Skip to main content

Get20thOfMonth

Function Get20thOfMonth(const aNow: TDateTime): TDateTime

Example​

procedure ScriptEvent(var Value: variant);
var
  InputValue: TDateTime;
begin
  InputValue := EncodeDateTime(2026, 7, 31, 14, 30, 0, 0);
  Value := Get20thOfMonth(InputValue); // 20 July 2026, 14:30
end;

Usage​

Get20thOfMonth replaces a TDateTime value's day with 20 in the same month while preserving its time of day.

Parameters

NameTypeDescription
aNowTDateTime, constSupported date/time whose day field is replaced.

Returns

The 20th day of aNow's calendar month with the original hour, minute, second and millisecond.

Important usage notes

  • The function does not return midnight unless aNow was already at midnight.
  • It can move backwards or forwards within the month depending on the original day.
  • The recode path handles negative pre-epoch dates correctly; it does not perform unsafe raw fractional addition.
  • No timezone conversion occurs.

Errors

Unsupported or non-finite raw values can fail while the recoder decodes and re-encodes the date. No Velox exception handler is present.

Additional Technical Info​

Get20thOfMonth is a Velox convenience wrapper that changes only the calendar day field to 20. The year, month and complete time-of-day fields remain unchanged.

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

Implementation

The Velox date-tools implementation is exactly RecodeDay(aNow, 20). Delphi's recoder decodes all fields, substitutes day 20 and re-encodes the complete value. Because every calendar month has a day 20, a valid input cannot fail because of the replacement day.

Side effects

None.

Performance and concurrency

Constant-time field decoding/encoding with no shared state.

Related entries

External references

Created 2026-07-15