Implement pcre2_set_max_pattern_length()

git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@414 6239d852-aaf2-0410-a92c-79f79f948069

1 files changed, 395 insertions, 351 deletions

diff --git a/doc/pcre2test.txt b/doc/pcre2test.txt
index 562a859..e880b9a 100644
--- a/doc/pcre2test.txt
+++ b/doc/pcre2test.txt
@@ -209,107 +209,108 @@ DESCRIPTION
        or  \r\n,  etc.,  depending on the newline setting) in a single line of
        input to encode the newline sequences. There is no limit on the  length
        of  subject  lines; the input buffer is automatically extended if it is
-       too small. There is a replication feature that  makes  it  possible  to
-       generate long subject lines without having to supply them explicitly.
+       too small. There are replication features that  makes  it  possible  to
+       generate  long  repetitive  pattern  or subject lines without having to
+       supply them explicitly.
 
-       An  empty  line  or  the end of the file signals the end of the subject
-       lines for a test, at which point a  new  pattern  or  command  line  is
+       An empty line or the end of the file signals the  end  of  the  subject
+       lines  for  a  test,  at  which  point a new pattern or command line is
        expected if there is still input to be read.
 
 
 COMMAND LINES
 
-       In  between sets of test data, a line that begins with # is interpreted
+       In between sets of test data, a line that begins with # is  interpreted
        as a command line. If the first character is followed by white space or
-       an  exclamation  mark,  the  line is treated as a comment, and ignored.
+       an exclamation mark, the line is treated as  a  comment,  and  ignored.
        Otherwise, the following commands are recognized:
 
          #forbid_utf
 
-       Subsequent  patterns  automatically  have   the   PCRE2_NEVER_UTF   and
-       PCRE2_NEVER_UCP  options  set, which locks out the use of the PCRE2_UTF
-       and PCRE2_UCP options and the use of (*UTF) and (*UCP) at the start  of
-       patterns.  This  command  also  forces an error if a subsequent pattern
-       contains any occurrences of \P, \p, or \X, which  are  still  supported
-       when  PCRE2_UTF  is not set, but which require Unicode property support
+       Subsequent   patterns   automatically   have  the  PCRE2_NEVER_UTF  and
+       PCRE2_NEVER_UCP options set, which locks out the use of  the  PCRE2_UTF
+       and  PCRE2_UCP options and the use of (*UTF) and (*UCP) at the start of
+       patterns. This command also forces an error  if  a  subsequent  pattern
+       contains  any  occurrences  of \P, \p, or \X, which are still supported
+       when PCRE2_UTF is not set, but which require Unicode  property  support
        to be included in the library.
 
-       This is a trigger guard that is used in test files to ensure  that  UTF
-       or  Unicode property tests are not accidentally added to files that are
-       used when Unicode support is  not  included  in  the  library.  Setting
-       PCRE2_NEVER_UTF  and  PCRE2_NEVER_UCP as a default can also be obtained
-       by the use of #pattern; the difference is that  #forbid_utf  cannot  be
-       unset,  and the automatic options are not displayed in pattern informa-
+       This  is  a trigger guard that is used in test files to ensure that UTF
+       or Unicode property tests are not accidentally added to files that  are
+       used  when  Unicode  support  is  not  included in the library. Setting
+       PCRE2_NEVER_UTF and PCRE2_NEVER_UCP as a default can also  be  obtained
+       by  the  use  of #pattern; the difference is that #forbid_utf cannot be
+       unset, and the automatic options are not displayed in pattern  informa-
        tion, to avoid cluttering up test output.
 
          #load <filename>
 
        This command is used to load a set of precompiled patterns from a file,
-       as  described  in  the  section entitled "Saving and restoring compiled
+       as described in the section entitled  "Saving  and  restoring  compiled
        patterns" below.
 
          #newline_default [<newline-list>]
 
-       When PCRE2 is built, a default newline  convention  can  be  specified.
-       This  determines which characters and/or character pairs are recognized
+       When  PCRE2  is  built,  a default newline convention can be specified.
+       This determines which characters and/or character pairs are  recognized
        as indicating a newline in a pattern or subject string. The default can
-       be  overridden when a pattern is compiled. The standard test files con-
-       tain tests of various newline conventions,  but  the  majority  of  the
-       tests  expect  a  single  linefeed  to  be  recognized  as a newline by
+       be overridden when a pattern is compiled. The standard test files  con-
+       tain  tests  of  various  newline  conventions, but the majority of the
+       tests expect a single  linefeed  to  be  recognized  as  a  newline  by
        default. Without special action the tests would fail when PCRE2 is com-
        piled with either CR or CRLF as the default newline.
 
        The #newline_default command specifies a list of newline types that are
-       acceptable as the default. The types must be one of CR, LF, CRLF,  ANY-
+       acceptable  as the default. The types must be one of CR, LF, CRLF, ANY-
        CRLF, or ANY (in upper or lower case), for example:
 
          #newline_default LF Any anyCRLF
 
        If the default newline is in the list, this command has no effect. Oth-
-       erwise, except when testing the POSIX  API,  a  newline  modifier  that
-       specifies  the  first  newline  convention in the list (LF in the above
-       example) is added to any pattern that does not already have  a  newline
+       erwise,  except  when  testing  the  POSIX API, a newline modifier that
+       specifies the first newline convention in the list  (LF  in  the  above
+       example)  is  added to any pattern that does not already have a newline
        modifier. If the newline list is empty, the feature is turned off. This
        command is present in a number of the standard test input files.
 
-       When the POSIX API is being tested there is  no  way  to  override  the
-       default  newline  convention,  though it is possible to set the newline
-       convention from within the pattern. A warning is  given  if  the  posix
+       When  the  POSIX  API  is  being tested there is no way to override the
+       default newline convention, though it is possible to  set  the  newline
+       convention  from  within  the  pattern. A warning is given if the posix
        modifier is used when #newline_default would set a default for the non-
        POSIX API.
 
          #pattern <modifier-list>
 
-       This command sets a default modifier list that applies  to  all  subse-
+       This  command  sets  a default modifier list that applies to all subse-
        quent patterns. Modifiers on a pattern can change these settings.
 
          #perltest
 
-       The  appearance of this line causes all subsequent modifier settings to
+       The appearance of this line causes all subsequent modifier settings  to
        be checked for compatibility with the perltest.sh script, which is used
-       to  confirm that Perl gives the same results as PCRE2. Also, apart from
-       comment lines, none of the other command lines are  permitted,  because
-       they  and  many  of the modifiers are specific to pcre2test, and should
-       not be used in test files that are also processed by  perltest.sh.  The
-       #perltest  command  helps detect tests that are accidentally put in the
+       to confirm that Perl gives the same results as PCRE2. Also, apart  from
+       comment  lines,  none of the other command lines are permitted, because
+       they and many of the modifiers are specific to  pcre2test,  and  should
+       not  be  used in test files that are also processed by perltest.sh. The
+       #perltest command helps detect tests that are accidentally put  in  the
        wrong file.
 
          #pop [<modifiers>]
 
-       This command is used to manipulate the stack of compiled  patterns,  as
-       described  in  the section entitled "Saving and restoring compiled pat-
+       This  command  is used to manipulate the stack of compiled patterns, as
+       described in the section entitled "Saving and restoring  compiled  pat-
        terns" below.
 
          #save <filename>
 
-       This command is used to save a set of compiled patterns to a  file,  as
-       described  in  the section entitled "Saving and restoring compiled pat-
+       This  command  is used to save a set of compiled patterns to a file, as
+       described in the section entitled "Saving and restoring  compiled  pat-
        terns" below.
 
          #subject <modifier-list>
 
-       This command sets a default modifier list that applies  to  all  subse-
-       quent  subject lines. Modifiers on a subject line can change these set-
+       This  command  sets  a default modifier list that applies to all subse-
+       quent subject lines. Modifiers on a subject line can change these  set-
        tings.
 
 
@@ -317,58 +318,58 @@ MODIFIER SYNTAX
 
        Modifier lists are used with both pattern and subject lines. Items in a
        list are separated by commas followed by optional white space. Trailing
-       whitespace in a modifier list is ignored. Some modifiers may  be  given
-       for  both patterns and subject lines, whereas others are valid only for
+       whitespace  in  a modifier list is ignored. Some modifiers may be given
+       for both patterns and subject lines, whereas others are valid only  for
        one  or  the  other.  Each  modifier  has  a  long  name,  for  example
-       "anchored",  and  some of them must be followed by an equals sign and a
-       value, for example, "offset=12". Values cannot  contain  comma  charac-
-       ters,  but may contain spaces. Modifiers that do not take values may be
+       "anchored", and some of them must be followed by an equals sign  and  a
+       value,  for  example,  "offset=12". Values cannot contain comma charac-
+       ters, but may contain spaces. Modifiers that do not take values may  be
        preceded by a minus sign to turn off a previous setting.
 
