/[pcre]/code/trunk/doc/pcre.txt
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revision 227 by ph10, Tue Aug 21 15:00:15 2007 UTC revision 231 by ph10, Tue Sep 11 11:15:33 2007 UTC
# Line 361  CODE VALUE OF NEWLINE Line 361  CODE VALUE OF NEWLINE
361         conventional to use the standard for your operating system.         conventional to use the standard for your operating system.
362    
363    
364    WHAT \R MATCHES
365    
366           By default, the sequence \R in a pattern matches  any  Unicode  newline
367           sequence,  whatever  has  been selected as the line ending sequence. If
368           you specify
369    
370             --enable-bsr-anycrlf
371    
372           the default is changed so that \R matches only CR, LF, or  CRLF.  What-
373           ever  is selected when PCRE is built can be overridden when the library
374           functions are called.
375    
376    
377  BUILDING SHARED AND STATIC LIBRARIES  BUILDING SHARED AND STATIC LIBRARIES
378    
379         The PCRE building process uses libtool to build both shared and  static         The PCRE building process uses libtool to build both shared and  static
# Line 513  AUTHOR Line 526  AUTHOR
526    
527  REVISION  REVISION
528    
529         Last updated: 30 July 2007         Last updated: 11 September 2007
530         Copyright (c) 1997-2007 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.
531  ------------------------------------------------------------------------------  ------------------------------------------------------------------------------
532    
# Line 919  NEWLINES Line 932  NEWLINES
932         dollar metacharacters, the handling of #-comments in /x mode, and, when         dollar metacharacters, the handling of #-comments in /x mode, and, when
933         CRLF is a recognized line ending sequence, the match position  advance-         CRLF is a recognized line ending sequence, the match position  advance-
934         ment for a non-anchored pattern. There is more detail about this in the         ment for a non-anchored pattern. There is more detail about this in the
935         section on pcre_exec() options below. The choice of newline  convention         section on pcre_exec() options below.
936         does not affect the interpretation of the \n or \r escape sequences.  
937           The choice of newline convention does not affect the interpretation  of
938           the  \n  or  \r  escape  sequences, nor does it affect what \R matches,
939           which is controlled in a similar way, but by separate options.
940    
941    
942  MULTITHREADING  MULTITHREADING
943    
944         The  PCRE  functions  can be used in multi-threading applications, with         The PCRE functions can be used in  multi-threading  applications,  with
945         the  proviso  that  the  memory  management  functions  pointed  to  by         the  proviso  that  the  memory  management  functions  pointed  to  by
946         pcre_malloc, pcre_free, pcre_stack_malloc, and pcre_stack_free, and the         pcre_malloc, pcre_free, pcre_stack_malloc, and pcre_stack_free, and the
947         callout function pointed to by pcre_callout, are shared by all threads.         callout function pointed to by pcre_callout, are shared by all threads.
948    
949         The  compiled form of a regular expression is not altered during match-         The compiled form of a regular expression is not altered during  match-
950         ing, so the same compiled pattern can safely be used by several threads         ing, so the same compiled pattern can safely be used by several threads
951         at once.         at once.
952    
# Line 938  MULTITHREADING Line 954  MULTITHREADING
954  SAVING PRECOMPILED PATTERNS FOR LATER USE  SAVING PRECOMPILED PATTERNS FOR LATER USE
955    
956         The compiled form of a regular expression can be saved and re-used at a         The compiled form of a regular expression can be saved and re-used at a
957         later time, possibly by a different program, and even on a  host  other         later  time,  possibly by a different program, and even on a host other
958         than  the  one  on  which  it  was  compiled.  Details are given in the         than the one on which  it  was  compiled.  Details  are  given  in  the
959         pcreprecompile documentation. However, compiling a  regular  expression         pcreprecompile  documentation.  However, compiling a regular expression
960         with  one version of PCRE for use with a different version is not guar-         with one version of PCRE for use with a different version is not  guar-
961         anteed to work and may cause crashes.         anteed to work and may cause crashes.
962    
963    
# Line 949  CHECKING BUILD-TIME OPTIONS Line 965  CHECKING BUILD-TIME OPTIONS
965    
966         int pcre_config(int what, void *where);         int pcre_config(int what, void *where);
967    
968         The function pcre_config() makes it possible for a PCRE client to  dis-         The  function pcre_config() makes it possible for a PCRE client to dis-
969         cover which optional features have been compiled into the PCRE library.         cover which optional features have been compiled into the PCRE library.
970         The pcrebuild documentation has more details about these optional  fea-         The  pcrebuild documentation has more details about these optional fea-
971         tures.         tures.
972    
973         The  first  argument  for pcre_config() is an integer, specifying which         The first argument for pcre_config() is an  integer,  specifying  which
974         information is required; the second argument is a pointer to a variable         information is required; the second argument is a pointer to a variable
975         into  which  the  information  is  placed. The following information is         into which the information is  placed.  The  following  information  is
976         available:         available:
977    
978           PCRE_CONFIG_UTF8           PCRE_CONFIG_UTF8
979    
980         The output is an integer that is set to one if UTF-8 support is  avail-         The  output is an integer that is set to one if UTF-8 support is avail-
981         able; otherwise it is set to zero.         able; otherwise it is set to zero.
982    
983           PCRE_CONFIG_UNICODE_PROPERTIES           PCRE_CONFIG_UNICODE_PROPERTIES
984    
985         The  output  is  an  integer  that is set to one if support for Unicode         The output is an integer that is set to  one  if  support  for  Unicode
986         character properties is available; otherwise it is set to zero.         character properties is available; otherwise it is set to zero.
987    
988           PCRE_CONFIG_NEWLINE           PCRE_CONFIG_NEWLINE
989    
990         The output is an integer whose value specifies  the  default  character         The  output  is  an integer whose value specifies the default character
991         sequence  that is recognized as meaning "newline". The four values that         sequence that is recognized as meaning "newline". The four values  that
992         are supported are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF,         are supported are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF,
993         and  -1  for  ANY. The default should normally be the standard sequence         and -1 for ANY. The default should normally be  the  standard  sequence
994         for your operating system.         for your operating system.
995    
996             PCRE_CONFIG_BSR
997    
998           The output is an integer whose value indicates what character sequences
999           the \R escape sequence matches by default. A value of 0 means  that  \R
1000           matches  any  Unicode  line ending sequence; a value of 1 means that \R
1001           matches only CR, LF, or CRLF. The default can be overridden when a pat-
1002           tern is compiled or matched.
1003    
1004           PCRE_CONFIG_LINK_SIZE           PCRE_CONFIG_LINK_SIZE
1005    
1006         The output is an integer that contains the number  of  bytes  used  for         The  output  is  an  integer that contains the number of bytes used for
1007         internal linkage in compiled regular expressions. The value is 2, 3, or         internal linkage in compiled regular expressions. The value is 2, 3, or
1008         4. Larger values allow larger regular expressions to  be  compiled,  at         4.  Larger  values  allow larger regular expressions to be compiled, at
1009         the  expense  of  slower matching. The default value of 2 is sufficient         the expense of slower matching. The default value of  2  is  sufficient
1010         for all but the most massive patterns, since  it  allows  the  compiled         for  all  but  the  most massive patterns, since it allows the compiled
1011         pattern to be up to 64K in size.         pattern to be up to 64K in size.
1012    
1013           PCRE_CONFIG_POSIX_MALLOC_THRESHOLD           PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1014    
1015         The  output  is  an integer that contains the threshold above which the         The output is an integer that contains the threshold  above  which  the
1016         POSIX interface uses malloc() for output vectors. Further  details  are         POSIX  interface  uses malloc() for output vectors. Further details are
1017         given in the pcreposix documentation.         given in the pcreposix documentation.
1018    
1019           PCRE_CONFIG_MATCH_LIMIT           PCRE_CONFIG_MATCH_LIMIT
1020    
1021         The output is an integer that gives the default limit for the number of         The output is an integer that gives the default limit for the number of
1022         internal matching function calls in a  pcre_exec()  execution.  Further         internal  matching  function  calls in a pcre_exec() execution. Further
1023         details are given with pcre_exec() below.         details are given with pcre_exec() below.
1024    
1025           PCRE_CONFIG_MATCH_LIMIT_RECURSION           PCRE_CONFIG_MATCH_LIMIT_RECURSION
1026    
1027         The  output is an integer that gives the default limit for the depth of         The output is an integer that gives the default limit for the depth  of
1028         recursion when calling the internal matching function in a  pcre_exec()         recursion  when calling the internal matching function in a pcre_exec()
1029         execution. Further details are given with pcre_exec() below.         execution. Further details are given with pcre_exec() below.
1030    
1031           PCRE_CONFIG_STACKRECURSE           PCRE_CONFIG_STACKRECURSE
1032    
1033         The  output is an integer that is set to one if internal recursion when         The output is an integer that is set to one if internal recursion  when
1034         running pcre_exec() is implemented by recursive function calls that use         running pcre_exec() is implemented by recursive function calls that use
1035         the  stack  to remember their state. This is the usual way that PCRE is         the stack to remember their state. This is the usual way that  PCRE  is
1036         compiled. The output is zero if PCRE was compiled to use blocks of data         compiled. The output is zero if PCRE was compiled to use blocks of data
1037         on  the  heap  instead  of  recursive  function  calls.  In  this case,         on the  heap  instead  of  recursive  function  calls.  In  this  case,
1038         pcre_stack_malloc and  pcre_stack_free  are  called  to  manage  memory         pcre_stack_malloc  and  pcre_stack_free  are  called  to  manage memory
1039         blocks on the heap, thus avoiding the use of the stack.         blocks on the heap, thus avoiding the use of the stack.
1040    
1041    
# Line 1028  COMPILING A PATTERN Line 1052  COMPILING A PATTERN
1052    
1053         Either of the functions pcre_compile() or pcre_compile2() can be called         Either of the functions pcre_compile() or pcre_compile2() can be called
1054         to compile a pattern into an internal form. The only difference between         to compile a pattern into an internal form. The only difference between
1055         the  two interfaces is that pcre_compile2() has an additional argument,         the two interfaces is that pcre_compile2() has an additional  argument,
1056         errorcodeptr, via which a numerical error code can be returned.         errorcodeptr, via which a numerical error code can be returned.
1057    
1058         The pattern is a C string terminated by a binary zero, and is passed in         The pattern is a C string terminated by a binary zero, and is passed in
1059         the  pattern  argument.  A  pointer to a single block of memory that is         the pattern argument. A pointer to a single block  of  memory  that  is
1060         obtained via pcre_malloc is returned. This contains the  compiled  code         obtained  via  pcre_malloc is returned. This contains the compiled code
1061         and related data. The pcre type is defined for the returned block; this         and related data. The pcre type is defined for the returned block; this
1062         is a typedef for a structure whose contents are not externally defined.         is a typedef for a structure whose contents are not externally defined.
1063         It is up to the caller to free the memory (via pcre_free) when it is no         It is up to the caller to free the memory (via pcre_free) when it is no
1064         longer required.         longer required.
1065    
1066         Although the compiled code of a PCRE regex is relocatable, that is,  it         Although  the compiled code of a PCRE regex is relocatable, that is, it
1067         does not depend on memory location, the complete pcre data block is not         does not depend on memory location, the complete pcre data block is not
1068         fully relocatable, because it may contain a copy of the tableptr  argu-         fully  relocatable, because it may contain a copy of the tableptr argu-
1069         ment, which is an address (see below).         ment, which is an address (see below).
1070    
1071         The options argument contains various bit settings that affect the com-         The options argument contains various bit settings that affect the com-
1072         pilation. It should be zero if no options are required.  The  available         pilation.  It  should be zero if no options are required. The available
1073         options  are  described  below. Some of them, in particular, those that         options are described below. Some of them, in  particular,  those  that
1074         are compatible with Perl, can also be set and  unset  from  within  the         are  compatible  with  Perl,  can also be set and unset from within the
1075         pattern  (see  the  detailed  description in the pcrepattern documenta-         pattern (see the detailed description  in  the  pcrepattern  documenta-
1076         tion). For these options, the contents of the options  argument  speci-         tion).  For  these options, the contents of the options argument speci-
1077         fies  their initial settings at the start of compilation and execution.         fies their initial settings at the start of compilation and  execution.
1078         The PCRE_ANCHORED and PCRE_NEWLINE_xxx options can be set at  the  time         The  PCRE_ANCHORED  and PCRE_NEWLINE_xxx options can be set at the time
1079         of matching as well as at compile time.         of matching as well as at compile time.
1080    
1081         If errptr is NULL, pcre_compile() returns NULL immediately.  Otherwise,         If errptr is NULL, pcre_compile() returns NULL immediately.  Otherwise,
1082         if compilation of a pattern fails,  pcre_compile()  returns  NULL,  and         if  compilation  of  a  pattern fails, pcre_compile() returns NULL, and
1083         sets the variable pointed to by errptr to point to a textual error mes-         sets the variable pointed to by errptr to point to a textual error mes-
1084         sage. This is a static string that is part of the library. You must not         sage. This is a static string that is part of the library. You must not
1085         try to free it. The offset from the start of the pattern to the charac-         try to free it. The offset from the start of the pattern to the charac-
1086         ter where the error was discovered is placed in the variable pointed to         ter where the error was discovered is placed in the variable pointed to
1087         by  erroffset,  which must not be NULL. If it is, an immediate error is         by erroffset, which must not be NULL. If it is, an immediate  error  is
1088         given.         given.
