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      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 #pragma weak _gethz = gethz
     33 
     34 #include "lint.h"
     35 #include <stdio.h>
     36 #include <ctype.h>
     37 #include <stdlib.h>
     38 
     39 /*
     40  *	gethz -- get the value of the clock hertz from the environment.
     41  *
     42  *	return the clock hertz value if the string "HZ" in the environment is:
     43  *		1) Composed entirely of numbers.
     44  *		2) Not equal to zero.
     45  *	Otherwise 0 is returned.
     46  */
     47 int
     48 gethz(void)
     49 {
     50 	char *sptr, *cptr;
     51 
     52 	if ((sptr = getenv("HZ")) == NULL) {
     53 		return (0);
     54 	} else {
     55 		cptr = sptr;
     56 
     57 		/* Check that all characters are numeric */
     58 		while (*cptr) {
     59 			if (!isdigit((unsigned char)*cptr))
     60 				return (0);
     61 			cptr++;
     62 		}
     63 		return (atoi(sptr));
     64 	}
     65 }
     66