        A few of the more common modifiers can also be specified as single let-
-       ters,  for  example "i" for "caseless". In documentation, following the
+       ters, for example "i" for "caseless". In documentation,  following  the
        Perl convention, these are written with a slash ("the /i modifier") for
-       clarity.  Abbreviated  modifiers  must all be concatenated in the first
-       item of a modifier list. If the first item is not recognized as a  long
-       modifier  name, it is interpreted as a sequence of these abbreviations.
+       clarity. Abbreviated modifiers must all be concatenated  in  the  first
+       item  of a modifier list. If the first item is not recognized as a long
+       modifier name, it is interpreted as a sequence of these  abbreviations.
        For example:
 
          /abc/ig,newline=cr,jit=3
 
-       This is a pattern line whose modifier list starts with  two  one-letter
-       modifiers  (/i  and  /g).  The lower-case abbreviated modifiers are the
+       This  is  a pattern line whose modifier list starts with two one-letter
+       modifiers (/i and /g). The lower-case  abbreviated  modifiers  are  the
        same as used in Perl.
 
 
 PATTERN SYNTAX
 
-       A pattern line must start with one of the following characters  (common
+       A  pattern line must start with one of the following characters (common
        symbols, excluding pattern meta-characters):
 
          / ! " ' ` - = _ : ; , % & @ ~
 
-       This  is  interpreted  as the pattern's delimiter. A regular expression
-       may be continued over several input lines, in which  case  the  newline
+       This is interpreted as the pattern's delimiter.  A  regular  expression
+       may  be  continued  over several input lines, in which case the newline
        characters are included within it. It is possible to include the delim-
        iter within the pattern by escaping it with a backslash, for example
 
          /abc\/def/
 
-       If you do this, the escape and the delimiter form part of the  pattern,
+       If  you do this, the escape and the delimiter form part of the pattern,
        but since the delimiters are all non-alphanumeric, this does not affect
-       its interpretation. If the terminating delimiter  is  immediately  fol-
+       its  interpretation.  If  the terminating delimiter is immediately fol-
        lowed by a backslash, for example,
 
          /abc/\
 
-       then  a  backslash  is added to the end of the pattern. This is done to
-       provide a way of testing the error condition that arises if  a  pattern
+       then a backslash is added to the end of the pattern. This  is  done  to
+       provide  a  way of testing the error condition that arises if a pattern
        finishes with a backslash, because
 
          /abc\/
 
-       is  interpreted as the first line of a pattern that starts with "abc/",
-       causing pcre2test to read the next line as a continuation of the  regu-
+       is interpreted as the first line of a pattern that starts with  "abc/",
+       causing  pcre2test to read the next line as a continuation of the regu-
        lar expression.
 
        A pattern can be followed by a modifier list (details below).
@@ -376,7 +377,7 @@ PATTERN SYNTAX
 
 SUBJECT LINE SYNTAX
 
-       Before    each   subject   line   is   passed   to   pcre2_match()   or
+       Before   each   subject   line   is   passed   to   pcre2_match()    or
        pcre2_dfa_match(), leading and trailing white space is removed, and the
        line is scanned for backslash escapes. The following provide a means of
        encoding non-printing characters in a visible way:
@@ -396,23 +397,23 @@ SUBJECT LINE SYNTAX
          \x{hh...}  hexadecimal character (any number of hex digits)
 
        The use of \x{hh...} is not dependent on the use of the utf modifier on
-       the  pattern. It is recognized always. There may be any number of hexa-
-       decimal digits inside the braces; invalid  values  provoke  error  mes-
+       the pattern. It is recognized always. There may be any number of  hexa-
+       decimal  digits  inside  the  braces; invalid values provoke error mes-
        sages.
 
-       Note  that  \xhh  specifies one byte rather than one character in UTF-8
-       mode; this makes it possible to construct invalid UTF-8  sequences  for
-       testing  purposes.  On the other hand, \x{hh} is interpreted as a UTF-8
-       character in UTF-8 mode, generating more than one byte if the value  is
-       greater  than  127.   When testing the 8-bit library not in UTF-8 mode,
+       Note that \xhh specifies one byte rather than one  character  in  UTF-8
+       mode;  this  makes it possible to construct invalid UTF-8 sequences for
+       testing purposes. On the other hand, \x{hh} is interpreted as  a  UTF-8
+       character  in UTF-8 mode, generating more than one byte if the value is
+       greater than 127.  When testing the 8-bit library not  in  UTF-8  mode,
        \x{hh} generates one byte for values less than 256, and causes an error
        for greater values.
 
        In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
        possible to construct invalid UTF-16 sequences for testing purposes.
 
-       In UTF-32 mode, all 4- to 8-digit \x{...}  values  are  accepted.  This
-       makes  it  possible  to  construct invalid UTF-32 sequences for testing
+       In  UTF-32  mode,  all  4- to 8-digit \x{...} values are accepted. This
+       makes it possible to construct invalid  UTF-32  sequences  for  testing
        purposes.
 
        There is a special backslash sequence that specifies replication of one
@@ -420,45 +421,45 @@ SUBJECT LINE SYNTAX
 
          \[<characters>]{<count>}
 
-       This  makes  it possible to test long strings without having to provide
+       This makes it possible to test long strings without having  to  provide
        them as part of the file. For example:
 
          \[abc]{4}
 
-       is converted to "abcabcabcabc". This feature does not support  nesting.
+       is  converted to "abcabcabcabc". This feature does not support nesting.
        To include a closing square bracket in the characters, code it as \x5D.
 
-       A  backslash  followed  by  an equals sign marks the end of the subject
+       A backslash followed by an equals sign marks the  end  of  the  subject
        string and the start of a modifier list. For example:
 
          abc\=notbol,notempty
 
-       If the subject string is empty and \= is followed  by  whitespace,  the
-       line  is  treated  as a comment line, and is not used for matching. For
+       If  the  subject  string is empty and \= is followed by whitespace, the
+       line is treated as a comment line, and is not used  for  matching.  For
        example:
 
          \= This is a comment.
          abc\= This is an invalid modifier list.
 
-       A backslash followed  by  any  other  non-alphanumeric  character  just
+       A  backslash  followed  by  any  other  non-alphanumeric character just
        escapes that character. A backslash followed by anything else causes an
-       error. However, if the very last character in the line is  a  backslash
-       (and  there  is  no  modifier list), it is ignored. This gives a way of
-       passing an empty line as data, since a real empty line  terminates  the
+       error.  However,  if the very last character in the line is a backslash
+       (and there is no modifier list), it is ignored. This  gives  a  way  of
+       passing  an  empty line as data, since a real empty line terminates the
        data input.
 
 
 PATTERN MODIFIERS
 
-       There are three types of modifier that can appear in pattern lines, two
-       of which may also be used in a #pattern command. A  pattern's  modifier
-       list can add to or override default modifiers that were set by a previ-
-       ous #pattern command.
+       There are several types of modifier that can appear in  pattern  lines.
+       Except where noted below, they may also be used in #pattern commands. A
+       pattern's modifier list can add to or override default  modifiers  that
+       were set by a previous #pattern command.
 
    Setting compilation options
 
-       The following modifiers set options for pcre2_compile(). The most  com-
-       mon  ones have single-letter abbreviations. See pcre2api for a descrip-
+       The  following modifiers set options for pcre2_compile(). The most com-
+       mon ones have single-letter abbreviations. See pcre2api for a  descrip-
        tion of their effects.
 
              allow_empty_class         set PCRE2_ALLOW_EMPTY_CLASS
@@ -489,13 +490,13 @@ PATTERN MODIFIERS
              utf                       set PCRE2_UTF
 
        As well as turning on the PCRE2_UTF option, the utf modifier causes all
-       non-printing  characters  in  output  strings  to  be printed using the
-       \x{hh...} notation. Otherwise, those less than 0x100 are output in  hex
+       non-printing characters in output  strings  to  be  printed  using  the
+       \x{hh...}  notation. Otherwise, those less than 0x100 are output in hex
        without the curly brackets.
 
