I am curious as to how global variables in packages are kept. For instance.. 
Package Pack;
my $image;
sub one
{
($image)=@_;
}
sub two
{
print $image;
}

##main code

use Pack;
Pack::one("param");
my $ret=Pack::two();
print $ret;

[download]
This code prints "param". I guess I'm confused as to how instances of packages are created. I assumed that the two calls to subs one and two in the main code above were separate and that the variable image would not retain its value between the two calls.
How does package instantiation occcur? Is one instance of the package create everytime you use the "use" function?
Can I also assume that global variables in packages will stay the same as in the example above? Thanks.

In reply to Instance Module by Anonymous Monk

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.