Right, this is a part of my code:
    my $from = "";
    if (@movement == (0, 1)) {$from = "north"}
    elsif (@movement == (1, 0)) {$from = "east"}
    elsif (@movement == (0, -1)) {$from = "south"}
    elsif (@movement == (-1, 0)) {$from = "west"}

[download]
@movement is set somewhere before and it can only have the shown values.
Depending on it's value, I need to find a wind direction.
For some reason, Perl keeps saying 
Useless use of a constant in void context at D:\data\Proggen\perl\mtgr
+pg\FOE.PM
line 149.

[download]

This is the last elsif line shown.
Why is it useless?
The $from variable is to be used somewhere below.

In reply to Strange "Useless use of constant" message: should not appear at all! by muba

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.