#!/usr/bin/perl -w

open FH, "<$myFile" or die "Can't open $myFile: $!\n";

&myFunc(\*FH);

&myFonc(\*FH);

sub myFunc {
  while (<$_&#91;0&#93;>) {
    #do something
  }
}

sub myFonc {
  my $handle = shift;
  while(<$handle>) {
    # do someything
  }
}