Perl 打印缓冲刷新

Question

我有以下 Perl 代码:

STDOUT->autoflush(1);

foreach(...)
{
    ...

    foreach(...)
    {
        print("Processing $folder");
        $|=1;
        process($folder);
    }
    ...
}

但是 print 语句仅在循环的第一次迭代中有效，之后不再打印任何内容。知道为什么吗？

编辑:我找到了原因并将其添加到答案中。
解决方案是:

I added the following line inside the loop and it worked:

select STDOUT;

I think the code in process() function should have been modifying the default output buffer. It was a code written by somebody else!

I am not sure if this is a problem with Perl which allows this or the developer who did not change it back to the default.

The final code looked like this:

foreach(...)
{
    ...

    foreach(...)
    {
        select STDOUT;

        print("Processing $folder");
        $|=1;
        process($folder);
    }
    ...
}

Thanks all...

Answer 1

很好的侦探工作来追踪这个问题!

我想提出一个替代解决方案。

而不是 select()与 process() 的作者的 war ，您可以使用 IO::Handle标准输出接口(interface):

use IO::Handle;

foreach(...)
{
    ...

    foreach(...)
    {
        STDOUT->printflush("Processing $folder");

        process($folder);
    }
    ...
}