/* * Copyright (c) 1983 Regents of the University of California. * All rights reserved. The Berkeley software License Agreement * specifies the terms and conditions for redistribution. */ #ifndef lint static char sccsid[] = "@(#)hertz.c 5.1 (Berkeley) 6/4/85"; #endif not lint #include <sys/time.h> /* * discover the tick frequency of the machine * if something goes wrong, we return 0, an impossible hertz. */ #define HZ_WRONG 0 hertz() { struct itimerval tim; tim.it_interval.tv_sec = 0; tim.it_interval.tv_usec = 1; tim.it_value.tv_sec = 0; tim.it_value.tv_usec = 0; setitimer(ITIMER_REAL, &tim, 0); setitimer(ITIMER_REAL, 0, &tim); if (tim.it_interval.tv_usec < 2) return(HZ_WRONG); return (1000000 / tim.it_interval.tv_usec); }