即使打开了strict和warnings选项也无妨，下面代码并无错误和警告。

复制代码 代码如下:

#!/usr/bin/perl

use strict;

use warnings;

sub test {

$a = 1;

$b = 2;

print $a, "n";

print $b, "n";

}

test();

1;

下面是perl文档中对这两个变量的解释：

perldoc perlvar

$a

$b Special package variables when using sort(), see "sort" in perlfunc.

Because of this specialness $a and $b don't need to be declared (using use vars, or our()) even when using the "strict 'vars'" pragma. Don't lexicalize them with "my $a" or "my $b" if you want to be able to use them in the sort() comparison block or function.