usr/src/lib/libc/port/gen/clock.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include "lint.h"
  33 #include <sys/types.h>
  34 #include <sys/times.h>
  35 #include <time.h>
  36 #include <sys/param.h>  /* for HZ (clock frequency in Hz) */
  37
  38 #define TIMES(B)        (B.tms_utime+B.tms_stime+B.tms_cutime+B.tms_cstime)
  39
  40
  41 clock_t
  42 clock(void)
  43 {
  44         struct tms buffer;
  45         static int Hz = 0;
  46         static clock_t first;
  47         extern int gethz(void);         /* XXX should be in a header file! */
  48
  49         if (times(&buffer) == (clock_t)-1)
  50                 return ((clock_t)-1);
  51         if (Hz == 0) {
  52                 if ((Hz = gethz()) == 0)
  53                         Hz = HZ;
  54                 first = TIMES(buffer);
  55         }
  56
  57         return ((TIMES(buffer) - first) * (CLOCKS_PER_SEC/Hz));
  58 }