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HourOfTheMonth

Function HourOfTheMonth(const AValue: TDateTime): Word

Example​

procedure ScriptEvent(var Value: variant);
begin
  Value := HourOfTheMonth(EncodeDateTime(2026, 7, 3, 5, 30, 0, 0));
  // 2 complete days * 24 + hour 5 = 53
end;

Usage​

HourOfTheMonth returns the zero-based encoded hour index within the containing calendar month.

Parameters

NameTypeDescription
AValueTDateTime, constEncoded date/time whose calendar day and hour fields are used.

Returns

HourOf(AValue) + (DayOfTheMonth(AValue) - 1) * 24. The range is 0..743 for a 31-day month.

Important usage notes

  • This is a field-derived calendar index, not a timezone-aware elapsed duration. It still advances by exactly 24 per calendar day across daylight-saving changes.
  • Minutes, seconds and milliseconds are discarded. The first day at 00:59:59.999 returns 0.
  • The index restarts at zero on the first of each calendar month.
  • The result type Word easily contains the maximum value.
  • No locale or timezone is read.

Errors

Unsupported raw values can fail during date/time decoding. No function catches the exception.

Additional Technical Info​

HourOfTheMonth returns a zero-based calendar index formed from the number of complete prior days in the month plus the current hour-of-day field.

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.HourOfTheMonth. The terminal extracts the hour and one-based calendar day, converts preceding days to groups of 24 hours and adds the current hour.

Side effects

None.

Performance and concurrency

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

Related entries

External references

Created 2026-07-15