From c84a06c96e57933ab8055b74e7d25e481e37cbf3 Mon Sep 17 00:00:00 2001 From: "Philip.Hazel" Date: Sun, 21 Jul 2019 16:48:13 +0000 Subject: [PATCH] Update definition of partial match and fix \z and \Z (as documented). --- ChangeLog | 10 + doc/html/pcre2api.html | 18 +- doc/html/pcre2partial.html | 86 ++-- doc/pcre2.txt | 869 ++++++++++++++++++------------------- doc/pcre2api.3 | 19 +- doc/pcre2partial.3 | 85 ++-- src/pcre2_dfa_match.c | 32 +- src/pcre2_intmodedep.h | 2 + src/pcre2_match.c | 55 ++- testdata/testinput2 | 29 +- testdata/testinput6 | 26 ++ testdata/testoutput2 | 46 +- testdata/testoutput6 | 42 ++ 13 files changed, 715 insertions(+), 604 deletions(-) diff --git a/ChangeLog b/ChangeLog index e9a3cc4..9b75055 100644 --- a/ChangeLog +++ b/ChangeLog @@ -97,6 +97,16 @@ within it, the nested lookbehind was not correctly processed. For example, if 20. Implemented pcre2_get_match_data_size(). +21. Two alterations to partial matching (not yet done by JIT): + + (a) The definition of a partial match is slightly changed: if a pattern + contains any lookbehinds, an empty partial match may be given, because this + is another situation where adding characters to the current subject can + lead to a full match. Example: /c*+(?<=[bc])/ with subject "ab". + + (b) An empty string partial hard match can be returned for \z and \Z as it + is documented that they shouldn't match. + Version 10.33 16-April-2019 --------------------------- diff --git a/doc/html/pcre2api.html b/doc/html/pcre2api.html index a7d3588..7dcc695 100644 --- a/doc/html/pcre2api.html +++ b/doc/html/pcre2api.html @@ -2725,12 +2725,16 @@ Your program may crash or loop indefinitely or give wrong results. These options turn on the partial matching feature. A partial match occurs if the end of the subject string is reached successfully, but there are not enough -subject characters to complete the match. If this happens when -PCRE2_PARTIAL_SOFT (but not PCRE2_PARTIAL_HARD) is set, matching continues by -testing any remaining alternatives. Only if no complete match can be found is -PCRE2_ERROR_PARTIAL returned instead of PCRE2_ERROR_NOMATCH. In other words, -PCRE2_PARTIAL_SOFT specifies that the caller is prepared to handle a partial -match, but only if no complete match can be found. +subject characters to complete the match. In addition, either at least one +character must have been inspected or the pattern must contain a lookbehind. +

+

+If this situation arises when PCRE2_PARTIAL_SOFT (but not PCRE2_PARTIAL_HARD) +is set, matching continues by testing any remaining alternatives. Only if no +complete match can be found is PCRE2_ERROR_PARTIAL returned instead of +PCRE2_ERROR_NOMATCH. In other words, PCRE2_PARTIAL_SOFT specifies that the +caller is prepared to handle a partial match, but only if no complete match can +be found.

If PCRE2_PARTIAL_HARD is set, it overrides PCRE2_PARTIAL_SOFT. In this case, if @@ -3846,7 +3850,7 @@ Cambridge, England.


REVISION

-Last updated: 25 June 2019 +Last updated: 20 July 2019
Copyright © 1997-2019 University of Cambridge.
diff --git a/doc/html/pcre2partial.html b/doc/html/pcre2partial.html index df0ed13..900719a 100644 --- a/doc/html/pcre2partial.html +++ b/doc/html/pcre2partial.html @@ -45,7 +45,7 @@ as soon as a mistake is made, by beeping and not reflecting the character that has been typed, for example. This immediate feedback is likely to be a better user interface than a check that is delayed until the entire string has been entered. Partial matching can also be useful when the subject string is very -long and is not all available at once. +long and is not all available at once, as discussed below.

PCRE2 supports partial matching by means of the PCRE2_PARTIAL_SOFT and @@ -79,13 +79,18 @@ is also disabled for partial matching.

A partial match occurs during a call to pcre2_match() when the end of the subject string is reached successfully, but matching cannot continue because -more characters are needed. However, at least one character in the subject must -have been inspected. This character need not form part of the final matched -string; lookbehind assertions and the \K escape sequence provide ways of -inspecting characters before the start of a matched string. The requirement for -inspecting at least one character exists because an empty string can always be -matched; without such a restriction there would always be a partial match of an -empty string at the end of the subject. +more characters are needed, and in addition, either at least one character in +the subject has been inspected or the pattern contains a lookbehind. An +inspected character need not form part of the final matched string; lookbehind +assertions and the \K escape sequence provide ways of inspecting characters +before the start of a matched string. +

+

+The two additional requirements define the cases where adding more characters +to the existing subject may complete the match. Without these conditions there +would be a partial match of an empty string at the end of the subject for all +unanchored patterns (and also for anchored patterns if the subject itself is +empty).

When a partial match is returned, the first two elements in the ovector point @@ -104,7 +109,7 @@ characters.

What happens when a partial match is identified depends on which of the two -partial matching options are set. +partial matching options is set.


PCRE2_PARTIAL_SOFT WITH pcre2_match() @@ -128,12 +133,12 @@ the data that is returned. Consider this pattern: 
   /123\w+X|dogY/
-If this is matched against the subject string "abc123dog", both -alternatives fail to match, but the end of the subject is reached during -matching, so PCRE2_ERROR_PARTIAL is returned. The offsets are set to 3 and 9, -identifying "123dog" as the first partial match that was found. (In this -example, there are two partial matches, because "dog" on its own partially -matches the second alternative.) +If this is matched against the subject string "abc123dog", both alternatives +fail to match, but the end of the subject is reached during matching, so +PCRE2_ERROR_PARTIAL is returned. The offsets are set to 3 and 9, identifying +"123dog" as the first partial match that was found. (In this example, there are +two partial matches, because "dog" on its own partially matches the second +alternative.)


PCRE2_PARTIAL_HARD WITH pcre2_match() @@ -145,8 +150,8 @@ possible complete matches. This option is "hard" because it prefers an earlier partial match over a later complete match. For this reason, the assumption is made that the end of the supplied subject string may not be the true end of the available data, and so, if \z, \Z, \b, \B, or $ are encountered at the end -of the subject, the result is PCRE2_ERROR_PARTIAL, provided that at least one -character in the subject has been inspected. +of the subject, the result is PCRE2_ERROR_PARTIAL, whether or not any +characters have been inspected.


Comparing hard and soft partial matching @@ -346,44 +351,25 @@ string "xx123ab", the ovector offsets are 5 and 7 ("ab"). The maximum lookbehind count is 3, so all characters before offset 2 can be discarded. The value of startoffset for the next match should be 3. When pcre2test displays a partial match, it indicates the lookbehind characters with '<' -characters: +characters if the "allusedtext" modifier is set: 
     re> "(?<=123)abc"
-  data> xx123ab\=ph
+  data> xx123ab\=ph,allusedtext
   Partial match: 123ab
                  <<<
-
-

-

-3. The maximum lookbehind count is also important when the result of a partial -match attempt is "no match". In this case, the maximum lookbehind characters -from the end of the current segment must be retained at the start of the next -segment, in case the lookbehind is at the start of the pattern. Matching the -next segment must then start at the appropriate offset. -

-

-4. Because a partial match must always contain at least one character, what -might be considered a partial match of an empty string actually gives a "no -match" result. For example: -

-    re> /c(?<=abc)x/
-  data> ab\=ps
-  No match
-If the next segment begins "cx", a match should be found, but this will only -happen if characters from the previous segment are retained. For this reason, a -"no match" result should be interpreted as "partial match of an empty string" -when the pattern contains lookbehinds. +However, the "allusedtext" modifier is not available for JIT matching, because +JIT matching does not maintain the first and last consulted characters.

-5. Matching a subject string that is split into multiple segments may not -always produce exactly the same result as matching over one single long string, -especially when PCRE2_PARTIAL_SOFT is used. The section "Partial Matching and -Word Boundaries" above describes an issue that arises if the pattern ends with -\b or \B. Another kind of difference may occur when there are multiple -matching possibilities, because (for PCRE2_PARTIAL_SOFT) a partial match result -is given only when there are no completed matches. This means that as soon as -the shortest match has been found, continuation to a new subject segment is no +3. Matching a subject string that is split into multiple segments may not +always produce exactly the same result as matching over one single long string +when PCRE2_PARTIAL_SOFT is used. The section "Partial Matching and Word +Boundaries" above describes an issue that arises if the pattern ends with \b +or \B. Another kind of difference may occur when there are multiple matching +possibilities, because (for PCRE2_PARTIAL_SOFT) a partial match result is given +only when there are no completed matches. This means that as soon as the +shortest match has been found, continuation to a new subject segment is no longer possible. Consider this pcre2test example: 

     re> /dog(sbody)?/
@@ -418,7 +404,7 @@ multi-segment data. The example above then behaves differently:
   data> gsb\=ph,dfa,dfa_restart
   Partial match: gsb
-6. Patterns that contain alternatives at the top level which do not all start +4. Patterns that contain alternatives at the top level which do not all start with the same pattern item may not work as expected when PCRE2_DFA_RESTART is used. For example, consider this pattern: 
@@ -463,7 +449,7 @@ Cambridge, England.
 

 
REVISION

 

-Last updated: 21 June 2019
+Last updated: 21 July 2019
 

 Copyright © 1997-2019 University of Cambridge.
 

diff --git a/doc/pcre2.txt b/doc/pcre2.txt
index 33e6096..8852ce3 100644
--- a/doc/pcre2.txt
+++ b/doc/pcre2.txt
@@ -2661,17 +2661,20 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION
 
        These options turn on the partial matching feature. A partial match oc-
        curs if the end of the subject  string  is  reached  successfully,  but
-       there  are not enough subject characters to complete the match. If this
-       happens when PCRE2_PARTIAL_SOFT (but not  PCRE2_PARTIAL_HARD)  is  set,
-       matching  continues  by  testing any remaining alternatives. Only if no
-       complete match can be found is PCRE2_ERROR_PARTIAL returned instead  of
-       PCRE2_ERROR_NOMATCH.  In other words, PCRE2_PARTIAL_SOFT specifies that
-       the caller is prepared to handle a partial match, but only if  no  com-
-       plete match can be found.
+       there are not enough subject characters to complete the match. In addi-
+       tion, either at least one character must have  been  inspected  or  the
+       pattern must contain a lookbehind.
 
-       If  PCRE2_PARTIAL_HARD is set, it overrides PCRE2_PARTIAL_SOFT. In this
-       case, if a partial match is found,  pcre2_match()  immediately  returns
-       PCRE2_ERROR_PARTIAL,  without  considering  any  other alternatives. In
+       If  this  situation  arises when PCRE2_PARTIAL_SOFT (but not PCRE2_PAR-
+       TIAL_HARD) is set, matching continues by testing any remaining alterna-
+       tives.  Only  if  no complete match can be found is PCRE2_ERROR_PARTIAL
+       returned instead of PCRE2_ERROR_NOMATCH.  In  other  words,  PCRE2_PAR-
+       TIAL_SOFT  specifies  that  the  caller is prepared to handle a partial
+       match, but only if no complete match can be found.
+
+       If PCRE2_PARTIAL_HARD is set, it overrides PCRE2_PARTIAL_SOFT. In  this
+       case,  if  a  partial match is found, pcre2_match() immediately returns
+       PCRE2_ERROR_PARTIAL, without considering  any  other  alternatives.  In
        other words, when PCRE2_PARTIAL_HARD is set, a partial match is consid-
        ered to be more important that an alternative complete match.
 
@@ -2681,38 +2684,38 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION
 
 NEWLINE HANDLING WHEN MATCHING
 
-       When PCRE2 is built, a default newline convention is set; this is  usu-
-       ally  the standard convention for the operating system. The default can
-       be overridden in a compile context by calling  pcre2_set_newline().  It
-       can  also be overridden by starting a pattern string with, for example,
-       (*CRLF), as described in the section  on  newline  conventions  in  the
-       pcre2pattern  page. During matching, the newline choice affects the be-
-       haviour of the dot, circumflex, and dollar metacharacters. It may  also
-       alter  the  way  the  match starting position is advanced after a match
+       When  PCRE2 is built, a default newline convention is set; this is usu-
+       ally the standard convention for the operating system. The default  can
+       be  overridden  in a compile context by calling pcre2_set_newline(). It
+       can also be overridden by starting a pattern string with, for  example,
+       (*CRLF),  as  described  in  the  section on newline conventions in the
+       pcre2pattern page. During matching, the newline choice affects the  be-
+       haviour  of the dot, circumflex, and dollar metacharacters. It may also
+       alter the way the match starting position is  advanced  after  a  match
        failure for an unanchored pattern.
 
        When PCRE2_NEWLINE_CRLF, PCRE2_NEWLINE_ANYCRLF, or PCRE2_NEWLINE_ANY is
-       set  as  the  newline convention, and a match attempt for an unanchored
+       set as the newline convention, and a match attempt  for  an  unanchored
        pattern fails when the current starting position is at a CRLF sequence,
-       and  the  pattern contains no explicit matches for CR or LF characters,
-       the match position is advanced by two characters  instead  of  one,  in
+       and the pattern contains no explicit matches for CR or  LF  characters,
+       the  match  position  is  advanced by two characters instead of one, in
        other words, to after the CRLF.
 
        The above rule is a compromise that makes the most common cases work as
-       expected. For example, if the pattern is .+A (and the PCRE2_DOTALL  op-
-       tion  is  not set), it does not match the string "\r\nA" because, after
-       failing at the start, it skips both the CR and the LF before  retrying.
-       However,  the  pattern  [\r\n]A does match that string, because it con-
+       expected.  For example, if the pattern is .+A (and the PCRE2_DOTALL op-
+       tion is not set), it does not match the string "\r\nA"  because,  after
+       failing  at the start, it skips both the CR and the LF before retrying.
+       However, the pattern [\r\n]A does match that string,  because  it  con-
        tains an explicit CR or LF reference, and so advances only by one char-
        acter after the first failure.
 
