When I need a subroutine to modify one (or more) scalar variables I usually use a 3rd method: I send the value back in the return.

It seems that you want the subroutine to return a status. But even then couldn't you use undef as a failure signal?

unless( defined( $variable= foo( $variable))) die "horrible death: $sn
+afu::ERROR";
package snafu;
my $ERROR;
sub foo {
     # interesting things happen
     if ( $things_worked ) {
       return $baz;
     else {
       $ERROR= "horrible death";
       return undef;
     }

[download]

I actually very rarely modify $_[0] and al. I don't like side effects and I prefer to see clearly which variables are modified by a function.

In reply to Re: Pass by reference: is it good form to grope @_? by mirod
in thread Pass by reference: is it good form to grope @_? by mikfire

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.