pipe

描述 (Description)

此功能打开一对连接的通信管道:READHANDLE用于读取，WRITEHANDLE用于写入。 你可能需要设置$ | 在每个命令后刷新你的WRITEHANDLE。

语法 (Syntax)

以下是此函数的简单语法 -

pipe READHANDLE, WRITEHANDLE

返回值 (Return Value)

此函数在失败时返回0，在成功时返回1。

例子 (Example)

以下是显示其基本用法的示例代码 -

#!/usr/bin/perl -w
use IO::Handle;
pipe(PARENTREAD, PARENTWRITE);
pipe(CHILDREAD, CHILDWRITE);
PARENTWRITE->autoflush(1);
CHILDWRITE->autoflush(1);
if ($child = fork) { # Parent code
   close CHILDREAD; # We don't need these in the parent
   close PARENTWRITE;
   print CHILDWRITE "34+56;\n";
   chomp($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;
}

它将产生以下结果:您可以看到计算被发送到CHILDWRITE，然后孩子从CHILDREAD读取。 然后计算结果并通过PARENTWRITE将其发送回父级，其中父级从PARENTREAD读取结果。

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