        An explicit match for CR of LF is either a literal appearance of one of
-       those characters in the pattern, or one of the \r or \n  or  equivalent
+       those  characters  in the pattern, or one of the \r or \n or equivalent
        octal or hexadecimal escape sequences. Implicit matches such as [^X] do
-       not count, nor does \s, even though it includes CR and LF in the  char-
+       not  count, nor does \s, even though it includes CR and LF in the char-
        acters that it matches.
 
-       Notwithstanding  the above, anomalous effects may still occur when CRLF
+       Notwithstanding the above, anomalous effects may still occur when  CRLF
        is a valid newline sequence and explicit \r or \n escapes appear in the
        pattern.
 
@@ -2723,82 +2726,82 @@ HOW PCRE2_MATCH() RETURNS A STRING AND CAPTURED SUBSTRINGS
 
        PCRE2_SIZE *pcre2_get_ovector_pointer(pcre2_match_data *match_data);
 
-       In  general, a pattern matches a certain portion of the subject, and in
-       addition, further substrings from the subject  may  be  picked  out  by
-       parenthesized  parts  of  the  pattern.  Following the usage in Jeffrey
-       Friedl's book, this is called "capturing"  in  what  follows,  and  the
-       phrase  "capture  group" (Perl terminology) is used for a fragment of a
-       pattern that picks out a substring. PCRE2 supports several other  kinds
+       In general, a pattern matches a certain portion of the subject, and  in
+       addition,  further  substrings  from  the  subject may be picked out by
+       parenthesized parts of the pattern.  Following  the  usage  in  Jeffrey
+       Friedl's  book,  this  is  called  "capturing" in what follows, and the
+       phrase "capture group" (Perl terminology) is used for a fragment  of  a
+       pattern  that picks out a substring. PCRE2 supports several other kinds
        of parenthesized group that do not cause substrings to be captured. The
-       pcre2_pattern_info() function can be used to find out how many  capture
+       pcre2_pattern_info()  function can be used to find out how many capture
        groups there are in a compiled pattern.
 
-       You  can  use  auxiliary functions for accessing captured substrings by
+       You can use auxiliary functions for accessing  captured  substrings  by
        number or by name, as described in sections below.
 
        Alternatively, you can make direct use of the vector of PCRE2_SIZE val-
-       ues,  called  the  ovector,  which  contains  the  offsets  of captured
-       strings.  It  is  part  of  the  match  data   block.    The   function
-       pcre2_get_ovector_pointer()  returns  the  address  of the ovector, and
+       ues, called  the  ovector,  which  contains  the  offsets  of  captured
+       strings.   It   is   part  of  the  match  data  block.   The  function
+       pcre2_get_ovector_pointer() returns the address  of  the  ovector,  and
        pcre2_get_ovector_count() returns the number of pairs of values it con-
        tains.
 
        Within the ovector, the first in each pair of values is set to the off-
        set of the first code unit of a substring, and the second is set to the
-       offset  of the first code unit after the end of a substring. These val-
-       ues are always code unit offsets, not character offsets. That is,  they
+       offset of the first code unit after the end of a substring. These  val-
+       ues  are always code unit offsets, not character offsets. That is, they
        are byte offsets in the 8-bit library, 16-bit offsets in the 16-bit li-
        brary, and 32-bit offsets in the 32-bit library.
 
-       After a partial match  (error  return  PCRE2_ERROR_PARTIAL),  only  the
-       first  pair  of  offsets  (that is, ovector[0] and ovector[1]) are set.
-       They identify the part of the subject that was partially  matched.  See
+       After  a  partial  match  (error  return PCRE2_ERROR_PARTIAL), only the
+       first pair of offsets (that is, ovector[0]  and  ovector[1])  are  set.
+       They  identify  the part of the subject that was partially matched. See
        the pcre2partial documentation for details of partial matching.
 
-       After  a  fully  successful match, the first pair of offsets identifies
-       the portion of the subject string that was matched by the  entire  pat-
-       tern.  The  next  pair is used for the first captured substring, and so
-       on. The value returned by pcre2_match() is one more  than  the  highest
-       numbered  pair  that  has been set. For example, if two substrings have
-       been captured, the returned value is 3. If there are no  captured  sub-
+       After a fully successful match, the first pair  of  offsets  identifies
+       the  portion  of the subject string that was matched by the entire pat-
+       tern. The next pair is used for the first captured  substring,  and  so
+       on.  The  value  returned by pcre2_match() is one more than the highest
+       numbered pair that has been set. For example, if  two  substrings  have
+       been  captured,  the returned value is 3. If there are no captured sub-
        strings, the return value from a successful match is 1, indicating that
        just the first pair of offsets has been set.
 
-       If a pattern uses the \K escape sequence within a  positive  assertion,
+       If  a  pattern uses the \K escape sequence within a positive assertion,
        the reported start of a successful match can be greater than the end of
-       the match.  For example, if the pattern  (?=ab\K)  is  matched  against
+       the  match.   For  example,  if the pattern (?=ab\K) is matched against
        "ab", the start and end offset values for the match are 2 and 0.
 
-       If  a  capture group is matched repeatedly within a single match opera-
+       If a capture group is matched repeatedly within a single  match  opera-
        tion, it is the last portion of the subject that it matched that is re-
        turned.
 
        If the ovector is too small to hold all the captured substring offsets,
-       as much as possible is filled in, and the function returns a  value  of
-       zero.  If captured substrings are not of interest, pcre2_match() may be
+       as  much  as possible is filled in, and the function returns a value of
+       zero. If captured substrings are not of interest, pcre2_match() may  be
        called with a match data block whose ovector is of minimum length (that
        is, one pair).
 
-       It  is  possible for capture group number n+1 to match some part of the
-       subject when group n has not been used at  all.  For  example,  if  the
+       It is possible for capture group number n+1 to match some part  of  the
+       subject  when  group  n  has  not been used at all. For example, if the
        string "abc" is matched against the pattern (a|(z))(bc) the return from
-       the function is 4, and groups 1 and 3 are matched, but 2 is  not.  When
-       this  happens,  both values in the offset pairs corresponding to unused
+       the  function  is 4, and groups 1 and 3 are matched, but 2 is not. When
+       this happens, both values in the offset pairs corresponding  to  unused
        groups are set to PCRE2_UNSET.
 
-       Offset values that correspond to unused groups at the end  of  the  ex-
-       pression  are also set to PCRE2_UNSET. For example, if the string "abc"
-       is matched against the pattern (abc)(x(yz)?)? groups 2 and  3  are  not
-       matched.  The  return  from the function is 2, because the highest used
-       capture group number is 1. The offsets for for  the  second  and  third
-       capture  groupss  (assuming  the vector is large enough, of course) are
+       Offset  values  that  correspond to unused groups at the end of the ex-
+       pression are also set to PCRE2_UNSET. For example, if the string  "abc"
+       is  matched  against  the pattern (abc)(x(yz)?)? groups 2 and 3 are not
+       matched. The return from the function is 2, because  the  highest  used
+       capture  group  number  is  1. The offsets for for the second and third
+       capture groupss (assuming the vector is large enough,  of  course)  are
        set to PCRE2_UNSET.
 
        Elements in the ovector that do not correspond to capturing parentheses
        in the pattern are never changed. That is, if a pattern contains n cap-
        turing parentheses, no more than ovector[0] to ovector[2n+1] are set by
-       pcre2_match().  The  other  elements retain whatever values they previ-
-       ously had. After a failed match attempt, the contents  of  the  ovector
+       pcre2_match(). The other elements retain whatever  values  they  previ-
+       ously  had.  After  a failed match attempt, the contents of the ovector
        are unchanged.
 
 
@@ -2808,69 +2811,69 @@ OTHER INFORMATION ABOUT A MATCH
 
        PCRE2_SIZE pcre2_get_startchar(pcre2_match_data *match_data);
 
-       As  well as the offsets in the ovector, other information about a match
-       is retained in the match data block and can be retrieved by  the  above
-       functions  in  appropriate  circumstances.  If they are called at other
+       As well as the offsets in the ovector, other information about a  match
+       is  retained  in the match data block and can be retrieved by the above
+       functions in appropriate circumstances. If they  are  called  at  other
        times, the result is undefined.
 
-       After a successful match, a partial match (PCRE2_ERROR_PARTIAL),  or  a
-       failure  to  match (PCRE2_ERROR_NOMATCH), a mark name may be available.
-       The function pcre2_get_mark() can be called to access this name,  which
-       can  be  specified  in  the  pattern by any of the backtracking control
+       After  a  successful match, a partial match (PCRE2_ERROR_PARTIAL), or a
+       failure to match (PCRE2_ERROR_NOMATCH), a mark name may  be  available.
+       The  function pcre2_get_mark() can be called to access this name, which
+       can be specified in the pattern by  any  of  the  backtracking  control
        verbs, not just (*MARK). The same function applies to all the verbs. It
        returns a pointer to the zero-terminated name, which is within the com-
        piled pattern. If no name is available, NULL is returned. The length of
-       the  name  (excluding  the terminating zero) is stored in the code unit
-       that precedes the name. You should use this length instead  of  relying
+       the name (excluding the terminating zero) is stored in  the  code  unit
+       that  precedes  the name. You should use this length instead of relying
        on the terminating zero if the name might contain a binary zero.
 
-       After  a  successful  match, the name that is returned is the last mark
+       After a successful match, the name that is returned is  the  last  mark
        name encountered on the matching path through the pattern. Instances of
-       backtracking  verbs  without  names do not count. Thus, for example, if
+       backtracking verbs without names do not count. Thus,  for  example,  if
        the matching path contains (*MARK:A)(*PRUNE), the name "A" is returned.
        After a "no match" or a partial match, the last encountered name is re-
        turned. For example, consider this pattern:
 
          ^(*MARK:A)((*MARK:B)a|b)c
 
-       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
+       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.
 
-       Warning:  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  en-
+       Warning: 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 en-
        gine. 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 pcre2_compile() or by starting
+       any  marks. You can disable the start-of-match optimizations by setting
+       the PCRE2_NO_START_OPTIMIZE option for pcre2_compile() or  by  starting
        the pattern with (*NO_START_OPT).
 
-       After a successful match, a partial match, or one of  the  invalid  UTF
-       errors  (for example, PCRE2_ERROR_UTF8_ERR5), pcre2_get_startchar() can
+       After  a  successful  match, a partial match, or one of the invalid UTF
+       errors (for example, PCRE2_ERROR_UTF8_ERR5), pcre2_get_startchar()  can
        be called. After a successful or partial match it returns the code unit
-       offset  of  the character at which the match started. For a non-partial
-       match, this can be different to the value of ovector[0] if the  pattern
-       contains  the  \K escape sequence. After a partial match, however, this
-       value is always the same as ovector[0] because \K does not  affect  the
+       offset of the character at which the match started. For  a  non-partial
+       match,  this can be different to the value of ovector[0] if the pattern
+       contains the \K escape sequence. After a partial match,  however,  this
+       value  is  always the same as ovector[0] because \K does not affect the
        result of a partial match.
 
-       After  a UTF check failure, pcre2_get_startchar() can be used to obtain
+       After a UTF check failure, pcre2_get_startchar() can be used to  obtain
        the code unit offset of the invalid UTF character. Details are given in
        the pcre2unicode page.
 
 
 ERROR RETURNS FROM pcre2_match()
 
-       If  pcre2_match() fails, it returns a negative number. This can be con-
-       verted to a text string by calling the pcre2_get_error_message()  func-
-       tion  (see  "Obtaining a textual error message" below).  Negative error
-       codes are also returned by other functions,  and  are  documented  with
-       them.  The codes are given names in the header file. If UTF checking is
+       If pcre2_match() fails, it returns a negative number. This can be  con-
+       verted  to a text string by calling the pcre2_get_error_message() func-
+       tion (see "Obtaining a textual error message" below).   Negative  error
+       codes  are  also  returned  by other functions, and are documented with
+       them. The codes are given names in the header file. If UTF checking  is
        in force and an invalid UTF subject string is detected, one of a number
-       of  UTF-specific negative error codes is returned. Details are given in
-       the pcre2unicode page. The following are the other errors that  may  be
+       of UTF-specific negative error codes is returned. Details are given  in
+       the  pcre2unicode  page. The following are the other errors that may be
        returned by pcre2_match():
 
          PCRE2_ERROR_NOMATCH
@@ -2879,20 +2882,20 @@ ERROR RETURNS FROM pcre2_match()
 
          PCRE2_ERROR_PARTIAL
 
-       The  subject  string did not match, but it did match partially. See the
+       The subject string did not match, but it did match partially.  See  the
        pcre2partial documentation for details of partial matching.
 
          PCRE2_ERROR_BADMAGIC
 
        PCRE2 stores a 4-byte "magic number" at the start of the compiled code,
-       to  catch  the case when it is passed a junk pointer. This is the error
+       to catch the case when it is passed a junk pointer. This is  the  error
        that is returned when the magic number is not present.
 
          PCRE2_ERROR_BADMODE
 
-       This error is given when a compiled pattern is passed to a function  in
-       a  library  of a different code unit width, for example, a pattern com-
-       piled by the 8-bit library is passed to  a  16-bit  or  32-bit  library
+       This  error is given when a compiled pattern is passed to a function in
+       a library of a different code unit width, for example, a  pattern  com-
+       piled  by  the  8-bit  library  is passed to a 16-bit or 32-bit library
        function.
 
          PCRE2_ERROR_BADOFFSET
@@ -2906,15 +2909,15 @@ ERROR RETURNS FROM pcre2_match()
          PCRE2_ERROR_BADUTFOFFSET
 
        The UTF code unit sequence that was passed as a subject was checked and
-       found to be valid (the PCRE2_NO_UTF_CHECK option was not set), but  the
-       value  of startoffset did not point to the beginning of a UTF character
+       found  to be valid (the PCRE2_NO_UTF_CHECK option was not set), but the
+       value of startoffset did not point to the beginning of a UTF  character
        or the end of the subject.
 
