A fix is available
APAR status
Closed as new function.
Error description
Language Environment Daylight Saving Time (DST) changes **************************************************************** * NOTE: As documented in the z/OS 1.6 (and up) Program * * Directory, please ensure that the PTFs for R709, R720 and * * R730 are applied using the matching levels of Binder, * * HLASM and SMP/E. * ****************************************************************
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of the TZ and _TZ environment * * variables and all users of the LC_TOD locale * * category. * **************************************************************** * PROBLEM DESCRIPTION: The U.S. Energy Policy Act of 2005 * * contains a provision that extends * * Daylight Saving Time (DST) by 4 (or 5) * * weeks beginning in 2007. * * * * The TZ and _TZ environment variables * * can be used for POSIX(ON) and * * POSIX(OFF) applications, respectively, * * to provide time zone information which * * may include rules for Daylight Saving * * Time. * * * * The default rules for Daylight Saving * * Time are based on U.S. rules, therefore * * the z/OS XL C/C++ Run-Time Library * * needs to be updated to reflect the new * * rules. * * * * The old rules were that Daylight Saving * * Time would begin on the first Sunday in * * April at 02:00:00 (2 AM) and end on the * * last Sunday in October at 02:00:00 (2 * * AM). * * * * The new rules are that Daylight Saving * * Time begins on the second Sunday in * * March at 02:00:00 (2 AM) and ends on * * the first Sunday in November at * * 02:00:00 (2 AM). * * * * Note: The defaults are used only when * * TZ or _TZ specifies a daylight saving * * time zone name that differs from the * * standard time zone name and the start * * and end dates are omitted. * * * * In the absence of the TZ or _TZ * * environment variable, daylight saving * * time rules may be picked up from the * * LC_TOD category of the current locale. * * The LC_TOD category is an IBM extension * * and is not part of any locale that is * * shipped by IBM, but it could have been * * added through customization. Default * * rules are not applied to LC_TOD * * category settings. * * * * Daylight Saving Time rules affect the * * following C library functions: * * * * - ctime() * * - localtime() * * - mktime() * * - strftime() * **************************************************************** * RECOMMENDATION: * **************************************************************** See problem description.
Problem conclusion
Temporary fix
Comments
The tzset() and _tzset() functions which parse TZ and _TZ, respectively, are updated to default to the new start and end dates for Daylight Saving Time (DST), for when the DST rule is omitted from the environment variable. These updates affect documentation and may require user action to avoid the effects of the default change. . ================================================================ = = = ACTION = = = ================================================================ . If you do not use TZ, _TZ, or LC_TOD, you are not affected. . If you do not use TZ or _TZ, but you have customized locales where the LC_TOD category was added, you must review the settings for the DST rules defined in LC_TOD and make appropriate changes. For example, if your LC_TOD specifies the old U.S. rules and you need to follow the new U.S. rules, then the locale needs to be updated. . If you use TZ or _TZ, but do not specify a daylight saving time zone name, you are not affected. Not having a daylight saving time zone name indicates that daylight saving time is not observed. . If you use TZ or _TZ and specify a daylight saving time zone name, but do not specify a DST rule, then you need to determine if the new default rules will be appropriate. If not, then you must change TZ or _TZ to specify the specific DST rule for your installation. Some countries that currently follow the old U.S. rules may not be changing to the new U.S. rules. . If you use TZ or _TZ, specify a daylight saving time zone name, and you specify your own DST rule, you must review the setting and make appropriate changes. For example, if your DST rule specifies the old U.S. rules and you need to follow the new U.S. rules, then the TZ or _TZ value needs to be updated. . If you do observe daylight saving time, but do not follow the U.S. rules, then you may have no action since your environment would have already been customized to specify your local DST rules. . Possible locations where TZ or _TZ may be defined include the Language Environment Installation Default Run-time Options CSECTs (CEEDOPT, CEECOPT, CELQDOPT), the Language Environment Region-Specific Options (CEEROPT), the Language Environment PARMLIB member (CEEPRMxx), /etc/rc, and /etc/profile for the z/OS UNIX shell environment. . In all cases where a change to TZ, _TZ, or LC_TOD is made, applications must be restarted. . All applications that use TZ or _TZ that specifies a daylight saving time zone name, but does not specify a DST rule, must be restarted after installing this PTF in order for the new default rules to become effective. . IBM recommends this PTF be installed and applications restarted before March 11, 2007. . . ================================================================ = = = DOCUMENTATION = = = ================================================================ . The following publications changes are made: . ================================================================ = z/OS XL C/C++ Programming Guide (SC09-4765-XX) = ================================================================ . 8.4.1 Using the TZ or _TZ environment variable to specify time zone . Under ,startdate /starttime ,enddate /endtime . Change the following paragraph: . Neither starttime nor endtime are required, and when omitted, their values default to 02:00:00. If this daylight savings time rule is omitted altogether, the values in the rule default to the standard American daylight savings time rules starting at 02:00:00 the first Sunday in April and ending at 02:00:00 the last Sunday in October. . to read as follows: . Neither starttime nor endtime are required, and when omitted, their values default to 02:00:00. If this daylight saving time rule is omitted altogether, the values in the rule default to the standard U.S. daylight saving time rules starting at 02:00:00 the second Sunday in March and ending at 02:00:00 the first Sunday in November. . ================================================================
APAR Information
APAR number
PK24076
Reported component name
LE C LIBRARY
Reported component ID
568819805
Reported release
720
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
YesSpecatt / Pervasive / DST2007
Submitted date
2006-04-27
Closed date
2006-11-08
Last modified date
2007-01-31
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK19503 UK19504 UK19505 UK19506 UK19507 UK19508 UK19509 UK19510
Modules/Macros
CELHTZST CELJTZST CELQTZST CELZTZST EDC40139
| SC094765XX |
Fix information
Fixed component name
LE C LIBRARY
Fixed component ID
568819805
Applicable component levels
R703 PSY UK19503
UP06/11/21 P F611
R705 PSY UK19504
UP06/11/21 P F611
R706 PSY UK19505
UP06/11/21 P F611
R707 PSY UK19506
UP06/11/21 P F611
R708 PSY UK19507
UP06/11/21 P F611
R709 PSY UK19508
UP06/11/21 P F611
R720 PSY UK19509
UP06/11/21 P F611
R730 PSY UK19510
UP06/11/21 P F611
Fix is available
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