    Setting compilation controls
 
-       The  following  modifiers  affect  the  compilation  process or request
+       The following modifiers  affect  the  compilation  process  or  request
        information about the pattern:
 
              bsr=[anycrlf|unicode]     specify \R handling
@@ -509,6 +510,7 @@ PATTERN MODIFIERS
              jitfast                   use JIT fast path
              jitverify                 verify JIT use
              locale=<name>             use this locale
+             max_pattern_length=<n>    set the maximum pattern length
              memory                    show memory used
              newline=<type>            set newline type
              null_context              compile with a NULL context
@@ -522,34 +524,34 @@ PATTERN MODIFIERS
 
    Newline and \R handling
 
-       The bsr modifier specifies what \R in a pattern should match. If it  is
-       set  to  "anycrlf",  \R  matches  CR, LF, or CRLF only. If it is set to
-       "unicode", \R matches any Unicode  newline  sequence.  The  default  is
+       The  bsr modifier specifies what \R in a pattern should match. If it is
+       set to "anycrlf", \R matches CR, LF, or CRLF only.  If  it  is  set  to
+       "unicode",  \R  matches  any  Unicode  newline sequence. The default is
        specified when PCRE2 is built, with the default default being Unicode.
 
-       The  newline  modifier specifies which characters are to be interpreted
+       The newline modifier specifies which characters are to  be  interpreted
        as newlines, both in the pattern and in subject lines. The type must be
        one of CR, LF, CRLF, ANYCRLF, or ANY (in upper or lower case).
 
    Information about a pattern
 
-       The  debug modifier is a shorthand for info,fullbincode, requesting all
+       The debug modifier is a shorthand for info,fullbincode, requesting  all
        available information.
 
        The bincode modifier causes a representation of the compiled code to be
-       output  after compilation. This information does not contain length and
+       output after compilation. This information does not contain length  and
        offset values, which ensures that the same output is generated for dif-
-       ferent  internal  link  sizes  and different code unit widths. By using
-       bincode, the same regression tests can be used  in  different  environ-
+       ferent internal link sizes and different code  unit  widths.  By  using
+       bincode,  the  same  regression tests can be used in different environ-
        ments.
 
-       The  fullbincode  modifier, by contrast, does include length and offset
-       values. This is used in a few special tests that run only for  specific
+       The fullbincode modifier, by contrast, does include length  and  offset
+       values.  This is used in a few special tests that run only for specific
        code unit widths and link sizes, and is also useful for one-off tests.
 
-       The  info  modifier  requests  information  about  the compiled pattern
-       (whether it is anchored, has a fixed first character, and so  on).  The
-       information  is  obtained  from the pcre2_pattern_info() function. Here
+       The info modifier  requests  information  about  the  compiled  pattern
+       (whether  it  is anchored, has a fixed first character, and so on). The
+       information is obtained from the  pcre2_pattern_info()  function.  Here
        are some typical examples:
 
            re> /(?i)(^a|^b)/m,info
@@ -567,57 +569,81 @@ PATTERN MODIFIERS
          Last code unit = 'c' (caseless)
          Subject length lower bound = 3
 
-       "Compile options" are those specified by modifiers;  "overall  options"
-       have  added options that are taken or deduced from the pattern. If both
-       sets of options are the same, just a single "options" line  is  output;
-       if  there  are  no  options,  the line is omitted. "First code unit" is
-       where any match must start; if there is more than one they  are  listed
-       as  "starting  code  units".  "Last code unit" is the last literal code
-       unit that must be present in any match. This  is  not  necessarily  the
-       last  character.  These lines are omitted if no starting or ending code
+       "Compile  options"  are those specified by modifiers; "overall options"
+       have added options that are taken or deduced from the pattern. If  both
+       sets  of  options are the same, just a single "options" line is output;
+       if there are no options, the line is  omitted.  "First  code  unit"  is
+       where  any  match must start; if there is more than one they are listed
+       as "starting code units". "Last code unit" is  the  last  literal  code
+       unit  that  must  be  present in any match. This is not necessarily the
+       last character. These lines are omitted if no starting or  ending  code
        units are recorded.
 
-       The callout_info modifier requests information about all  the  callouts
+       The  callout_info  modifier requests information about all the callouts
        in the pattern. A list of them is output at the end of any other infor-
        mation that is requested. For each callout, either its number or string
        is given, followed by the item that follows it in the pattern.
 
    Passing a NULL context
 
-       Normally,  pcre2test  passes a context block to pcre2_compile(). If the
-       null_context modifier is set, however, NULL  is  passed.  This  is  for
-       testing  that  pcre2_compile()  behaves correctly in this case (it uses
+       Normally, pcre2test passes a context block to pcre2_compile().  If  the
+       null_context  modifier  is  set,  however,  NULL is passed. This is for
+       testing that pcre2_compile() behaves correctly in this  case  (it  uses
        default values).
 
    Specifying a pattern in hex
 
        The hex modifier specifies that the characters of the pattern are to be
-       interpreted  as  pairs  of hexadecimal digits. White space is permitted
+       interpreted as pairs of hexadecimal digits. White  space  is  permitted
        between pairs. For example:
 
          /ab 32 59/hex
 
-       This feature is provided as a way of  creating  patterns  that  contain
-       binary  zero  and  other non-printing characters. By default, pcre2test
-       passes patterns as zero-terminated strings to  pcre2_compile(),  giving
+       This  feature  is  provided  as a way of creating patterns that contain
+       binary zero and other non-printing characters.  By  default,  pcre2test
+       passes  patterns  as zero-terminated strings to pcre2_compile(), giving
        the length as PCRE2_ZERO_TERMINATED. However, for patterns specified in
        hexadecimal, the actual length of the pattern is passed.
 
+   Generating long repetitive patterns
+
+       Some  tests use long patterns that are very repetitive. Instead of cre-
+       ating a very long input line for such a pattern, you can use a  special
+       repetition  feature,  similar  to  the  one described for subject lines
+       above. If the expand modifier is present on a  pattern,  parts  of  the
+       pattern that have the form
+
+         \[<characters>]{<count>}
+
+       are expanded before the pattern is passed to pcre2_compile(). For exam-
+       ple, \[AB]{6000} is expanded to "ABAB..." 6000 times. This construction
+       cannot  be  nested. An initial "\[" sequence is recognized only if "]{"
+       followed by decimal digits and "}" is found later in  the  pattern.  If
+       not, the characters remain in the pattern unaltered.
+
+       If  part  of an expanded pattern looks like an expansion, but is really
+       part of the actual pattern, unwanted expansion can be avoided by giving
+       two values in the quantifier. For example, \[AB]{6000,6000} is not rec-
+       ognized as an expansion item.
+
+       If the info modifier is set on an expanded pattern, the result  of  the
+       expansion is included in the information that is output.
+
    JIT compilation
 
-       Just-in-time (JIT) compiling is a  heavyweight  optimization  that  can
-       greatly  speed  up pattern matching. See the pcre2jit documentation for
-       details. JIT compiling happens, optionally, after a  pattern  has  been
-       successfully  compiled into an internal form. The JIT compiler converts
+       Just-in-time  (JIT)  compiling  is  a heavyweight optimization that can
+       greatly speed up pattern matching. See the pcre2jit  documentation  for
+       details.  JIT  compiling  happens, optionally, after a pattern has been
+       successfully compiled into an internal form. The JIT compiler  converts
        this to optimized machine code. It needs to know whether the match-time
        options PCRE2_PARTIAL_HARD and PCRE2_PARTIAL_SOFT are going to be used,
-       because different code is generated for the different  cases.  See  the
-       partial  modifier in "Subject Modifiers" below for details of how these
+       because  different  code  is generated for the different cases. See the
+       partial modifier in "Subject Modifiers" below for details of how  these
        options are specified for each match attempt.
 
-       JIT compilation is requested by the /jit pattern  modifier,  which  may
+       JIT  compilation  is  requested by the /jit pattern modifier, which may
        optionally be followed by an equals sign and a number in the range 0 to
-       7.  The three bits that make up the number specify which of  the  three
+       7.   The  three bits that make up the number specify which of the three
        JIT operating modes are to be compiled:
 
          1  compile JIT code for non-partial matching
@@ -634,31 +660,31 @@ PATTERN MODIFIERS
          6  soft and hard partial matching only
          7  all three modes
 
-       If  no  number  is  given,  7 is assumed. The phrase "partial matching"
+       If no number is given, 7 is  assumed.  The  phrase  "partial  matching"
        means a call to pcre2_match() with either the PCRE2_PARTIAL_SOFT or the
-       PCRE2_PARTIAL_HARD  option set. Note that such a call may return a com-
+       PCRE2_PARTIAL_HARD option set. Note that such a call may return a  com-
        plete match; the options enable the possibility of a partial match, but
-       do  not  require it. Note also that if you request JIT compilation only
-       for partial matching (for example, /jit=2) but do not set  the  partial
-       modifier  on  a  subject line, that match will not use JIT code because
+       do not require it. Note also that if you request JIT  compilation  only
+       for  partial  matching (for example, /jit=2) but do not set the partial
+       modifier on a subject line, that match will not use  JIT  code  because
        none was compiled for non-partial matching.
 
