title: Can someone explain Possessive Quantifiers to me? (Regular Expressions)
body: <p>I am reading the PCRE doc, and it refers to <em>possessive quantifiers</em>, but does not explicitly or specifically define them.  I know what a greedy quantifier is, and I know what a lazy quantifer is.  But possessive? </p>
  
  <p>The <a href="http://www.pcre.org/pcre.txt" rel="noreferrer">PCRE man page</a> seems to be cheating when it uses the term without defining it.  The man page specifically states that the term <em>possessive quantifiers</em> was first defined in <a href="https://rads.stackoverflow.com/amzn/click/com/0596528124" rel="noreferrer" rel="nofollow noreferrer">Friedl's book</a>.  Well, that's great, but I don't have Friedl's book, and in reading the man page, between the lines, I cannot figure out what distinguishes possessive quantifiers from greedy ones. </p>
  
  <ul>
  <li>? = zero or one, greedy</li>
  <li>?? = zero or one, lazy</li>
  <li>?+ = zero or one, possessive</li>
  <li>'+' = one or more, greedy</li>
  <li>+? = one or more, lazy</li>
  <li>++ = one or more, possessive</li>
  </ul>