Update documentation re JIT fast path and UTF validity

Author: PhilipHazel

doc/pcre2_jit_match.3

@@ -1,4 +1,4 @@
-.TH PCRE2_JIT_MATCH 3 "11 February 2020" "PCRE2 10.35"
+.TH PCRE2_JIT_MATCH 3 "20 January 2023" "PCRE2 10.43"
 .SH NAME
 PCRE2 - Perl-compatible regular expressions (revised API)
 .SH SYNOPSIS
@@ -20,7 +20,15 @@ This function matches a compiled regular expression that has been successfully
 processed by the JIT compiler against a given subject string, using a matching
 algorithm that is similar to Perl's. It is a "fast path" interface to JIT, and
 it bypasses some of the sanity checks that \fBpcre2_match()\fP applies.
-Its arguments are exactly the same as for
+.P
+In UTF mode, the subject string is not checked for UTF validity. Unless
+PCRE2_MATCH_INVALID_UTF was set when the pattern was compiled, passing an
+invalid UTF string results in undefined behaviour. Your program may crash or
+loop or give wrong results. In the absence of PCRE2_MATCH_INVALID_UTF you
+should only call \fBpcre2_jit_match()\fP in UTF mode if you are sure the
+subject is valid.
+.P
+The arguments for \fBpcre2_jit_match()\fP are exactly the same as for
 .\" HREF
 \fBpcre2_match()\fP,
 .\"
@@ -29,7 +37,7 @@ PCRE2_ZERO_TERMINATED is not supported.
 .P
 The supported options are PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY,
 PCRE2_NOTEMPTY_ATSTART, PCRE2_PARTIAL_HARD, and PCRE2_PARTIAL_SOFT. Unsupported
-options are ignored. The subject string is not checked for UTF validity.
+options are ignored.
 .P
 The return values are the same as for \fBpcre2_match()\fP plus
 PCRE2_ERROR_JIT_BADOPTION if a matching mode (partial or complete) is requested

doc/pcre2jit.3

@@ -1,4 +1,4 @@
-.TH PCRE2JIT 3 "30 November 2021" "PCRE2 10.40"
+.TH PCRE2JIT 3 "20 January 2023" "PCRE2 10.43"
 .SH NAME
 PCRE2 - Perl-compatible regular expressions (revised API)
 .SH "PCRE2 JUST-IN-TIME COMPILER SUPPORT"
@@ -419,7 +419,10 @@ number of other sanity checks are performed on the arguments. For example, if
 the subject pointer is NULL but the length is non-zero, an immediate error is
 given. Also, unless PCRE2_NO_UTF_CHECK is set, a UTF subject string is tested
 for validity. In the interests of speed, these checks do not happen on the JIT
-fast path, and if invalid data is passed, the result is undefined.
+fast path, and if invalid UTF data is passed, the result is undefined. The
+program may crash or loop or give wrong results. In the absence of
+PCRE2_MATCH_INVALID_UTF you should only call \fBpcre2_jit_match()\fP in UTF
+mode if you are sure the subject is valid.
 .P
 Bypassing the sanity checks and the \fBpcre2_match()\fP wrapping can give
 speedups of more than 10%.
@@ -445,6 +448,6 @@ Cambridge, England.
 .rs
 .sp
 .nf
-Last updated: 30 November 2021
-Copyright (c) 1997-2021 University of Cambridge.
+Last updated: 20 January 2023
+Copyright (c) 1997-2023 University of Cambridge.
 .fi