1089    
1090         If pcre_compile2() is used instead of pcre_compile(),  and  the  error-         If  pcre_compile2()  is  used instead of pcre_compile(), and the error-
1091         codeptr  argument is not NULL, a non-zero error code number is returned         codeptr argument is not NULL, a non-zero error code number is  returned
1092         via this argument in the event of an error. This is in addition to  the         via  this argument in the event of an error. This is in addition to the
1093         textual error message. Error codes and messages are listed below.         textual error message. Error codes and messages are listed below.
1094    
1095         If  the  final  argument, tableptr, is NULL, PCRE uses a default set of         If the final argument, tableptr, is NULL, PCRE uses a  default  set  of
1096         character tables that are  built  when  PCRE  is  compiled,  using  the         character  tables  that  are  built  when  PCRE  is compiled, using the
1097         default  C  locale.  Otherwise, tableptr must be an address that is the         default C locale. Otherwise, tableptr must be an address  that  is  the
1098         result of a call to pcre_maketables(). This value is  stored  with  the         result  of  a  call to pcre_maketables(). This value is stored with the
1099         compiled  pattern,  and used again by pcre_exec(), unless another table         compiled pattern, and used again by pcre_exec(), unless  another  table
1100         pointer is passed to it. For more discussion, see the section on locale         pointer is passed to it. For more discussion, see the section on locale
1101         support below.         support below.
1102    
1103         This  code  fragment  shows a typical straightforward call to pcre_com-         This code fragment shows a typical straightforward  call  to  pcre_com-
1104         pile():         pile():
1105    
1106           pcre *re;           pcre *re;
# Line 1089  COMPILING A PATTERN Line 1113  COMPILING A PATTERN
1113             &erroffset,       /* for error offset */             &erroffset,       /* for error offset */
1114             NULL);            /* use default character tables */             NULL);            /* use default character tables */
1115    
1116         The following names for option bits are defined in  the  pcre.h  header         The  following  names  for option bits are defined in the pcre.h header
1117         file:         file:
1118    
1119           PCRE_ANCHORED           PCRE_ANCHORED
1120    
1121         If this bit is set, the pattern is forced to be "anchored", that is, it         If this bit is set, the pattern is forced to be "anchored", that is, it
1122         is constrained to match only at the first matching point in the  string         is  constrained to match only at the first matching point in the string
1123         that  is being searched (the "subject string"). This effect can also be         that is being searched (the "subject string"). This effect can also  be
1124         achieved by appropriate constructs in the pattern itself, which is  the         achieved  by appropriate constructs in the pattern itself, which is the
1125         only way to do it in Perl.         only way to do it in Perl.
1126    
1127           PCRE_AUTO_CALLOUT           PCRE_AUTO_CALLOUT
1128    
1129         If this bit is set, pcre_compile() automatically inserts callout items,         If this bit is set, pcre_compile() automatically inserts callout items,
1130         all with number 255, before each pattern item. For  discussion  of  the         all  with  number  255, before each pattern item. For discussion of the
1131         callout facility, see the pcrecallout documentation.         callout facility, see the pcrecallout documentation.
1132    
1133             PCRE_BSR_ANYCRLF
1134             PCRE_BSR_UNICODE
1135    
1136           These options (which are mutually exclusive) control what the \R escape
1137           sequence  matches.  The choice is either to match only CR, LF, or CRLF,
1138           or to match any Unicode newline sequence. The default is specified when
1139           PCRE is built. It can be overridden from within the pattern, or by set-
1140           ting an option when a compiled pattern is matched.
1141    
1142           PCRE_CASELESS           PCRE_CASELESS
1143    
1144         If  this  bit is set, letters in the pattern match both upper and lower         If this bit is set, letters in the pattern match both upper  and  lower
1145         case letters. It is equivalent to Perl's  /i  option,  and  it  can  be         case  letters.  It  is  equivalent  to  Perl's /i option, and it can be
1146         changed  within a pattern by a (?i) option setting. In UTF-8 mode, PCRE         changed within a pattern by a (?i) option setting. In UTF-8 mode,  PCRE
1147         always understands the concept of case for characters whose values  are         always  understands the concept of case for characters whose values are
1148         less  than 128, so caseless matching is always possible. For characters         less than 128, so caseless matching is always possible. For  characters
1149         with higher values, the concept of case is supported if  PCRE  is  com-         with  higher  values,  the concept of case is supported if PCRE is com-
1150         piled  with Unicode property support, but not otherwise. If you want to         piled with Unicode property support, but not otherwise. If you want  to
1151         use caseless matching for characters 128 and  above,  you  must  ensure         use  caseless  matching  for  characters 128 and above, you must ensure
1152         that  PCRE  is  compiled  with Unicode property support as well as with         that PCRE is compiled with Unicode property support  as  well  as  with
1153         UTF-8 support.         UTF-8 support.
1154    
1155           PCRE_DOLLAR_ENDONLY           PCRE_DOLLAR_ENDONLY
1156    
1157         If this bit is set, a dollar metacharacter in the pattern matches  only         If  this bit is set, a dollar metacharacter in the pattern matches only
1158         at  the  end  of the subject string. Without this option, a dollar also         at the end of the subject string. Without this option,  a  dollar  also
1159         matches immediately before a newline at the end of the string (but  not         matches  immediately before a newline at the end of the string (but not
1160         before  any  other newlines). The PCRE_DOLLAR_ENDONLY option is ignored         before any other newlines). The PCRE_DOLLAR_ENDONLY option  is  ignored
1161         if PCRE_MULTILINE is set.  There is no equivalent  to  this  option  in         if  PCRE_MULTILINE  is  set.   There is no equivalent to this option in
1162         Perl, and no way to set it within a pattern.         Perl, and no way to set it within a pattern.
1163    
1164           PCRE_DOTALL           PCRE_DOTALL
1165    
1166         If this bit is set, a dot metacharater in the pattern matches all char-         If this bit is set, a dot metacharater in the pattern matches all char-
1167         acters, including those that indicate newline. Without it, a  dot  does         acters,  including  those that indicate newline. Without it, a dot does
1168         not  match  when  the  current position is at a newline. This option is         not match when the current position is at a  newline.  This  option  is
1169         equivalent to Perl's /s option, and it can be changed within a  pattern         equivalent  to Perl's /s option, and it can be changed within a pattern
1170         by  a (?s) option setting. A negative class such as [^a] always matches         by a (?s) option setting. A negative class such as [^a] always  matches
1171         newline characters, independent of the setting of this option.         newline characters, independent of the setting of this option.
1172    
1173           PCRE_DUPNAMES           PCRE_DUPNAMES
1174    
1175         If this bit is set, names used to identify capturing  subpatterns  need         If  this  bit is set, names used to identify capturing subpatterns need
1176         not be unique. This can be helpful for certain types of pattern when it         not be unique. This can be helpful for certain types of pattern when it
1177         is known that only one instance of the named  subpattern  can  ever  be         is  known  that  only  one instance of the named subpattern can ever be
1178         matched.  There  are  more details of named subpatterns below; see also         matched. There are more details of named subpatterns  below;  see  also
1179         the pcrepattern documentation.         the pcrepattern documentation.
1180    
1181           PCRE_EXTENDED           PCRE_EXTENDED
1182    
1183         If this bit is set, whitespace  data  characters  in  the  pattern  are         If  this  bit  is  set,  whitespace  data characters in the pattern are
1184         totally ignored except when escaped or inside a character class. White-         totally ignored except when escaped or inside a character class. White-
1185         space does not include the VT character (code 11). In addition, charac-         space does not include the VT character (code 11). In addition, charac-
1186         ters between an unescaped # outside a character class and the next new-         ters between an unescaped # outside a character class and the next new-
1187         line, inclusive, are also ignored. This  is  equivalent  to  Perl's  /x         line,  inclusive,  are  also  ignored.  This is equivalent to Perl's /x
1188         option,  and  it  can be changed within a pattern by a (?x) option set-         option, and it can be changed within a pattern by a  (?x)  option  set-
1189         ting.         ting.
1190    
1191         This option makes it possible to include  comments  inside  complicated         This  option  makes  it possible to include comments inside complicated
1192         patterns.   Note,  however,  that this applies only to data characters.         patterns.  Note, however, that this applies only  to  data  characters.
1193         Whitespace  characters  may  never  appear  within  special   character         Whitespace   characters  may  never  appear  within  special  character
1194         sequences  in  a  pattern,  for  example  within the sequence (?( which         sequences in a pattern, for  example  within  the  sequence  (?(  which
1195         introduces a conditional subpattern.         introduces a conditional subpattern.
1196    
1197           PCRE_EXTRA           PCRE_EXTRA
1198    
1199         This option was invented in order to turn on  additional  functionality         This  option  was invented in order to turn on additional functionality
1200         of  PCRE  that  is  incompatible with Perl, but it is currently of very         of PCRE that is incompatible with Perl, but it  is  currently  of  very
1201         little use. When set, any backslash in a pattern that is followed by  a         little  use. When set, any backslash in a pattern that is followed by a
1202         letter  that  has  no  special  meaning causes an error, thus reserving         letter that has no special meaning  causes  an  error,  thus  reserving
1203         these combinations for future expansion. By  default,  as  in  Perl,  a         these  combinations  for  future  expansion.  By default, as in Perl, a
1204         backslash  followed by a letter with no special meaning is treated as a         backslash followed by a letter with no special meaning is treated as  a
1205         literal. (Perl can, however, be persuaded to give a warning for  this.)         literal.  (Perl can, however, be persuaded to give a warning for this.)
1206         There  are  at  present no other features controlled by this option. It         There are at present no other features controlled by  this  option.  It
1207         can also be set by a (?X) option setting within a pattern.         can also be set by a (?X) option setting within a pattern.
1208    
1209           PCRE_FIRSTLINE           PCRE_FIRSTLINE
1210    
1211         If this option is set, an  unanchored  pattern  is  required  to  match         If  this  option  is  set,  an  unanchored pattern is required to match
1212         before  or  at  the  first  newline  in  the subject string, though the         before or at the first  newline  in  the  subject  string,  though  the
1213         matched text may continue over the newline.         matched text may continue over the newline.
1214    
1215           PCRE_MULTILINE           PCRE_MULTILINE
1216    
1217         By default, PCRE treats the subject string as consisting  of  a  single         By  default,  PCRE  treats the subject string as consisting of a single
1218         line  of characters (even if it actually contains newlines). The "start         line of characters (even if it actually contains newlines). The  "start
1219         of line" metacharacter (^) matches only at the  start  of  the  string,         of  line"  metacharacter  (^)  matches only at the start of the string,
1220         while  the  "end  of line" metacharacter ($) matches only at the end of         while the "end of line" metacharacter ($) matches only at  the  end  of
1221         the string, or before a terminating newline (unless PCRE_DOLLAR_ENDONLY         the string, or before a terminating newline (unless PCRE_DOLLAR_ENDONLY
1222         is set). This is the same as Perl.         is set). This is the same as Perl.
1223    
1224         When  PCRE_MULTILINE  it  is set, the "start of line" and "end of line"         When PCRE_MULTILINE it is set, the "start of line" and  "end  of  line"
1225         constructs match immediately following or immediately  before  internal         constructs  match  immediately following or immediately before internal
1226         newlines  in  the  subject string, respectively, as well as at the very         newlines in the subject string, respectively, as well as  at  the  very
1227         start and end. This is equivalent to Perl's /m option, and  it  can  be         start  and  end.  This is equivalent to Perl's /m option, and it can be
1228         changed within a pattern by a (?m) option setting. If there are no new-         changed within a pattern by a (?m) option setting. If there are no new-
1229         lines in a subject string, or no occurrences of ^ or $  in  a  pattern,         lines  in  a  subject string, or no occurrences of ^ or $ in a pattern,
1230         setting PCRE_MULTILINE has no effect.         setting PCRE_MULTILINE has no effect.
1231    
1232           PCRE_NEWLINE_CR           PCRE_NEWLINE_CR
# Line 1202  COMPILING A PATTERN Line 1235  COMPILING A PATTERN
1235           PCRE_NEWLINE_ANYCRLF           PCRE_NEWLINE_ANYCRLF
1236           PCRE_NEWLINE_ANY           PCRE_NEWLINE_ANY
1237    
1238         These  options  override the default newline definition that was chosen         These options override the default newline definition that  was  chosen
1239         when PCRE was built. Setting the first or the second specifies  that  a         when  PCRE  was built. Setting the first or the second specifies that a
1240         newline  is  indicated  by a single character (CR or LF, respectively).         newline is indicated by a single character (CR  or  LF,  respectively).
