Function ConvertReferenceDate(ReferenceDate, FromTimezone, ToTimezone, IgnoreDST)

ConvertReferenceDate

The function ConvertReferenceDate converts a reference date from one timezone to the other.

ConvertReferenceDate(
     ReferenceDate,          ! (input) a string expression
     FromTimezone,           ! (input) an element expression
     ToTimezone,             ! (input) an element expression
     IgnoreDST               ! (optional) a numerical expression (default 0)
     )

Arguments

ReferenceDate

A string that holds a reference date in FromTimezone.

FromTimezone

An element of AllTimeZones with respect to which ReferenceDate is expressed.

ToTimezone

An element of AllTimeZones with respect to which the resulting reference date must be expressed.

IgnoreDST

A numerical expression indicating whether daylight saving time must be ignored in the conversion.

Return Value

The result of ConvertReferenceDate is a reference date in ToTimezone corresponding to the reference date ReferenceDate in FromTimezone.

Example

Given a selection of timezones:

! Picking a few timezones relative to me.
_ep_CETTZ    := 'Central European Standard Time' ; ! Where I live.
_ep_BrazilTZ := 'Central Brazilian Standard Time' ;
_ep_IndianTZ := 'India Standard Time' ;

Wondering what time it is in the other timezones when I wake up…

_sp_wakeup := "2020-04-01 06:00" ; ! My alarm rings at 6 AM
_sp_refUTC := ConvertReferenceDate(
        ReferenceDate :  _sp_wakeup,
        FromTZ        :  _ep_CETTZ,
        ToTZ          :  'UTC',
        IgnoreDST     :  1);
_sp_refBrazil := ConvertReferenceDate(
        ReferenceDate :  _sp_wakeup,
        FromTZ        :  _ep_CETTZ,
        ToTZ          :  _ep_BrazilTZ,
        IgnoreDST     :  1);
_sp_refInda := ConvertReferenceDate(
        ReferenceDate :  _sp_wakeup,
        FromTZ        :  _ep_CETTZ,
        ToTZ          :  _ep_IndianTZ,
        IgnoreDST     :  1);
display _sp_refUTC, _sp_refBrazil, _sp_refInda ;

without considering daylight saving time, the result is:

_sp_refUTC    := "2020-04-01 05:00" ;
_sp_refBrazil := "2020-04-01 01:00" ;
_sp_refInda   := "2020-04-01 10:30" ;

See also