-       If JIT compilation is successful, the compiled JIT code will  automati-
-       cally  be  used  when  an appropriate type of match is run, except when
-       incompatible run-time options are specified. For more details, see  the
-       pcre2jit  documentation. See also the jitstack modifier below for a way
+       If  JIT compilation is successful, the compiled JIT code will automati-
+       cally be used when an appropriate type of match  is  run,  except  when
+       incompatible  run-time options are specified. For more details, see the
+       pcre2jit documentation. See also the jitstack modifier below for a  way
        of setting the size of the JIT stack.
 
-       If the jitfast modifier is specified, matching is done  using  the  JIT
-       "fast  path" interface, pcre2_jit_match(), which skips some of the san-
-       ity checks that are done by pcre2_match(), and of course does not  work
-       when  JIT  is not supported. If jitfast is specified without jit, jit=7
+       If  the  jitfast  modifier is specified, matching is done using the JIT
+       "fast path" interface, pcre2_jit_match(), which skips some of the  san-
+       ity  checks that are done by pcre2_match(), and of course does not work
+       when JIT is not supported. If jitfast is specified without  jit,  jit=7
        is assumed.
 
-       If the jitverify modifier is specified, information about the  compiled
-       pattern  shows  whether  JIT  compilation was or was not successful. If
-       jitverify is specified without jit, jit=7 is assumed. If  JIT  compila-
-       tion  is successful when jitverify is set, the text "(JIT)" is added to
+       If  the jitverify modifier is specified, information about the compiled
+       pattern shows whether JIT compilation was or  was  not  successful.  If
+       jitverify  is  specified without jit, jit=7 is assumed. If JIT compila-
+       tion is successful when jitverify is set, the text "(JIT)" is added  to
        the first output line after a match or non match when JIT-compiled code
        was actually used in the match.
 
@@ -669,18 +695,18 @@ PATTERN MODIFIERS
          /pattern/locale=fr_FR
 
        The given locale is set, pcre2_maketables() is called to build a set of
-       character tables for the locale, and this is then passed to  pcre2_com-
-       pile()  when compiling the regular expression. The same tables are used
+       character  tables for the locale, and this is then passed to pcre2_com-
+       pile() when compiling the regular expression. The same tables are  used
        when matching the following subject lines. The /locale modifier applies
        only to the pattern on which it appears, but can be given in a #pattern
-       command if a default is needed. Setting a locale and alternate  charac-
+       command  if a default is needed. Setting a locale and alternate charac-
        ter tables are mutually exclusive.
 
    Showing pattern memory
 
-       The  /memory  modifier  causes  the size in bytes of the memory used to
-       hold the compiled pattern to be output. This does not include the  size
-       of  the  pcre2_code  block; it is just the actual compiled data. If the
+       The /memory modifier causes the size in bytes of  the  memory  used  to
+       hold  the compiled pattern to be output. This does not include the size
+       of the pcre2_code block; it is just the actual compiled  data.  If  the
        pattern is subsequently passed to the JIT compiler, the size of the JIT
        compiled code is also output. Here is an example:
 
@@ -691,12 +717,19 @@ PATTERN MODIFIERS
 
    Limiting nested parentheses
 
-       The  parens_nest_limit  modifier  sets  a  limit on the depth of nested
-       parentheses in a pattern. Breaching  the  limit  causes  a  compilation
-       error.   The  default  for  the library is set when PCRE2 is built, but
-       pcre2test sets its own default of 220, which is  required  for  running
+       The parens_nest_limit modifier sets a limit  on  the  depth  of  nested
+       parentheses  in  a  pattern.  Breaching  the limit causes a compilation
+       error.  The default for the library is set when  PCRE2  is  built,  but
+       pcre2test  sets  its  own default of 220, which is required for running
        the standard test suite.
 
+   Limiting the pattern length
+
+       The max_pattern_length modifier sets a limit, in  code  units,  to  the
+       length of pattern that pcre2_compile() will accept. Breaching the limit
+       causes a compilation  error.  The  default  is  the  largest  number  a
+       PCRE2_SIZE variable can hold (essentially unlimited).
+
    Using the POSIX wrapper API
 
        The  /posix modifier causes pcre2test to call PCRE2 via the POSIX wrap-
@@ -714,6 +747,16 @@ PATTERN MODIFIERS
          ucp                REG_UCP        )   the POSIX standard
          utf                REG_UTF8       )
 
+       The regerror_buffsize modifier specifies a size for  the  error  buffer
+       that  is  passed to regerror() in the event of a compilation error. For
+       example:
+
+         /abc/posix,regerror_buffsize=20
+
+       This provides a means of testing the behaviour of regerror()  when  the
+       buffer  is  too  small  for the error message. If this modifier has not
+       been set, a large buffer is used.
+
        The aftertext and allaftertext  subject  modifiers  work  as  described
        below. All other modifiers cause an error.
 
@@ -751,7 +794,8 @@ PATTERN MODIFIERS
        The following modifiers are really subject modifiers, and are described
        below.  However, they may be included in a pattern's modifier list,  in
        which  case  they  are  applied to every subject line that is processed
-       with that pattern. They do not affect the compilation process.
+       with that pattern. They may not appear in #pattern commands. These mod-
+       ifiers do not affect the compilation process.
 
              aftertext           show text after match
              allaftertext        show text after captures
@@ -762,20 +806,20 @@ PATTERN MODIFIERS
              replace=<string>    specify a replacement string
              startchar           show starting character when relevant
 
-       These modifiers may not appear in a #pattern command. If you want  them
+       These  modifiers may not appear in a #pattern command. If you want them
        as defaults, set them in a #subject command.
 
    Saving a compiled pattern
 
-       When  a  pattern with the push modifier is successfully compiled, it is
-       pushed onto a stack of compiled patterns,  and  pcre2test  expects  the
-       next  line to contain a new pattern (or a command) instead of a subject
+       When a pattern with the push modifier is successfully compiled,  it  is
+       pushed  onto  a  stack  of compiled patterns, and pcre2test expects the
+       next line to contain a new pattern (or a command) instead of a  subject
        line. This facility is used when saving compiled patterns to a file, as
-       described  in  the section entitled "Saving and restoring compiled pat-
+       described in the section entitled "Saving and restoring  compiled  pat-
        terns" below.  The push modifier is incompatible with compilation modi-
        fiers such as global that act at match time. Any that are specified are
-       ignored, with a warning message, except for replace,  which  causes  an
-       error.  Note  that, jitverify, which is allowed, does not carry through
+       ignored,  with  a  warning message, except for replace, which causes an
+       error. Note that, jitverify, which is allowed, does not  carry  through
        to any subsequent matching that uses this pattern.
 
 
@@ -786,7 +830,7 @@ SUBJECT MODIFIERS
 
    Setting match options
 
-       The    following   modifiers   set   options   for   pcre2_match()   or
+       The   following   modifiers   set   options   for   pcre2_match()    or
        pcre2_dfa_match(). See pcreapi for a description of their effects.
 
              anchored                  set PCRE2_ANCHORED
@@ -800,20 +844,20 @@ SUBJECT MODIFIERS
              partial_hard (or ph)      set PCRE2_PARTIAL_HARD
              partial_soft (or ps)      set PCRE2_PARTIAL_SOFT
 
-       The partial matching modifiers are provided with abbreviations  because
+       The  partial matching modifiers are provided with abbreviations because
        they appear frequently in tests.
 
-       If  the  /posix  modifier was present on the pattern, causing the POSIX
+       If the /posix modifier was present on the pattern,  causing  the  POSIX
        wrapper API to be used, the only option-setting modifiers that have any
-       effect   are   notbol,   notempty,   and  noteol,  causing  REG_NOTBOL,
-       REG_NOTEMPTY, and REG_NOTEOL, respectively, to be passed to  regexec().
+       effect  are  notbol,  notempty,   and   noteol,   causing   REG_NOTBOL,
+       REG_NOTEMPTY,  and REG_NOTEOL, respectively, to be passed to regexec().
        Any other modifiers cause an error.
 