1241         Setting PCRE_NEWLINE_CRLF specifies that a newline is indicated by  the         Setting  PCRE_NEWLINE_CRLF specifies that a newline is indicated by the
1242         two-character  CRLF  sequence.  Setting  PCRE_NEWLINE_ANYCRLF specifies         two-character CRLF  sequence.  Setting  PCRE_NEWLINE_ANYCRLF  specifies
1243         that any of the three preceding sequences should be recognized. Setting         that any of the three preceding sequences should be recognized. Setting
1244         PCRE_NEWLINE_ANY  specifies that any Unicode newline sequence should be         PCRE_NEWLINE_ANY specifies that any Unicode newline sequence should  be
1245         recognized. The Unicode newline sequences are the three just mentioned,         recognized. The Unicode newline sequences are the three just mentioned,
1246         plus  the  single  characters  VT (vertical tab, U+000B), FF (formfeed,         plus the single characters VT (vertical  tab,  U+000B),  FF  (formfeed,
1247         U+000C), NEL (next line, U+0085), LS (line separator, U+2028),  and  PS         U+000C),  NEL  (next line, U+0085), LS (line separator, U+2028), and PS
1248         (paragraph  separator,  U+2029).  The  last  two are recognized only in         (paragraph separator, U+2029). The last  two  are  recognized  only  in
1249         UTF-8 mode.         UTF-8 mode.
1250    
1251         The newline setting in the  options  word  uses  three  bits  that  are         The  newline  setting  in  the  options  word  uses three bits that are
1252         treated as a number, giving eight possibilities. Currently only six are         treated as a number, giving eight possibilities. Currently only six are
1253         used (default plus the five values above). This means that if  you  set         used  (default  plus the five values above). This means that if you set
1254         more  than one newline option, the combination may or may not be sensi-         more than one newline option, the combination may or may not be  sensi-
1255         ble. For example, PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to         ble. For example, PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to
1256         PCRE_NEWLINE_CRLF,  but other combinations may yield unused numbers and         PCRE_NEWLINE_CRLF, but other combinations may yield unused numbers  and
1257         cause an error.         cause an error.
1258    
1259         The only time that a line break is specially recognized when  compiling         The  only time that a line break is specially recognized when compiling
1260         a  pattern  is  if  PCRE_EXTENDED  is set, and an unescaped # outside a         a pattern is if PCRE_EXTENDED is set, and  an  unescaped  #  outside  a
1261         character class is encountered. This indicates  a  comment  that  lasts         character  class  is  encountered.  This indicates a comment that lasts
1262         until  after the next line break sequence. In other circumstances, line         until after the next line break sequence. In other circumstances,  line
1263         break  sequences  are  treated  as  literal  data,   except   that   in         break   sequences   are   treated  as  literal  data,  except  that  in
1264         PCRE_EXTENDED mode, both CR and LF are treated as whitespace characters         PCRE_EXTENDED mode, both CR and LF are treated as whitespace characters
1265         and are therefore ignored.         and are therefore ignored.
1266    
1267         The newline option that is set at compile time becomes the default that         The newline option that is set at compile time becomes the default that
1268         is  used for pcre_exec() and pcre_dfa_exec(), but it can be overridden.         is used for pcre_exec() and pcre_dfa_exec(), but it can be  overridden.
1269    
1270           PCRE_NO_AUTO_CAPTURE           PCRE_NO_AUTO_CAPTURE
1271    
1272         If this option is set, it disables the use of numbered capturing paren-         If this option is set, it disables the use of numbered capturing paren-
1273         theses  in the pattern. Any opening parenthesis that is not followed by         theses in the pattern. Any opening parenthesis that is not followed  by
1274         ? behaves as if it were followed by ?: but named parentheses can  still         ?  behaves as if it were followed by ?: but named parentheses can still
1275         be  used  for  capturing  (and  they acquire numbers in the usual way).         be used for capturing (and they acquire  numbers  in  the  usual  way).
1276         There is no equivalent of this option in Perl.         There is no equivalent of this option in Perl.
1277    
1278           PCRE_UNGREEDY           PCRE_UNGREEDY
1279    
1280         This option inverts the "greediness" of the quantifiers  so  that  they         This  option  inverts  the "greediness" of the quantifiers so that they
1281         are  not greedy by default, but become greedy if followed by "?". It is         are not greedy by default, but become greedy if followed by "?". It  is
1282         not compatible with Perl. It can also be set by a (?U)  option  setting         not  compatible  with Perl. It can also be set by a (?U) option setting
1283         within the pattern.         within the pattern.
1284    
1285           PCRE_UTF8           PCRE_UTF8
1286    
1287         This  option  causes PCRE to regard both the pattern and the subject as         This option causes PCRE to regard both the pattern and the  subject  as
1288         strings of UTF-8 characters instead of single-byte  character  strings.         strings  of  UTF-8 characters instead of single-byte character strings.
1289         However,  it is available only when PCRE is built to include UTF-8 sup-         However, it is available only when PCRE is built to include UTF-8  sup-
1290         port. If not, the use of this option provokes an error. Details of  how         port.  If not, the use of this option provokes an error. Details of how
1291         this  option  changes the behaviour of PCRE are given in the section on         this option changes the behaviour of PCRE are given in the  section  on
1292         UTF-8 support in the main pcre page.         UTF-8 support in the main pcre page.
1293    
1294           PCRE_NO_UTF8_CHECK           PCRE_NO_UTF8_CHECK
1295    
1296         When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is         When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
1297         automatically  checked.  There  is  a  discussion about the validity of         automatically checked. There is a  discussion  about  the  validity  of
1298         UTF-8 strings in the main pcre page. If an invalid  UTF-8  sequence  of         UTF-8  strings  in  the main pcre page. If an invalid UTF-8 sequence of
1299         bytes  is  found,  pcre_compile() returns an error. If you already know         bytes is found, pcre_compile() returns an error. If  you  already  know
1300         that your pattern is valid, and you want to skip this check for perfor-         that your pattern is valid, and you want to skip this check for perfor-
1301         mance  reasons,  you  can set the PCRE_NO_UTF8_CHECK option. When it is         mance reasons, you can set the PCRE_NO_UTF8_CHECK option.  When  it  is
1302         set, the effect of passing an invalid UTF-8  string  as  a  pattern  is         set,  the  effect  of  passing  an invalid UTF-8 string as a pattern is
1303         undefined.  It  may  cause your program to crash. Note that this option         undefined. It may cause your program to crash. Note  that  this  option
1304         can also be passed to pcre_exec() and pcre_dfa_exec(), to suppress  the         can  also be passed to pcre_exec() and pcre_dfa_exec(), to suppress the
1305         UTF-8 validity checking of subject strings.         UTF-8 validity checking of subject strings.
1306    
1307    
1308  COMPILATION ERROR CODES  COMPILATION ERROR CODES
1309    
1310         The  following  table  lists  the  error  codes than may be returned by         The following table lists the error  codes  than  may  be  returned  by
1311         pcre_compile2(), along with the error messages that may be returned  by         pcre_compile2(),  along with the error messages that may be returned by
1312         both  compiling functions. As PCRE has developed, some error codes have         both compiling functions. As PCRE has developed, some error codes  have
1313         fallen out of use. To avoid confusion, they have not been re-used.         fallen out of use. To avoid confusion, they have not been re-used.
1314    
1315            0  no error            0  no error
# Line 1332  COMPILATION ERROR CODES Line 1365  COMPILATION ERROR CODES
1365           50  [this code is not in use]           50  [this code is not in use]
1366           51  octal value is greater than \377 (not in UTF-8 mode)           51  octal value is greater than \377 (not in UTF-8 mode)
1367           52  internal error: overran compiling workspace           52  internal error: overran compiling workspace
1368           53  internal  error:  previously-checked  referenced  subpattern  not           53   internal  error:  previously-checked  referenced  subpattern not
1369         found         found
1370           54  DEFINE group contains more than one branch           54  DEFINE group contains more than one branch
1371           55  repeating a DEFINE group is not allowed           55  repeating a DEFINE group is not allowed
1372           56  inconsistent NEWLINE options"           56  inconsistent NEWLINE options
1373           57  \g is not followed by a braced name or an optionally braced           57  \g is not followed by a braced name or an optionally braced
1374                 non-zero number                 non-zero number
1375           58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number           58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number
# Line 1347  STUDYING A PATTERN Line 1380  STUDYING A PATTERN
1380         pcre_extra *pcre_study(const pcre *code, int options         pcre_extra *pcre_study(const pcre *code, int options
1381              const char **errptr);              const char **errptr);
1382    
1383         If  a  compiled  pattern is going to be used several times, it is worth         If a compiled pattern is going to be used several times,  it  is  worth
1384         spending more time analyzing it in order to speed up the time taken for         spending more time analyzing it in order to speed up the time taken for
1385         matching.  The function pcre_study() takes a pointer to a compiled pat-         matching. The function pcre_study() takes a pointer to a compiled  pat-
1386         tern as its first argument. If studying the pattern produces additional         tern as its first argument. If studying the pattern produces additional
1387         information  that  will  help speed up matching, pcre_study() returns a         information that will help speed up matching,  pcre_study()  returns  a
1388         pointer to a pcre_extra block, in which the study_data field points  to         pointer  to a pcre_extra block, in which the study_data field points to
1389         the results of the study.         the results of the study.
1390    
1391         The  returned  value  from  pcre_study()  can  be  passed  directly  to         The  returned  value  from  pcre_study()  can  be  passed  directly  to
1392         pcre_exec(). However, a pcre_extra block  also  contains  other  fields         pcre_exec().  However,  a  pcre_extra  block also contains other fields
1393         that  can  be  set  by the caller before the block is passed; these are         that can be set by the caller before the block  is  passed;  these  are
1394         described below in the section on matching a pattern.         described below in the section on matching a pattern.
1395    
1396         If studying the pattern does not  produce  any  additional  information         If  studying  the  pattern  does not produce any additional information
1397         pcre_study() returns NULL. In that circumstance, if the calling program         pcre_study() returns NULL. In that circumstance, if the calling program
1398         wants to pass any of the other fields to pcre_exec(), it  must  set  up         wants  to  pass  any of the other fields to pcre_exec(), it must set up
1399         its own pcre_extra block.         its own pcre_extra block.
1400    
1401         The  second  argument of pcre_study() contains option bits. At present,         The second argument of pcre_study() contains option bits.  At  present,
1402         no options are defined, and this argument should always be zero.         no options are defined, and this argument should always be zero.
1403    
1404         The third argument for pcre_study() is a pointer for an error  message.         The  third argument for pcre_study() is a pointer for an error message.
1405         If  studying  succeeds  (even  if no data is returned), the variable it         If studying succeeds (even if no data is  returned),  the  variable  it
1406         points to is set to NULL. Otherwise it is set to  point  to  a  textual         points  to  is  set  to NULL. Otherwise it is set to point to a textual
1407         error message. This is a static string that is part of the library. You         error message. This is a static string that is part of the library. You
1408         must not try to free it. You should test the  error  pointer  for  NULL         must  not  try  to  free it. You should test the error pointer for NULL
1409         after calling pcre_study(), to be sure that it has run successfully.         after calling pcre_study(), to be sure that it has run successfully.
1410    
1411         This is a typical call to pcre_study():         This is a typical call to pcre_study():
# Line 1384  STUDYING A PATTERN Line 1417  STUDYING A PATTERN
1417             &error);        /* set to NULL or points to a message */             &error);        /* set to NULL or points to a message */
1418    
1419         At present, studying a pattern is useful only for non-anchored patterns         At present, studying a pattern is useful only for non-anchored patterns
1420         that do not have a single fixed starting character. A bitmap of  possi-         that  do not have a single fixed starting character. A bitmap of possi-
1421         ble starting bytes is created.         ble starting bytes is created.
1422    
1423    
1424  LOCALE SUPPORT  LOCALE SUPPORT
1425    
1426         PCRE  handles  caseless matching, and determines whether characters are         PCRE handles caseless matching, and determines whether  characters  are
1427         letters, digits, or whatever, by reference to a set of tables,  indexed         letters,  digits, or whatever, by reference to a set of tables, indexed
1428         by  character  value.  When running in UTF-8 mode, this applies only to         by character value. When running in UTF-8 mode, this  applies  only  to
1429         characters with codes less than 128. Higher-valued  codes  never  match         characters  with  codes  less than 128. Higher-valued codes never match
1430         escapes  such  as  \w or \d, but can be tested with \p if PCRE is built         escapes such as \w or \d, but can be tested with \p if  PCRE  is  built
1431         with Unicode character property support. The use of locales  with  Uni-         with  Unicode  character property support. The use of locales with Uni-
1432         code  is discouraged. If you are handling characters with codes greater         code is discouraged. If you are handling characters with codes  greater
1433         than 128, you should either use UTF-8 and Unicode, or use locales,  but         than  128, you should either use UTF-8 and Unicode, or use locales, but
1434         not try to mix the two.         not try to mix the two.
1435    
1436         PCRE  contains  an  internal set of tables that are used when the final         PCRE contains an internal set of tables that are used  when  the  final
1437         argument of pcre_compile() is  NULL.  These  are  sufficient  for  many         argument  of  pcre_compile()  is  NULL.  These  are sufficient for many
1438         applications.  Normally, the internal tables recognize only ASCII char-         applications.  Normally, the internal tables recognize only ASCII char-
1439         acters. However, when PCRE is built, it is possible to cause the inter-         acters. However, when PCRE is built, it is possible to cause the inter-
1440         nal tables to be rebuilt in the default "C" locale of the local system,         nal tables to be rebuilt in the default "C" locale of the local system,
1441         which may cause them to be different.         which may cause them to be different.
1442    
1443         The internal tables can always be overridden by tables supplied by  the         The  internal tables can always be overridden by tables supplied by the
1444         application that calls PCRE. These may be created in a different locale         application that calls PCRE. These may be created in a different locale
1445         from the default. As more and more applications change  to  using  Uni-         from  the  default.  As more and more applications change to using Uni-
1446         code, the need for this locale support is expected to die away.         code, the need for this locale support is expected to die away.
