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EndOfADay

Function EndOfADay(const AYear, AMonth, ADay: Word): TDateTime

Example​

procedure ScriptEvent(var Value: variant);
begin
  Value := EndOfADay(2028, 2, 29); // 2028-02-29 23:59:59.999
end;

Usage​

EndOfADay returns the final millisecond of an explicitly supplied valid calendar date.

Parameters

NameTypeDescription
AYearWord, constGregorian year 1..9999.
AMonthWord, constMonth 1..12.
ADayWord, constDay valid for the supplied month and year.

Returns

The requested date at 23:59:59.999.

Errors

Invalid date fields raise EConvertError; the exception propagates into the script.

Additional Technical Info​

EndOfADay constructs the last millisecond of a calendar date supplied as year, month and day fields. It is useful for display-oriented inclusive day boundaries; for filtering higher-precision timestamps, an exclusive next-day boundary is often safer.

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

Implementation

The DateUtils import binds directly to the three-field overload of Delphi 37.0 System.DateUtils.EndOfADay. It calls EncodeDate(AYear, AMonth, ADay) and passes that midnight value to EndOfTheDay, which recodes the time fields to 23, 59, 59 and 999.

Edge cases and quirks

  • Velox exposes only this three-field overload here; the upstream DateUtils unit also has a year/day-of-year overload.
  • The boundary is inclusive only to millisecond resolution. A database or external timestamp with microseconds after .999000 can lie later in the same day but compare greater than this value after a higher-precision conversion.
  • The result is timezone-neutral. A daylight-saving day is still represented by a wall-clock end value, not an elapsed 24-hour calculation.
  • Invalid fields are not normalised into another date.

Side effects

None.

Performance and concurrency

Constant-time calendar encoding with no shared state.

Related entries

  • EndOfTheDay uses the date contained in an existing value.
  • EncodeDate returns the corresponding start-of-day midnight.

External references

Created 2026-07-15