perl中的lock

#!/usr/bin/env perl -w
use strict;
use threads;
use threads::shared;

my $count:shared = 1;
print "count的起始值为:$count\n";
sub th_lock{
        $count++;
        print "已把变量增加1并锁定10秒\n";
        lock($count);
        sleep(10);
}
sub th_wait{
        print "准备量锁定count\n";
        lock($count);
        print "变量锁定成功\n";
}
my $th_lock = threads->new(\&th_lock);
my $th_wait = threads->new('th_wait');
$th_lock->join();
$th_wait->join;
print "count的最后值为:$count\n";