Delphi.FileInUse.pas

function FileInUse(AFileName: String): Boolean;
var
  HFileRes : HFILE;
begin
  Result := false;
  if not FileExists(fName) then
    Exit;
  HFileRes := CreateFile(PChar(AFileName), GENERIC_READ or GENERIC_WRITE,0, nil, OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL, 0);
  Result := (HFileRes = INVALID_HANDLE_VALUE);
  if not Result then
    CloseHandle(HFileRes);
end;