use Win32API::File qw( SetFilePointer GetOsFHandle );
sub BigTell {
    my( $fh )= @_;
    seek( $fh, 0, 1 );    # Flush buffers
    my $osf= GetOsFHandle( $fh );
    my $hi= 0;
    my $lo= SetFilePointer( $osf, 0, $hi, 1 );
    return pack "NN", $hi, $lo;
}
sub BigSeek {
    my( $fh, $pos, $whence )= @_;
    my $osf= GetOsFHandle( $fh );
    seek($fh,0,1);    # Flush buffers
    my( $posHi, $posLo )= unpack "NN", $pos;
    $posLo= SetFilePointer( $osf, $posLo, $posHi, $whence )
      or  return;
    return pack "NN", $posHi, $posLo;
}