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Convert Date Time, Given a Time Zone, to GMT Secs - OMDZ2GMT

Convert Date/Time, Given a Time Zone, to GMT Secs (OMDZ2GMT)

Required Parameter Group:

1 Date/Time String Input Char(50)
2 Convert to Time Zone Input Char(3)
3 Obey Daylight Savings Input Char(1)
4 Date/Time Format Input Char(4)
5 Return Status Output Char(1)
6 GMT Seconds Output Packed(13,0)

API Overview:
The Convert Date/Time, Given a Time Zone, to GMT Seconds API (OMDZ2GMT) allows you to convert a date/time string to GMT seconds based on a specific time zone and obey-daylight-savings flag.

Required Parameter Group Details:
(1) Date/Time String
This parameter contains a left-justified date/time in the indicated format. A time zone may optionally be specified; otherwise, the user's time zone is assumed. If hours, minutes or seconds are not specified, then zero is assumed for those portions of the time.

The input date must be in the following range: January 1, 1988 @ 00:00:00 through December 31, 2039 @ 23:59:59. Dates outside of this range will be rejected.

(2) Convert to Time Zone
This parameter indicates what time zone code should be used to convert the GMT seconds. Valid time zone codes are range between 000-047. Valid values are:

000 GMT-12.0 012 Central 024 GMT 036 GMT+6.0
001 GMT-11.5 013 GMT-5.5 025 GMT+0.5 037 GMT+6.5
002 GMT-11.0 014 Eastern 026 European 038 GMT+7.0
003 GMT-10.5 015 GMT-4.5 027 GMT+1.5 039 GMT+7.5
004 Hawaii 016 Atlantic 028 Euro-Asian 040 GMT+8.0
005 GMT-9.5 017 Newfoundland 029 GMT+2.5 041 GMT+8.5
006 Alaska 018 Brasilia 030 Moscow 042 Japanese
007 GMT-8.5 019 GMT-2.5 031 GMT+3.5 043 GMT+9.5
008 Pacific 020 Mid-Atlantic 032 GMT+4.0 044 GMT+10.0
009 GMT-7.5 021 GMT-1.5 033 GMT+4.5 045 GMT+10.5
010 Mountain 022 GMT-1.0 034 GMT+5.0 046 GMT+11.0
011 GMT-6.5 023 GMT-0.5 035 GMT+5.5 047 GMT+11.5

(3) Obey Daylight Savings
This parameter indicates if the Date/Time String should obey the daylight savings time rules. Valid values are:

Y Yes
N No

(4) Date/Time Format
This parameter contains the requested output format for the Date/Time String. Valid values are:

*MDY Month, day, year format (MM/DD/YY)
*DMY Day, month, year format (DD/MM/YY)
*YMD Year, month, day format (YY/MM/DD)
*JUL Julian format (YY/JJJ)
*JOB Evaluates to one of the above

(5) Return Status
Status value returned to the caller will be set as follows:

0 Success, date returned
1 Failure, error encountered

(6) GMT Seconds
This parameter returns the converted date/time expressed in the number of whole seconds since January 1, 1988 in GMT time zone.

This API must make an assumption with respect to interpreting the Date/Time String in one special case. This special case deals with the end of daylight savings time. In the US, this occurs on the last Sunday in October at 2:00AM. At exactly that time, the clocks are turned back one hour, and it becomes 1:00 AM. So, during that night, the hour of 1:00AM through 2:00AM occurs twice. The problem is that when a time that is within that hour is passed to this API, it cannot tell which of the two instances is being implied.

For example, the input date/time is simply something like 10/31/99 01:47:02. The API cannot tell if this is referring to 1:47:02 before the clock is turned back, or 1:47:02 after the clock was turned back.

Therefore, the API must make an assumption. The API is coded to assume that the time that is passed represents the actual time before the clock was turned back (i.e. still in daylight savings time).

Appendix J provides a comprehensive list of the valid date/time formats that may be passed to this API.

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