1447    
1448         External  tables  are  built by calling the pcre_maketables() function,         External tables are built by calling  the  pcre_maketables()  function,
1449         which has no arguments, in the relevant locale. The result can then  be         which  has no arguments, in the relevant locale. The result can then be
1450         passed  to  pcre_compile()  or  pcre_exec()  as often as necessary. For         passed to pcre_compile() or pcre_exec()  as  often  as  necessary.  For
1451         example, to build and use tables that are appropriate  for  the  French         example,  to  build  and use tables that are appropriate for the French
1452         locale  (where  accented  characters  with  values greater than 128 are         locale (where accented characters with  values  greater  than  128  are
1453         treated as letters), the following code could be used:         treated as letters), the following code could be used:
1454    
1455           setlocale(LC_CTYPE, "fr_FR");           setlocale(LC_CTYPE, "fr_FR");
1456           tables = pcre_maketables();           tables = pcre_maketables();
1457           re = pcre_compile(..., tables);           re = pcre_compile(..., tables);
1458    
1459         The locale name "fr_FR" is used on Linux and other  Unix-like  systems;         The  locale  name "fr_FR" is used on Linux and other Unix-like systems;
1460         if you are using Windows, the name for the French locale is "french".         if you are using Windows, the name for the French locale is "french".
1461    
1462         When  pcre_maketables()  runs,  the  tables are built in memory that is         When pcre_maketables() runs, the tables are built  in  memory  that  is
1463         obtained via pcre_malloc. It is the caller's responsibility  to  ensure         obtained  via  pcre_malloc. It is the caller's responsibility to ensure
1464         that  the memory containing the tables remains available for as long as         that the memory containing the tables remains available for as long  as
1465         it is needed.         it is needed.
1466    
1467         The pointer that is passed to pcre_compile() is saved with the compiled         The pointer that is passed to pcre_compile() is saved with the compiled
1468         pattern,  and the same tables are used via this pointer by pcre_study()         pattern, and the same tables are used via this pointer by  pcre_study()
1469         and normally also by pcre_exec(). Thus, by default, for any single pat-         and normally also by pcre_exec(). Thus, by default, for any single pat-
1470         tern, compilation, studying and matching all happen in the same locale,         tern, compilation, studying and matching all happen in the same locale,
1471         but different patterns can be compiled in different locales.         but different patterns can be compiled in different locales.
1472    
1473         It is possible to pass a table pointer or NULL (indicating the  use  of         It  is  possible to pass a table pointer or NULL (indicating the use of
1474         the  internal  tables)  to  pcre_exec(). Although not intended for this         the internal tables) to pcre_exec(). Although  not  intended  for  this
1475         purpose, this facility could be used to match a pattern in a  different         purpose,  this facility could be used to match a pattern in a different
1476         locale from the one in which it was compiled. Passing table pointers at         locale from the one in which it was compiled. Passing table pointers at
1477         run time is discussed below in the section on matching a pattern.         run time is discussed below in the section on matching a pattern.
1478    
# Line 1449  INFORMATION ABOUT A PATTERN Line 1482  INFORMATION ABOUT A PATTERN
1482         int pcre_fullinfo(const pcre *code, const pcre_extra *extra,         int pcre_fullinfo(const pcre *code, const pcre_extra *extra,
1483              int what, void *where);              int what, void *where);
1484    
1485         The pcre_fullinfo() function returns information about a compiled  pat-         The  pcre_fullinfo() function returns information about a compiled pat-
1486         tern. It replaces the obsolete pcre_info() function, which is neverthe-         tern. It replaces the obsolete pcre_info() function, which is neverthe-
1487         less retained for backwards compability (and is documented below).         less retained for backwards compability (and is documented below).
1488    
1489         The first argument for pcre_fullinfo() is a  pointer  to  the  compiled         The  first  argument  for  pcre_fullinfo() is a pointer to the compiled
1490         pattern.  The second argument is the result of pcre_study(), or NULL if         pattern. The second argument is the result of pcre_study(), or NULL  if
1491         the pattern was not studied. The third argument specifies  which  piece         the  pattern  was not studied. The third argument specifies which piece
1492         of  information  is required, and the fourth argument is a pointer to a         of information is required, and the fourth argument is a pointer  to  a
1493         variable to receive the data. The yield of the  function  is  zero  for         variable  to  receive  the  data. The yield of the function is zero for
1494         success, or one of the following negative numbers:         success, or one of the following negative numbers:
1495    
1496           PCRE_ERROR_NULL       the argument code was NULL           PCRE_ERROR_NULL       the argument code was NULL
# Line 1465  INFORMATION ABOUT A PATTERN Line 1498  INFORMATION ABOUT A PATTERN
1498           PCRE_ERROR_BADMAGIC   the "magic number" was not found           PCRE_ERROR_BADMAGIC   the "magic number" was not found
1499           PCRE_ERROR_BADOPTION  the value of what was invalid           PCRE_ERROR_BADOPTION  the value of what was invalid
1500    
1501         The  "magic  number" is placed at the start of each compiled pattern as         The "magic number" is placed at the start of each compiled  pattern  as
1502         an simple check against passing an arbitrary memory pointer. Here is  a         an  simple check against passing an arbitrary memory pointer. Here is a
1503         typical  call  of pcre_fullinfo(), to obtain the length of the compiled         typical call of pcre_fullinfo(), to obtain the length of  the  compiled
1504         pattern:         pattern:
1505    
1506           int rc;           int rc;
# Line 1478  INFORMATION ABOUT A PATTERN Line 1511  INFORMATION ABOUT A PATTERN
1511             PCRE_INFO_SIZE,   /* what is required */             PCRE_INFO_SIZE,   /* what is required */
1512             &length);         /* where to put the data */             &length);         /* where to put the data */
1513    
1514         The possible values for the third argument are defined in  pcre.h,  and         The  possible  values for the third argument are defined in pcre.h, and
1515         are as follows:         are as follows:
1516    
1517           PCRE_INFO_BACKREFMAX           PCRE_INFO_BACKREFMAX
1518    
1519         Return  the  number  of  the highest back reference in the pattern. The         Return the number of the highest back reference  in  the  pattern.  The
1520         fourth argument should point to an int variable. Zero  is  returned  if         fourth  argument  should  point to an int variable. Zero is returned if
1521         there are no back references.         there are no back references.
1522    
1523           PCRE_INFO_CAPTURECOUNT           PCRE_INFO_CAPTURECOUNT
1524    
1525         Return  the  number of capturing subpatterns in the pattern. The fourth         Return the number of capturing subpatterns in the pattern.  The  fourth
1526         argument should point to an int variable.         argument should point to an int variable.
1527    
1528           PCRE_INFO_DEFAULT_TABLES           PCRE_INFO_DEFAULT_TABLES
1529    
1530         Return a pointer to the internal default character tables within  PCRE.         Return  a pointer to the internal default character tables within PCRE.
1531         The  fourth  argument should point to an unsigned char * variable. This         The fourth argument should point to an unsigned char *  variable.  This
1532         information call is provided for internal use by the pcre_study() func-         information call is provided for internal use by the pcre_study() func-
1533         tion.  External  callers  can  cause PCRE to use its internal tables by         tion. External callers can cause PCRE to use  its  internal  tables  by
1534         passing a NULL table pointer.         passing a NULL table pointer.
1535    
1536           PCRE_INFO_FIRSTBYTE           PCRE_INFO_FIRSTBYTE
1537    
1538         Return information about the first byte of any matched  string,  for  a         Return  information  about  the first byte of any matched string, for a
1539         non-anchored  pattern. The fourth argument should point to an int vari-         non-anchored pattern. The fourth argument should point to an int  vari-
1540         able. (This option used to be called PCRE_INFO_FIRSTCHAR; the old  name         able.  (This option used to be called PCRE_INFO_FIRSTCHAR; the old name
1541         is still recognized for backwards compatibility.)         is still recognized for backwards compatibility.)
1542    
1543         If  there  is  a  fixed first byte, for example, from a pattern such as         If there is a fixed first byte, for example, from  a  pattern  such  as
1544         (cat|cow|coyote), its value is returned. Otherwise, if either         (cat|cow|coyote), its value is returned. Otherwise, if either
1545    
1546         (a) the pattern was compiled with the PCRE_MULTILINE option, and  every         (a)  the pattern was compiled with the PCRE_MULTILINE option, and every
1547         branch starts with "^", or         branch starts with "^", or
1548    
1549         (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not         (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not
1550         set (if it were set, the pattern would be anchored),         set (if it were set, the pattern would be anchored),
1551    
1552         -1 is returned, indicating that the pattern matches only at  the  start         -1  is  returned, indicating that the pattern matches only at the start
1553         of  a  subject string or after any newline within the string. Otherwise         of a subject string or after any newline within the  string.  Otherwise
1554         -2 is returned. For anchored patterns, -2 is returned.         -2 is returned. For anchored patterns, -2 is returned.
1555    
1556           PCRE_INFO_FIRSTTABLE           PCRE_INFO_FIRSTTABLE
1557    
1558         If the pattern was studied, and this resulted in the construction of  a         If  the pattern was studied, and this resulted in the construction of a
1559         256-bit table indicating a fixed set of bytes for the first byte in any         256-bit table indicating a fixed set of bytes for the first byte in any
1560         matching string, a pointer to the table is returned. Otherwise NULL  is         matching  string, a pointer to the table is returned. Otherwise NULL is
1561         returned.  The fourth argument should point to an unsigned char * vari-         returned. The fourth argument should point to an unsigned char *  vari-
1562         able.         able.
1563    
1564           PCRE_INFO_HASCRORLF           PCRE_INFO_HASCRORLF
1565    
1566         Return 1 if the pattern contains any explicit  matches  for  CR  or  LF         Return  1  if  the  pattern  contains any explicit matches for CR or LF
1567         characters,  otherwise  0.  The  fourth argument should point to an int         characters, otherwise 0. The fourth argument should  point  to  an  int
1568         variable.         variable.
1569    
1570           PCRE_INFO_JCHANGED           PCRE_INFO_JCHANGED
1571    
1572         Return 1 if the (?J) option setting is used in the  pattern,  otherwise         Return  1  if the (?J) option setting is used in the pattern, otherwise
1573         0. The fourth argument should point to an int variable. The (?J) inter-         0. The fourth argument should point to an int variable. The (?J) inter-
1574         nal option setting changes the local PCRE_DUPNAMES option.         nal option setting changes the local PCRE_DUPNAMES option.
1575    
1576           PCRE_INFO_LASTLITERAL           PCRE_INFO_LASTLITERAL
1577    
1578         Return the value of the rightmost literal byte that must exist  in  any         Return  the  value of the rightmost literal byte that must exist in any
1579         matched  string,  other  than  at  its  start,  if such a byte has been         matched string, other than at its  start,  if  such  a  byte  has  been
1580         recorded. The fourth argument should point to an int variable. If there         recorded. The fourth argument should point to an int variable. If there
1581         is  no such byte, -1 is returned. For anchored patterns, a last literal         is no such byte, -1 is returned. For anchored patterns, a last  literal
1582         byte is recorded only if it follows something of variable  length.  For         byte  is  recorded only if it follows something of variable length. For
1583         example, for the pattern /^a\d+z\d+/ the returned value is "z", but for         example, for the pattern /^a\d+z\d+/ the returned value is "z", but for
1584         /^a\dz\d/ the returned value is -1.         /^a\dz\d/ the returned value is -1.
1585    
# Line 1554  INFORMATION ABOUT A PATTERN Line 1587  INFORMATION ABOUT A PATTERN
1587           PCRE_INFO_NAMEENTRYSIZE           PCRE_INFO_NAMEENTRYSIZE
1588           PCRE_INFO_NAMETABLE           PCRE_INFO_NAMETABLE
1589    
1590         PCRE supports the use of named as well as numbered capturing  parenthe-         PCRE  supports the use of named as well as numbered capturing parenthe-
1591         ses.  The names are just an additional way of identifying the parenthe-         ses. The names are just an additional way of identifying the  parenthe-
1592         ses, which still acquire numbers. Several convenience functions such as         ses, which still acquire numbers. Several convenience functions such as
1593         pcre_get_named_substring()  are  provided  for extracting captured sub-         pcre_get_named_substring() are provided for  extracting  captured  sub-
1594         strings by name. It is also possible to extract the data  directly,  by         strings  by  name. It is also possible to extract the data directly, by
1595         first  converting  the  name to a number in order to access the correct         first converting the name to a number in order to  access  the  correct
1596         pointers in the output vector (described with pcre_exec() below). To do         pointers in the output vector (described with pcre_exec() below). To do
1597         the  conversion,  you  need  to  use  the  name-to-number map, which is         the conversion, you need  to  use  the  name-to-number  map,  which  is
1598         described by these three values.         described by these three values.
1599    
1600         The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT         The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT
1601         gives the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size         gives the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size
1602         of each entry; both of these  return  an  int  value.  The  entry  size         of  each  entry;  both  of  these  return  an int value. The entry size
1603         depends  on the length of the longest name. PCRE_INFO_NAMETABLE returns         depends on the length of the longest name. PCRE_INFO_NAMETABLE  returns
1604         a pointer to the first entry of the table  (a  pointer  to  char).  The         a  pointer  to  the  first  entry of the table (a pointer to char). The
1605         first two bytes of each entry are the number of the capturing parenthe-         first two bytes of each entry are the number of the capturing parenthe-
1606         sis, most significant byte first. The rest of the entry is  the  corre-         sis,  most  significant byte first. The rest of the entry is the corre-
1607         sponding  name,  zero  terminated. The names are in alphabetical order.         sponding name, zero terminated. The names are  in  alphabetical  order.