          PCRE2_ERROR_CALLOUT
 
-       This error is never generated by pcre2_match() itself. It  is  provided
-       for  use  by  callout  functions  that  want  to cause pcre2_match() or
-       pcre2_callout_enumerate() to return a distinctive error code.  See  the
+       This  error  is never generated by pcre2_match() itself. It is provided
+       for use by callout  functions  that  want  to  cause  pcre2_match()  or
+       pcre2_callout_enumerate()  to  return a distinctive error code. See the
        pcre2callout documentation for details.
 
          PCRE2_ERROR_DEPTHLIMIT
@@ -2927,14 +2930,14 @@ ERROR RETURNS FROM pcre2_match()
 
          PCRE2_ERROR_INTERNAL
 
-       An  unexpected  internal error has occurred. This error could be caused
+       An unexpected internal error has occurred. This error could  be  caused
        by a bug in PCRE2 or by overwriting of the compiled pattern.
 
          PCRE2_ERROR_JIT_STACKLIMIT
 
        This error is returned when a pattern that was successfully studied us-
        ing JIT is being matched, but the memory available for the just-in-time
-       processing stack is not large enough. See  the  pcre2jit  documentation
+       processing  stack  is  not large enough. See the pcre2jit documentation
        for more details.
 
          PCRE2_ERROR_MATCHLIMIT
@@ -2943,11 +2946,11 @@ ERROR RETURNS FROM pcre2_match()
 
          PCRE2_ERROR_NOMEMORY
 
-       If  a  pattern contains many nested backtracking points, heap memory is
-       used to remember them. This error is given when the  memory  allocation
-       function  (default  or  custom)  fails.  Note  that  a different error,
-       PCRE2_ERROR_HEAPLIMIT, is given if the amount of memory needed  exceeds
-       the    heap   limit.   PCRE2_ERROR_NOMEMORY   is   also   returned   if
+       If a pattern contains many nested backtracking points, heap  memory  is
+       used  to  remember them. This error is given when the memory allocation
+       function (default or  custom)  fails.  Note  that  a  different  error,
+       PCRE2_ERROR_HEAPLIMIT,  is given if the amount of memory needed exceeds
+       the   heap   limit.   PCRE2_ERROR_NOMEMORY   is   also   returned    if
        PCRE2_COPY_MATCHED_SUBJECT is set and memory allocation fails.
 
          PCRE2_ERROR_NULL
@@ -2956,12 +2959,12 @@ ERROR RETURNS FROM pcre2_match()
 
          PCRE2_ERROR_RECURSELOOP
 
-       This error is returned when  pcre2_match()  detects  a  recursion  loop
-       within  the  pattern. Specifically, it means that either the whole pat-
+       This  error  is  returned  when  pcre2_match() detects a recursion loop
+       within the pattern. Specifically, it means that either the  whole  pat-
        tern or a capture group has been called recursively for the second time
-       at  the  same position in the subject string. Some simple patterns that
-       might do this are detected and faulted at compile time, but  more  com-
-       plicated  cases,  in particular mutual recursions between two different
+       at the same position in the subject string. Some simple  patterns  that
+       might  do  this are detected and faulted at compile time, but more com-
+       plicated cases, in particular mutual recursions between  two  different
        groups, cannot be detected until matching is attempted.
 
 
@@ -2970,20 +2973,20 @@ OBTAINING A TEXTUAL ERROR MESSAGE
        int pcre2_get_error_message(int errorcode, PCRE2_UCHAR *buffer,
          PCRE2_SIZE bufflen);
 
-       A text message for an error code  from  any  PCRE2  function  (compile,
-       match,  or  auxiliary)  can be obtained by calling pcre2_get_error_mes-
-       sage(). The code is passed as the first argument,  with  the  remaining
-       two  arguments  specifying  a  code  unit buffer and its length in code
-       units, into which the text message is placed. The message  is  returned
-       in  code  units  of the appropriate width for the library that is being
+       A  text  message  for  an  error code from any PCRE2 function (compile,
+       match, or auxiliary) can be obtained  by  calling  pcre2_get_error_mes-
+       sage().  The  code  is passed as the first argument, with the remaining
+       two arguments specifying a code unit buffer  and  its  length  in  code
+       units,  into  which the text message is placed. The message is returned
+       in code units of the appropriate width for the library  that  is  being
        used.
 
-       The returned message is terminated with a trailing zero, and the  func-
-       tion  returns  the  number  of  code units used, excluding the trailing
+       The  returned message is terminated with a trailing zero, and the func-
+       tion returns the number of code  units  used,  excluding  the  trailing
        zero. If the error number is unknown, the negative error code PCRE2_ER-
-       ROR_BADDATA  is  returned.  If  the buffer is too small, the message is
+       ROR_BADDATA is returned. If the buffer is too  small,  the  message  is
        truncated (but still with a trailing zero), and the negative error code
-       PCRE2_ERROR_NOMEMORY  is returned.  None of the messages are very long;
+       PCRE2_ERROR_NOMEMORY is returned.  None of the messages are very  long;
        a buffer size of 120 code units is ample.
 
 
@@ -3002,39 +3005,39 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
 
        void pcre2_substring_free(PCRE2_UCHAR *buffer);
 
-       Captured substrings can be accessed directly by using  the  ovector  as
+       Captured  substrings  can  be accessed directly by using the ovector as
        described above.  For convenience, auxiliary functions are provided for
-       extracting  captured  substrings  as  new,  separate,   zero-terminated
+       extracting   captured  substrings  as  new,  separate,  zero-terminated
        strings. A substring that contains a binary zero is correctly extracted
-       and has a further zero added on the end, but  the  result  is  not,  of
+       and  has  a  further  zero  added on the end, but the result is not, of
        course, a C string.
 
        The functions in this section identify substrings by number. The number
        zero refers to the entire matched substring, with higher numbers refer-
-       ring  to  substrings  captured by parenthesized groups. After a partial
-       match, only substring zero is available.  An  attempt  to  extract  any
-       other  substring  gives the error PCRE2_ERROR_PARTIAL. The next section
+       ring to substrings captured by parenthesized groups.  After  a  partial
+       match,  only  substring  zero  is  available. An attempt to extract any
+       other substring gives the error PCRE2_ERROR_PARTIAL. The  next  section
        describes similar functions for extracting captured substrings by name.
 
-       If a pattern uses the \K escape sequence within a  positive  assertion,
+       If  a  pattern uses the \K escape sequence within a positive assertion,
        the reported start of a successful match can be greater than the end of
-       the match.  For example, if the pattern  (?=ab\K)  is  matched  against
-       "ab",  the  start  and  end offset values for the match are 2 and 0. In
-       this situation, calling these functions with a  zero  substring  number
+       the  match.   For  example,  if the pattern (?=ab\K) is matched against
+       "ab", the start and end offset values for the match are  2  and  0.  In
+       this  situation,  calling  these functions with a zero substring number
        extracts a zero-length empty string.
 
-       You  can  find the length in code units of a captured substring without
-       extracting it by calling pcre2_substring_length_bynumber().  The  first
-       argument  is a pointer to the match data block, the second is the group
-       number, and the third is a pointer to a variable into which the  length
-       is  placed.  If  you just want to know whether or not the substring has
+       You can find the length in code units of a captured  substring  without
+       extracting  it  by calling pcre2_substring_length_bynumber(). The first
+       argument is a pointer to the match data block, the second is the  group
+       number,  and the third is a pointer to a variable into which the length
+       is placed. If you just want to know whether or not  the  substring  has
        been captured, you can pass the third argument as NULL.
 
-       The pcre2_substring_copy_bynumber() function  copies  a  captured  sub-
-       string  into  a supplied buffer, whereas pcre2_substring_get_bynumber()
-       copies it into new memory, obtained using the  same  memory  allocation
-       function  that  was  used for the match data block. The first two argu-
-       ments of these functions are a pointer to the match data  block  and  a
+       The  pcre2_substring_copy_bynumber()  function  copies  a captured sub-
+       string into a supplied buffer,  whereas  pcre2_substring_get_bynumber()
+       copies  it  into  new memory, obtained using the same memory allocation
+       function that was used for the match data block. The  first  two  argu-
+       ments  of  these  functions are a pointer to the match data block and a
        capture group number.
 
        The final arguments of pcre2_substring_copy_bynumber() are a pointer to
@@ -3043,25 +3046,25 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
        for the extracted substring, excluding the terminating zero.
 
        For pcre2_substring_get_bynumber() the third and fourth arguments point
-       to  variables that are updated with a pointer to the new memory and the
-       number of code units that comprise the substring, again  excluding  the
-       terminating  zero.  When  the substring is no longer needed, the memory
+       to variables that are updated with a pointer to the new memory and  the
+       number  of  code units that comprise the substring, again excluding the
+       terminating zero. When the substring is no longer  needed,  the  memory
        should be freed by calling pcre2_substring_free().
 
-       The return value from all these functions is zero  for  success,  or  a
-       negative  error  code.  If  the pattern match failed, the match failure
-       code is returned.  If a substring number greater than zero is used  af-
-       ter  a  partial  match, PCRE2_ERROR_PARTIAL is returned. Other possible
+       The  return  value  from  all these functions is zero for success, or a
+       negative error code. If the pattern match  failed,  the  match  failure
+       code  is returned.  If a substring number greater than zero is used af-
+       ter a partial match, PCRE2_ERROR_PARTIAL is  returned.  Other  possible
        error codes are:
 
          PCRE2_ERROR_NOMEMORY
 
-       The buffer was too small for  pcre2_substring_copy_bynumber(),  or  the
+       The  buffer  was  too small for pcre2_substring_copy_bynumber(), or the
        attempt to get memory failed for pcre2_substring_get_bynumber().
 
          PCRE2_ERROR_NOSUBSTRING
 
-       There  is  no  substring  with that number in the pattern, that is, the
+       There is no substring with that number in the  pattern,  that  is,  the
        number is greater than the number of capturing parentheses.
 
          PCRE2_ERROR_UNAVAILABLE
@@ -3072,8 +3075,8 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
 
          PCRE2_ERROR_UNSET
 
-       The substring did not participate in the match.  For  example,  if  the
-       pattern  is  (abc)|(def) and the subject is "def", and the ovector con-
+       The  substring  did  not  participate in the match. For example, if the
+       pattern is (abc)|(def) and the subject is "def", and the  ovector  con-
        tains at least two capturing slots, substring number 1 is unset.
 
 
@@ -3084,31 +3087,31 @@ EXTRACTING A LIST OF ALL CAPTURED SUBSTRINGS
 
        void pcre2_substring_list_free(PCRE2_SPTR *list);
 
-       The pcre2_substring_list_get() function  extracts  all  available  sub-
-       strings  and  builds  a  list of pointers to them. It also (optionally)
-       builds a second list that contains their lengths (in code  units),  ex-
-       cluding  a  terminating zero that is added to each of them. All this is
+       The  pcre2_substring_list_get()  function  extracts  all available sub-
+       strings and builds a list of pointers to  them.  It  also  (optionally)
+       builds  a  second list that contains their lengths (in code units), ex-
+       cluding a terminating zero that is added to each of them. All  this  is
        done in a single block of memory that is obtained using the same memory
        allocation function that was used to get the match data block.
 
-       This  function  must be called only after a successful match. If called
+       This function must be called only after a successful match.  If  called
        after a partial match, the error code PCRE2_ERROR_PARTIAL is returned.
 
-       The address of the memory block is returned via listptr, which is  also
+       The  address of the memory block is returned via listptr, which is also
        the start of the list of string pointers. The end of the list is marked
-       by a NULL pointer. The address of the list of lengths is  returned  via
-       lengthsptr.  If your strings do not contain binary zeros and you do not
+       by  a  NULL pointer. The address of the list of lengths is returned via
+       lengthsptr. If your strings do not contain binary zeros and you do  not
        therefore need the lengths, you may supply NULL as the lengthsptr argu-
-       ment  to  disable  the  creation of a list of lengths. The yield of the
-       function is zero if all went well, or PCRE2_ERROR_NOMEMORY if the  mem-
-       ory  block could not be obtained. When the list is no longer needed, it
+       ment to disable the creation of a list of lengths.  The  yield  of  the
+       function  is zero if all went well, or PCRE2_ERROR_NOMEMORY if the mem-
+       ory block could not be obtained. When the list is no longer needed,  it
        should be freed by calling pcre2_substring_list_free().
 
        If this function encounters a substring that is unset, which can happen
-       when  capture  group  number  n+1 matches some part of the subject, but
-       group n has not been used at all, it returns an empty string. This  can
+       when capture group number n+1 matches some part  of  the  subject,  but
+       group  n has not been used at all, it returns an empty string. This can
        be distinguished from a genuine zero-length substring by inspecting the
-       appropriate offset in the ovector, which contain PCRE2_UNSET for  unset
+       appropriate  offset in the ovector, which contain PCRE2_UNSET for unset
        substrings, or by calling pcre2_substring_length_bynumber().
 
 
@@ -3128,7 +3131,7 @@ EXTRACTING CAPTURED SUBSTRINGS BY NAME
 
        void pcre2_substring_free(PCRE2_UCHAR *buffer);
 
-       To  extract a substring by name, you first have to find associated num-
+       To extract a substring by name, you first have to find associated  num-
        ber.  For example, for this pattern:
 
          (a+)b(?\d+)...
@@ -3136,32 +3139,32 @@ EXTRACTING CAPTURED SUBSTRINGS BY NAME
        the number of the capture group called "xxx" is 2. If the name is known
        to be unique (PCRE2_DUPNAMES was not set), you can find the number from
        the name by calling pcre2_substring_number_from_name(). The first argu-
-       ment  is the compiled pattern, and the second is the name. The yield of
-       the function is the group number, PCRE2_ERROR_NOSUBSTRING if  there  is
-       no  group  with that name, or PCRE2_ERROR_NOUNIQUESUBSTRING if there is
-       more than one group with that name.  Given the number, you can  extract
-       the  substring  directly from the ovector, or use one of the "bynumber"
+       ment is the compiled pattern, and the second is the name. The yield  of
+       the  function  is the group number, PCRE2_ERROR_NOSUBSTRING if there is
+       no group with that name, or PCRE2_ERROR_NOUNIQUESUBSTRING if  there  is
+       more  than one group with that name.  Given the number, you can extract
+       the substring directly from the ovector, or use one of  the  "bynumber"
        functions described above.
 
