Perl pipe 函数

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  描述

  pipe 此函数打开一对连接的通信管道：READHANDLE用于读取，WRITEHANDLE用于写入。您可能需要设置$| 在每个命令后刷新您的WRITEHANDLE。
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  句法

  以下是此函数的简单语法-

  
  pipe READHANDLE, WRITEHANDLE
  

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  返回值

  如果失败，此函数返回0，如果成功，则返回1。
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  示例

  以下是显示其基本用法的示例代码-

   
  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;
  }
  

  尝试一下

  执行结果：

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