Ok, I have tested it on 3 machines now:

  1. Linux Debian
    • Perl v5.8.0
    • Net::POP3 v2.24

  2. Linux Slackware
    • Perl v5.6.0
    • Net::POP3 v2.23

  3. FreeBSD
    • Perl v5.8.0
    • Net::POP3 v2.24
And got the following results:

Machine Result
1 Initially gave the same error message, but that got solved after moving $pop->quit() outside the if-statement.
2 Initially gave the same error message, but that got solved after moving $pop->quit() outside the if-statement.
3 Initially gave the same error message, but that got solved after moving $pop->quit() outside the if-statement.

I tested your posted code verbatim first, and with my slight alteration afterwards. I did not take out the "use diagnostics;". So I am now curious what Perl and Net:POP3 versions you use. Oh, maybe it has anything to do with it, but I tested the script on a qpopper POP3 daemon, first with one line in "./addresses" and later with multiple lines.

Update: now also tested with the "POP3 Server (Version 1.006d)" daemon, same result.

--
b10m

In reply to Re: How to check number of messages using Net::POP3? by b10m
in thread How to check number of messages using Net::POP3? by BjoernD

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.