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MonthOf

Function MonthOf(const AValue: TDateTime): Word

Example​

procedure ScriptEvent(var Value: variant);
var
  InputValue: TDateTime;
begin
  InputValue := EncodeDateTime(2026, 7, 18, 9, 30, 0, 0);
  Value := MonthOf(InputValue); // 7
end;

Usage​

MonthOf returns the decoded calendar month number from 1 through 12.

Parameters

NameTypeDescription
AValueTDateTime, constEncoded date/time whose calendar month component is required.

Returns

A Word from 1 for January through 12 for December.

Behaviour

  • The time-of-day component does not affect the result.
  • The same month number is returned for every day in that calendar month.
  • Valid pre-epoch TDateTime values are decoded using Velox's sign-aware date logic.
  • No locale, timezone or month-name lookup is involved.

Important usage notes

  • The result is numeric and one-based; zero is never returned for a successfully decoded date.
  • This is a calendar month component, not an elapsed-month count or ISO week-month concept.
  • Invalid or non-finite encoded input can raise during decoding.

Usage notes

Use the month-name helpers only when converting locale-specific text. MonthOf itself is independent of locale.

Additional Technical Info​

MonthOf returns the calendar month number encoded in a TDateTime, where January is 1 and December is 12.

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.MonthOf. It calls DecodeDate, retains the decoded month and discards the year and day outputs.

Side effects

None.

Errors

Velox does not catch or translate date decode exceptions.

Performance and concurrency

Constant-time calendar decoding with no external I/O or shared mutable state.

Related entries

External references

Created 2026-07-15