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TFileTime

TFileTime = record
  dwLowDateTime: LongWord;
  dwHighDateTime: LongWord;
end

Example​

function CompareFileTime(const A, B: TFileTime): Integer;
begin
  if A.dwHighDateTime < B.dwHighDateTime then
    Result := -1
  else if A.dwHighDateTime > B.dwHighDateTime then
    Result := 1
  else if A.dwLowDateTime < B.dwLowDateTime then
    Result := -1
  else if A.dwLowDateTime > B.dwLowDateTime then
    Result := 1
  else
    Result := 0;
end;

Usage​

TFileTime represents a Windows UTC file-time interval count as low-order and high-order unsigned 32-bit fields.

Interpretation and comparison​

  • Neither field is a standalone time value. The low half rolls over about every 429.4967296 seconds and increments the high half.
  • Compare the unsigned high field first, then the unsigned low field, as in the example.
  • A FILETIME is not a Velox TDateTime, Unix timestamp, DOS file date or local calendar time.
  • The epoch is UTC, but a filesystem or API can have lower precision, delayed timestamp updates or context-specific sentinel values. Interpret it using the producing API's contract.
  • Calendar formatting, timezone conversion and duration arithmetic require an appropriate conversion layer. The current public Code Library index exposes no function/property that accepts or returns this record.

Script behaviour​

Record assignment copies both fields. Velox provides no methods, operators, validation or formatting for this record. Do not reinterpret it as a 64-bit value through a pointer. Use a documented conversion operation that combines the two unsigned fields safely.

Additional Technical Info​

TFileTime is a plain PascalScript record registered by SysUtilsTypesImport. Its layout matches the current Delphi/Windows FILETIME structure: dwLowDateTime contains bits 0..31 and dwHighDateTime contains bits 32..63 of one unsigned 64-bit value.

For ordinary Windows file timestamps, that combined value counts 100-nanosecond intervals since 1601-01-01 00:00:00 UTC:

ticks = (dwHighDateTime * 4294967296) + dwLowDateTime

This mathematical relationship explains layout; it is not a recommendation to perform date conversion with floating-point arithmetic. Preserve all 64 integer bits and use a documented conversion API at an actual Windows boundary.

Related Code Library entries

  • Cardinal - public unsigned 32-bit alias corresponding to each LongWord field.
  • Records - value-copy and interchange rules.

External references

Created 2026-07-15