thanks.
aacturally I used pack/unpack for this porblem, but the result is binary string:
like
-----------------------
sub dec2bin{
my $str = unpack("B*", pack("f", shift));
$str =~ s/^0+(?=\d)//;
return $str;
}
open (FH, ">c.dat" || die "$!");
binmode (FH);
print FH...