-       For convenience, there are also "byname" functions that  correspond  to
+       For  convenience,  there are also "byname" functions that correspond to
        the "bynumber" functions, the only difference being that the second ar-
-       gument is a name instead of a number.  If  PCRE2_DUPNAMES  is  set  and
+       gument  is  a  name  instead  of a number. If PCRE2_DUPNAMES is set and
        there are duplicate names, these functions scan all the groups with the
-       given name, and return the captured  substring  from  the  first  named
+       given  name,  and  return  the  captured substring from the first named
        group that is set.
 
-       If  there are no groups with the given name, PCRE2_ERROR_NOSUBSTRING is
-       returned. If all groups with the name have  numbers  that  are  greater
+       If there are no groups with the given name, PCRE2_ERROR_NOSUBSTRING  is
+       returned.  If  all  groups  with the name have numbers that are greater
        than the number of slots in the ovector, PCRE2_ERROR_UNAVAILABLE is re-
-       turned. If there is at least one group with a slot in the ovector,  but
+       turned.  If there is at least one group with a slot in the ovector, but
        no group is found to be set, PCRE2_ERROR_UNSET is returned.
 
        Warning: If the pattern uses the (?| feature to set up multiple capture
-       groups with the same number, as described in the section  on  duplicate
+       groups  with  the same number, as described in the section on duplicate
        group numbers in the pcre2pattern page, you cannot use names to distin-
-       guish the different capture groups, because names are not  included  in
-       the  compiled  code.  The  matching process uses only numbers. For this
-       reason, the use of different names for  groups  with  the  same  number
+       guish  the  different capture groups, because names are not included in
+       the compiled code. The matching process uses  only  numbers.  For  this
+       reason,  the  use  of  different  names for groups with the same number
        causes an error at compile time.
 
 
@@ -3174,91 +3177,91 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
          PCRE2_SIZE rlength, PCRE2_UCHAR *outputbuffer,
          PCRE2_SIZE *outlengthptr);
 
-       This  function calls pcre2_match() and then makes a copy of the subject
-       string in outputbuffer, replacing one or more parts that  were  matched
+       This function calls pcre2_match() and then makes a copy of the  subject
+       string  in  outputbuffer, replacing one or more parts that were matched
        with the replacement string, whose length is supplied in rlength.  This
-       can be given as PCRE2_ZERO_TERMINATED  for  a  zero-terminated  string.
-       The  default is to perform just one replacement, but there is an option
-       that requests multiple replacements (see PCRE2_SUBSTITUTE_GLOBAL  below
+       can  be  given  as  PCRE2_ZERO_TERMINATED for a zero-terminated string.
+       The default is to perform just one replacement, but there is an  option
+       that  requests multiple replacements (see PCRE2_SUBSTITUTE_GLOBAL below
        for details).
 
-       Matches  in  which  a  \K item in a lookahead in the pattern causes the
-       match to end before it starts are not supported, and give  rise  to  an
+       Matches in which a \K item in a lookahead in  the  pattern  causes  the
+       match  to  end  before it starts are not supported, and give rise to an
        error return. For global replacements, matches in which \K in a lookbe-
-       hind causes the match to start earlier than the point that was  reached
+       hind  causes the match to start earlier than the point that was reached
        in the previous iteration are also not supported.
 
-       The  first  seven  arguments  of pcre2_substitute() are the same as for
+       The first seven arguments of pcre2_substitute() are  the  same  as  for
        pcre2_match(), except that the partial matching options are not permit-
-       ted,  and  match_data may be passed as NULL, in which case a match data
-       block is obtained and freed within this function, using memory  manage-
-       ment  functions from the match context, if provided, or else those that
+       ted, and match_data may be passed as NULL, in which case a  match  data
+       block  is obtained and freed within this function, using memory manage-
+       ment functions from the match context, if provided, or else those  that
        were used to allocate memory for the compiled code.
 
-       If an external match_data block is provided,  its  contents  afterwards
-       are  those  set by the final call to pcre2_match(). For global changes,
-       this will have ended in a matching error. The contents of  the  ovector
+       If  an  external  match_data block is provided, its contents afterwards
+       are those set by the final call to pcre2_match(). For  global  changes,
+       this  will  have ended in a matching error. The contents of the ovector
        within the match data block may or may not have been changed.
 
-       The  outlengthptr  argument  must point to a variable that contains the
-       length, in code units, of the output buffer. If the  function  is  suc-
-       cessful,  the value is updated to contain the length of the new string,
+       The outlengthptr argument must point to a variable  that  contains  the
+       length,  in  code  units, of the output buffer. If the function is suc-
+       cessful, the value is updated to contain the length of the new  string,
        excluding the trailing zero that is automatically added.
 
-       If the function is not successful, the value set via  outlengthptr  de-
-       pends  on  the  type  of  error.  For  syntax errors in the replacement
+       If  the  function is not successful, the value set via outlengthptr de-
+       pends on the type of  error.  For  syntax  errors  in  the  replacement
        string, the value is the offset in the replacement string where the er-
-       ror  was  detected.  For  other errors, the value is PCRE2_UNSET by de-
+       ror was detected. For other errors, the value  is  PCRE2_UNSET  by  de-
        fault. This includes the case of the output buffer being too small, un-
        less PCRE2_SUBSTITUTE_OVERFLOW_LENGTH is set (see below), in which case
-       the value is the minimum length needed, including space for the  trail-
+       the  value is the minimum length needed, including space for the trail-
        ing zero. Note that in order to compute the required length, pcre2_sub-
        stitute() has to simulate all the matching and copying, instead of giv-
        ing an error return as soon as the buffer overflows. Note also that the
        length is in code units, not bytes.
 
-       In the replacement string, which is interpreted as a UTF string in  UTF
+       In  the replacement string, which is interpreted as a UTF string in UTF
        mode, and is checked for UTF validity unless the PCRE2_NO_UTF_CHECK op-
        tion is set, a dollar character is an escape character that can specify
-       the  insertion  of characters from capture groups or names from (*MARK)
-       or other control verbs in the pattern. The following forms  are  always
+       the insertion of characters from capture groups or names  from  (*MARK)
+       or  other  control verbs in the pattern. The following forms are always
        recognized:
 
          $$                  insert a dollar character
          $ or ${}      insert the contents of group 
          $*MARK or ${*MARK}  insert a control verb name
 
-       Either  a  group  number  or  a  group name can be given for . Curly
-       brackets are required only if the following character would  be  inter-
+       Either a group number or a group name  can  be  given  for  .  Curly
+       brackets  are  required only if the following character would be inter-
        preted as part of the number or name. The number may be zero to include
-       the entire matched string.   For  example,  if  the  pattern  a(b)c  is
-       matched  with "=abc=" and the replacement string "+$1$0$1+", the result
+       the  entire  matched  string.   For  example,  if  the pattern a(b)c is
+       matched with "=abc=" and the replacement string "+$1$0$1+", the  result
        is "=+babcb+=".
 
-       $*MARK inserts the name from the last encountered backtracking  control
-       verb  on the matching path that has a name. (*MARK) must always include
-       a name, but the other verbs need not.  For  example,  in  the  case  of
+       $*MARK  inserts the name from the last encountered backtracking control
+       verb on the matching path that has a name. (*MARK) must always  include
+       a  name,  but  the  other  verbs  need not. For example, in the case of
        (*MARK:A)(*PRUNE) the name inserted is "A", but for (*MARK:A)(*PRUNE:B)
-       the relevant name is "B". This facility can be used to  perform  simple
+       the  relevant  name is "B". This facility can be used to perform simple
        simultaneous substitutions, as this pcre2test example shows:
 
          /(*MARK:pear)apple|(*MARK:orange)lemon/g,replace=${*MARK}
              apple lemon
           2: pear orange
 
-       As  well as the usual options for pcre2_match(), a number of additional
+       As well as the usual options for pcre2_match(), a number of  additional
        options can be set in the options argument of pcre2_substitute().
 
        PCRE2_SUBSTITUTE_GLOBAL causes the function to iterate over the subject
-       string,  replacing every matching substring. If this option is not set,
-       only the first matching substring is replaced. The search  for  matches
-       takes  place in the original subject string (that is, previous replace-
-       ments do not affect it).  Iteration is  implemented  by  advancing  the
-       startoffset  value  for  each search, which is always passed the entire
+       string, replacing every matching substring. If this option is not  set,
+       only  the  first matching substring is replaced. The search for matches
+       takes place in the original subject string (that is, previous  replace-
+       ments  do  not  affect  it).  Iteration is implemented by advancing the
+       startoffset value for each search, which is always  passed  the  entire
        subject string. If an offset limit is set in the match context, search-
        ing stops when that limit is reached.
 
-       You  can  restrict  the effect of a global substitution to a portion of
+       You can restrict the effect of a global substitution to  a  portion  of
        the subject string by setting either or both of startoffset and an off-
        set limit. Here is a pcre2test example:
 
@@ -3266,87 +3269,87 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
          ABC ABC ABC ABC\=offset=3,offset_limit=12
           2: ABC A!C A!C ABC
 
-       When  continuing  with  global substitutions after matching a substring
+       When continuing with global substitutions after  matching  a  substring
        with zero length, an attempt to find a non-empty match at the same off-
        set is performed.  If this is not successful, the offset is advanced by
        one character except when CRLF is a valid newline sequence and the next
-       two  characters are CR, LF. In this case, the offset is advanced by two
+       two characters are CR, LF. In this case, the offset is advanced by  two
        characters.
 
-       PCRE2_SUBSTITUTE_OVERFLOW_LENGTH changes what happens when  the  output
+       PCRE2_SUBSTITUTE_OVERFLOW_LENGTH  changes  what happens when the output
        buffer is too small. The default action is to return PCRE2_ERROR_NOMEM-
-       ORY immediately. If this option  is  set,  however,  pcre2_substitute()
+       ORY  immediately.  If  this  option is set, however, pcre2_substitute()
        continues to go through the motions of matching and substituting (with-
-       out, of course, writing anything) in order to compute the size of  buf-
-       fer  that  is  needed.  This  value is passed back via the outlengthptr
-       variable, with  the  result  of  the  function  still  being  PCRE2_ER-
+       out,  of course, writing anything) in order to compute the size of buf-
+       fer that is needed. This value is  passed  back  via  the  outlengthptr
+       variable,  with  the  result  of  the  function  still  being PCRE2_ER-
        ROR_NOMEMORY.
 
-       Passing  a  buffer  size  of zero is a permitted way of finding out how
-       much memory is needed for given substitution. However, this  does  mean
+       Passing a buffer size of zero is a permitted way  of  finding  out  how
+       much  memory  is needed for given substitution. However, this does mean
        that the entire operation is carried out twice. Depending on the appli-
-       cation, it may be more efficient to allocate a large  buffer  and  free
-       the   excess   afterwards,   instead  of  using  PCRE2_SUBSTITUTE_OVER-
+       cation,  it  may  be more efficient to allocate a large buffer and free
+       the  excess  afterwards,  instead   of   using   PCRE2_SUBSTITUTE_OVER-
        FLOW_LENGTH.
 
        PCRE2_SUBSTITUTE_UNKNOWN_UNSET causes references to capture groups that
        do not appear in the pattern to be treated as unset groups. This option
-       should be used with care, because it means that a typo in a group  name
+       should  be used with care, because it means that a typo in a group name
        or number no longer causes the PCRE2_ERROR_NOSUBSTRING error.
 
        PCRE2_SUBSTITUTE_UNSET_EMPTY causes unset capture groups (including un-
-       known groups when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set) to be  treated
-       as  empty  strings  when inserted as described above. If this option is
+       known  groups when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set) to be treated
+       as empty strings when inserted as described above. If  this  option  is
        not set, an attempt to insert an unset group causes the PCRE2_ERROR_UN-
-       SET  error.  This  option  does not influence the extended substitution
+       SET error. This option does not  influence  the  extended  substitution
        syntax described below.
 
-       PCRE2_SUBSTITUTE_EXTENDED causes extra processing to be applied to  the
-       replacement  string.  Without this option, only the dollar character is
-       special, and only the group insertion forms  listed  above  are  valid.
+       PCRE2_SUBSTITUTE_EXTENDED  causes extra processing to be applied to the
+       replacement string. Without this option, only the dollar  character  is
+       special,  and  only  the  group insertion forms listed above are valid.
        When PCRE2_SUBSTITUTE_EXTENDED is set, two things change:
 
-       Firstly,  backslash in a replacement string is interpreted as an escape
+       Firstly, backslash in a replacement string is interpreted as an  escape
        character. The usual forms such as \n or \x{ddd} can be used to specify
-       particular  character codes, and backslash followed by any non-alphanu-
-       meric character quotes that character. Extended quoting  can  be  coded
+       particular character codes, and backslash followed by any  non-alphanu-
+       meric  character  quotes  that character. Extended quoting can be coded
        using \Q...\E, exactly as in pattern strings.
 
-       There  are  also four escape sequences for forcing the case of inserted
-       letters.  The insertion mechanism has three states:  no  case  forcing,
+       There are also four escape sequences for forcing the case  of  inserted
+       letters.   The  insertion  mechanism has three states: no case forcing,
        force upper case, and force lower case. The escape sequences change the
        current state: \U and \L change to upper or lower case forcing, respec-
-       tively,  and  \E (when not terminating a \Q quoted sequence) reverts to
-       no case forcing. The sequences \u and \l force the next  character  (if
-       it  is  a  letter)  to  upper or lower case, respectively, and then the
+       tively, and \E (when not terminating a \Q quoted sequence)  reverts  to
+       no  case  forcing. The sequences \u and \l force the next character (if
+       it is a letter) to upper or lower  case,  respectively,  and  then  the
        state automatically reverts to no case forcing. Case forcing applies to
-       all  inserted  characters, including those from capture groups and let-
+       all inserted  characters, including those from capture groups and  let-
        ters within \Q...\E quoted sequences.
 