    Setting match controls
 
-       The  following  modifiers  affect the matching process or request addi-
-       tional information. Some of them may also be  specified  on  a  pattern
-       line  (see  above), in which case they apply to every subject line that
+       The following modifiers affect the matching process  or  request  addi-
+       tional  information.  Some  of  them may also be specified on a pattern
+       line (see above), in which case they apply to every subject  line  that
        is matched against that pattern.
 
              aftertext                 show text after match
@@ -848,23 +892,23 @@ SUBJECT MODIFIERS
 
    Showing more text
 
-       The aftertext modifier requests that as well as outputting the part  of
+       The  aftertext modifier requests that as well as outputting the part of
        the subject string that matched the entire pattern, pcre2test should in
        addition output the remainder of the subject string. This is useful for
        tests where the subject contains multiple copies of the same substring.
-       The allaftertext modifier requests the same action  for  captured  sub-
+       The  allaftertext  modifier  requests the same action for captured sub-
        strings as well as the main matched substring. In each case the remain-
        der is output on the following line with a plus character following the
        capture number.
 
-       The  allusedtext modifier requests that all the text that was consulted
-       during a successful pattern match by the interpreter should  be  shown.
-       This  feature  is not supported for JIT matching, and if requested with
-       JIT it is ignored (with  a  warning  message).  Setting  this  modifier
+       The allusedtext modifier requests that all the text that was  consulted
+       during  a  successful pattern match by the interpreter should be shown.
+       This feature is not supported for JIT matching, and if  requested  with
+       JIT  it  is  ignored  (with  a  warning message). Setting this modifier
        affects the output if there is a lookbehind at the start of a match, or
-       a lookahead at the end, or if \K is used  in  the  pattern.  Characters
-       that  precede or follow the start and end of the actual match are indi-
-       cated in the output by '<' or '>' characters underneath them.  Here  is
+       a  lookahead  at  the  end, or if \K is used in the pattern. Characters
+       that precede or follow the start and end of the actual match are  indi-
+       cated  in  the output by '<' or '>' characters underneath them. Here is
        an example:
 
            re> /(?<=pqr)abc(?=xyz)/
@@ -872,16 +916,16 @@ SUBJECT MODIFIERS
           0: pqrabcxyz
              <<<   >>>
 
-       This  shows  that  the  matched string is "abc", with the preceding and
-       following strings "pqr" and "xyz"  having  been  consulted  during  the
+       This shows that the matched string is "abc",  with  the  preceding  and
+       following  strings  "pqr"  and  "xyz"  having been consulted during the
        match (when processing the assertions).
 
-       The  startchar  modifier  requests  that the starting character for the
-       match be indicated, if it is different to  the  start  of  the  matched
+       The startchar modifier requests that the  starting  character  for  the
+       match  be  indicated,  if  it  is different to the start of the matched
        string. The only time when this occurs is when \K has been processed as
        part of the match. In this situation, the output for the matched string
-       is  displayed  from  the  starting  character instead of from the match
-       point, with circumflex characters under  the  earlier  characters.  For
+       is displayed from the starting character  instead  of  from  the  match
+       point,  with  circumflex  characters  under the earlier characters. For
        example:
 
            re> /abc\Kxyz/
@@ -889,7 +933,7 @@ SUBJECT MODIFIERS
           0: abcxyz
              ^^^
 
-       Unlike  allusedtext, the startchar modifier can be used with JIT.  How-
+       Unlike allusedtext, the startchar modifier can be used with JIT.   How-
        ever, these two modifiers are mutually exclusive.
 
    Showing the value of all capture groups
@@ -897,88 +941,88 @@ SUBJECT MODIFIERS
        The allcaptures modifier requests that the values of all potential cap-
        tured parentheses be output after a match. By default, only those up to
        the highest one actually used in the match are output (corresponding to
-       the  return  code from pcre2_match()). Groups that did not take part in
+       the return code from pcre2_match()). Groups that did not take  part  in
        the match are output as "<unset>".
 
    Testing callouts
 
-       A callout function is supplied when pcre2test calls the library  match-
-       ing  functions, unless callout_none is specified. If callout_capture is
+       A  callout function is supplied when pcre2test calls the library match-
+       ing functions, unless callout_none is specified. If callout_capture  is
        set, the current captured groups are output when a callout occurs.
 
-       The callout_fail modifier can be given one or two numbers. If there  is
+       The  callout_fail modifier can be given one or two numbers. If there is
        only one number, 1 is returned instead of 0 when a callout of that num-
-       ber is reached. If two numbers are given, 1 is  returned  when  callout
+       ber  is  reached.  If two numbers are given, 1 is returned when callout
        <n> is reached for the <m>th time. Note that callouts with string argu-
-       ments are always given the number zero.  See  "Callouts"  below  for  a
+       ments  are  always  given  the  number zero. See "Callouts" below for a
        description of the output when a callout it taken.
 
-       The  callout_data  modifier can be given an unsigned or a negative num-
-       ber.  This is set as the "user data" that is  passed  to  the  matching
-       function,  and  passed  back  when the callout function is invoked. Any
-       value other than zero is used as  a  return  from  pcre2test's  callout
+       The callout_data modifier can be given an unsigned or a  negative  num-
+       ber.   This  is  set  as the "user data" that is passed to the matching
+       function, and passed back when the callout  function  is  invoked.  Any
+       value  other  than  zero  is  used as a return from pcre2test's callout
        function.
 
    Finding all matches in a string
 
        Searching for all possible matches within a subject can be requested by
-       the global or /altglobal modifier. After finding a match, the  matching
-       function  is  called  again to search the remainder of the subject. The
-       difference between global and altglobal is that  the  former  uses  the
-       start_offset  argument  to  pcre2_match() or pcre2_dfa_match() to start
-       searching at a new point within the entire string (which is  what  Perl
+       the  global or /altglobal modifier. After finding a match, the matching
+       function is called again to search the remainder of  the  subject.  The
+       difference  between  global  and  altglobal is that the former uses the
+       start_offset argument to pcre2_match() or  pcre2_dfa_match()  to  start
+       searching  at  a new point within the entire string (which is what Perl
        does), whereas the latter passes over a shortened subject. This makes a
        difference to the matching process if the pattern begins with a lookbe-
        hind assertion (including \b or \B).
 
-       If  an  empty  string  is  matched,  the  next  match  is done with the
+       If an empty string  is  matched,  the  next  match  is  done  with  the
        PCRE2_NOTEMPTY_ATSTART and PCRE2_ANCHORED flags set, in order to search
        for another, non-empty, match at the same point in the subject. If this
-       match fails, the start offset is advanced,  and  the  normal  match  is
-       retried.  This  imitates the way Perl handles such cases when using the
-       /g modifier or the split() function.  Normally,  the  start  offset  is
-       advanced  by  one  character,  but if the newline convention recognizes
-       CRLF as a newline, and the current character is CR followed by  LF,  an
+       match  fails,  the  start  offset  is advanced, and the normal match is
+       retried. This imitates the way Perl handles such cases when  using  the
+       /g  modifier  or  the  split()  function. Normally, the start offset is
+       advanced by one character, but if  the  newline  convention  recognizes
+       CRLF  as  a newline, and the current character is CR followed by LF, an
        advance of two characters occurs.
 
    Testing substring extraction functions
 
-       The  copy  and  get  modifiers  can  be  used  to  test  the pcre2_sub-
+       The copy  and  get  modifiers  can  be  used  to  test  the  pcre2_sub-
        string_copy_xxx() and pcre2_substring_get_xxx() functions.  They can be
-       given  more than once, and each can specify a group name or number, for
+       given more than once, and each can specify a group name or number,  for
        example:
 
           abcd\=copy=1,copy=3,get=G1
 
-       If the #subject command is used to set default copy and/or  get  lists,
-       these  can  be unset by specifying a negative number to cancel all num-
+       If  the  #subject command is used to set default copy and/or get lists,
+       these can be unset by specifying a negative number to cancel  all  num-
        bered groups and an empty name to cancel all named groups.
 
-       The getall modifier tests  pcre2_substring_list_get(),  which  extracts
+       The  getall  modifier  tests pcre2_substring_list_get(), which extracts
        all captured substrings.
 
-       If  the  subject line is successfully matched, the substrings extracted
-       by the convenience functions are output with  C,  G,  or  L  after  the
-       string  number  instead  of  a colon. This is in addition to the normal
-       full list. The string length (that is, the return from  the  extraction
+       If the subject line is successfully matched, the  substrings  extracted
+       by  the  convenience  functions  are  output  with C, G, or L after the
+       string number instead of a colon. This is in  addition  to  the  normal
+       full  list.  The string length (that is, the return from the extraction
        function) is given in parentheses after each substring, followed by the
        name when the extraction was by name.
 
