Not just that. It's also to allow the bare 1; at the end of modules to make it end in a true value, without a complaint under perl -c Foo.pm.

Note that no true value at the end of a module, whatever you choose, causes a complaint under normal cicrumstances, actually because a module is loaded in scalar context.

As a test: I saved this little module as "Temp.pm" in the current directory: 

# Temp.pm
package Temp;
printf "Context = %s\n", defined wantarray ? 0+wantarray : 'undef';
# true value, but may cause warning:
"nothing";

[download]
This command line makes it work without warning: 
perl -lib=. -MTemp -we1

[download]
Result: 
Context = 0

But with perl -wc, you do get a warning: 

perl -wc Temp.pm

[download]
Useless use of a constant in void context at Temp.pm line 3.
Temp.pm syntax OK

Replace the string "nothing" with 1, and you're fine: 

Temp.pm syntax OK

In reply to Re^5: expression which does nothing by bart
in thread expression which does nothing by jesuashok

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.