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soFromEnd

soFromEnd = 2

Example​

function MoveToLastFourBytes(Stream: TStream): Int64;
begin
  Result := Stream.Seek(-4, soFromEnd);
end;

Usage​

soFromEnd makes TStream.Seek add a signed Int64 offset to Size, commonly using a negative value to reach bytes near the tail.

Additional Technical Info​

soFromEnd makes TStream.Seek calculate new position = Size + Offset. Use a negative offset to move before the end, zero to position exactly at the end for append-style writing, or a positive offset to request a position beyond the current end.

Velox registers the legacy LongInt value 2 and exposes an Int64 offset/result with a Word origin. Current Delphi maps ordinal 2 to typed soEnd and dispatches to the concrete stream.

Important cases

  • Seek(-N, soFromEnd) requires N <= Size for ordinary streams; otherwise the result would be negative and can fail.
  • Seeking to end does not itself append, reserve bytes or lock the end. Another consumer can change Size before the later write.
  • Seeking beyond end normally does not change Size immediately. A later write can extend the stream and create a gap whose contents and physical allocation are descendant/filesystem specific.
  • This is cursor movement, not a stable tail snapshot. Synchronize externally when Size or content can change concurrently.

The Int64 return reports the resulting absolute position. Keep it rather than round-tripping a large value through Velox's LongInt Position property.

The example assumes Size is at least four bytes; production code should verify that precondition. It is source-reviewed only and was not executed.

External references

Created 2026-07-15