ch as \d, when matched with <b>pcre2_match()</b>; the performance loss is
less with a DFA matching function, and in both cases there is not much
difference for \b.
</P>
<P>
When a pattern begins with .* not in atomic parentheses, nor in parentheses
that are the subject of a backreference, and the PCRE2_DOTALL option is set,
the pattern is implicitly anchored by PCRE2, since it can match only at the
start of a subject string. If the pattern has multiple top-level branches, they
must all be anchorable. The op