 If the appropriate JIT mode has not been compiled,
interpretive matching code is used.
</P>
<P>
Setting a partial matching option disables two of PCRE2's standard
optimizations. PCRE2 remembers the last literal code unit in a pattern, and
abandons matching immediately if it is not present in the subject string. This
optimization cannot be used for a subject string that might match only
partially. PCRE2 also knows the minimum length of a matching string, and does
not bother to run the matching function on s