    Testing the substitution function
 
-       If the replace modifier is  set,  the  pcre2_substitute()  function  is
-       called  instead  of  one  of  the  matching  functions.  Unlike subject
-       strings, pcre2test does not  process  replacement  strings  for  escape
+       If  the  replace  modifier  is  set, the pcre2_substitute() function is
+       called instead  of  one  of  the  matching  functions.  Unlike  subject
+       strings,  pcre2test  does  not  process  replacement strings for escape
        sequences. In UTF mode, a replacement string is checked to see if it is
        a valid UTF-8 string.  If so, it is correctly converted to a UTF string
-       of  the appropriate code unit width. If it is not a valid UTF-8 string,
+       of the appropriate code unit width. If it is not a valid UTF-8  string,
        the individual code units are copied directly. This provides a means of
        passing an invalid UTF-8 string for testing purposes.
 
-       If  the  global  modifier  is set, PCRE2_SUBSTITUTE_GLOBAL is passed to
+       If the global modifier is set,  PCRE2_SUBSTITUTE_GLOBAL  is  passed  to
        pcre2_substitute().  After  a  successful  substitution,  the  modified
-       string  is  output, preceded by the number of replacements. This may be
-       zero if there were no matches. Here is a simple example of a  substitu-
+       string is output, preceded by the number of replacements. This  may  be
+       zero  if there were no matches. Here is a simple example of a substitu-
        tion test:
 
          /abc/replace=xxx
@@ -987,11 +1031,11 @@ SUBJECT MODIFIERS
              =abc=abc=\=global
           2: =xxx=xxx=
 
-       Subject  and  replacement  strings  should be kept relatively short for
-       substitution tests, as fixed-size buffers are used. To make it easy  to
-       test  for buffer overflow, if the replacement string starts with a num-
-       ber in square brackets, that number is passed to pcre2_substitute()  as
-       the  size of the output buffer, with the replacement string starting at
+       Subject and replacement strings should be  kept  relatively  short  for
+       substitution  tests, as fixed-size buffers are used. To make it easy to
+       test for buffer overflow, if the replacement string starts with a  num-
+       ber  in square brackets, that number is passed to pcre2_substitute() as
+       the size of the output buffer, with the replacement string starting  at
        the next character. Here is an example that tests the edge case:
 
          /abc/
@@ -1001,140 +1045,140 @@ SUBJECT MODIFIERS
          Failed: error -47: no more memory
 
        A replacement string is ignored with POSIX and DFA matching. Specifying
-       partial  matching  provokes  an  error return ("bad option value") from
+       partial matching provokes an error return  ("bad  option  value")  from
        pcre2_substitute().
 
    Setting the JIT stack size
 
-       The jitstack modifier provides a way of setting the maximum stack  size
-       that  is  used  by the just-in-time optimization code. It is ignored if
+       The  jitstack modifier provides a way of setting the maximum stack size
+       that is used by the just-in-time optimization code. It  is  ignored  if
        JIT optimization is not being used. The value is a number of kilobytes.
        Providing a stack that is larger than the default 32K is necessary only
        for very complicated patterns.
 
    Setting match and recursion limits
 
-       The match_limit and recursion_limit modifiers set the appropriate  lim-
+       The  match_limit and recursion_limit modifiers set the appropriate lim-
        its in the match context. These values are ignored when the find_limits
        modifier is specified.
 
    Finding minimum limits
 
-       If the find_limits modifier is present, pcre2test  calls  pcre2_match()
-       several  times,  setting  different  values  in  the  match context via
-       pcre2_set_match_limit() and pcre2_set_recursion_limit() until it  finds
-       the  minimum values for each parameter that allow pcre2_match() to com-
+       If  the  find_limits modifier is present, pcre2test calls pcre2_match()
+       several times, setting  different  values  in  the  match  context  via
+       pcre2_set_match_limit()  and pcre2_set_recursion_limit() until it finds
+       the minimum values for each parameter that allow pcre2_match() to  com-
        plete without error.
 
        If JIT is being used, only the match limit is relevant. If DFA matching
-       is  being used, neither limit is relevant, and this modifier is ignored
+       is being used, neither limit is relevant, and this modifier is  ignored
        (with a warning message).
 
-       The match_limit number is a measure of the amount of backtracking  that
-       takes  place,  and  learning  the minimum value can be instructive. For
-       most simple matches, the number is quite small, but for  patterns  with
-       very  large numbers of matching possibilities, it can become large very
-       quickly   with   increasing   length    of    subject    string.    The
-       match_limit_recursion  number  is  a  measure of how much stack (or, if
-       PCRE2 is compiled with NO_RECURSE, how much heap) memory is  needed  to
+       The  match_limit number is a measure of the amount of backtracking that
+       takes place, and learning the minimum value  can  be  instructive.  For
+       most  simple  matches, the number is quite small, but for patterns with
+       very large numbers of matching possibilities, it can become large  very
+       quickly    with    increasing    length    of   subject   string.   The
+       match_limit_recursion number is a measure of how  much  stack  (or,  if
+       PCRE2  is  compiled with NO_RECURSE, how much heap) memory is needed to
        complete the match attempt.
 
    Showing MARK names
 
 
        The mark modifier causes the names from backtracking control verbs that
-       are returned from calls to pcre2_match() to be displayed. If a mark  is
-       returned  for a match, non-match, or partial match, pcre2test shows it.
-       For a match, it is on a line by itself, tagged with  "MK:".  Otherwise,
+       are  returned from calls to pcre2_match() to be displayed. If a mark is
+       returned for a match, non-match, or partial match, pcre2test shows  it.
+       For  a  match, it is on a line by itself, tagged with "MK:". Otherwise,
        it is added to the non-match message.
 
    Showing memory usage
 
-       The  memory  modifier causes pcre2test to log all memory allocation and
+       The memory modifier causes pcre2test to log all memory  allocation  and
        freeing calls that occur during a match operation.
 
    Setting a starting offset
 
-       The offset modifier sets an offset  in  the  subject  string  at  which
+       The  offset  modifier  sets  an  offset  in the subject string at which
        matching starts. Its value is a number of code units, not characters.
 
    Setting an offset limit
 
-       The  offset_limit  modifier  sets  a limit for unanchored matches. If a
+       The offset_limit modifier sets a limit for  unanchored  matches.  If  a
        match cannot be found starting at or before this offset in the subject,
        a "no match" return is given. The data value is a number of code units,
-       not characters. When this modifier is used, the use_offset_limit  modi-
+       not  characters. When this modifier is used, the use_offset_limit modi-
        fier must have been set for the pattern; if not, an error is generated.
 
    Setting the size of the output vector
 
-       The  ovector  modifier  applies  only  to  the subject line in which it
-       appears, though of course it can also be used to set  a  default  in  a
-       #subject  command. It specifies the number of pairs of offsets that are
+       The ovector modifier applies only to  the  subject  line  in  which  it
+       appears,  though  of  course  it can also be used to set a default in a
+       #subject command. It specifies the number of pairs of offsets that  are
        available for storing matching information. The default is 15.
 
-       A value of zero is useful when testing the POSIX API because it  causes
+       A  value of zero is useful when testing the POSIX API because it causes
        regexec() to be called with a NULL capture vector. When not testing the
-       POSIX API, a value of  zero  is  used  to  cause  pcre2_match_data_cre-
-       ate_from_pattern()  to  be  called, in order to create a match block of
+       POSIX  API,  a  value  of  zero  is used to cause pcre2_match_data_cre-
+       ate_from_pattern() to be called, in order to create a  match  block  of
        exactly the right size for the pattern. (It is not possible to create a
-       match  block  with  a zero-length ovector; there is always at least one
+       match block with a zero-length ovector; there is always  at  least  one
        pair of offsets.)
 
    Passing the subject as zero-terminated
 
        By default, the subject string is passed to a native API matching func-
        tion with its correct length. In order to test the facility for passing
-       a zero-terminated string, the zero_terminate modifier is  provided.  It
+       a  zero-terminated  string, the zero_terminate modifier is provided. It
        causes the length to be passed as PCRE2_ZERO_TERMINATED. (When matching
-       via the POSIX interface, this modifier has no effect, as  there  is  no
+       via  the  POSIX  interface, this modifier has no effect, as there is no
        facility for passing a length.)
 