        Note that case forcing sequences such as \U...\E do not nest. For exam-
-       ple,  the  result of processing "\Uaa\LBB\Ecc\E" is "AAbbcc"; the final
-       \E has no effect. Note  also  that  the  PCRE2_ALT_BSUX  and  PCRE2_EX-
+       ple, the result of processing "\Uaa\LBB\Ecc\E" is "AAbbcc";  the  final
+       \E  has  no  effect.  Note  also  that the PCRE2_ALT_BSUX and PCRE2_EX-
        TRA_ALT_BSUX options do not apply to not apply to replacement strings.
 
-       The  second  effect of setting PCRE2_SUBSTITUTE_EXTENDED is to add more
-       flexibility to capture group substitution. The  syntax  is  similar  to
+       The second effect of setting PCRE2_SUBSTITUTE_EXTENDED is to  add  more
+       flexibility  to  capture  group  substitution. The syntax is similar to
        that used by Bash:
 
          ${:-}
          ${:+:}
 
-       As  before,   may be a group number or a name. The first form speci-
-       fies a default value. If group  is set, its value  is  inserted;  if
-       not,    is  expanded  and  the result inserted. The second form
-       specifies strings that are expanded and inserted when group  is  set
-       or  unset,  respectively. The first form is just a convenient shorthand
+       As before,  may be a group number or a name. The first  form  speci-
+       fies  a  default  value. If group  is set, its value is inserted; if
+       not,  is expanded and the  result  inserted.  The  second  form
+       specifies  strings that are expanded and inserted when group  is set
+       or unset, respectively. The first form is just a  convenient  shorthand
        for
 
          ${:+${}:}
 
-       Backslash can be used to escape colons and closing  curly  brackets  in
-       the  replacement  strings.  A change of the case forcing state within a
-       replacement string remains  in  force  afterwards,  as  shown  in  this
+       Backslash  can  be  used to escape colons and closing curly brackets in
+       the replacement strings. A change of the case forcing  state  within  a
+       replacement  string  remains  in  force  afterwards,  as  shown in this
        pcre2test example:
 
          /(some)?(body)/substitute_extended,replace=${1:+\U:\L}HeLLo
@@ -3355,42 +3358,42 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
              somebody
           1: HELLO
 
-       The  PCRE2_SUBSTITUTE_UNSET_EMPTY option does not affect these extended
-       substitutions. However, PCRE2_SUBSTITUTE_UNKNOWN_UNSET does  cause  un-
+       The PCRE2_SUBSTITUTE_UNSET_EMPTY option does not affect these  extended
+       substitutions.  However,  PCRE2_SUBSTITUTE_UNKNOWN_UNSET does cause un-
        known groups in the extended syntax forms to be treated as unset.
 
-       If  successful,  pcre2_substitute()  returns  the  number of successful
-       matches. This may be zero if  no  matches  were  found,  and  is  never
+       If successful, pcre2_substitute()  returns  the  number  of  successful
+       matches.  This  may  be  zero  if  no  matches were found, and is never
        greater than 1 unless PCRE2_SUBSTITUTE_GLOBAL is set.
 
        In the event of an error, a negative error code is returned. Except for
-       PCRE2_ERROR_NOMATCH   (which   is   never   returned),   errors    from
+       PCRE2_ERROR_NOMATCH    (which   is   never   returned),   errors   from
        pcre2_match() are passed straight back.
 
        PCRE2_ERROR_NOSUBSTRING is returned for a non-existent substring inser-
        tion, unless PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set.
 
        PCRE2_ERROR_UNSET is returned for an unset substring insertion (includ-
-       ing  an  unknown  substring when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set)
-       when the simple (non-extended) syntax is used and  PCRE2_SUBSTITUTE_UN-
+       ing an unknown substring when  PCRE2_SUBSTITUTE_UNKNOWN_UNSET  is  set)
+       when  the simple (non-extended) syntax is used and PCRE2_SUBSTITUTE_UN-
        SET_EMPTY is not set.
 
-       PCRE2_ERROR_NOMEMORY  is  returned  if  the  output  buffer  is not big
+       PCRE2_ERROR_NOMEMORY is returned  if  the  output  buffer  is  not  big
        enough. If the PCRE2_SUBSTITUTE_OVERFLOW_LENGTH option is set, the size
-       of  buffer  that is needed is returned via outlengthptr. Note that this
+       of buffer that is needed is returned via outlengthptr. Note  that  this
        does not happen by default.
 
-       PCRE2_ERROR_BADREPLACEMENT is used for miscellaneous syntax  errors  in
-       the  replacement  string,  with  more particular errors being PCRE2_ER-
+       PCRE2_ERROR_BADREPLACEMENT  is  used for miscellaneous syntax errors in
+       the replacement string, with more  particular  errors  being  PCRE2_ER-
        ROR_BADREPESCAPE (invalid escape sequence), PCRE2_ERROR_REPMISSINGBRACE
-       (closing  curly bracket not found), PCRE2_ERROR_BADSUBSTITUTION (syntax
-       error in extended group substitution),  and  PCRE2_ERROR_BADSUBSPATTERN
+       (closing curly bracket not found), PCRE2_ERROR_BADSUBSTITUTION  (syntax
+       error  in  extended group substitution), and PCRE2_ERROR_BADSUBSPATTERN
        (the pattern match ended before it started or the match started earlier
-       than the current position in the subject, which can  happen  if  \K  is
+       than  the  current  position  in the subject, which can happen if \K is
        used in an assertion).
 
        As for all PCRE2 errors, a text message that describes the error can be
-       obtained by calling the pcre2_get_error_message()  function  (see  "Ob-
+       obtained  by  calling  the pcre2_get_error_message() function (see "Ob-
        taining a textual error message" above).
 
    Substitution callouts
@@ -3399,15 +3402,15 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
          int (*callout_function)(pcre2_substitute_callout_block *, void *),
          void *callout_data);
 
-       The  pcre2_set_substitution_callout() function can be used to specify a
-       callout function for pcre2_substitute(). This information is passed  in
+       The pcre2_set_substitution_callout() function can be used to specify  a
+       callout  function for pcre2_substitute(). This information is passed in
        a match context. The callout function is called after each substitution
        has been processed, but it can cause the replacement not to happen. The
-       callout  function is not called for simulated substitutions that happen
+       callout function is not called for simulated substitutions that  happen
        as a result of the PCRE2_SUBSTITUTE_OVERFLOW_LENGTH option.
 
        The first argument of the callout function is a pointer to a substitute
-       callout  block structure, which contains the following fields, not nec-
+       callout block structure, which contains the following fields, not  nec-
        essarily in this order:
 
          uint32_t    version;
@@ -3418,34 +3421,34 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
          uint32_t    oveccount;
          PCRE2_SIZE  output_offsets[2];
 
-       The version field contains the version number of the block format.  The
-       current  version  is  0.  The version number will increase in future if
-       more fields are added, but the intention is never to remove any of  the
+       The  version field contains the version number of the block format. The
+       current version is 0. The version number will  increase  in  future  if
+       more  fields are added, but the intention is never to remove any of the
        existing fields.
 
        The subscount field is the number of the current match. It is 1 for the
        first callout, 2 for the second, and so on. The input and output point-
        ers are copies of the values passed to pcre2_substitute().
 
-       The  ovector  field points to the ovector, which contains the result of
+       The ovector field points to the ovector, which contains the  result  of
        the most recent match. The oveccount field contains the number of pairs
        that are set in the ovector, and is always greater than zero.
 
-       The  output_offsets  vector  contains the offsets of the replacement in
-       the output string. This has already been processed for dollar  and  (if
+       The output_offsets vector contains the offsets of  the  replacement  in
+       the  output  string. This has already been processed for dollar and (if
        requested) backslash substitutions as described above.
 
-       The  second  argument  of  the  callout function is the value passed as
-       callout_data when the function was registered. The  value  returned  by
+       The second argument of the callout function  is  the  value  passed  as
+       callout_data  when  the  function was registered. The value returned by
        the callout function is interpreted as follows:
 
-       If  the  value is zero, the replacement is accepted, and, if PCRE2_SUB-
-       STITUTE_GLOBAL is set, processing continues with a search for the  next
-       match.  If  the  value  is not zero, the current replacement is not ac-
-       cepted. If the value is greater than zero,  processing  continues  when
-       PCRE2_SUBSTITUTE_GLOBAL  is set. Otherwise (the value is less than zero
-       or PCRE2_SUBSTITUTE_GLOBAL is not set), the the rest of  the  input  is
-       copied  to the output and the call to pcre2_substitute() exits, return-
+       If the value is zero, the replacement is accepted, and,  if  PCRE2_SUB-
+       STITUTE_GLOBAL  is set, processing continues with a search for the next
+       match. If the value is not zero, the current  replacement  is  not  ac-
+       cepted.  If  the  value is greater than zero, processing continues when
+       PCRE2_SUBSTITUTE_GLOBAL is set. Otherwise (the value is less than  zero
+       or  PCRE2_SUBSTITUTE_GLOBAL  is  not set), the the rest of the input is
+       copied to the output and the call to pcre2_substitute() exits,  return-
        ing the number of matches so far.
 
 
@@ -3454,56 +3457,56 @@ DUPLICATE CAPTURE GROUP NAMES
        int pcre2_substring_nametable_scan(const pcre2_code *code,
          PCRE2_SPTR name, PCRE2_SPTR *first, PCRE2_SPTR *last);
 
-       When a pattern is compiled with the PCRE2_DUPNAMES  option,  names  for
-       capture  groups  are not required to be unique. Duplicate names are al-
-       ways allowed for groups with the same number, created by using the  (?|
+       When  a  pattern  is compiled with the PCRE2_DUPNAMES option, names for
+       capture groups are not required to be unique. Duplicate names  are  al-
+       ways  allowed for groups with the same number, created by using the (?|
        feature. Indeed, if such groups are named, they are required to use the
        same names.
 
-       Normally, patterns that use duplicate names are such that  in  any  one
-       match,  only  one of each set of identically-named groups participates.
+       Normally,  patterns  that  use duplicate names are such that in any one
+       match, only one of each set of identically-named  groups  participates.
        An example is shown in the pcre2pattern documentation.
 
-       When  duplicates   are   present,   pcre2_substring_copy_byname()   and
-       pcre2_substring_get_byname()  return  the first substring corresponding
-       to the given name that is set. Only if none are set is  PCRE2_ERROR_UN-
-       SET  is  returned.  The pcre2_substring_number_from_name() function re-
-       turns the error PCRE2_ERROR_NOUNIQUESUBSTRING when there are  duplicate
+       When   duplicates   are   present,   pcre2_substring_copy_byname()  and
+       pcre2_substring_get_byname() return the first  substring  corresponding
+       to  the given name that is set. Only if none are set is PCRE2_ERROR_UN-
+       SET is returned. The  pcre2_substring_number_from_name()  function  re-
+       turns  the error PCRE2_ERROR_NOUNIQUESUBSTRING when there are duplicate
        names.
 
-       If  you want to get full details of all captured substrings for a given
-       name, you must use the pcre2_substring_nametable_scan()  function.  The
-       first  argument is the compiled pattern, and the second is the name. If
-       the third and fourth arguments are NULL, the function returns  a  group
+       If you want to get full details of all captured substrings for a  given
+       name,  you  must use the pcre2_substring_nametable_scan() function. The
+       first argument is the compiled pattern, and the second is the name.  If
+       the  third  and fourth arguments are NULL, the function returns a group
        number for a unique name, or PCRE2_ERROR_NOUNIQUESUBSTRING otherwise.
 
        When the third and fourth arguments are not NULL, they must be pointers
-       to variables that are updated by the function. After it has  run,  they
+       to  variables  that are updated by the function. After it has run, they
        point to the first and last entries in the name-to-number table for the
-       given name, and the function returns the length of each entry  in  code
-       units.  In both cases, PCRE2_ERROR_NOSUBSTRING is returned if there are
+       given  name,  and the function returns the length of each entry in code
+       units. In both cases, PCRE2_ERROR_NOSUBSTRING is returned if there  are
        no entries for the given name.
 
        The format of the name table is described above in the section entitled
-       Information  about  a  pattern.  Given all the relevant entries for the
-       name, you can extract each of their numbers,  and  hence  the  captured
+       Information about a pattern. Given all the  relevant  entries  for  the
+       name,  you  can  extract  each of their numbers, and hence the captured
        data.
 
 
 FINDING ALL POSSIBLE MATCHES AT ONE POSITION
 
-       The  traditional  matching  function  uses a similar algorithm to Perl,
-       which stops when it finds the first match at a given point in the  sub-
+       The traditional matching function uses a  similar  algorithm  to  Perl,
+       which  stops when it finds the first match at a given point in the sub-
        ject. If you want to find all possible matches, or the longest possible
-       match at a given position,  consider  using  the  alternative  matching
-       function  (see  below) instead. If you cannot use the alternative func-
+       match  at  a  given  position,  consider using the alternative matching
+       function (see below) instead. If you cannot use the  alternative  func-
        tion, you can kludge it up by making use of the callout facility, which
        is described in the pcre2callout documentation.
 
        What you have to do is to insert a callout right at the end of the pat-
-       tern.  When your callout function is called, extract and save the  cur-
-       rent  matched  substring.  Then return 1, which forces pcre2_match() to
-       backtrack and try other alternatives. Ultimately, when it runs  out  of
+       tern.   When your callout function is called, extract and save the cur-
+       rent matched substring. Then return 1, which  forces  pcre2_match()  to
+       backtrack  and  try other alternatives. Ultimately, when it runs out of
        matches, pcre2_match() will yield PCRE2_ERROR_NOMATCH.
 