1608         When PCRE_DUPNAMES is set, duplicate names are in order of their paren-         When PCRE_DUPNAMES is set, duplicate names are in order of their paren-
1609         theses  numbers.  For  example,  consider the following pattern (assume         theses numbers. For example, consider  the  following  pattern  (assume
1610         PCRE_EXTENDED is  set,  so  white  space  -  including  newlines  -  is         PCRE_EXTENDED  is  set,  so  white  space  -  including  newlines  - is
1611         ignored):         ignored):
1612    
1613           (?<date> (?<year>(\d\d)?\d\d) -           (?<date> (?<year>(\d\d)?\d\d) -
1614           (?<month>\d\d) - (?<day>\d\d) )           (?<month>\d\d) - (?<day>\d\d) )
1615    
1616         There  are  four  named subpatterns, so the table has four entries, and         There are four named subpatterns, so the table has  four  entries,  and
1617         each entry in the table is eight bytes long. The table is  as  follows,         each  entry  in the table is eight bytes long. The table is as follows,
1618         with non-printing bytes shows in hexadecimal, and undefined bytes shown         with non-printing bytes shows in hexadecimal, and undefined bytes shown
1619         as ??:         as ??:
1620    
# Line 1590  INFORMATION ABOUT A PATTERN Line 1623  INFORMATION ABOUT A PATTERN
1623           00 04 m  o  n  t  h  00           00 04 m  o  n  t  h  00
1624           00 02 y  e  a  r  00 ??           00 02 y  e  a  r  00 ??
1625    
1626         When writing code to extract data  from  named  subpatterns  using  the         When  writing  code  to  extract  data from named subpatterns using the
1627         name-to-number  map,  remember that the length of the entries is likely         name-to-number map, remember that the length of the entries  is  likely
1628         to be different for each compiled pattern.         to be different for each compiled pattern.
1629    
1630           PCRE_INFO_OKPARTIAL           PCRE_INFO_OKPARTIAL
1631    
1632         Return 1 if the pattern can be used for partial matching, otherwise  0.         Return  1 if the pattern can be used for partial matching, otherwise 0.
1633         The  fourth  argument  should point to an int variable. The pcrepartial         The fourth argument should point to an int  variable.  The  pcrepartial
1634         documentation lists the restrictions that apply to patterns  when  par-         documentation  lists  the restrictions that apply to patterns when par-
1635         tial matching is used.         tial matching is used.
1636    
1637           PCRE_INFO_OPTIONS           PCRE_INFO_OPTIONS
1638    
1639         Return  a  copy of the options with which the pattern was compiled. The         Return a copy of the options with which the pattern was  compiled.  The
1640         fourth argument should point to an unsigned long  int  variable.  These         fourth  argument  should  point to an unsigned long int variable. These
1641         option bits are those specified in the call to pcre_compile(), modified         option bits are those specified in the call to pcre_compile(), modified
1642         by any top-level option settings at the start of the pattern itself. In         by any top-level option settings at the start of the pattern itself. In
1643         other  words,  they are the options that will be in force when matching         other words, they are the options that will be in force  when  matching
1644         starts. For example, if the pattern /(?im)abc(?-i)d/ is  compiled  with         starts.  For  example, if the pattern /(?im)abc(?-i)d/ is compiled with
1645         the  PCRE_EXTENDED option, the result is PCRE_CASELESS, PCRE_MULTILINE,         the PCRE_EXTENDED option, the result is PCRE_CASELESS,  PCRE_MULTILINE,
1646         and PCRE_EXTENDED.         and PCRE_EXTENDED.
1647    
1648         A pattern is automatically anchored by PCRE if  all  of  its  top-level         A  pattern  is  automatically  anchored by PCRE if all of its top-level
1649         alternatives begin with one of the following:         alternatives begin with one of the following:
1650    
1651           ^     unless PCRE_MULTILINE is set           ^     unless PCRE_MULTILINE is set
# Line 1626  INFORMATION ABOUT A PATTERN Line 1659  INFORMATION ABOUT A PATTERN
1659    
1660           PCRE_INFO_SIZE           PCRE_INFO_SIZE
1661    
1662         Return the size of the compiled pattern, that is, the  value  that  was         Return  the  size  of the compiled pattern, that is, the value that was
1663         passed as the argument to pcre_malloc() when PCRE was getting memory in         passed as the argument to pcre_malloc() when PCRE was getting memory in
1664         which to place the compiled data. The fourth argument should point to a         which to place the compiled data. The fourth argument should point to a
1665         size_t variable.         size_t variable.
# Line 1634  INFORMATION ABOUT A PATTERN Line 1667  INFORMATION ABOUT A PATTERN
1667           PCRE_INFO_STUDYSIZE           PCRE_INFO_STUDYSIZE
1668    
1669         Return the size of the data block pointed to by the study_data field in         Return the size of the data block pointed to by the study_data field in
1670         a pcre_extra block. That is,  it  is  the  value  that  was  passed  to         a  pcre_extra  block.  That  is,  it  is  the  value that was passed to
1671         pcre_malloc() when PCRE was getting memory into which to place the data         pcre_malloc() when PCRE was getting memory into which to place the data
1672         created by pcre_study(). The fourth argument should point to  a  size_t         created  by  pcre_study(). The fourth argument should point to a size_t
1673         variable.         variable.
1674    
1675    
# Line 1644  OBSOLETE INFO FUNCTION Line 1677  OBSOLETE INFO FUNCTION
1677    
1678         int pcre_info(const pcre *code, int *optptr, int *firstcharptr);         int pcre_info(const pcre *code, int *optptr, int *firstcharptr);
1679    
1680         The  pcre_info()  function is now obsolete because its interface is too         The pcre_info() function is now obsolete because its interface  is  too
1681         restrictive to return all the available data about a compiled  pattern.         restrictive  to return all the available data about a compiled pattern.
1682         New   programs   should  use  pcre_fullinfo()  instead.  The  yield  of         New  programs  should  use  pcre_fullinfo()  instead.  The   yield   of
1683         pcre_info() is the number of capturing subpatterns, or one of the  fol-         pcre_info()  is the number of capturing subpatterns, or one of the fol-
1684         lowing negative numbers:         lowing negative numbers:
1685    
1686           PCRE_ERROR_NULL       the argument code was NULL           PCRE_ERROR_NULL       the argument code was NULL
1687           PCRE_ERROR_BADMAGIC   the "magic number" was not found           PCRE_ERROR_BADMAGIC   the "magic number" was not found
1688    
1689         If  the  optptr  argument is not NULL, a copy of the options with which         If the optptr argument is not NULL, a copy of the  options  with  which
1690         the pattern was compiled is placed in the integer  it  points  to  (see         the  pattern  was  compiled  is placed in the integer it points to (see
1691         PCRE_INFO_OPTIONS above).         PCRE_INFO_OPTIONS above).
1692    
1693         If  the  pattern  is  not anchored and the firstcharptr argument is not         If the pattern is not anchored and the  firstcharptr  argument  is  not
1694         NULL, it is used to pass back information about the first character  of         NULL,  it is used to pass back information about the first character of
1695         any matched string (see PCRE_INFO_FIRSTBYTE above).         any matched string (see PCRE_INFO_FIRSTBYTE above).
1696    
1697    
# Line 1666  REFERENCE COUNTS Line 1699  REFERENCE COUNTS
1699    
1700         int pcre_refcount(pcre *code, int adjust);         int pcre_refcount(pcre *code, int adjust);
1701    
1702         The  pcre_refcount()  function is used to maintain a reference count in         The pcre_refcount() function is used to maintain a reference  count  in
1703         the data block that contains a compiled pattern. It is provided for the         the data block that contains a compiled pattern. It is provided for the
1704         benefit  of  applications  that  operate  in an object-oriented manner,         benefit of applications that  operate  in  an  object-oriented  manner,
1705         where different parts of the application may be using the same compiled         where different parts of the application may be using the same compiled
1706         pattern, but you want to free the block when they are all done.         pattern, but you want to free the block when they are all done.
1707    
1708         When a pattern is compiled, the reference count field is initialized to         When a pattern is compiled, the reference count field is initialized to
1709         zero.  It is changed only by calling this function, whose action is  to         zero.   It is changed only by calling this function, whose action is to
1710         add  the  adjust  value  (which may be positive or negative) to it. The         add the adjust value (which may be positive or  negative)  to  it.  The
1711         yield of the function is the new value. However, the value of the count         yield of the function is the new value. However, the value of the count
1712         is  constrained to lie between 0 and 65535, inclusive. If the new value         is constrained to lie between 0 and 65535, inclusive. If the new  value
1713         is outside these limits, it is forced to the appropriate limit value.         is outside these limits, it is forced to the appropriate limit value.
1714    
1715         Except when it is zero, the reference count is not correctly  preserved         Except  when it is zero, the reference count is not correctly preserved
1716         if  a  pattern  is  compiled on one host and then transferred to a host         if a pattern is compiled on one host and then  transferred  to  a  host
1717         whose byte-order is different. (This seems a highly unlikely scenario.)         whose byte-order is different. (This seems a highly unlikely scenario.)
1718    
1719    
# Line 1690  MATCHING A PATTERN: THE TRADITIONAL FUNC Line 1723  MATCHING A PATTERN: THE TRADITIONAL FUNC
1723              const char *subject, int length, int startoffset,              const char *subject, int length, int startoffset,
1724              int options, int *ovector, int ovecsize);              int options, int *ovector, int ovecsize);
1725    
1726         The  function pcre_exec() is called to match a subject string against a         The function pcre_exec() is called to match a subject string against  a
1727         compiled pattern, which is passed in the code argument. If the  pattern         compiled  pattern, which is passed in the code argument. If the pattern
1728         has been studied, the result of the study should be passed in the extra         has been studied, the result of the study should be passed in the extra
1729         argument. This function is the main matching facility of  the  library,         argument.  This  function is the main matching facility of the library,
1730         and it operates in a Perl-like manner. For specialist use there is also         and it operates in a Perl-like manner. For specialist use there is also
1731         an alternative matching function, which is described below in the  sec-         an  alternative matching function, which is described below in the sec-
1732         tion about the pcre_dfa_exec() function.         tion about the pcre_dfa_exec() function.
1733    
1734         In  most applications, the pattern will have been compiled (and option-         In most applications, the pattern will have been compiled (and  option-
1735         ally studied) in the same process that calls pcre_exec().  However,  it         ally  studied)  in the same process that calls pcre_exec(). However, it
1736         is possible to save compiled patterns and study data, and then use them         is possible to save compiled patterns and study data, and then use them
1737         later in different processes, possibly even on different hosts.  For  a         later  in  different processes, possibly even on different hosts. For a
1738         discussion about this, see the pcreprecompile documentation.         discussion about this, see the pcreprecompile documentation.
1739    
1740         Here is an example of a simple call to pcre_exec():         Here is an example of a simple call to pcre_exec():
# Line 1720  MATCHING A PATTERN: THE TRADITIONAL FUNC Line 1753  MATCHING A PATTERN: THE TRADITIONAL FUNC
1753    
1754     Extra data for pcre_exec()     Extra data for pcre_exec()
1755    
1756         If  the  extra argument is not NULL, it must point to a pcre_extra data         If the extra argument is not NULL, it must point to a  pcre_extra  data
1757         block. The pcre_study() function returns such a block (when it  doesn't         block.  The pcre_study() function returns such a block (when it doesn't
1758         return  NULL), but you can also create one for yourself, and pass addi-         return NULL), but you can also create one for yourself, and pass  addi-
1759         tional information in it. The pcre_extra block contains  the  following         tional  information  in it. The pcre_extra block contains the following
1760         fields (not necessarily in this order):         fields (not necessarily in this order):
1761    
1762           unsigned long int flags;           unsigned long int flags;
# Line 1733  MATCHING A PATTERN: THE TRADITIONAL FUNC Line 1766  MATCHING A PATTERN: THE TRADITIONAL FUNC
1766           void *callout_data;           void *callout_data;
1767           const unsigned char *tables;           const unsigned char *tables;
1768    
1769         The  flags  field  is a bitmap that specifies which of the other fields         The flags field is a bitmap that specifies which of  the  other  fields
1770         are set. The flag bits are:         are set. The flag bits are:
1771    
1772           PCRE_EXTRA_STUDY_DATA           PCRE_EXTRA_STUDY_DATA
# Line 1742  MATCHING A PATTERN: THE TRADITIONAL FUNC Line 1775  MATCHING A PATTERN: THE TRADITIONAL FUNC
1775           PCRE_EXTRA_CALLOUT_DATA           PCRE_EXTRA_CALLOUT_DATA
1776           PCRE_EXTRA_TABLES           PCRE_EXTRA_TABLES
1777    
1778         Other flag bits should be set to zero. The study_data field is  set  in         Other  flag  bits should be set to zero. The study_data field is set in
1779         the  pcre_extra  block  that is returned by pcre_study(), together with         the pcre_extra block that is returned by  pcre_study(),  together  with
1780         the appropriate flag bit. You should not set this yourself, but you may         the appropriate flag bit. You should not set this yourself, but you may
1781         add  to  the  block by setting the other fields and their corresponding         add to the block by setting the other fields  and  their  corresponding
1782         flag bits.         flag bits.
