Perl pipe()函数

perl pipe()函数例子，pipe()函数实例代码 - 打开一个连接的通信管道：对READHANDLE为的读取和WRITEHANDLE为写。

语法

pipe READHANDLE, WRITEHANDLE

定义和用法

打开一个连接的通信管道：对READHANDLE为的读取和WRITEHANDLE为写。您可能需要设置$ |刷新您的WRITEHANDLE的每一个命令后。

返回值

• 0 - 返回

• 1 - 成功

例子

试试下面的例子：

#!/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;
}

这将产生以下结果：您可以看到，计算发送到CHILDWRITE，然后从CHILDREAD子读取。然后，结果被计算和发送回父，通过PARENTWRITE，其中父从PARENTREAD读取结果。

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