gprof/hertz.c

   1 /*
   2  * Copyright (c) 1983 Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that: (1) source distributions retain this entire copyright
   7  * notice and comment, and (2) distributions including binaries display
   8  * the following acknowledgement:  ``This product includes software
   9  * developed by the University of California, Berkeley and its contributors''
  10  * in the documentation or other materials provided with the distribution
  11  * and in all advertising materials mentioning features or use of this
  12  * software. Neither the name of the University nor the names of its
  13  * contributors may be used to endorse or promote products derived
  14  * from this software without specific prior written permission.
  15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  */
  19 #include <sys/time.h>
  20 #include "hertz.h"
  21
  22
  23 #ifdef __MSDOS__
  24 #define HERTZ 18
  25 #endif
  26
  27 int
  28 hertz ()
  29 {
  30 #ifdef HERTZ
  31   return HERTZ;
  32 #else
  33   struct itimerval tim;
  34
  35   tim.it_interval.tv_sec = 0;
  36   tim.it_interval.tv_usec = 1;
  37   tim.it_value.tv_sec = 0;
  38   tim.it_value.tv_usec = 0;
  39   setitimer (ITIMER_REAL, &tim, 0);
  40   setitimer (ITIMER_REAL, 0, &tim);
  41   if (tim.it_interval.tv_usec < 2)
  42     {
  43       return HZ_WRONG;
  44     }                           /* if */
  45   return 1000000 / tim.it_interval.tv_usec;
  46 #endif
  47 }                               /* hertz */