Even if select could see the contents of the buffers (which it sometimes does, I believe), you still couldn't use readline (<$fh>).

I listed two conditions that make sysread suitable. Its non-buffering aspect was just one of them. The other is that it returns as soon as there's data available, so it doesn't block. readline, on the other hand, blocks.

What makes sysread complicated, the use of buffers, is the result of it's non-blocking nature. Its non-blocking nature is the reason you want to use it. If readline was non-blocking, you'd have to jump through the same hoops.

select is inherently complicated. Imagine if you had both readers and writers! Again, if you want simplicity, you want threads.

In reply to Re^3: select() and input buffering by ikegami
in thread select() and input buffering by declan

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.