my $varA = "this is varA";
my $varB = "this is varB";
my $varC;

print "\n";

##   my @vars = ( $varA, $varB, $varC );
my @vars = ( \$varA, \$varB, \$varC );

foreach my $f ( @vars ) {
    if ( defined $$f ) {
        print "--- $$f \n";
        my $tmp = $$f . " and some more ";
        print "----- $tmp \n";

        no strict 'refs';
        ##   ${$f} = $tmp;
        ##   ${"f"} = $tmp;
        ##   my $ref = \$f;    $ref = $tmp;
        my $f = \$tmp;

        use strict;
        print "===== $$f \n";
    }
}

print "\n";
foreach my $f ( @vars ) {
    print "+ $f \n";
}

print "\n";