris 2.3 has libposix4, and 
         *      hence nanosleep. Select (or poll) is a better option if 
         *      you need portability across those versions.
         *
         *      If you define USE_NANOSLEEP, be sure to link with -lposix4
         *
         */

        #include <unistd.h>
        #include <stdlib.h>
        #include <stdio.h>
        #include <errno.h>
        #include <time.h>
        #include <sys/time.h>
        #include <sys/param.h>
        #include <sys/types.h>
        #ifdef  USE_POLL
        #include <stropts.h>
        #include <poll.h>
        #endif  /* USE_POLL */
        
        int     usleep(unsigned long int useconds)
        {
        #ifdef  USE_NANOSLEEP
          struct timespec rqtp;
        
          rqtp.tv_sec  = useconds / (unsigned long)  1000000;
          rqtp.tv_nsec = (useconds % (unsigned long) 1000000) * 1000 ;
        
          if (nanosleep(&rqtp,  (struct  timespec *) NULL) == -1)
            perror("nanosleep");
          return (0);
        
        #elif   USE_POOL
          struct pollfd unused;
        
          if (poll(&unused,0,(useconds/1000)) == -1) 
            perror("poll");
          return(0);
        #elif   USE_USLEEP
          struct timeval delay;
        
          delay.tv_sec = 0;
          delay.tv_usec = useconds;
          if (select(0,
                     (fd_set *) NULL,
                     (fd_set *) NULL,
                     (fd_set *) NULL,
                     &delay) == -1)
            perror("select");
          return (0);
        #endif                  /* USE_NANOSLEEP */