4.3BSD - /usr/src/ucb/gprof/hertz.c

   1: /*
   2:  * Copyright (c) 1983 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #ifndef lint
   8: static char sccsid[] = "@(#)hertz.c	5.1 (Berkeley) 6/4/85";
   9: #endif not lint
  10: 
  11: #include <sys/time.h>
  12: 
  13:     /*
  14:      *	discover the tick frequency of the machine
  15:      *	if something goes wrong, we return 0, an impossible hertz.
  16:      */
  17: #define HZ_WRONG    0
  18: 
  19: hertz()
  20: {
  21:     struct itimerval tim;
  22: 
  23:     tim.it_interval.tv_sec = 0;
  24:     tim.it_interval.tv_usec = 1;
  25:     tim.it_value.tv_sec = 0;
  26:     tim.it_value.tv_usec = 0;
  27:     setitimer(ITIMER_REAL, &tim, 0);
  28:     setitimer(ITIMER_REAL, 0, &tim);
  29:     if (tim.it_interval.tv_usec < 2)
  30:         return(HZ_WRONG);
  31:     return (1000000 / tim.it_interval.tv_usec);
  32: }

Defined functions

Defined variables

Defined macros