Add a system independent sleep/clock to your program

Add a system independent sleep/clock to your program

http://www.faqs.org/faqs/unix-faq/faq/part4/section-6.html

extern int        select();

     int
     usleep( usec )                            /* returns 0 if ok, else -1 */
           long                usec;           /* delay in microseconds */
           {
           static struct                       /* `timeval' */
                   {
                   long        tv_sec;         /* seconds */
                   long        tv_usec;        /* microsecs */
                   }   delay;          /* _select() timeout */

           delay.tv_sec = usec / 1000000L;
           delay.tv_usec = usec % 1000000L;

           return select( 0, (long *)0, (long *)0, (long *)0, &delay );
           }