I tought there was a function in Scalar::Util that returns the refcount of an object, but I couldn't find it. But also in Scalar::Util, you find the weaken function, which lets you pass around weak references. From your description, I think you have a "master" object that holds all "relevant" children, but over time, some of the children become irrelevant yet are kept alive by some references. If you make your master hold strong (normal) references but pass out only weak references, your children will be removed if the master removes them from the list.

Such an approach will have different problems, because weak references can turn into strong references again if you copy them, unfortunately. Maybe another approach would be to (always) ask the master whether a child is still relevant or not ...

In reply to Re: The number of references to a variable by Corion
in thread The number of references to a variable by jeanluca

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.