Yes, that is correct.

Consider what happens with my re-coded sub a1, 

my $href = a1();
$href = a1();

[download]
The first call makes a hash and returns a reference to it. The second call also makes a hash and returns a reference to it. However after the second call, the reference to the first hash is now "lost" as it was replaced by a reference to the second hash that was generated. The memory for the first hash is then recylced because its reference count is zero and there is no way for the program to access that data anymore.

Of course in a "real" example, probably there are some parameters to sub a1 so that it generates a different kind of hash on the second call. One reason to do this might be in a GUI interface where a1() winds up being say a "button factory". If the references returned are kept in scope, say in an array, then each button is a distinct thing.

For the most part, Perl memory management does the "right thing" under the covers and is transparent to you. There are of course special considerations with certain types of data structures and when making truly huge structures in the sub.

In reply to Re^3: Do subroutine variables get destroyed? by Marshall
in thread Do subroutine variables get destroyed? by bt101

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.