1783    
1784         The match_limit field provides a means of preventing PCRE from using up         The match_limit field provides a means of preventing PCRE from using up
1785         a  vast amount of resources when running patterns that are not going to         a vast amount of resources when running patterns that are not going  to
1786         match, but which have a very large number  of  possibilities  in  their         match,  but  which  have  a very large number of possibilities in their
1787         search  trees.  The  classic  example  is  the  use of nested unlimited         search trees. The classic  example  is  the  use  of  nested  unlimited
1788         repeats.         repeats.
1789    
1790         Internally, PCRE uses a function called match() which it calls  repeat-         Internally,  PCRE uses a function called match() which it calls repeat-
1791         edly  (sometimes  recursively). The limit set by match_limit is imposed         edly (sometimes recursively). The limit set by match_limit  is  imposed
1792         on the number of times this function is called during  a  match,  which         on  the  number  of times this function is called during a match, which
1793         has  the  effect  of  limiting the amount of backtracking that can take         has the effect of limiting the amount of  backtracking  that  can  take
1794         place. For patterns that are not anchored, the count restarts from zero         place. For patterns that are not anchored, the count restarts from zero
1795         for each position in the subject string.         for each position in the subject string.
1796    
1797         The  default  value  for  the  limit can be set when PCRE is built; the         The default value for the limit can be set  when  PCRE  is  built;  the
1798         default default is 10 million, which handles all but the  most  extreme         default  default  is 10 million, which handles all but the most extreme
1799         cases.  You  can  override  the  default by suppling pcre_exec() with a         cases. You can override the default  by  suppling  pcre_exec()  with  a
1800         pcre_extra    block    in    which    match_limit    is    set,     and         pcre_extra     block    in    which    match_limit    is    set,    and
1801         PCRE_EXTRA_MATCH_LIMIT  is  set  in  the  flags  field. If the limit is         PCRE_EXTRA_MATCH_LIMIT is set in the  flags  field.  If  the  limit  is
1802         exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.         exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1803    
1804         The match_limit_recursion field is similar to match_limit, but  instead         The  match_limit_recursion field is similar to match_limit, but instead
1805         of limiting the total number of times that match() is called, it limits         of limiting the total number of times that match() is called, it limits
1806         the depth of recursion. The recursion depth is a  smaller  number  than         the  depth  of  recursion. The recursion depth is a smaller number than
1807         the  total number of calls, because not all calls to match() are recur-         the total number of calls, because not all calls to match() are  recur-
1808         sive.  This limit is of use only if it is set smaller than match_limit.         sive.  This limit is of use only if it is set smaller than match_limit.
1809    
1810         Limiting  the  recursion  depth  limits the amount of stack that can be         Limiting the recursion depth limits the amount of  stack  that  can  be
1811         used, or, when PCRE has been compiled to use memory on the heap instead         used, or, when PCRE has been compiled to use memory on the heap instead
1812         of the stack, the amount of heap memory that can be used.         of the stack, the amount of heap memory that can be used.
1813    
1814         The  default  value  for  match_limit_recursion can be set when PCRE is         The default value for match_limit_recursion can be  set  when  PCRE  is
1815         built; the default default  is  the  same  value  as  the  default  for         built;  the  default  default  is  the  same  value  as the default for
1816         match_limit.  You can override the default by suppling pcre_exec() with         match_limit. You can override the default by suppling pcre_exec()  with
1817         a  pcre_extra  block  in  which  match_limit_recursion  is   set,   and         a   pcre_extra   block  in  which  match_limit_recursion  is  set,  and
1818         PCRE_EXTRA_MATCH_LIMIT_RECURSION  is  set  in  the  flags field. If the         PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in  the  flags  field.  If  the
1819         limit is exceeded, pcre_exec() returns PCRE_ERROR_RECURSIONLIMIT.         limit is exceeded, pcre_exec() returns PCRE_ERROR_RECURSIONLIMIT.
1820    
1821         The pcre_callout field is used in conjunction with the  "callout"  fea-         The  pcre_callout  field is used in conjunction with the "callout" fea-
1822         ture, which is described in the pcrecallout documentation.         ture, which is described in the pcrecallout documentation.
1823    
1824         The  tables  field  is  used  to  pass  a  character  tables pointer to         The tables field  is  used  to  pass  a  character  tables  pointer  to
1825         pcre_exec(); this overrides the value that is stored with the  compiled         pcre_exec();  this overrides the value that is stored with the compiled
1826         pattern.  A  non-NULL value is stored with the compiled pattern only if         pattern. A non-NULL value is stored with the compiled pattern  only  if
1827         custom tables were supplied to pcre_compile() via  its  tableptr  argu-         custom  tables  were  supplied to pcre_compile() via its tableptr argu-
1828         ment.  If NULL is passed to pcre_exec() using this mechanism, it forces         ment.  If NULL is passed to pcre_exec() using this mechanism, it forces
1829         PCRE's internal tables to be used. This facility is  helpful  when  re-         PCRE's  internal  tables  to be used. This facility is helpful when re-
1830         using  patterns  that  have been saved after compiling with an external         using patterns that have been saved after compiling  with  an  external
1831         set of tables, because the external tables  might  be  at  a  different         set  of  tables,  because  the  external tables might be at a different
1832         address  when  pcre_exec() is called. See the pcreprecompile documenta-         address when pcre_exec() is called. See the  pcreprecompile  documenta-
1833         tion for a discussion of saving compiled patterns for later use.         tion for a discussion of saving compiled patterns for later use.
1834    
1835     Option bits for pcre_exec()     Option bits for pcre_exec()
1836    
1837         The unused bits of the options argument for pcre_exec() must  be  zero.         The  unused  bits of the options argument for pcre_exec() must be zero.
1838         The  only  bits  that  may  be set are PCRE_ANCHORED, PCRE_NEWLINE_xxx,         The only bits that may  be  set  are  PCRE_ANCHORED,  PCRE_NEWLINE_xxx,
1839         PCRE_NOTBOL,   PCRE_NOTEOL,   PCRE_NOTEMPTY,   PCRE_NO_UTF8_CHECK   and         PCRE_NOTBOL,   PCRE_NOTEOL,   PCRE_NOTEMPTY,   PCRE_NO_UTF8_CHECK   and
1840         PCRE_PARTIAL.         PCRE_PARTIAL.
1841    
1842           PCRE_ANCHORED           PCRE_ANCHORED
1843    
1844         The  PCRE_ANCHORED  option  limits pcre_exec() to matching at the first         The PCRE_ANCHORED option limits pcre_exec() to matching  at  the  first
1845         matching position. If a pattern was  compiled  with  PCRE_ANCHORED,  or         matching  position.  If  a  pattern was compiled with PCRE_ANCHORED, or
1846         turned  out to be anchored by virtue of its contents, it cannot be made         turned out to be anchored by virtue of its contents, it cannot be  made
1847         unachored at matching time.         unachored at matching time.
1848    
1849             PCRE_BSR_ANYCRLF
1850             PCRE_BSR_UNICODE
1851    
1852           These options (which are mutually exclusive) control what the \R escape
1853           sequence matches. The choice is either to match only CR, LF,  or  CRLF,
1854           or  to  match  any Unicode newline sequence. These options override the
1855           choice that was made or defaulted when the pattern was compiled.
1856    
1857           PCRE_NEWLINE_CR           PCRE_NEWLINE_CR
1858           PCRE_NEWLINE_LF           PCRE_NEWLINE_LF
1859           PCRE_NEWLINE_CRLF           PCRE_NEWLINE_CRLF
# Line 1829  MATCHING A PATTERN: THE TRADITIONAL FUNC Line 1870  MATCHING A PATTERN: THE TRADITIONAL FUNC
1870         When  PCRE_NEWLINE_CRLF,  PCRE_NEWLINE_ANYCRLF,  or PCRE_NEWLINE_ANY is         When  PCRE_NEWLINE_CRLF,  PCRE_NEWLINE_ANYCRLF,  or PCRE_NEWLINE_ANY is
1871         set, and a match attempt for an unanchored pattern fails when the  cur-         set, and a match attempt for an unanchored pattern fails when the  cur-
1872         rent  position  is  at  a  CRLF  sequence,  and the pattern contains no         rent  position  is  at  a  CRLF  sequence,  and the pattern contains no
1873         explicit matches for  CR  or  NL  characters,  the  match  position  is         explicit matches for  CR  or  LF  characters,  the  match  position  is
1874         advanced by two characters instead of one, in other words, to after the         advanced by two characters instead of one, in other words, to after the
1875         CRLF.         CRLF.
1876    
# Line 1839  MATCHING A PATTERN: THE TRADITIONAL FUNC Line 1880  MATCHING A PATTERN: THE TRADITIONAL FUNC
1880         failing  at the start, it skips both the CR and the LF before retrying.         failing  at the start, it skips both the CR and the LF before retrying.
1881         However, the pattern [\r\n]A does match that string,  because  it  con-         However, the pattern [\r\n]A does match that string,  because  it  con-
1882         tains an explicit CR or LF reference, and so advances only by one char-         tains an explicit CR or LF reference, and so advances only by one char-
1883         acter after the first failure.  Note than an explicit CR or  LF  refer-         acter after the first failure.
        ence occurs for negated character classes such as [^X] because they can  
        match CR or LF characters.  
1884    
1885         Notwithstanding the above, anomalous effects may still occur when  CRLF         An explicit match for CR of LF is either a literal appearance of one of
1886           those  characters,  or  one  of the \r or \n escape sequences. Implicit
1887           matches such as [^X] do not count, nor does \s (which includes  CR  and
1888           LF in the characters that it matches).
1889    
1890           Notwithstanding  the above, anomalous effects may still occur when CRLF
1891         is a valid newline sequence and explicit \r or \n escapes appear in the         is a valid newline sequence and explicit \r or \n escapes appear in the
1892         pattern.         pattern.
1893    
1894           PCRE_NOTBOL           PCRE_NOTBOL
1895    
1896         This option specifies that first character of the subject string is not         This option specifies that first character of the subject string is not
1897         the  beginning  of  a  line, so the circumflex metacharacter should not         the beginning of a line, so the  circumflex  metacharacter  should  not
1898         match before it. Setting this without PCRE_MULTILINE (at compile  time)         match  before it. Setting this without PCRE_MULTILINE (at compile time)
1899         causes  circumflex  never to match. This option affects only the behav-         causes circumflex never to match. This option affects only  the  behav-
1900         iour of the circumflex metacharacter. It does not affect \A.         iour of the circumflex metacharacter. It does not affect \A.
1901    
1902           PCRE_NOTEOL           PCRE_NOTEOL
1903    
1904         This option specifies that the end of the subject string is not the end         This option specifies that the end of the subject string is not the end
1905         of  a line, so the dollar metacharacter should not match it nor (except         of a line, so the dollar metacharacter should not match it nor  (except
1906         in multiline mode) a newline immediately before it. Setting this  with-         in  multiline mode) a newline immediately before it. Setting this with-
1907         out PCRE_MULTILINE (at compile time) causes dollar never to match. This         out PCRE_MULTILINE (at compile time) causes dollar never to match. This
1908         option affects only the behaviour of the dollar metacharacter. It  does         option  affects only the behaviour of the dollar metacharacter. It does
1909         not affect \Z or \z.         not affect \Z or \z.
1910    
1911           PCRE_NOTEMPTY           PCRE_NOTEMPTY
1912    
1913         An empty string is not considered to be a valid match if this option is         An empty string is not considered to be a valid match if this option is
1914         set. If there are alternatives in the pattern, they are tried.  If  all         set.  If  there are alternatives in the pattern, they are tried. If all
1915         the  alternatives  match  the empty string, the entire match fails. For         the alternatives match the empty string, the entire  match  fails.  For
1916         example, if the pattern         example, if the pattern
1917    
1918           a?b?           a?b?
1919    
1920         is applied to a string not beginning with "a" or "b",  it  matches  the         is  applied  to  a string not beginning with "a" or "b", it matches the
1921         empty  string at the start of the subject. With PCRE_NOTEMPTY set, this         empty string at the start of the subject. With PCRE_NOTEMPTY set,  this
1922         match is not valid, so PCRE searches further into the string for occur-         match is not valid, so PCRE searches further into the string for occur-
1923         rences of "a" or "b".         rences of "a" or "b".
1924    
1925         Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe-         Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe-
1926         cial case of a pattern match of the empty  string  within  its  split()         cial  case  of  a  pattern match of the empty string within its split()
1927         function,  and  when  using  the /g modifier. It is possible to emulate         function, and when using the /g modifier. It  is  possible  to  emulate
1928         Perl's behaviour after matching a null string by first trying the match         Perl's behaviour after matching a null string by first trying the match
1929         again at the same offset with PCRE_NOTEMPTY and PCRE_ANCHORED, and then         again at the same offset with PCRE_NOTEMPTY and PCRE_ANCHORED, and then
1930         if that fails by advancing the starting offset (see below)  and  trying         if  that  fails by advancing the starting offset (see below) and trying
1931         an ordinary match again. There is some code that demonstrates how to do         an ordinary match again. There is some code that demonstrates how to do
1932         this in the pcredemo.c sample program.         this in the pcredemo.c sample program.
