Perl运算符: $|++; dollar sign pipe plus plus

Question

我正在开发一个已经发布的 perl 代码的新版本，并发现了这一行:

$|++;

据我所知，$|与管道有关，如所解释的 in this link ，我明白这一点，但我无法弄清楚++ (加号)在这里意味着什么。

提前谢谢您。

编辑:找到答案 in this link :

简而言之:它强制在下一条语句之前打印(刷新)到控制台，以防脚本太快。

Sometimes, if you put a print statement inside of a loop that runs really really quickly, you won’t see the output of your print statement until the program terminates. sometimes, you don’t even see the output at all. the solution to this problem is to “flush” the output buffer after each print statement; this can be performed in perl with the following command:

$|++;

[update] as has been pointed out by r. schwartz, i’ve misspoken; the above command causes print to flush the buffer preceding the next output.

Answer 1

$| 默认为 0；执行 $|++ 会将其增加到 1。将其设置为非零会启用当前选定文件句柄的自动刷新，默认情况下为 STDOUT，并且很少更改。

所以效果是保证print语句之类的立即输出。如果您要输出到套接字等，这非常有用。