##
$ perl -E '
my $fo = "";
update($fo);
print "|$fo|";
sub update {
my ($arg) = @_;
$arg .= "XXX";
}
'
||
##
##
$ perl -E '
my $fo = "";
update(\$fo);
print "|$fo|";
sub update {
my ($arg) = @_;
$$arg .= "XXX";
}
'
|XXX|