 
@@ -3515,26 +3518,26 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
          pcre2_match_context *mcontext,
          int *workspace, PCRE2_SIZE wscount);
 
-       The  function  pcre2_dfa_match()  is  called  to match a subject string
-       against a compiled pattern, using a matching algorithm that  scans  the
+       The function pcre2_dfa_match() is called  to  match  a  subject  string
+       against  a  compiled pattern, using a matching algorithm that scans the
        subject string just once (not counting lookaround assertions), and does
-       not backtrack.  This has different characteristics to the normal  algo-
-       rithm,  and  is not compatible with Perl. Some of the features of PCRE2
-       patterns are not supported.  Nevertheless, there are  times  when  this
-       kind  of  matching  can be useful. For a discussion of the two matching
+       not  backtrack.  This has different characteristics to the normal algo-
+       rithm, and is not compatible with Perl. Some of the features  of  PCRE2
+       patterns  are  not  supported.  Nevertheless, there are times when this
+       kind of matching can be useful. For a discussion of  the  two  matching
        algorithms, and a list of features that pcre2_dfa_match() does not sup-
        port, see the pcre2matching documentation.
 
-       The  arguments  for  the pcre2_dfa_match() function are the same as for
+       The arguments for the pcre2_dfa_match() function are the  same  as  for
        pcre2_match(), plus two extras. The ovector within the match data block
        is used in a different way, and this is described below. The other com-
-       mon arguments are used in the same way as for pcre2_match(),  so  their
+       mon  arguments  are used in the same way as for pcre2_match(), so their
        description is not repeated here.
 
-       The  two  additional  arguments provide workspace for the function. The
-       workspace vector should contain at least 20 elements. It  is  used  for
+       The two additional arguments provide workspace for  the  function.  The
+       workspace  vector  should  contain at least 20 elements. It is used for
        keeping  track  of  multiple  paths  through  the  pattern  tree.  More
-       workspace is needed for patterns and subjects where there are a lot  of
+       workspace  is needed for patterns and subjects where there are a lot of
        potential matches.
 
        Here is an example of a simple call to pcre2_dfa_match():
@@ -3554,45 +3557,45 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
 
    Option bits for pcre_dfa_match()
 
-       The  unused  bits of the options argument for pcre2_dfa_match() must be
-       zero.  The  only   bits   that   may   be   set   are   PCRE2_ANCHORED,
-       PCRE2_COPY_MATCHED_SUBJECT,  PCRE2_ENDANCHORED, PCRE2_NOTBOL, PCRE2_NO-
+       The unused bits of the options argument for pcre2_dfa_match()  must  be
+       zero.   The   only   bits   that   may   be   set  are  PCRE2_ANCHORED,
+       PCRE2_COPY_MATCHED_SUBJECT, PCRE2_ENDANCHORED, PCRE2_NOTBOL,  PCRE2_NO-
        TEOL,   PCRE2_NOTEMPTY,   PCRE2_NOTEMPTY_ATSTART,   PCRE2_NO_UTF_CHECK,
-       PCRE2_PARTIAL_HARD,    PCRE2_PARTIAL_SOFT,    PCRE2_DFA_SHORTEST,   and
-       PCRE2_DFA_RESTART. All but the last four of these are exactly the  same
+       PCRE2_PARTIAL_HARD,   PCRE2_PARTIAL_SOFT,    PCRE2_DFA_SHORTEST,    and
+       PCRE2_DFA_RESTART.  All but the last four of these are exactly the same
        as for pcre2_match(), so their description is not repeated here.
 
          PCRE2_PARTIAL_HARD
          PCRE2_PARTIAL_SOFT
 
-       These  have  the  same general effect as they do for pcre2_match(), but
-       the details are slightly different. When PCRE2_PARTIAL_HARD is set  for
-       pcre2_dfa_match(),  it  returns  PCRE2_ERROR_PARTIAL  if the end of the
+       These have the same general effect as they do  for  pcre2_match(),  but
+       the  details are slightly different. When PCRE2_PARTIAL_HARD is set for
+       pcre2_dfa_match(), it returns PCRE2_ERROR_PARTIAL if  the  end  of  the
        subject is reached and there is still at least one matching possibility
        that requires additional characters. This happens even if some complete
-       matches have already been found. When PCRE2_PARTIAL_SOFT  is  set,  the
-       return  code  PCRE2_ERROR_NOMATCH is converted into PCRE2_ERROR_PARTIAL
-       if the end of the subject is  reached,  there  have  been  no  complete
+       matches  have  already  been found. When PCRE2_PARTIAL_SOFT is set, the
+       return code PCRE2_ERROR_NOMATCH is converted  into  PCRE2_ERROR_PARTIAL
+       if  the  end  of  the  subject  is reached, there have been no complete
        matches, but there is still at least one matching possibility. The por-
-       tion of the string that was inspected when the  longest  partial  match
+       tion  of  the  string that was inspected when the longest partial match
        was found is set as the first matching string in both cases. There is a
-       more detailed discussion of partial and  multi-segment  matching,  with
+       more  detailed  discussion  of partial and multi-segment matching, with
        examples, in the pcre2partial documentation.
 
          PCRE2_DFA_SHORTEST
 
-       Setting  the PCRE2_DFA_SHORTEST option causes the matching algorithm to
+       Setting the PCRE2_DFA_SHORTEST option causes the matching algorithm  to
        stop as soon as it has found one match. Because of the way the alterna-
-       tive  algorithm  works, this is necessarily the shortest possible match
+       tive algorithm works, this is necessarily the shortest  possible  match
        at the first possible matching point in the subject string.
 
          PCRE2_DFA_RESTART
 
-       When pcre2_dfa_match() returns a partial match, it is possible to  call
+       When  pcre2_dfa_match() returns a partial match, it is possible to call
        it again, with additional subject characters, and have it continue with
        the same match. The PCRE2_DFA_RESTART option requests this action; when
-       it  is  set,  the workspace and wscount options must reference the same
-       vector as before because data about the match so far is  left  in  them
+       it is set, the workspace and wscount options must  reference  the  same
+       vector  as  before  because data about the match so far is left in them
        after a partial match. There is more discussion of this facility in the
        pcre2partial documentation.
 
@@ -3600,8 +3603,8 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
 
        When pcre2_dfa_match() succeeds, it may have matched more than one sub-
        string in the subject. Note, however, that all the matches from one run
-       of the function start at the same point in  the  subject.  The  shorter
-       matches  are all initial substrings of the longer matches. For example,
+       of  the  function  start  at the same point in the subject. The shorter
+       matches are all initial substrings of the longer matches. For  example,
        if the pattern
 
          <.*>
@@ -3616,80 +3619,80 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
           
          
 
-       On success, the yield of the function is a number  greater  than  zero,
-       which  is  the  number  of  matched substrings. The offsets of the sub-
-       strings are returned in the ovector, and can be extracted by number  in
-       the  same way as for pcre2_match(), but the numbers bear no relation to
-       any capture groups that may exist in the pattern, because DFA  matching
+       On  success,  the  yield of the function is a number greater than zero,
+       which is the number of matched substrings.  The  offsets  of  the  sub-
+       strings  are returned in the ovector, and can be extracted by number in
+       the same way as for pcre2_match(), but the numbers bear no relation  to
+       any  capture groups that may exist in the pattern, because DFA matching
        does not support capturing.
 
-       Calls  to the convenience functions that extract substrings by name re-
+       Calls to the convenience functions that extract substrings by name  re-
        turn the error PCRE2_ERROR_DFA_UFUNC (unsupported function) if used af-
-       ter  a  DFA match. The convenience functions that extract substrings by
+       ter a DFA match. The convenience functions that extract  substrings  by
        number never return PCRE2_ERROR_NOSUBSTRING.
 
-       The matched strings are stored in  the  ovector  in  reverse  order  of
-       length;  that  is,  the longest matching string is first. If there were
-       too many matches to fit into the ovector, the yield of the function  is
+       The  matched  strings  are  stored  in  the ovector in reverse order of
+       length; that is, the longest matching string is first.  If  there  were
+       too  many matches to fit into the ovector, the yield of the function is
        zero, and the vector is filled with the longest matches.
 
-       NOTE:  PCRE2's  "auto-possessification" optimization usually applies to
-       character repeats at the end of a pattern (as well as internally).  For
-       example,  the pattern "a\d+" is compiled as if it were "a\d++". For DFA
-       matching, this means that only one possible match is found. If you  re-
+       NOTE: PCRE2's "auto-possessification" optimization usually  applies  to
+       character  repeats at the end of a pattern (as well as internally). For
+       example, the pattern "a\d+" is compiled as if it were "a\d++". For  DFA
+       matching,  this means that only one possible match is found. If you re-
        ally do want multiple matches in such cases, either use an ungreedy re-
-       peat such as "a\d+?" or set the PCRE2_NO_AUTO_POSSESS option when  com-
+       peat  such as "a\d+?" or set the PCRE2_NO_AUTO_POSSESS option when com-
        piling.
 
    Error returns from pcre2_dfa_match()
 
        The pcre2_dfa_match() function returns a negative number when it fails.
-       Many of the errors are the same  as  for  pcre2_match(),  as  described
+       Many  of  the  errors  are  the same as for pcre2_match(), as described
        above.  There are in addition the following errors that are specific to
        pcre2_dfa_match():
 
          PCRE2_ERROR_DFA_UITEM
 
-       This return is given if pcre2_dfa_match() encounters  an  item  in  the
-       pattern  that it does not support, for instance, the use of \C in a UTF
+       This  return  is  given  if pcre2_dfa_match() encounters an item in the
+       pattern that it does not support, for instance, the use of \C in a  UTF
        mode or a backreference.
 
          PCRE2_ERROR_DFA_UCOND
 
-       This return is given if pcre2_dfa_match() encounters a  condition  item
+       This  return  is given if pcre2_dfa_match() encounters a condition item
        that uses a backreference for the condition, or a test for recursion in
        a specific capture group. These are not supported.
 
          PCRE2_ERROR_DFA_UINVALID_UTF
 
-       This return is given if pcre2_dfa_match() is called for a pattern  that
-       was  compiled  with  PCRE2_MATCH_INVALID_UTF. This is not supported for
+       This  return is given if pcre2_dfa_match() is called for a pattern that
+       was compiled with PCRE2_MATCH_INVALID_UTF. This is  not  supported  for
        DFA matching.
 
          PCRE2_ERROR_DFA_WSSIZE
 
-       This return is given if pcre2_dfa_match() runs  out  of  space  in  the
+       This  return  is  given  if  pcre2_dfa_match() runs out of space in the
        workspace vector.
 
          PCRE2_ERROR_DFA_RECURSE
 
        When a recursion or subroutine call is processed, the matching function
-       calls itself recursively, using private  memory  for  the  ovector  and
-       workspace.   This  error  is given if the internal ovector is not large
-       enough. This should be extremely rare, as a  vector  of  size  1000  is
+       calls  itself  recursively,  using  private  memory for the ovector and
+       workspace.  This error is given if the internal ovector  is  not  large
+       enough.  This  should  be  extremely  rare, as a vector of size 1000 is
        used.
 
          PCRE2_ERROR_DFA_BADRESTART
 
-       When  pcre2_dfa_match()  is  called  with the PCRE2_DFA_RESTART option,
-       some plausibility checks are made on the  contents  of  the  workspace,
-       which  should  contain data about the previous partial match. If any of
+       When pcre2_dfa_match() is called  with  the  PCRE2_DFA_RESTART  option,
+       some  plausibility  checks  are  made on the contents of the workspace,
+       which should contain data about the previous partial match. If  any  of
        these checks fail, this error is given.
 
 
 SEE ALSO
 
-       pcre2build(3),   pcre2callout(3),    pcre2demo(3),    pcre2matching(3),
+       pcre2build(3),    pcre2callout(3),    pcre2demo(3),   pcre2matching(3),
        pcre2partial(3), pcre2posix(3), pcre2sample(3), pcre2unicode(3).
 
 
@@ -3702,7 +3705,7 @@ AUTHOR
 
 REVISION
 
-       Last updated: 25 June 2019
+       Last updated: 20 July 2019
        Copyright (c) 1997-2019 University of Cambridge.
 ------------------------------------------------------------------------------
  
@@ -5665,7 +5668,7 @@ PARTIAL MATCHING IN PCRE2
        feedback  is  likely to be a better user interface than a check that is
        delayed until the entire string has been entered. Partial matching  can
        also  be  useful  when  the  subject string is very long and is not all
-       available at once.
+       available at once, as discussed below.
 
        PCRE2 supports partial matching by means of the PCRE2_PARTIAL_SOFT  and
        PCRE2_PARTIAL_HARD  options,  which  can be set when calling a matching
@@ -5698,14 +5701,18 @@ PARTIAL MATCHING USING pcre2_match()
 
        A  partial  match occurs during a call to pcre2_match() when the end of
        the subject string is reached successfully, but  matching  cannot  con-
-       tinue because more characters are needed. However, at least one charac-
-       ter in the subject must have been inspected. This  character  need  not
-       form part of the final matched string; lookbehind assertions and the \K
-       escape sequence provide ways of inspecting characters before the  start
-       of  a matched string. The requirement for inspecting at least one char-
-       acter exists because an empty string can  always  be  matched;  without
-       such  a  restriction  there would always be a partial match of an empty
-       string at the end of the subject.
+       tinue  because  more  characters are needed, and in addition, either at
+       least one character in the subject has been inspected  or  the  pattern
+       contains a lookbehind. An inspected character need not form part of the
+       final matched string; lookbehind assertions and the \K escape  sequence
+       provide  ways  of  inspecting  characters before the start of a matched
+       string.
+
+       The two additional requirements define  the  cases  where  adding  more
+       characters  to  the  existing  subject  may complete the match. Without
+       these conditions there would be a partial match of an empty  string  at
+       the  end  of  the subject for all unanchored patterns (and also for an-
+       chored patterns if the subject itself is empty).
 