1933    
1934           PCRE_NO_UTF8_CHECK           PCRE_NO_UTF8_CHECK
1935    
1936         When PCRE_UTF8 is set at compile time, the validity of the subject as a         When PCRE_UTF8 is set at compile time, the validity of the subject as a
1937         UTF-8  string is automatically checked when pcre_exec() is subsequently         UTF-8 string is automatically checked when pcre_exec() is  subsequently
1938         called.  The value of startoffset is also checked  to  ensure  that  it         called.   The  value  of  startoffset is also checked to ensure that it
1939         points  to  the start of a UTF-8 character. There is a discussion about         points to the start of a UTF-8 character. There is a  discussion  about
1940         the validity of UTF-8 strings in the section on UTF-8  support  in  the         the  validity  of  UTF-8 strings in the section on UTF-8 support in the
1941         main  pcre  page.  If  an  invalid  UTF-8  sequence  of bytes is found,         main pcre page. If  an  invalid  UTF-8  sequence  of  bytes  is  found,
1942         pcre_exec() returns the error PCRE_ERROR_BADUTF8. If  startoffset  con-         pcre_exec()  returns  the error PCRE_ERROR_BADUTF8. If startoffset con-
1943         tains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.         tains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.
1944    
1945         If  you  already  know that your subject is valid, and you want to skip         If you already know that your subject is valid, and you  want  to  skip
1946         these   checks   for   performance   reasons,   you   can    set    the         these    checks    for   performance   reasons,   you   can   set   the
1947         PCRE_NO_UTF8_CHECK  option  when calling pcre_exec(). You might want to         PCRE_NO_UTF8_CHECK option when calling pcre_exec(). You might  want  to
1948         do this for the second and subsequent calls to pcre_exec() if  you  are         do  this  for the second and subsequent calls to pcre_exec() if you are
1949         making  repeated  calls  to  find  all  the matches in a single subject         making repeated calls to find all  the  matches  in  a  single  subject
1950         string. However, you should be  sure  that  the  value  of  startoffset         string.  However,  you  should  be  sure  that the value of startoffset
1951         points  to  the  start of a UTF-8 character. When PCRE_NO_UTF8_CHECK is         points to the start of a UTF-8 character.  When  PCRE_NO_UTF8_CHECK  is
1952         set, the effect of passing an invalid UTF-8 string as a subject,  or  a         set,  the  effect of passing an invalid UTF-8 string as a subject, or a
1953         value  of startoffset that does not point to the start of a UTF-8 char-         value of startoffset that does not point to the start of a UTF-8  char-
1954         acter, is undefined. Your program may crash.         acter, is undefined. Your program may crash.
1955    
1956           PCRE_PARTIAL           PCRE_PARTIAL
1957    
1958         This option turns on the  partial  matching  feature.  If  the  subject         This  option  turns  on  the  partial  matching feature. If the subject
1959         string  fails to match the pattern, but at some point during the match-         string fails to match the pattern, but at some point during the  match-
1960         ing process the end of the subject was reached (that  is,  the  subject         ing  process  the  end of the subject was reached (that is, the subject
1961         partially  matches  the  pattern and the failure to match occurred only         partially matches the pattern and the failure to  match  occurred  only
1962         because there were not enough subject characters), pcre_exec()  returns         because  there were not enough subject characters), pcre_exec() returns
1963         PCRE_ERROR_PARTIAL  instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is         PCRE_ERROR_PARTIAL instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL  is
1964         used, there are restrictions on what may appear in the  pattern.  These         used,  there  are restrictions on what may appear in the pattern. These
1965         are discussed in the pcrepartial documentation.         are discussed in the pcrepartial documentation.
1966    
1967     The string to be matched by pcre_exec()     The string to be matched by pcre_exec()
1968    
1969         The  subject string is passed to pcre_exec() as a pointer in subject, a         The subject string is passed to pcre_exec() as a pointer in subject,  a
1970         length in length, and a starting byte offset in startoffset.  In  UTF-8         length  in  length, and a starting byte offset in startoffset. In UTF-8
1971         mode,  the  byte  offset  must point to the start of a UTF-8 character.         mode, the byte offset must point to the start  of  a  UTF-8  character.
1972         Unlike the pattern string, the subject may contain binary  zero  bytes.         Unlike  the  pattern string, the subject may contain binary zero bytes.
1973         When  the starting offset is zero, the search for a match starts at the         When the starting offset is zero, the search for a match starts at  the
1974         beginning of the subject, and this is by far the most common case.         beginning of the subject, and this is by far the most common case.
1975    
1976         A non-zero starting offset is useful when searching for  another  match         A  non-zero  starting offset is useful when searching for another match
1977         in  the same subject by calling pcre_exec() again after a previous suc-         in the same subject by calling pcre_exec() again after a previous  suc-
1978         cess.  Setting startoffset differs from just passing over  a  shortened         cess.   Setting  startoffset differs from just passing over a shortened
1979         string  and  setting  PCRE_NOTBOL  in the case of a pattern that begins         string and setting PCRE_NOTBOL in the case of  a  pattern  that  begins
1980         with any kind of lookbehind. For example, consider the pattern         with any kind of lookbehind. For example, consider the pattern
1981    
1982           \Biss\B           \Biss\B
1983    
1984         which finds occurrences of "iss" in the middle of  words.  (\B  matches         which  finds  occurrences  of "iss" in the middle of words. (\B matches
1985         only  if  the  current position in the subject is not a word boundary.)         only if the current position in the subject is not  a  word  boundary.)
1986         When applied to the string "Mississipi" the first call  to  pcre_exec()         When  applied  to the string "Mississipi" the first call to pcre_exec()
1987         finds  the  first  occurrence. If pcre_exec() is called again with just         finds the first occurrence. If pcre_exec() is called  again  with  just
1988         the remainder of the subject,  namely  "issipi",  it  does  not  match,         the  remainder  of  the  subject,  namely  "issipi", it does not match,
1989         because \B is always false at the start of the subject, which is deemed         because \B is always false at the start of the subject, which is deemed
1990         to be a word boundary. However, if pcre_exec()  is  passed  the  entire         to  be  a  word  boundary. However, if pcre_exec() is passed the entire
1991         string again, but with startoffset set to 4, it finds the second occur-         string again, but with startoffset set to 4, it finds the second occur-
1992         rence of "iss" because it is able to look behind the starting point  to         rence  of "iss" because it is able to look behind the starting point to
1993         discover that it is preceded by a letter.         discover that it is preceded by a letter.
1994    
1995         If  a  non-zero starting offset is passed when the pattern is anchored,         If a non-zero starting offset is passed when the pattern  is  anchored,
1996         one attempt to match at the given offset is made. This can only succeed         one attempt to match at the given offset is made. This can only succeed
1997         if  the  pattern  does  not require the match to be at the start of the         if the pattern does not require the match to be at  the  start  of  the
1998         subject.         subject.
1999    
2000     How pcre_exec() returns captured substrings     How pcre_exec() returns captured substrings
2001    
2002         In general, a pattern matches a certain portion of the subject, and  in         In  general, a pattern matches a certain portion of the subject, and in
2003         addition,  further  substrings  from  the  subject may be picked out by         addition, further substrings from the subject  may  be  picked  out  by
2004         parts of the pattern. Following the usage  in  Jeffrey  Friedl's  book,         parts  of  the  pattern.  Following the usage in Jeffrey Friedl's book,
2005         this  is  called "capturing" in what follows, and the phrase "capturing         this is called "capturing" in what follows, and the  phrase  "capturing
2006         subpattern" is used for a fragment of a pattern that picks out  a  sub-         subpattern"  is  used for a fragment of a pattern that picks out a sub-
2007         string.  PCRE  supports several other kinds of parenthesized subpattern         string. PCRE supports several other kinds of  parenthesized  subpattern
2008         that do not cause substrings to be captured.         that do not cause substrings to be captured.
2009    
2010         Captured substrings are returned to the caller via a vector of  integer         Captured  substrings are returned to the caller via a vector of integer
2011         offsets  whose  address is passed in ovector. The number of elements in         offsets whose address is passed in ovector. The number of  elements  in
2012         the vector is passed in ovecsize, which must be a non-negative  number.         the  vector is passed in ovecsize, which must be a non-negative number.
2013         Note: this argument is NOT the size of ovector in bytes.         Note: this argument is NOT the size of ovector in bytes.
2014    
2015         The  first  two-thirds of the vector is used to pass back captured sub-         The first two-thirds of the vector is used to pass back  captured  sub-
2016         strings, each substring using a pair of integers. The  remaining  third         strings,  each  substring using a pair of integers. The remaining third
2017         of  the  vector is used as workspace by pcre_exec() while matching cap-         of the vector is used as workspace by pcre_exec() while  matching  cap-
2018         turing subpatterns, and is not available for passing back  information.         turing  subpatterns, and is not available for passing back information.
2019         The  length passed in ovecsize should always be a multiple of three. If         The length passed in ovecsize should always be a multiple of three.  If
2020         it is not, it is rounded down.         it is not, it is rounded down.
2021    
2022         When a match is successful, information about  captured  substrings  is         When  a  match  is successful, information about captured substrings is
2023         returned  in  pairs  of integers, starting at the beginning of ovector,         returned in pairs of integers, starting at the  beginning  of  ovector,
2024         and continuing up to two-thirds of its length at the  most.  The  first         and  continuing  up  to two-thirds of its length at the most. The first
2025         element of a pair is set to the offset of the first character in a sub-         element of a pair is set to the offset of the first character in a sub-
2026         string, and the second is set to the  offset  of  the  first  character         string,  and  the  second  is  set to the offset of the first character
2027         after  the  end  of  a  substring. The first pair, ovector[0] and ovec-         after the end of a substring. The  first  pair,  ovector[0]  and  ovec-
2028         tor[1], identify the portion of  the  subject  string  matched  by  the         tor[1],  identify  the  portion  of  the  subject string matched by the
2029         entire  pattern.  The next pair is used for the first capturing subpat-         entire pattern. The next pair is used for the first  capturing  subpat-
2030         tern, and so on. The value returned by pcre_exec() is one more than the         tern, and so on. The value returned by pcre_exec() is one more than the
2031         highest numbered pair that has been set. For example, if two substrings         highest numbered pair that has been set. For example, if two substrings
2032         have been captured, the returned value is 3. If there are no  capturing         have  been captured, the returned value is 3. If there are no capturing
2033         subpatterns,  the return value from a successful match is 1, indicating         subpatterns, the return value from a successful match is 1,  indicating
2034         that just the first pair of offsets has been set.         that just the first pair of offsets has been set.
2035    
2036         If a capturing subpattern is matched repeatedly, it is the last portion         If a capturing subpattern is matched repeatedly, it is the last portion
2037         of the string that it matched that is returned.         of the string that it matched that is returned.
2038    
2039         If  the vector is too small to hold all the captured substring offsets,         If the vector is too small to hold all the captured substring  offsets,
2040         it is used as far as possible (up to two-thirds of its length), and the         it is used as far as possible (up to two-thirds of its length), and the
2041         function  returns a value of zero. In particular, if the substring off-         function returns a value of zero. In particular, if the substring  off-
2042         sets are not of interest, pcre_exec() may be called with ovector passed         sets are not of interest, pcre_exec() may be called with ovector passed
2043         as  NULL  and  ovecsize  as zero. However, if the pattern contains back         as NULL and ovecsize as zero. However, if  the  pattern  contains  back
2044         references and the ovector is not big enough to  remember  the  related         references  and  the  ovector is not big enough to remember the related
2045         substrings,  PCRE has to get additional memory for use during matching.         substrings, PCRE has to get additional memory for use during  matching.
2046         Thus it is usually advisable to supply an ovector.         Thus it is usually advisable to supply an ovector.
2047    
2048         The pcre_info() function can be used to find  out  how  many  capturing         The  pcre_info()  function  can  be used to find out how many capturing
2049         subpatterns  there  are  in  a  compiled pattern. The smallest size for         subpatterns there are in a compiled  pattern.  The  smallest  size  for
2050         ovector that will allow for n captured substrings, in addition  to  the         ovector  that  will allow for n captured substrings, in addition to the
2051         offsets of the substring matched by the whole pattern, is (n+1)*3.         offsets of the substring matched by the whole pattern, is (n+1)*3.
2052    
2053         It  is  possible for capturing subpattern number n+1 to match some part         It is possible for capturing subpattern number n+1 to match  some  part
2054         of the subject when subpattern n has not been used at all. For example,         of the subject when subpattern n has not been used at all. For example,
2055         if  the  string  "abc"  is  matched against the pattern (a|(z))(bc) the         if the string "abc" is matched  against  the  pattern  (a|(z))(bc)  the
2056         return from the function is 4, and subpatterns 1 and 3 are matched, but         return from the function is 4, and subpatterns 1 and 3 are matched, but
2057         2  is  not.  When  this happens, both values in the offset pairs corre-         2 is not. When this happens, both values in  the  offset  pairs  corre-
2058         sponding to unused subpatterns are set to -1.         sponding to unused subpatterns are set to -1.
2059    
2060         Offset values that correspond to unused subpatterns at the end  of  the         Offset  values  that correspond to unused subpatterns at the end of the
2061         expression  are  also  set  to  -1. For example, if the string "abc" is         expression are also set to -1. For example,  if  the  string  "abc"  is
2062         matched against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are  not         matched  against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not
2063         matched.  The  return  from the function is 2, because the highest used         matched. The return from the function is 2, because  the  highest  used
2064         capturing subpattern number is 1. However, you can refer to the offsets         capturing subpattern number is 1. However, you can refer to the offsets
2065         for  the  second  and third capturing subpatterns if you wish (assuming         for the second and third capturing subpatterns if  you  wish  (assuming
2066         the vector is large enough, of course).         the vector is large enough, of course).
