These have been
added at the request of users who want to make use of certain PCRE2-specific
features via the POSIX calling interface or to add BSD or GNU functionality.
</p>
<p>
When PCRE2 is called via these functions, it is only the API that is POSIX-like
in style. The syntax and semantics of the regular expressions themselves are
still those of Perl, subject to the setting of various PCRE2 options, as
described below. "POSIX-like in style" means that the API approximates to the
POSIX definition; it is n