You'll need to store the filename in a string beforehand. Given a file handle, one cannot retrieve the filename without inode hopping which you're not interested in since the real solution is far simpler.

my $stringy='c:/data.txt';
open FH,">$stringy" or  die;
print $stringy;
[download]

Done.

AgentM Systems nor Nasca Enterprises nor Bone::Easy nor Macperl is responsible for the comments made by AgentM. Remember, you can build any logical system with NOR.