1  /*
       2   * Copyright (c) 1983, 1993
       3   *      The Regents of the University of California.  All rights reserved.
       4   *
       5   * Redistribution and use in source and binary forms, with or without
       6   * modification, are permitted provided that the following conditions
       7   * are met:
       8   * 1. Redistributions of source code must retain the above copyright
       9   *    notice, this list of conditions and the following disclaimer.
      10   * 2. Redistributions in binary form must reproduce the above copyright
      11   *    notice, this list of conditions and the following disclaimer in the
      12   *    documentation and/or other materials provided with the distribution.
      13   * 3. Neither the name of the University nor the names of its contributors
      14   *    may be used to endorse or promote products derived from this software
      15   *    without specific prior written permission.
      16   *
      17   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
      18   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      19   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
      20   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
      21   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
      22   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
      23   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
      24   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
      25   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
      26   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
      27   * SUCH DAMAGE.
      28   */
      29  #include "gprof.h"
      30  #include "hertz.h"
      31  
      32  
      33  int
      34  hertz (void)
      35  {
      36  #ifdef HERTZ
      37    return HERTZ;
      38  #else /* ! defined (HERTZ) */
      39  #ifdef HAVE_SETITIMER
      40    struct itimerval tim;
      41  
      42    tim.it_interval.tv_sec = 0;
      43    tim.it_interval.tv_usec = 1;
      44    tim.it_value.tv_sec = 0;
      45    tim.it_value.tv_usec = 0;
      46    setitimer (ITIMER_REAL, &tim, 0);
      47    setitimer (ITIMER_REAL, 0, &tim);
      48    if (tim.it_interval.tv_usec >= 2)
      49      {
      50        return 1000000 / tim.it_interval.tv_usec;
      51      }
      52  #endif /* ! defined (HAVE_SETITIMER) */
      53  #if defined (HAVE_SYSCONF) && defined (_SC_CLK_TCK)
      54    return sysconf (_SC_CLK_TCK);
      55  #else /* ! defined (HAVE_SYSCONF) || ! defined (_SC_CLK_TCK) */
      56  #ifdef __MSDOS__
      57    return 18;
      58  #else  /* ! defined (__MSDOS__) */
      59    return HZ_WRONG;
      60  #endif /* ! defined (__MSDOS__) */
      61  #endif /* ! defined (HAVE_SYSCONF) || ! defined (_SC_CLK_TCK) */
      62  #endif /* ! defined (HERTZ) */
      63  }