The reason for your error is because the snippet

sub pr { print main::FO1; }

[download]

is compiled before the the snippet

use constant {
FO1 => "value"
};

[download]

(BTW braces for constant?? Weird.)

so perl has to apply some heuristics while parsing the former code. An all uppercase bareword ("FO1") as a first parameter to print, makes perl assume it's a filehandle.

So what you must do is one of the following:

  1. Mark up the print line so it's clear that you don't mean a filehandle. Unfortunately, this: 

    sub pr { print +main::FO1; }

    [download]
    still isn't enough.. (Why not? I really expected that this would work.)

    But even if it did work, that probably would still leave you with a prototype mismatch error

  2. compile the constant definition for before you use pq;

BTW It's considered best practice to start package (and module) names with an uppercase letter.

Seeing the trouble with the former attempt at a solution, the latter definitely looks like the best option.

In reply to Re: Accessing main::Constant by bart
in thread Accessing main::Constant by nagalenoj

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.