Skip to main content

DayOfTheMonth

Function DayOfTheMonth(const AValue: TDateTime): Word

Example​

procedure ScriptEvent(var Value: variant);
begin
  Value := DayOfTheMonth(EncodeDate(2026, 7, 18)); // 18
end;

Usage​

DayOfTheMonth returns the ordinal day within the calendar month for a TDateTime value.

Parameters

NameTypeDescription
AValueTDateTime, constDate/time value from which the day number is decoded.

Returns

1 for the first day of a month through 28, 29, 30 or 31 for its last day, according to the supplied date.

Behaviour

The time component is ignored. This value is a calendar component, not the count of complete 24-hour periods since the month's first timestamp.

Errors

No ordinary exception for valid dates. The function adds no validation or error handling.

Additional Technical Info​

DayOfTheMonth returns the one-based day number within the value's calendar month. In Velox's installed Delphi runtime it is an exact alias for DayOf, not a week-based calculation.

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

Implementation

The DateUtils scripting import binds directly to Delphi 37.0 System.DateUtils.DayOfTheMonth. Its implementation is Result := DayOf(AValue), which in turn calls DecodeDate and returns its day output.

Edge cases and quirks

  • Because this is an exact wrapper, every DayOf boundary applies, including a possible 0 from unsupported dates before year 1.
  • The result is not WeekOfTheMonth and says nothing about ISO week boundaries.
  • Free Pascal describes the same one-based value but its implementation is not the terminal used by Velox.

Side effects

None.

Performance and concurrency

Constant-time wrapper and calendar decode, with no shared state.

Related entries

External references

Created 2026-07-15