perl脚本——引用和指针
一、使用反斜线（\）操作符
反斜线操作符与C语言中传递地址的操作符&功能类似。一般是用\创建变量又一个新的引用。下面为创建简单变量的引用的例子：
$variavle = 22;
$pointer = \$variable;
$ice = "jello";
$iceprt = \$ice;
引用$pointer指向存有$variable值的位置，引用$iceptr指向"jello"。即使最初的引用$variable销毁了，仍然可以通过$pointer访问该值，这是一个硬引用，所以必须同时销毁$pointer和$variable以便该空间释放到内存池中。
在上面的例子中，引用变量$pointer存的是$variable的地址，而不是值本身，要获得值，形式为两个$符号，如下：
1 #!/usr/bin/perl 2 # 3 # Using Array references 4 # 5 %weekday = ( 6 '01' => 'Mon', 7 '02' => 'Tue', 8 '03' => 'Wed', 9 '04' => 'Thu', 10 '05' => 'Fri', 11 '06' => 'Sat', 12 '07' => 'Sun', 13 ); 14 $pointer = \%weekday; 15 $i = '05'; 16 printf "\n ================== start test ================= \n"; 17 # 18 # These next two lines should show an output 19 # 20 printf '$$pointer{$i} is '; 21 printf "$$pointer{$i} \n"; 22 printf '${$pointer}{$i} is '; 23 printf "${$pointer}{$i} \n"; 24 printf '$pointer->{$i} is '; 25 26 printf "$pointer->{$i}\n"; 27 # 28 # These next two lines should not show anything 29 # 30 printf '${$pointer{$i}} is '; 31 printf "${$pointer{$i}} \n"; 32 printf '${$pointer->{$i}} is '; 33 printf "${$pointer->{$i}}"; 34 printf "\n ================== end of test ================= \n"; 35