Implement PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL.

git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@816 6239d852-aaf2-0410-a92c-79f79f948069

1 files changed, 19 insertions, 1 deletions

diff --git a/doc/pcre2.txt b/doc/pcre2.txt
index 477ad6f..4341a61 100644
--- a/doc/pcre2.txt
+++ b/doc/pcre2.txt
@@ -1688,6 +1688,24 @@ COMPILING A PATTERN
        only match subject characters if the matching function is  called  with
        PCRE2_NO_UTF_CHECK set.
 
+         PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL
+
+       This  is a dangerous option. Use with care. By default, an unrecognized
+       escape such as \j or a malformed one such as \x{2z} causes  a  compile-
+       time error when detected by pcre2_compile(). Perl is somewhat inconsis-
+       tent in handling such items: for example, \j is treated  as  a  literal
+       "j",  and non-hexadecimal digits in \x{} are just ignored, though warn-
+       ings are given in both cases if Perl's warning switch is enabled.  How-
+       ever,  a  malformed  octal  number  after \o{ always causes an error in
+       Perl.
+
+       If the PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL  extra  option  is  passed  to
+       pcre2_compile(),  all  unrecognized  or  erroneous escape sequences are
+       treated as single-character escapes. For example, \j is a  literal  "j"
+       and  \x{2z}  is  treated  as  the  literal string "x{2z}". Setting this
+       option means that typos in patterns may go undetected  and  have  unex-
+       pected results. This is a dangerous option. Use with care.
+
 
 COMPILATION ERROR CODES
 
@@ -3350,7 +3368,7 @@ AUTHOR
 
 REVISION
 
-       Last updated: 30 May 2017
+       Last updated: 01 June 2017
        Copyright (c) 1997-2017 University of Cambridge.
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