-       When  testing  pcre2_substitute(), this modifier also has the effect of
+       When testing pcre2_substitute(), this modifier also has the  effect  of
        passing the replacement string as zero-terminated.
 
    Passing a NULL context
 
-       Normally,  pcre2test  passes  a   context   block   to   pcre2_match(),
+       Normally,   pcre2test   passes   a   context  block  to  pcre2_match(),
        pcre2_dfa_match() or pcre2_jit_match(). If the null_context modifier is
-       set, however, NULL is passed. This is for  testing  that  the  matching
+       set,  however,  NULL  is  passed. This is for testing that the matching
        functions behave correctly in this case (they use default values). This
-       modifier cannot be used with the find_limits modifier or  when  testing
+       modifier  cannot  be used with the find_limits modifier or when testing
        the substitution function.
 
 
 THE ALTERNATIVE MATCHING FUNCTION
 
-       By  default,  pcre2test  uses  the  standard  PCRE2  matching function,
+       By default,  pcre2test  uses  the  standard  PCRE2  matching  function,
        pcre2_match() to match each subject line. PCRE2 also supports an alter-
-       native  matching  function, pcre2_dfa_match(), which operates in a dif-
-       ferent way, and has some restrictions. The differences between the  two
+       native matching function, pcre2_dfa_match(), which operates in  a  dif-
+       ferent  way, and has some restrictions. The differences between the two
        functions are described in the pcre2matching documentation.
 
-       If  the dfa modifier is set, the alternative matching function is used.
-       This function finds all possible matches at a given point in  the  sub-
-       ject.  If,  however, the dfa_shortest modifier is set, processing stops
-       after the first match is found. This is always  the  shortest  possible
+       If the dfa modifier is set, the alternative matching function is  used.
+       This  function  finds all possible matches at a given point in the sub-
+       ject. If, however, the dfa_shortest modifier is set,  processing  stops
+       after  the  first  match is found. This is always the shortest possible
        match.
 
 
 DEFAULT OUTPUT FROM pcre2test
 
-       This  section  describes  the output when the normal matching function,
+       This section describes the output when the  normal  matching  function,
        pcre2_match(), is being used.
 
-       When a match succeeds, pcre2test outputs  the  list  of  captured  sub-
-       strings,  starting  with number 0 for the string that matched the whole
-       pattern.   Otherwise,  it  outputs  "No  match"  when  the  return   is
-       PCRE2_ERROR_NOMATCH,  or  "Partial  match:"  followed  by the partially
-       matching substring when the return is PCRE2_ERROR_PARTIAL.  (Note  that
-       this  is  the  entire  substring  that was inspected during the partial
-       match; it may include characters before the actual  match  start  if  a
+       When  a  match  succeeds,  pcre2test  outputs the list of captured sub-
+       strings, starting with number 0 for the string that matched  the  whole
+       pattern.    Otherwise,  it  outputs  "No  match"  when  the  return  is
+       PCRE2_ERROR_NOMATCH, or "Partial  match:"  followed  by  the  partially
+       matching  substring  when the return is PCRE2_ERROR_PARTIAL. (Note that
+       this is the entire substring that  was  inspected  during  the  partial
+       match;  it  may  include  characters before the actual match start if a
        lookbehind assertion, \K, \b, or \B was involved.)
 
        For any other return, pcre2test outputs the PCRE2 negative error number
-       and a short descriptive phrase. If the error is  a  failed  UTF  string
-       check,  the  code  unit offset of the start of the failing character is
+       and  a  short  descriptive  phrase. If the error is a failed UTF string
+       check, the code unit offset of the start of the  failing  character  is
        also output. Here is an example of an interactive pcre2test run.
 
          $ pcre2test
@@ -1150,8 +1194,8 @@ DEFAULT OUTPUT FROM pcre2test
        Unset capturing substrings that are not followed by one that is set are
        not shown by pcre2test unless the allcaptures modifier is specified. In
        the following example, there are two capturing substrings, but when the
-       first  data  line is matched, the second, unset substring is not shown.
-       An "internal" unset substring is shown as "<unset>", as for the  second
+       first data line is matched, the second, unset substring is  not  shown.
+       An  "internal" unset substring is shown as "<unset>", as for the second
        data line.
 
            re> /(a)|(b)/
@@ -1163,11 +1207,11 @@ DEFAULT OUTPUT FROM pcre2test
           1: <unset>
           2: b
 
-       If  the strings contain any non-printing characters, they are output as
-       \xhh escapes if the value is less than 256 and UTF  mode  is  not  set.
+       If the strings contain any non-printing characters, they are output  as
+       \xhh  escapes  if  the  value is less than 256 and UTF mode is not set.
        Otherwise they are output as \x{hh...} escapes. See below for the defi-
-       nition of non-printing characters. If the /aftertext modifier  is  set,
-       the  output  for substring 0 is followed by the the rest of the subject
+       nition  of  non-printing characters. If the /aftertext modifier is set,
+       the output for substring 0 is followed by the the rest of  the  subject
        string, identified by "0+" like this:
 
            re> /cat/aftertext
@@ -1175,7 +1219,7 @@ DEFAULT OUTPUT FROM pcre2test
           0: cat
           0+ aract
 
-       If global matching is requested, the  results  of  successive  matching
+       If  global  matching  is  requested, the results of successive matching
        attempts are output in sequence, like this:
 
            re> /\Bi(\w\w)/g
@@ -1187,8 +1231,8 @@ DEFAULT OUTPUT FROM pcre2test
           0: ipp
           1: pp
 
-       "No  match" is output only if the first match attempt fails. Here is an
-       example of a failure message (the offset 4 that  is  specified  by  the
+       "No match" is output only if the first match attempt fails. Here is  an
+       example  of  a  failure  message (the offset 4 that is specified by the
        offset modifier is past the end of the subject string):
 
            re> /xyz/
@@ -1196,7 +1240,7 @@ DEFAULT OUTPUT FROM pcre2test
          Error -24 (bad offset value)
 
        Note that whereas patterns can be continued over several lines (a plain
-       ">" prompt is used for continuations), subject lines may  not.  However
+       ">"  prompt  is used for continuations), subject lines may not. However
        newlines can be included in a subject by means of the \n escape (or \r,
        \r\n, etc., depending on the newline sequence setting).
 
@@ -1204,7 +1248,7 @@ DEFAULT OUTPUT FROM pcre2test
 OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
 
        When the alternative matching function, pcre2_dfa_match(), is used, the
-       output  consists  of  a list of all the matches that start at the first
+       output consists of a list of all the matches that start  at  the  first
        point in the subject where there is at least one match. For example:
 
            re> /(tang|tangerine|tan)/
@@ -1213,11 +1257,11 @@ OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
           1: tang
           2: tan
 
-       Using the normal matching function on this data finds only "tang".  The
-       longest  matching  string  is  always  given first (and numbered zero).
-       After a PCRE2_ERROR_PARTIAL return, the  output  is  "Partial  match:",
-       followed  by  the  partially  matching substring. Note that this is the
-       entire substring that was inspected during the partial  match;  it  may
+       Using  the normal matching function on this data finds only "tang". The
+       longest matching string is always  given  first  (and  numbered  zero).
+       After  a  PCRE2_ERROR_PARTIAL  return,  the output is "Partial match:",
+       followed by the partially matching substring. Note  that  this  is  the
+       entire  substring  that  was inspected during the partial match; it may
        include characters before the actual match start if a lookbehind asser-
        tion, \b, or \B was involved. (\K is not supported for DFA matching.)
 
@@ -1233,16 +1277,16 @@ OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
           1: tan
           0: tan
 
-       The  alternative  matching function does not support substring capture,
-       so the modifiers that are concerned with captured  substrings  are  not
+       The alternative matching function does not support  substring  capture,
+       so  the  modifiers  that are concerned with captured substrings are not
        relevant.
 
 
 RESTARTING AFTER A PARTIAL MATCH
 
-       When  the  alternative matching function has given the PCRE2_ERROR_PAR-
+       When the alternative matching function has given  the  PCRE2_ERROR_PAR-
        TIAL return, indicating that the subject partially matched the pattern,
-       you  can restart the match with additional subject data by means of the
+       you can restart the match with additional subject data by means of  the
        dfa_restart modifier. For example:
 
            re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
@@ -1251,44 +1295,44 @@ RESTARTING AFTER A PARTIAL MATCH
          data> n05\=dfa,dfa_restart
           0: n05
 
-       For further information about partial matching,  see  the  pcre2partial
+       For  further  information  about partial matching, see the pcre2partial
        documentation.
 
