Ah, you've confused people with your terminology. You seem to mean that the function reads from a filehandle and returns the contents. Is this correct?

If so, something like:

my $filedata = myfunction();
if (defined $filedata) {
   print FILEHANDLE $filedata;
} else {
   # handle error...
}
[download]

P.S. Showing some or all of myfunction() would really help us help you.