function FileAge(const FileName: string): Integer;
{$IFDEF MSWINDOWS}
var
     Handle: THandle;
     FindData: TWin32FindData;
     LocalFileTime: TFileTime;
begin
     Handle:=FindFirstFile(PChar(FileName), FindData);
     if Handle<>INVALID_HANDLE_VALUE then
     begin
        Windows.FindClose(Handle);
        if (FindData.dwFileAttributes and FILE_ATTRIBUTE_DIRECTORY)=0 then
        begin
           FileTimeToLocalFileTime(FindData.ftLastWriteTime, LocalFileTime);
           if FileTimeToDosDateTime(LocalFileTime, LongRec(Result).Hi,
              LongRec(Result).Lo) then
              Exit;
        end;
     end;
     Result:=-1;
end;
{$ENDIF}
{$IFDEF LINUX}
var
     st: TStatBuf;
begin
     if stat(PChar(FileName), st)=0 then
        Result:=st.st_mtime
     else
        Result:=-1;
end;
{$ENDIF}

function FileExists(const FileName: string): Boolean;
{$IFDEF MSWINDOWS}
begin
     Result:=FileAge(FileName)<>-1;
end;