Modern Tz TimeZone MapLocal

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TimeZone.MapLocal

Counts the moments a wall-clock reading names in the zone: 1, 2 or 0.

Syntax

TimeZone.MapLocal( byref wall as chrono.DateTime, byref a as chrono.Instant, byref b as chrono.Instant ) as long

Notes

• 2 when the clocks went back and the reading happened twice; 0 when they went forward and it never happened. a and b hold the moments, earlier first.
• The reading's own offset, if it has one, is ignored.
• To pick one moment, use TryResolve or Resolve.

Examples

#import "std/tz"
#import "std/tzdata"
#import "std/chrono"
using tz
dim as TimeZone ny = TimeZone.FindById( "America/New_York" )
dim as chrono.Instant a, b
print ny.MapLocal( chrono.DateTime( 2025, 11, 2, 1, 30, 0, 0 ), a, b )     '' 2
print a.ToIsoString( )                                                     '' 2025-11-02T05:30:00Z
print b.ToIsoString( )                                                     '' 2025-11-02T06:30:00Z
print ny.MapLocal( chrono.DateTime( 2025, 3, 9, 2, 30, 0, 0 ), a, b )      '' 0

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Library: Time Zones (std/tz)
Category: Time Zones
Documented under: TimeZone