        When a partial match is returned, the first two elements in the ovector
        point to the portion of the subject that was matched, but the values in
@@ -5722,7 +5729,7 @@ PARTIAL MATCHING USING pcre2_match()
        quent re-match with additional characters.
 
        What happens when a partial match is identified depends on which of the
-       two partial matching options are set.
+       two partial matching options is set.
 
    PCRE2_PARTIAL_SOFT WITH pcre2_match()
 
@@ -5759,8 +5766,8 @@ PARTIAL MATCHING USING pcre2_match()
        reason,  the  assumption  is  made that the end of the supplied subject
        string may not be the true end of the available data, and  so,  if  \z,
        \Z,  \b, \B, or $ are encountered at the end of the subject, the result
-       is PCRE2_ERROR_PARTIAL, provided that at least  one  character  in  the
-       subject has been inspected.
+       is PCRE2_ERROR_PARTIAL, whether or not any  characters  have  been  in-
+       spected.
 
    Comparing hard and soft partial matching
 
@@ -5963,43 +5970,25 @@ ISSUES WITH MULTI-SEGMENT MATCHING
        mum  lookbehind  count  is  3, so all characters before offset 2 can be
        discarded. The value of startoffset for the next  match  should  be  3.
        When  pcre2test  displays  a partial match, it indicates the lookbehind
-       characters with '<' characters:
+       characters with '<' characters if the "allusedtext" modifier is set:
 
            re> "(?<=123)abc"
-         data> xx123ab\=ph
+         data> xx123ab\=ph,allusedtext
          Partial match: 123ab
-                        <<<
+                        <<< However, the "allusedtext" modifier is not  avail-
+       able for JIT matching, because JIT matching does not maintain the first
+       and last consulted characters.
 
-       3. The maximum lookbehind count is also important when the result of  a
-       partial  match attempt is "no match". In this case, the maximum lookbe-
-       hind characters from the end of the current segment must be retained at
-       the  start  of the next segment, in case the lookbehind is at the start
-       of the pattern. Matching the next segment must then start at the appro-
-       priate offset.
-
-       4.  Because a partial match must always contain at least one character,
-       what might be considered a partial match of an  empty  string  actually
-       gives a "no match" result. For example:
-
-           re> /c(?<=abc)x/
-         data> ab\=ps
-         No match
-
-       If the next segment begins "cx", a match should be found, but this will
-       only happen if characters from the previous segment are  retained.  For
-       this  reason,  a  "no  match"  result should be interpreted as "partial
-       match of an empty string" when the pattern contains lookbehinds.
-
-       5. Matching a subject string that is split into multiple  segments  may
+       3. Matching a subject string that is split into multiple  segments  may
        not  always produce exactly the same result as matching over one single
-       long string, especially when PCRE2_PARTIAL_SOFT is  used.  The  section
-       "Partial  Matching  and  Word Boundaries" above describes an issue that
-       arises if the pattern ends with \b or \B. Another  kind  of  difference
-       may  occur when there are multiple matching possibilities, because (for
-       PCRE2_PARTIAL_SOFT) a partial match result is given only when there are
-       no completed matches. This means that as soon as the shortest match has
-       been found, continuation to a new subject segment is no  longer  possi-
-       ble. Consider this pcre2test example:
+       long string when  PCRE2_PARTIAL_SOFT  is  used.  The  section  "Partial
+       Matching  and  Word Boundaries" above describes an issue that arises if
+       the pattern ends with \b or \B. Another kind of  difference  may  occur
+       when there are multiple matching possibilities, because (for PCRE2_PAR-
+       TIAL_SOFT) a partial match result is given only when there are no  com-
+       pleted  matches. This means that as soon as the shortest match has been
+       found, continuation to a new subject segment  is  no  longer  possible.
+       Consider this pcre2test example:
 
            re> /dog(sbody)?/
          data> dogsb\=ps
@@ -6034,7 +6023,7 @@ ISSUES WITH MULTI-SEGMENT MATCHING
          data> gsb\=ph,dfa,dfa_restart
          Partial match: gsb
 
-       6. Patterns that contain alternatives at the top level which do not all
+       4. Patterns that contain alternatives at the top level which do not all
        start with the  same  pattern  item  may  not  work  as  expected  when
        PCRE2_DFA_RESTART is used. For example, consider this pattern:
 
@@ -6079,7 +6068,7 @@ AUTHOR
 
 REVISION
 
-       Last updated: 21 June 2019
+       Last updated: 21 July 2019
        Copyright (c) 1997-2019 University of Cambridge.
 ------------------------------------------------------------------------------
  
diff --git a/doc/pcre2api.3 b/doc/pcre2api.3
index 633e648..82d8564 100644
--- a/doc/pcre2api.3
+++ b/doc/pcre2api.3
@@ -1,4 +1,4 @@
-.TH PCRE2API 3 "25 June 2019" "PCRE2 10.34"
+.TH PCRE2API 3 "20 July 2019" "PCRE2 10.34"
 .SH NAME
 PCRE2 - Perl-compatible regular expressions (revised API)
 .sp
@@ -2719,12 +2719,15 @@ Your program may crash or loop indefinitely or give wrong results.
 .sp
 These options turn on the partial matching feature. A partial match occurs if
 the end of the subject string is reached successfully, but there are not enough
-subject characters to complete the match. If this happens when
-PCRE2_PARTIAL_SOFT (but not PCRE2_PARTIAL_HARD) is set, matching continues by
-testing any remaining alternatives. Only if no complete match can be found is
-PCRE2_ERROR_PARTIAL returned instead of PCRE2_ERROR_NOMATCH. In other words,
-PCRE2_PARTIAL_SOFT specifies that the caller is prepared to handle a partial
-match, but only if no complete match can be found.
+subject characters to complete the match. In addition, either at least one 
+character must have been inspected or the pattern must contain a lookbehind.
+.P
+If this situation arises when PCRE2_PARTIAL_SOFT (but not PCRE2_PARTIAL_HARD)
+is set, matching continues by testing any remaining alternatives. Only if no
+complete match can be found is PCRE2_ERROR_PARTIAL returned instead of
+PCRE2_ERROR_NOMATCH. In other words, PCRE2_PARTIAL_SOFT specifies that the
+caller is prepared to handle a partial match, but only if no complete match can
+be found.
 .P
 If PCRE2_PARTIAL_HARD is set, it overrides PCRE2_PARTIAL_SOFT. In this case, if
 a partial match is found, \fBpcre2_match()\fP immediately returns
@@ -3859,6 +3862,6 @@ Cambridge, England.
 .rs
 .sp
 .nf
-Last updated: 25 June 2019
+Last updated: 20 July 2019
 Copyright (c) 1997-2019 University of Cambridge.
 .fi
diff --git a/doc/pcre2partial.3 b/doc/pcre2partial.3
index 7b3bf24..7af75e2 100644
--- a/doc/pcre2partial.3
+++ b/doc/pcre2partial.3
@@ -1,4 +1,4 @@
-.TH PCRE2PARTIAL 3 "21 June 2019" "PCRE2 10.34"
+.TH PCRE2PARTIAL 3 "21 July 2019" "PCRE2 10.34"
 .SH NAME
 PCRE2 - Perl-compatible regular expressions
 .SH "PARTIAL MATCHING IN PCRE2"
@@ -22,7 +22,7 @@ as soon as a mistake is made, by beeping and not reflecting the character that
 has been typed, for example. This immediate feedback is likely to be a better
 user interface than a check that is delayed until the entire string has been
 entered. Partial matching can also be useful when the subject string is very
-long and is not all available at once.
+long and is not all available at once, as discussed below.
 .P
 PCRE2 supports partial matching by means of the PCRE2_PARTIAL_SOFT and
 PCRE2_PARTIAL_HARD options, which can be set when calling a matching function.
@@ -55,13 +55,17 @@ is also disabled for partial matching.
 .sp
 A partial match occurs during a call to \fBpcre2_match()\fP when the end of the
 subject string is reached successfully, but matching cannot continue because
-more characters are needed. However, at least one character in the subject must
-have been inspected. This character need not form part of the final matched
-string; lookbehind assertions and the \eK escape sequence provide ways of
-inspecting characters before the start of a matched string. The requirement for
-inspecting at least one character exists because an empty string can always be
-matched; without such a restriction there would always be a partial match of an
-empty string at the end of the subject.
+more characters are needed, and in addition, either at least one character in
+the subject has been inspected or the pattern contains a lookbehind. An
+inspected character need not form part of the final matched string; lookbehind
+assertions and the \eK escape sequence provide ways of inspecting characters
+before the start of a matched string.
+.P
+The two additional requirements define the cases where adding more characters
+to the existing subject may complete the match. Without these conditions there
+would be a partial match of an empty string at the end of the subject for all 
+unanchored patterns (and also for anchored patterns if the subject itself is 
+empty).
 .P
 When a partial match is returned, the first two elements in the ovector point
 to the portion of the subject that was matched, but the values in the rest of
@@ -78,7 +82,7 @@ these characters are needed for a subsequent re-match with additional
 characters.
 .P
 What happens when a partial match is identified depends on which of the two
-partial matching options are set.
+partial matching options is set.
 .
 .
 .SS "PCRE2_PARTIAL_SOFT WITH pcre2_match()"
@@ -100,12 +104,12 @@ the data that is returned. Consider this pattern:
 .sp
   /123\ew+X|dogY/
 .sp
-If this is matched against the subject string "abc123dog", both
-alternatives fail to match, but the end of the subject is reached during
-matching, so PCRE2_ERROR_PARTIAL is returned. The offsets are set to 3 and 9,
-identifying "123dog" as the first partial match that was found. (In this
-example, there are two partial matches, because "dog" on its own partially
-matches the second alternative.)
+If this is matched against the subject string "abc123dog", both alternatives
+fail to match, but the end of the subject is reached during matching, so
+PCRE2_ERROR_PARTIAL is returned. The offsets are set to 3 and 9, identifying
+"123dog" as the first partial match that was found. (In this example, there are
+two partial matches, because "dog" on its own partially matches the second
+alternative.)
 .
 .
 .SS "PCRE2_PARTIAL_HARD WITH pcre2_match()"
@@ -117,8 +121,8 @@ possible complete matches. This option is "hard" because it prefers an earlier
 partial match over a later complete match. For this reason, the assumption is
 made that the end of the supplied subject string may not be the true end of the
 available data, and so, if \ez, \eZ, \eb, \eB, or $ are encountered at the end
-of the subject, the result is PCRE2_ERROR_PARTIAL, provided that at least one
-character in the subject has been inspected.
+of the subject, the result is PCRE2_ERROR_PARTIAL, whether or not any 
+characters have been inspected.
 .
 .
 .SS "Comparing hard and soft partial matching"
@@ -319,40 +323,23 @@ string "xx123ab", the ovector offsets are 5 and 7 ("ab"). The maximum
 lookbehind count is 3, so all characters before offset 2 can be discarded. The
 value of \fBstartoffset\fP for the next match should be 3. When \fBpcre2test\fP
 displays a partial match, it indicates the lookbehind characters with '<'
-characters:
+characters if the "allusedtext" modifier is set:
 .sp
     re> "(?<=123)abc"
-  data> xx123ab\e=ph
+  data> xx123ab\e=ph,allusedtext
   Partial match: 123ab
                  <<<
+However, the "allusedtext" modifier is not available for JIT matching, because 
+JIT matching does not maintain the first and last consulted characters.
 .P
-3. The maximum lookbehind count is also important when the result of a partial
-match attempt is "no match". In this case, the maximum lookbehind characters
-from the end of the current segment must be retained at the start of the next
-segment, in case the lookbehind is at the start of the pattern. Matching the
-next segment must then start at the appropriate offset.
-.P
-4. Because a partial match must always contain at least one character, what
-might be considered a partial match of an empty string actually gives a "no
-match" result. For example:
-.sp
-    re> /c(?<=abc)x/
-  data> ab\e=ps
-  No match
-.sp
-If the next segment begins "cx", a match should be found, but this will only
-happen if characters from the previous segment are retained. For this reason, a
-"no match" result should be interpreted as "partial match of an empty string"
-when the pattern contains lookbehinds.
-.P
-5. Matching a subject string that is split into multiple segments may not
-always produce exactly the same result as matching over one single long string,
-especially when PCRE2_PARTIAL_SOFT is used. The section "Partial Matching and
-Word Boundaries" above describes an issue that arises if the pattern ends with
-\eb or \eB. Another kind of difference may occur when there are multiple
-matching possibilities, because (for PCRE2_PARTIAL_SOFT) a partial match result
-is given only when there are no completed matches. This means that as soon as
-the shortest match has been found, continuation to a new subject segment is no
+3. Matching a subject string that is split into multiple segments may not
+always produce exactly the same result as matching over one single long string
+when PCRE2_PARTIAL_SOFT is used. The section "Partial Matching and Word
+Boundaries" above describes an issue that arises if the pattern ends with \eb
+or \eB. Another kind of difference may occur when there are multiple matching
+possibilities, because (for PCRE2_PARTIAL_SOFT) a partial match result is given
+only when there are no completed matches. This means that as soon as the
+shortest match has been found, continuation to a new subject segment is no
 longer possible. Consider this \fBpcre2test\fP example:
 .sp
     re> /dog(sbody)?/
@@ -386,7 +373,7 @@ multi-segment data. The example above then behaves differently:
   data> gsb\e=ph,dfa,dfa_restart
   Partial match: gsb
 .sp
-6. Patterns that contain alternatives at the top level which do not all start
+4. Patterns that contain alternatives at the top level which do not all start
 with the same pattern item may not work as expected when PCRE2_DFA_RESTART is
 used. For example, consider this pattern:
 .sp
@@ -435,6 +422,6 @@ Cambridge, England.
 .rs
 .sp
 .nf
-Last updated: 21 June 2019
+Last updated: 21 July 2019
 Copyright (c) 1997-2019 University of Cambridge.
 .fi
diff --git a/src/pcre2_dfa_match.c b/src/pcre2_dfa_match.c
index 580dbe7..a526344 100644
--- a/src/pcre2_dfa_match.c
+++ b/src/pcre2_dfa_match.c
@@ -174,7 +174,7 @@ static const uint8_t coptable[] = {
   0,                             /* Assert behind                          */
   0,                             /* Assert behind not                      */
   0,                             /* NA assert                              */
-  0,                             /* NA assert behind                       */ 
+  0,                             /* NA assert behind                       */
   0,                             /* ONCE                                   */
   0,                             /* SCRIPT_RUN                             */
   0, 0, 0, 0, 0,                 /* BRA, BRAPOS, CBRA, CBRAPOS, COND       */
@@ -251,7 +251,7 @@ static const uint8_t poptable[] = {
   0,                             /* Assert behind                          */
   0,                             /* Assert behind not                      */
   0,                             /* NA assert                              */
-  0,                             /* NA assert behind                       */ 
+  0,                             /* NA assert behind                       */
   0,                             /* ONCE                                   */
   0,                             /* SCRIPT_RUN                             */
   0, 0, 0, 0, 0,                 /* BRA, BRAPOS, CBRA, CBRAPOS, COND       */
@@ -966,7 +966,7 @@ for (;;)
       if (ptr >= end_subject)
         {
         if ((mb->moptions & PCRE2_PARTIAL_HARD) != 0)
-          could_continue = TRUE;
+          return PCRE2_ERROR_PARTIAL;
         else { ADD_ACTIVE(state_offset + 1, 0); }
         }
       break;
@@ -1015,10 +1015,12 @@ for (;;)
 
