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varDate

varDate = 7

Example​

function IsVariantDate(const Value: Variant): Boolean;
begin
  Result := (VarType(Value) and varTypeMask) = varDate;
end;

Usage​

varDate identifies an OLE Automation date/time Variant stored as a floating day count compatible with Velox TDateTime.

Additional Technical Info​

varDate is the base TVarType code $0007 for an OLE Automation date/time. Delphi stores it as TDateTime, a Double-compatible count of days relative to 30 December 1899; the fractional part represents time of day.

The tag contains no timezone, UTC offset, calendar-format text, precision guarantee or business meaning such as invoice date versus processing timestamp. A value passed between systems must carry those rules in the integration contract.

Conversion boundaries

  • Binary floating representation limits precision, particularly far from the epoch. Repeated text/number conversions can lose sub-second detail.
  • Negative day values have historical fractional-date semantics that should be handled through date routines rather than hand-written arithmetic.
  • Text-to-date conversion can depend on format and locale. Prefer explicit Velox parsing/formatting functions and governed formats.
  • Spreadsheet serial dates use related but not universally identical epoch/leap-year rules; do not assume direct numeric interchange.
  • Null, Empty and zero are distinct. Numeric zero is a valid date value at the Delphi epoch.

VarAsType can request this representation and may raise for invalid or out-of-range input. VarType only reports the raw tag; mask away array/reference flags before a base-type comparison.

The example is source-reviewed only; no date was parsed or converted.

External references

Created 2026-07-15