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MilliSecondOfTheWeek

Function MilliSecondOfTheWeek(const AValue: TDateTime): LongWord

Example​

procedure ScriptEvent(var Value: variant);
var
  InputValue: TDateTime;
begin
  InputValue := EncodeDateTime(2026, 7, 20, 1, 2, 3, 4); // Monday
  Value := MilliSecondOfTheWeek(InputValue); // 3723004
end;

Usage​

MilliSecondOfTheWeek returns the zero-based millisecond index within the Monday-based ISO week.

Parameters

NameTypeDescription
AValueTDateTime, constEncoded date/time whose position within the ISO week is required.

Returns

A LongWord from 0 for Monday 00:00:00.000 through 604,799,999 for Sunday 23:59:59.999.

Behaviour

  • Monday is day one of the ISO week and therefore the zero-day offset.
  • The value increases through Sunday and resets at the following Monday midnight.
  • It can cross calendar month and year boundaries without changing the Monday-based rule.
  • No locale-specific first-day-of-week setting is consulted.

Important usage notes

  • This is an encoded field index, not an elapsed timezone-aware duration. Daylight-saving gaps or repeated local times do not alter its arithmetic.
  • It does not return an ISO week number or ISO week-year; only the position within the containing week is returned.
  • The Velox uses Cardinal, equivalent to the exposed unsigned 32-bit LongWord.
  • Invalid or non-finite input can raise during decoding.

Usage notes

Use this entry when the start boundary must be ISO Monday. Do not infer a locale-specific Sunday start from the host machine.

Additional Technical Info​

MilliSecondOfTheWeek returns the zero-based position of an encoded date/time within its Monday-to-Sunday ISO week, measured in whole milliseconds from Monday at midnight.

The example is fictional, deterministic and source-reviewed. It was not executed by the documentation workflow.

Implementation

The DateUtils import binds directly to Delphi 37.0 System.DateUtils.MilliSecondOfTheWeek. The routine calculates the ISO weekday-based whole-second index, multiplies it by 1,000 and adds the decoded millisecond component.

Side effects

None.

Errors

Velox performs no validation or exception translation. Decode failures propagate.

Performance and concurrency

Constant-time field extraction and integer arithmetic with no shared mutable state.

Related entries

External references

Created 2026-07-15