Documentation update.

doc/pcre2api.3

@@ -1,4 +1,4 @@
-.TH PCRE2API 3 "27 April 2018" "PCRE2 10.32"
+.TH PCRE2API 3 "18 June 2018" "PCRE2 10.32"
 .SH NAME
 PCRE2 - Perl-compatible regular expressions (revised API)
 .sp
@@ -2552,7 +2552,7 @@ performance reasons, you can set the PCRE2_NO_UTF_CHECK option when calling
 calls to \fBpcre2_match()\fP if you are making repeated calls to find other
 matches in the same subject string.
 .P
-WARNING: When PCRE2_NO_UTF_CHECK is set, the effect of passing an invalid
+\fBWarning:\fP When PCRE2_NO_UTF_CHECK is set, the effect of passing an invalid
 string as a subject, or an invalid value of \fIstartoffset\fP, is undefined.
 Your program may crash or loop indefinitely.
 .sp
@@ -2769,6 +2769,14 @@ When it matches "bc", the returned name is A. The B mark is "seen" in the first
 branch of the group, but it is not on the matching path. On the other hand,
 when this pattern fails to match "bx", the returned name is B.
 .P
+\fBWarning:\fP By default, certain start-of-match optimizations are used to
+give a fast "no match" result in some situations. For example, if the anchoring
+is removed from the pattern above, there is an initial check for the presence
+of "c" in the subject before running the matching engine. This check fails for
+"bx", causing a match failure without seeing any marks. You can disable the
+start-of-match optimizations by setting the PCRE2_NO_START_OPTIMIZE option for
+\fBpcre2_compile()\fP or starting the pattern with (*NO_START_OPT).
+.P
 After a successful match, a partial match, or one of the invalid UTF errors
 (for example, PCRE2_ERROR_UTF8_ERR5), \fBpcre2_get_startchar()\fP can be
 called. After a successful or partial match it returns the code unit offset of
@@ -3613,6 +3621,6 @@ Cambridge, England.
 .rs
 .sp
 .nf
-Last updated: 27 April 2018
+Last updated: 18 June 2018
 Copyright (c) 1997-2018 University of Cambridge.
 .fi