my $x = \*FH;
x $x
# prints: 
#0  GLOB(0x1d6c408)
#   -> *main::FH
open ($x, "<","somefile") or warn "error\n";
print "open FH ref: <$x>\n";
# prints: 
0  GLOB(0x1d6c408)
   -> *main::FH
         FileHandle({*main::FH}) => fileno(6)