ar expressions compiled with regcomp
        can also be shared between threads.
      </p>
<p>
        The <a class="link" href="../ref/deprecated/old_regex.html" title="High Level Class RegEx (Deprecated)">class RegEx</a>
        is only thread safe if each thread gets its own RegEx instance (apartment
        threading) - this is a consequence of RegEx handling both compiling and matching
        regular expressions.
      </p>
<p>
        Finally note that changing the global locale invalidates all comp