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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 /*
     33  * This routine converts time as follows.
     34  * The epoch is 0000 Jan 1 1970 GMT.
     35  * The argument time is in seconds since then.
     36  * The localtime(t) entry returns a pointer to an array
     37  * containing
     38  *  seconds (0-59)
     39  *  minutes (0-59)
     40  *  hours (0-23)
     41  *  day of month (1-31)
     42  *  month (0-11)
     43  *  year-1970
     44  *  weekday (0-6, Sun is 0)
     45  *  day of the year
     46  *  daylight savings flag
     47  *
     48  * The routine corrects for daylight saving
     49  * time and will work in any time zone provided
     50  * "timezone" is adjusted to the difference between
     51  * Greenwich and local standard time (measured in seconds).
     52  * In places like Michigan "daylight" must
     53  * be initialized to 0 to prevent the conversion
     54  * to daylight time.
     55  * There is a table which accounts for the peculiarities
     56  * undergone by daylight time in 1974-1975.
     57  *
     58  * The routine does not work
     59  * in Saudi Arabia which runs on Solar time.
     60  *
     61  * asctime(tvec)
     62  * where tvec is produced by localtime
     63  * returns a ptr to a character string
     64  * that has the ascii time in the form
     65  *	Thu Jan 01 00:00:00 1970\n\0
     66  *	01234567890123456789012345
     67  *	0	  1	    2
     68  *
     69  * ctime(t) just calls localtime, then asctime.
     70  *
     71  * tzset() looks for an environment variable named
     72  * TZ.
     73  * If the variable is present, it will set the external
     74  * variables "timezone", "altzone", "daylight", and "tzname"
     75  * appropriately. It is called by localtime, and
     76  * may also be called explicitly by the user.
     77  */
     78 
     79 #include "lint.h"
     80 #include <time.h>
     81 #include <sys/types.h>
     82 #include <errno.h>
     83 #include <thread.h>
     84 #include <synch.h>
     85 #include <mtlib.h>
     86 #include "libc.h"
     87 
     88 
     89 /*
     90  * POSIX.1c Draft-6 version of the function ctime_r.
     91  * It was implemented by Solaris 2.3.
     92  */
     93 char *
     94 ctime_r(const time_t *t, char *buffer, int buflen)
     95 {
     96 	struct tm res;
     97 
     98 	if (localtime_r(t, &res) == NULL)
     99 		return (NULL);
    100 
    101 	if (asctime_r(&res, buffer, buflen) == NULL)
    102 		return (NULL);
    103 
    104 	return (buffer);
    105 }
    106 
    107 /*
    108  * POSIX.1c standard version of the function ctime_r.
    109  * User gets it via static ctime_r from the header file.
    110  */
    111 char *
    112 __posix_ctime_r(const time_t *t, char *buffer)
    113 {
    114 	struct tm res;
    115 
    116 	if (localtime_r(t, &res) == NULL)
    117 		return (NULL);
    118 
    119 	if (__posix_asctime_r(&res, buffer) == NULL)
    120 		return (NULL);
    121 
    122 	return (buffer);
    123 }
    124