Perl pipe()函數

perl pipe()函數例子，pipe()函數實例代碼 - 打開一個連接的通信管道：對READHANDLE為的讀取和WRITEHANDLE為寫。

語法

pipe READHANDLE, WRITEHANDLE

定義和用法

打開一個連接的通信管道：對READHANDLE為的讀取和WRITEHANDLE為寫。您可能需要設置$ |刷新您的WRITEHANDLE的每一個命令後。

返回值

• 0 - 返回

• 1 - 成功

例子

試試下麵的例子：

#!/usr/bin/perl -w
#by www.gitbook.net

use IO::Handle;

pipe(PARENTREAD, PARENTWRITE);
pipe(CHILDREAD, CHILDWRITE);

PARENTWRITE->autoflush(1);
CHILDWRITE->autoflush(1);

if ($child = fork) # Parent code
{
   close CHILDTREAD; # We don't need these in the parent
   close PARENTWRITE;
   print CHILDWRITE "34+56;\n";
   chomp($result = <PARENTREAD>);
   print "Got a value of $result from child\n";
   close PARENTREAD;
   close CHILDWRITE;
   waitpid($child,0);
}else{
   close PARENTREAD; # We don't need these in the child
   close CHILDWRITE;
   chomp($calculation = <CHILDREAD>);
   print "Got $calculation\n";
   $result = eval "$calculation";
   print PARENTWRITE "$result\n";
   close CHILDREAD;
   close PARENTWRITE;
   exit;
}

這將產生以下結果：您可以看到，計算發送到CHILDWRITE，然後從CHILDREAD子讀取。然後，結果被計算和發送回父，通過PARENTWRITE，其中父從PARENTREAD讀取結果。

Got 34+56;
Got a value of 90 from child