RROR_PARTIAL for a partial match
  PCRE_DFA_SHORTEST  Return only the shortest match
  PCRE_DFA_RESTART   This is a restart after a partial match
</pre>
There are restrictions on what may appear in a pattern when using this matching
function. Details are given in the
<a href="pcrematching.html"><b>pcrematching</b></a>
documentation.
</P>
<P>
A <b>pcre_extra</b> structure contains the following fields:
<pre>
  <i>flags</i>        Bits indicating which fields are set
  <i>study_data</i>   Opaque data from <b>