 
 CALLOUTS
 
        If the pattern contains any callout requests, pcre2test's callout func-
-       tion is called during matching unless callout_none is specified.   This
+       tion  is called during matching unless callout_none is specified.  This
        works with both matching functions.
 
-       The  callout  function in pcre2test returns zero (carry on matching) by
-       default, but you can use a callout_fail modifier in a subject line  (as
+       The callout function in pcre2test returns zero (carry on  matching)  by
+       default,  but you can use a callout_fail modifier in a subject line (as
        described above) to change this and other parameters of the callout.
 
        Inserting callouts can be helpful when using pcre2test to check compli-
-       cated regular expressions. For further information about callouts,  see
+       cated  regular expressions. For further information about callouts, see
        the pcre2callout documentation.
 
-       The  output for callouts with numerical arguments and those with string
+       The output for callouts with numerical arguments and those with  string
        arguments is slightly different.
 
    Callouts with numerical arguments
 
        By default, the callout function displays the callout number, the start
-       and  current positions in the subject text at the callout time, and the
+       and current positions in the subject text at the callout time, and  the
        next pattern item to be tested. For example:
 
          --->pqrabcdef
            0    ^  ^     \d
 
-       This output indicates that  callout  number  0  occurred  for  a  match
-       attempt  starting  at  the fourth character of the subject string, when
-       the pointer was at the seventh character, and  when  the  next  pattern
-       item  was  \d.  Just  one circumflex is output if the start and current
+       This  output  indicates  that  callout  number  0  occurred for a match
+       attempt starting at the fourth character of the  subject  string,  when
+       the  pointer  was  at  the seventh character, and when the next pattern
+       item was \d. Just one circumflex is output if  the  start  and  current
        positions are the same.
 
        Callouts numbered 255 are assumed to be automatic callouts, inserted as
-       a  result  of the /auto_callout pattern modifier. In this case, instead
+       a result of the /auto_callout pattern modifier. In this  case,  instead
        of showing the callout number, the offset in the pattern, preceded by a
        plus, is output. For example:
 
@@ -1302,7 +1346,7 @@ CALLOUTS
           0: E*
 
        If a pattern contains (*MARK) items, an additional line is output when-
-       ever a change of latest mark is passed to  the  callout  function.  For
+       ever  a  change  of  latest mark is passed to the callout function. For
        example:
 
            re> /a(*MARK:X)bc/auto_callout
@@ -1316,17 +1360,17 @@ CALLOUTS
          +12 ^  ^
           0: abc
 
-       The  mark  changes between matching "a" and "b", but stays the same for
-       the rest of the match, so nothing more is output. If, as  a  result  of
-       backtracking,  the  mark  reverts to being unset, the text "<unset>" is
+       The mark changes between matching "a" and "b", but stays the  same  for
+       the  rest  of  the match, so nothing more is output. If, as a result of
+       backtracking, the mark reverts to being unset, the  text  "<unset>"  is
        output.
 
    Callouts with string arguments
 
        The output for a callout with a string argument is similar, except that
-       instead  of outputting a callout number before the position indicators,
-       the callout string and its offset in  the  pattern  string  are  output
-       before  the reflection of the subject string, and the subject string is
+       instead of outputting a callout number before the position  indicators,
+       the  callout  string  and  its  offset in the pattern string are output
+       before the reflection of the subject string, and the subject string  is
        reflected for each callout. For example:
 
            re> /^ab(?C'first')cd(?C"second")ef/
@@ -1343,59 +1387,59 @@ CALLOUTS
 NON-PRINTING CHARACTERS
 
        When pcre2test is outputting text in the compiled version of a pattern,
-       bytes  other  than 32-126 are always treated as non-printing characters
+       bytes other than 32-126 are always treated as  non-printing  characters
        and are therefore shown as hex escapes.
 
-       When pcre2test is outputting text that is a matched part of  a  subject
-       string,  it behaves in the same way, unless a different locale has been
-       set for the pattern (using the /locale modifier).  In  this  case,  the
-       isprint()  function  is  used  to distinguish printing and non-printing
+       When  pcre2test  is outputting text that is a matched part of a subject
+       string, it behaves in the same way, unless a different locale has  been
+       set  for  the  pattern  (using the /locale modifier). In this case, the
+       isprint() function is used to  distinguish  printing  and  non-printing
        characters.
 
 
 SAVING AND RESTORING COMPILED PATTERNS
 
-       It is possible to save compiled patterns  on  disc  or  elsewhere,  and
+       It  is  possible  to  save  compiled patterns on disc or elsewhere, and
        reload them later, subject to a number of restrictions. JIT data cannot
-       be saved. The host on which the patterns are reloaded must  be  running
+       be  saved.  The host on which the patterns are reloaded must be running
        the same version of PCRE2, with the same code unit width, and must also
-       have the same endianness, pointer width  and  PCRE2_SIZE  type.  Before
-       compiled  patterns  can be saved they must be serialized, that is, con-
-       verted to a stream of bytes. A single byte stream may contain any  num-
-       ber  of  compiled  patterns,  but  they must all use the same character
+       have  the  same  endianness,  pointer width and PCRE2_SIZE type. Before
+       compiled patterns can be saved they must be serialized, that  is,  con-
+       verted  to a stream of bytes. A single byte stream may contain any num-
+       ber of compiled patterns, but they must  all  use  the  same  character
        tables. A single copy of the tables is included in the byte stream (its
        size is 1088 bytes).
 
-       The  functions  whose  names  begin  with pcre2_serialize_ are used for
-       serializing and de-serializing. They are described in the  pcre2serial-
+       The functions whose names begin  with  pcre2_serialize_  are  used  for
+       serializing  and de-serializing. They are described in the pcre2serial-
        ize  documentation.  In  this  section  we  describe  the  features  of
        pcre2test that can be used to test these functions.
 
-       When a pattern with push  modifier  is  successfully  compiled,  it  is
-       pushed  onto  a  stack  of compiled patterns, and pcre2test expects the
-       next line to contain a new pattern (or command) instead  of  a  subject
+       When  a  pattern  with  push  modifier  is successfully compiled, it is
+       pushed onto a stack of compiled patterns,  and  pcre2test  expects  the
+       next  line  to  contain a new pattern (or command) instead of a subject
        line. By this means, a number of patterns can be compiled and retained.
-       The push modifier is incompatible with  posix,  and  control  modifiers
+       The  push  modifier  is  incompatible with posix, and control modifiers
        that act at match time are ignored (with a message). The jitverify mod-
        ifier applies only at compile time. The command
 
          #save <filename>
 
        causes all the stacked patterns to be serialized and the result written
-       to  the named file. Afterwards, all the stacked patterns are freed. The
+       to the named file. Afterwards, all the stacked patterns are freed.  The
        command
 
          #load <filename>
 
-       reads the data in the file, and then arranges for it to  be  de-serial-
-       ized,  with the resulting compiled patterns added to the pattern stack.
-       The pattern on the top of the stack can be retrieved by the  #pop  com-
-       mand,  which  must  be  followed  by  lines  of subjects that are to be
-       matched with the pattern, terminated as usual by an empty line  or  end
-       of  file.  This  command  may be followed by a modifier list containing
-       only control modifiers that act after a pattern has been  compiled.  In
-       particular,  hex,  posix, and push are not allowed, nor are any option-
-       setting modifiers.  The JIT modifiers are, however permitted.  Here  is
+       reads  the  data in the file, and then arranges for it to be de-serial-
+       ized, with the resulting compiled patterns added to the pattern  stack.
+       The  pattern  on the top of the stack can be retrieved by the #pop com-
+       mand, which must be followed by  lines  of  subjects  that  are  to  be
+       matched  with  the pattern, terminated as usual by an empty line or end
+       of file. This command may be followed by  a  modifier  list  containing
+       only  control  modifiers that act after a pattern has been compiled. In
+       particular, hex, posix, and push are not allowed, nor are  any  option-
+       setting  modifiers.   The JIT modifiers are, however permitted. Here is
        an example that saves and reloads two patterns.
 
          /abc/push
@@ -1408,7 +1452,7 @@ SAVING AND RESTORING COMPILED PATTERNS
          #pop jit,bincode
          abc
 
-       If  jitverify  is  used with #pop, it does not automatically imply jit,
+       If jitverify is used with #pop, it does not  automatically  imply  jit,
        which is different behaviour from when it is used on a pattern.
 
 
@@ -1427,5 +1471,5 @@ AUTHOR
 
 REVISION
 
-       Last updated: 17 October 2015
+       Last updated: 05 November 2015
        Copyright (c) 1997-2015 University of Cambridge.