       /*-----------------------------------------------------------------*/
       case OP_EODN:
-      if (clen == 0 && (mb->moptions & PCRE2_PARTIAL_HARD) != 0)
-        could_continue = TRUE;
-      else if (clen == 0 || (IS_NEWLINE(ptr) && ptr == end_subject - mb->nllen))
-        { ADD_ACTIVE(state_offset + 1, 0); }
+      if (clen == 0 || (IS_NEWLINE(ptr) && ptr == end_subject - mb->nllen))
+        {
+        if ((mb->moptions & PCRE2_PARTIAL_HARD) != 0)
+          return PCRE2_ERROR_PARTIAL;
+        ADD_ACTIVE(state_offset + 1, 0);
+        }
       break;
 
       /*-----------------------------------------------------------------*/
@@ -3175,15 +3177,18 @@ for (;;)
         (mb->moptions & PCRE2_PARTIAL_HARD) != 0      /* Hard partial */
         ||                                           /* or... */
         ((mb->moptions & PCRE2_PARTIAL_SOFT) != 0 &&  /* Soft partial and */
-         match_count < 0)                            /* no matches */
+         match_count < 0)                             /* no matches */
         ) &&                                         /* And... */
         (
-        partial_newline ||                     /* Either partial NL */
-          (                                    /* or ... */
-          ptr >= end_subject &&                /* End of subject and */
-          ptr > mb->start_used_ptr)            /* Inspected non-empty string */
+        partial_newline ||                   /* Either partial NL */
+          (                                  /* or ... */
+          ptr >= end_subject &&              /* End of subject and */
+            (                                  /* either */
+            ptr > mb->start_used_ptr ||        /* Inspected non-empty string */
+            mb->haslookbehind                  /* or pattern has lookbehind */
+            )
           )
-        )
+        ))
       match_count = PCRE2_ERROR_PARTIAL;
     break;  /* Exit from loop along the subject string */
     }
@@ -3412,6 +3417,7 @@ mb->tables = re->tables;
 mb->start_subject = subject;
 mb->end_subject = end_subject;
 mb->start_offset = start_offset;
+mb->haslookbehind = (re->max_lookbehind > 0);
 mb->moptions = options;
 mb->poptions = re->overall_options;
 mb->match_call_count = 0;
diff --git a/src/pcre2_intmodedep.h b/src/pcre2_intmodedep.h
index 9f909b3..14bc13e 100644
--- a/src/pcre2_intmodedep.h
+++ b/src/pcre2_intmodedep.h
@@ -854,6 +854,7 @@ typedef struct match_block {
   uint32_t match_call_count;      /* Number of times a new frame is created */
   BOOL hitend;                    /* Hit the end of the subject at some point */
   BOOL hasthen;                   /* Pattern contains (*THEN) */
+  BOOL haslookbehind;             /* Pattern contains sigificant lookbehind */ 
   const uint8_t *lcc;             /* Points to lower casing table */
   const uint8_t *fcc;             /* Points to case-flipping table */
   const uint8_t *ctypes;          /* Points to table of type maps */
@@ -909,6 +910,7 @@ typedef struct dfa_match_block {
   uint32_t poptions;              /* Pattern options */
   uint32_t nltype;                /* Newline type */
   uint32_t nllen;                 /* Newline string length */
+  BOOL haslookbehind;             /* Pattern contains significant lookbehind */ 
   PCRE2_UCHAR nl[4];              /* Newline string when fixed */
   uint16_t bsr_convention;        /* \R interpretation */
   pcre2_callout_block *cb;        /* Points to a callout block */
diff --git a/src/pcre2_match.c b/src/pcre2_match.c
index 80beb2c..bffe46b 100644
--- a/src/pcre2_match.c
+++ b/src/pcre2_match.c
@@ -415,8 +415,7 @@ if (caseless)
   else
 #endif
 
-    /* Not in UTF mode */
-
+  /* Not in UTF mode */
     {
     for (; length > 0; length--)
       {
@@ -491,11 +490,16 @@ heap is used for a larger vector.
 *************************************************/
 
 /* These macros pack up tests that are used for partial matching several times
-in the code. We set the "hit end" flag if the pointer is at the end of the
-subject and also past the earliest inspected character (i.e. something has been
-matched, even if not part of the actual matched string). For hard partial
-matching, we then return immediately. The second one is used when we already
-know we are past the end of the subject. */
+in the code. The second one is used when we already know we are past the end of
+the subject. We set the "hit end" flag if the pointer is at the end of the
+subject and either (a) the pointer is past the earliest inspected character
+(i.e. something has been matched, even if not part of the actual matched
+string), or (b) the pattern contains a lookbehind. These are the conditions for 
+which adding more characters may allow the current match to continue.
+
+For hard partial matching, we immediately return a partial match. Otherwise,
+carrying on means that a complete match on the current subject will be sought. 
+A partial match is returned only if no complete match can be found. */
 
 #define CHECK_PARTIAL()\
   if (Feptr >= mb->end_subject) \
@@ -503,31 +507,13 @@ know we are past the end of the subject. */
     SCHECK_PARTIAL(); \
     }
 
-/* Original version that allows hard partial to continue if no inspected
-characters. */
-
 #define SCHECK_PARTIAL()\
-  if (mb->partial != 0 && Feptr > mb->start_used_ptr) \
+  if (mb->partial != 0 && (Feptr > mb->start_used_ptr || mb->haslookbehind)) \
     { \
     mb->hitend = TRUE; \
     if (mb->partial > 1) return PCRE2_ERROR_PARTIAL; \
     }
 
-/* Experimental version that makes hard partial give no match instead of
-continuing if no characters have been inspected. */
-
-#ifdef NEVERNEVER
-#define SCHECK_PARTIAL()\
-  if (mb->partial != 0) \
-    { \
-    if (Feptr > mb->start_used_ptr) \
-      { \
-      mb->hitend = TRUE; \
-      if (mb->partial > 1) return PCRE2_ERROR_PARTIAL; \
-      } \
-    else if (mb->partial > 1) RRETURN(MATCH_NOMATCH); \
-    }
-#endif  /* NEVERNEVER */
 
 /* These macros are used to implement backtracking. They simulate a recursive
 call to the match() function by means of a local vector of frames which
@@ -5670,7 +5656,11 @@ fprintf(stderr, "++ op=%d\n", *Fecode);
 
     case OP_EOD:
     if (Feptr < mb->end_subject) RRETURN(MATCH_NOMATCH);
-    SCHECK_PARTIAL();
+    if (mb->partial != 0)
+      { 
+      mb->hitend = TRUE;
+      if (mb->partial > 1) return PCRE2_ERROR_PARTIAL;
+      } 
     Fecode++;
     break;
 
@@ -5695,7 +5685,11 @@ fprintf(stderr, "++ op=%d\n", *Fecode);
 
     /* Either at end of string or \n before end. */
 
-    SCHECK_PARTIAL();
+    if (mb->partial != 0)
+      { 
+      mb->hitend = TRUE;
+      if (mb->partial > 1) return PCRE2_ERROR_PARTIAL;
+      } 
     Fecode++;
     break;
 
@@ -6457,9 +6451,10 @@ mb->start_subject = subject;
 mb->start_offset = start_offset;
 mb->end_subject = end_subject;
 mb->hasthen = (re->flags & PCRE2_HASTHEN) != 0;
-mb->poptions = re->overall_options;     /* Pattern options */
+mb->haslookbehind = (re->max_lookbehind > 0);
+mb->poptions = re->overall_options;          /* Pattern options */
 mb->ignore_skip_arg = 0;
-mb->mark = mb->nomatch_mark = NULL;     /* In case never set */
+mb->mark = mb->nomatch_mark = NULL;          /* In case never set */
 
 /* The name table is needed for finding all the numbers associated with a
 given name, for condition testing. The code follows the name table. */
diff --git a/testdata/testinput2 b/testdata/testinput2
index 95c4c14..1ecc3fd 100644
--- a/testdata/testinput2
+++ b/testdata/testinput2
@@ -5690,10 +5690,33 @@ a)"xI
 
 # ----
 
-/(?<=(?=.(?<=x)))/
-    ab\=ph
-
 # Expect error (recursion => not fixed length)
 /(\2)((?=(?<=\1)))/
 
+/c*+(?<=[bc])/
+    abc\=ph,no_jit
+    ab\=ph,no_jit
+    abc\=ps,no_jit
+    ab\=ps,no_jit
+
+/c++(?<=[bc])/
+    abc\=ph,no_jit
+    ab\=ph,no_jit
+
+/(?<=(?=.(?<=x)))/
+    abx
+    ab\=ph,no_jit
+    bxyz 
+    xyz
+    
+/\z/
+   abc\=ph,no_jit 
+   abc\=ps 
+   
+/\Z/
+   abc\=ph,no_jit 
+   abc\=ps 
+   abc\n\=ph,no_jit
+   abc\n\=ps
+
 # End of testinput2
diff --git a/testdata/testinput6 b/testdata/testinput6
index cc3ebd0..e53efc7 100644
--- a/testdata/testinput6
+++ b/testdata/testinput6
@@ -4994,4 +4994,30 @@
     ab\=ps
     abcx  
 
+/\z/
+    abc\=ph 
+    abc\=ps 
+   
+/\Z/
+    abc\=ph 
+    abc\=ps 
+    abc\n\=ph
+    abc\n\=ps
+
+/c*+(?<=[bc])/
+    abc\=ph
+    ab\=ph
+    abc\=ps
+    ab\=ps
+
+/c++(?<=[bc])/
+    abc\=ph
+    ab\=ph
+
+/(?<=(?=.(?<=x)))/
+    abx
+    ab\=ph
+    bxyz 
+    xyz
+
 # End of testinput6
diff --git a/testdata/testoutput2 b/testdata/testoutput2
index ba1edbb..2849f06 100644
--- a/testdata/testoutput2
+++ b/testdata/testoutput2
@@ -17185,14 +17185,52 @@ Subject length lower bound = 1
 
 # ----
 
-/(?<=(?=.(?<=x)))/
-    ab\=ph
-No match
-
 # Expect error (recursion => not fixed length)
 /(\2)((?=(?<=\1)))/
 Failed: error 125 at offset 8: lookbehind assertion is not fixed length
 
+/c*+(?<=[bc])/
+    abc\=ph,no_jit
+Partial match: c
+    ab\=ph,no_jit
+Partial match: 
+    abc\=ps,no_jit
+ 0: c
+    ab\=ps,no_jit
+ 0: 
+
+/c++(?<=[bc])/
+    abc\=ph,no_jit
+Partial match: c
+    ab\=ph,no_jit
+Partial match: 
+
+/(?<=(?=.(?<=x)))/
+    abx
+ 0: 
+    ab\=ph,no_jit
+Partial match: 
+    bxyz 
+ 0: 
+    xyz
+ 0: 
+    
+/\z/
+   abc\=ph,no_jit 
+Partial match: 
+   abc\=ps 
+ 0: 
+   
+/\Z/
+   abc\=ph,no_jit 
+Partial match: 
+   abc\=ps 
+ 0: 
+   abc\n\=ph,no_jit
+Partial match: \x0a
+   abc\n\=ps
+ 0: 
+
 # End of testinput2
 Error -70: PCRE2_ERROR_BADDATA (unknown error number)
 Error -62: bad serialized data
diff --git a/testdata/testoutput6 b/testdata/testoutput6
index 61cbfe2..655f885 100644
--- a/testdata/testoutput6
+++ b/testdata/testoutput6
@@ -7845,4 +7845,46 @@ Partial match: ab
     abcx  
  0: abcx
 
+/\z/
+    abc\=ph 
+Partial match: 
+    abc\=ps 
+ 0: 
+   
+/\Z/
+    abc\=ph 
+Partial match: 
+    abc\=ps 
+ 0: 
+    abc\n\=ph
+Partial match: \x0a
+    abc\n\=ps
+ 0: 
+
+/c*+(?<=[bc])/
+    abc\=ph
+Partial match: c
+    ab\=ph
+Partial match: 
+    abc\=ps
+ 0: c
+    ab\=ps
+ 0: 
+
+/c++(?<=[bc])/
+    abc\=ph
+Partial match: c
+    ab\=ph
+Partial match: 
+
+/(?<=(?=.(?<=x)))/
+    abx
+ 0: 
+    ab\=ph
+Partial match: 
+    bxyz 
+ 0: 
+    xyz
+ 0: 
+
 # End of testinput6