2067    
2068         Some convenience functions are provided  for  extracting  the  captured         Some  convenience  functions  are  provided for extracting the captured
2069         substrings as separate strings. These are described below.         substrings as separate strings. These are described below.
2070    
2071     Error return values from pcre_exec()     Error return values from pcre_exec()
2072    
2073         If  pcre_exec()  fails, it returns a negative number. The following are         If pcre_exec() fails, it returns a negative number. The  following  are
2074         defined in the header file:         defined in the header file:
2075    
2076           PCRE_ERROR_NOMATCH        (-1)           PCRE_ERROR_NOMATCH        (-1)
# Line 2035  MATCHING A PATTERN: THE TRADITIONAL FUNC Line 2079  MATCHING A PATTERN: THE TRADITIONAL FUNC
2079    
2080           PCRE_ERROR_NULL           (-2)           PCRE_ERROR_NULL           (-2)
2081    
2082         Either code or subject was passed as NULL,  or  ovector  was  NULL  and         Either  code  or  subject  was  passed as NULL, or ovector was NULL and
2083         ovecsize was not zero.         ovecsize was not zero.
2084    
2085           PCRE_ERROR_BADOPTION      (-3)           PCRE_ERROR_BADOPTION      (-3)
# Line 2044  MATCHING A PATTERN: THE TRADITIONAL FUNC Line 2088  MATCHING A PATTERN: THE TRADITIONAL FUNC
2088    
2089           PCRE_ERROR_BADMAGIC       (-4)           PCRE_ERROR_BADMAGIC       (-4)
2090    
2091         PCRE  stores a 4-byte "magic number" at the start of the compiled code,         PCRE stores a 4-byte "magic number" at the start of the compiled  code,
2092         to catch the case when it is passed a junk pointer and to detect when a         to catch the case when it is passed a junk pointer and to detect when a
2093         pattern that was compiled in an environment of one endianness is run in         pattern that was compiled in an environment of one endianness is run in
2094         an environment with the other endianness. This is the error  that  PCRE         an  environment  with the other endianness. This is the error that PCRE
2095         gives when the magic number is not present.         gives when the magic number is not present.
2096    
2097           PCRE_ERROR_UNKNOWN_OPCODE (-5)           PCRE_ERROR_UNKNOWN_OPCODE (-5)
2098    
2099         While running the pattern match, an unknown item was encountered in the         While running the pattern match, an unknown item was encountered in the
2100         compiled pattern. This error could be caused by a bug  in  PCRE  or  by         compiled  pattern.  This  error  could be caused by a bug in PCRE or by
2101         overwriting of the compiled pattern.         overwriting of the compiled pattern.
2102    
2103           PCRE_ERROR_NOMEMORY       (-6)           PCRE_ERROR_NOMEMORY       (-6)
2104    
2105         If  a  pattern contains back references, but the ovector that is passed         If a pattern contains back references, but the ovector that  is  passed
2106         to pcre_exec() is not big enough to remember the referenced substrings,         to pcre_exec() is not big enough to remember the referenced substrings,
2107         PCRE  gets  a  block of memory at the start of matching to use for this         PCRE gets a block of memory at the start of matching to  use  for  this
2108         purpose. If the call via pcre_malloc() fails, this error is given.  The         purpose.  If the call via pcre_malloc() fails, this error is given. The
2109         memory is automatically freed at the end of matching.         memory is automatically freed at the end of matching.
2110    
2111           PCRE_ERROR_NOSUBSTRING    (-7)           PCRE_ERROR_NOSUBSTRING    (-7)
2112    
2113         This  error is used by the pcre_copy_substring(), pcre_get_substring(),         This error is used by the pcre_copy_substring(),  pcre_get_substring(),
2114         and  pcre_get_substring_list()  functions  (see  below).  It  is  never         and  pcre_get_substring_list()  functions  (see  below).  It  is  never
2115         returned by pcre_exec().         returned by pcre_exec().
2116    
2117           PCRE_ERROR_MATCHLIMIT     (-8)           PCRE_ERROR_MATCHLIMIT     (-8)
2118    
2119         The  backtracking  limit,  as  specified  by the match_limit field in a         The backtracking limit, as specified by  the  match_limit  field  in  a
2120         pcre_extra structure (or defaulted) was reached.  See  the  description         pcre_extra  structure  (or  defaulted) was reached. See the description
2121         above.         above.
2122    
2123           PCRE_ERROR_CALLOUT        (-9)           PCRE_ERROR_CALLOUT        (-9)
2124    
2125         This error is never generated by pcre_exec() itself. It is provided for         This error is never generated by pcre_exec() itself. It is provided for
2126         use by callout functions that want to yield a distinctive  error  code.         use  by  callout functions that want to yield a distinctive error code.
2127         See the pcrecallout documentation for details.         See the pcrecallout documentation for details.
2128    
2129           PCRE_ERROR_BADUTF8        (-10)           PCRE_ERROR_BADUTF8        (-10)
2130    
2131         A  string  that contains an invalid UTF-8 byte sequence was passed as a         A string that contains an invalid UTF-8 byte sequence was passed  as  a
2132         subject.         subject.
2133    
2134           PCRE_ERROR_BADUTF8_OFFSET (-11)           PCRE_ERROR_BADUTF8_OFFSET (-11)
2135    
2136         The UTF-8 byte sequence that was passed as a subject was valid, but the         The UTF-8 byte sequence that was passed as a subject was valid, but the
2137         value  of startoffset did not point to the beginning of a UTF-8 charac-         value of startoffset did not point to the beginning of a UTF-8  charac-
2138         ter.         ter.
2139    
2140           PCRE_ERROR_PARTIAL        (-12)           PCRE_ERROR_PARTIAL        (-12)
2141    
2142         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
2143         pcrepartial documentation for details of partial matching.         pcrepartial documentation for details of partial matching.
2144    
2145           PCRE_ERROR_BADPARTIAL     (-13)           PCRE_ERROR_BADPARTIAL     (-13)
2146    
2147         The  PCRE_PARTIAL  option  was  used with a compiled pattern containing         The PCRE_PARTIAL option was used with  a  compiled  pattern  containing
2148         items that are not supported for partial matching. See the  pcrepartial         items  that are not supported for partial matching. See the pcrepartial
2149         documentation for details of partial matching.         documentation for details of partial matching.
2150    
2151           PCRE_ERROR_INTERNAL       (-14)           PCRE_ERROR_INTERNAL       (-14)
2152    
2153         An  unexpected  internal error has occurred. This error could be caused         An unexpected internal error has occurred. This error could  be  caused
2154         by a bug in PCRE or by overwriting of the compiled pattern.         by a bug in PCRE or by overwriting of the compiled pattern.
2155    
2156           PCRE_ERROR_BADCOUNT       (-15)           PCRE_ERROR_BADCOUNT       (-15)
2157    
2158         This error is given if the value of the ovecsize argument is  negative.         This  error is given if the value of the ovecsize argument is negative.
2159    
2160           PCRE_ERROR_RECURSIONLIMIT (-21)           PCRE_ERROR_RECURSIONLIMIT (-21)
2161    
2162         The internal recursion limit, as specified by the match_limit_recursion         The internal recursion limit, as specified by the match_limit_recursion
2163         field in a pcre_extra structure (or defaulted)  was  reached.  See  the         field  in  a  pcre_extra  structure (or defaulted) was reached. See the
2164         description above.         description above.
2165    
2166           PCRE_ERROR_BADNEWLINE     (-23)           PCRE_ERROR_BADNEWLINE     (-23)
# Line 2139  EXTRACTING CAPTURED SUBSTRINGS BY NUMBER Line 2183  EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
2183         int pcre_get_substring_list(const char *subject,         int pcre_get_substring_list(const char *subject,
2184              int *ovector, int stringcount, const char ***listptr);              int *ovector, int stringcount, const char ***listptr);
2185    
2186         Captured  substrings  can  be  accessed  directly  by using the offsets         Captured substrings can be  accessed  directly  by  using  the  offsets
2187         returned by pcre_exec() in  ovector.  For  convenience,  the  functions         returned  by  pcre_exec()  in  ovector.  For convenience, the functions
2188         pcre_copy_substring(),    pcre_get_substring(),    and    pcre_get_sub-         pcre_copy_substring(),    pcre_get_substring(),    and    pcre_get_sub-
2189         string_list() are provided for extracting captured substrings  as  new,         string_list()  are  provided for extracting captured substrings as new,
2190         separate,  zero-terminated strings. These functions identify substrings         separate, zero-terminated strings. These functions identify  substrings
2191         by number. The next section describes functions  for  extracting  named         by  number.  The  next section describes functions for extracting named
2192         substrings.         substrings.
2193    
2194         A  substring that contains a binary zero is correctly extracted and has         A substring that contains a binary zero is correctly extracted and  has
2195         a further zero added on the end, but the result is not, of course, a  C         a  further zero added on the end, but the result is not, of course, a C
2196         string.   However,  you  can  process such a string by referring to the         string.  However, you can process such a string  by  referring  to  the
2197         length that is  returned  by  pcre_copy_substring()  and  pcre_get_sub-         length  that  is  returned  by  pcre_copy_substring() and pcre_get_sub-
2198         string().  Unfortunately, the interface to pcre_get_substring_list() is         string().  Unfortunately, the interface to pcre_get_substring_list() is
2199         not adequate for handling strings containing binary zeros, because  the         not  adequate for handling strings containing binary zeros, because the
2200         end of the final string is not independently indicated.         end of the final string is not independently indicated.
2201    
2202         The  first  three  arguments  are the same for all three of these func-         The first three arguments are the same for all  three  of  these  func-
2203         tions: subject is the subject string that has  just  been  successfully         tions:  subject  is  the subject string that has just been successfully
2204         matched, ovector is a pointer to the vector of integer offsets that was         matched, ovector is a pointer to the vector of integer offsets that was
2205         passed to pcre_exec(), and stringcount is the number of substrings that         passed to pcre_exec(), and stringcount is the number of substrings that
2206         were  captured  by  the match, including the substring that matched the         were captured by the match, including the substring  that  matched  the
2207         entire regular expression. This is the value returned by pcre_exec() if         entire regular expression. This is the value returned by pcre_exec() if
2208         it  is greater than zero. If pcre_exec() returned zero, indicating that         it is greater than zero. If pcre_exec() returned zero, indicating  that
2209         it ran out of space in ovector, the value passed as stringcount  should         it  ran out of space in ovector, the value passed as stringcount should
2210         be the number of elements in the vector divided by three.         be the number of elements in the vector divided by three.
2211    
2212         The  functions pcre_copy_substring() and pcre_get_substring() extract a         The functions pcre_copy_substring() and pcre_get_substring() extract  a
2213         single substring, whose number is given as  stringnumber.  A  value  of         single  substring,  whose  number  is given as stringnumber. A value of
2214         zero  extracts  the  substring that matched the entire pattern, whereas         zero extracts the substring that matched the  entire  pattern,  whereas
2215         higher values  extract  the  captured  substrings.  For  pcre_copy_sub-         higher  values  extract  the  captured  substrings.  For pcre_copy_sub-
2216         string(),  the  string  is  placed  in buffer, whose length is given by         string(), the string is placed in buffer,  whose  length  is  given  by
2217         buffersize, while for pcre_get_substring() a new  block  of  memory  is         buffersize,  while  for  pcre_get_substring()  a new block of memory is
2218         obtained  via  pcre_malloc,  and its address is returned via stringptr.         obtained via pcre_malloc, and its address is  returned  via  stringptr.
2219         The yield of the function is the length of the  string,  not  including         The  yield  of  the function is the length of the string, not including
2220         the terminating zero, or one of these error codes:         the terminating zero, or one of these error codes:
2221    
2222           PCRE_ERROR_NOMEMORY       (-6)           PCRE_ERROR_NOMEMORY       (-6)
2223    
2224         The  buffer  was too small for pcre_copy_substring(), or the attempt to         The buffer was too small for pcre_copy_substring(), or the  attempt  to
2225         get memory failed for pcre_get_substring().         get memory failed for pcre_get_substring().
2226    
2227           PCRE_ERROR_NOSUBSTRING    (-7)           PCRE_ERROR_NOSUBSTRING    (-7)
2228    
2229         There is no substring whose number is stringnumber.         There is no substring whose number is stringnumber.
2230    
2231         The pcre_get_substring_list()  function  extracts  all  available  sub-         The  pcre_get_substring_list()  function  extracts  all  available sub-
2232         strings  and  builds  a list of pointers to them. All this is done in a         strings and builds a list of pointers to them. All this is  done  in  a
2233         single block of memory that is obtained via pcre_malloc. The address of         single block of memory that is obtained via pcre_malloc. The address of
2234         the  memory  block  is returned via listptr, which is also the start of         the memory block is returned via listptr, which is also  the  start  of
2235         the list of string pointers. The end of the list is marked  by  a  NULL         the  list  of  string pointers. The end of the list is marked by a NULL
2236         pointer.  The  yield  of  the function is zero if all went well, or the         pointer. The yield of the function is zero if all  went  well,  or  the
2237         error code         error code
2238    
2239           PCRE_ERROR_NOMEMORY       (-6)           PCRE_ERROR_NOMEMORY       (-6)
2240    
2241         if the attempt to get the memory block failed.         if the attempt to get the memory block failed.
2242    
2243         When any of these functions encounter a substring that is unset,  which         When  any of these functions encounter a substring that is unset, which
2244         can  happen  when  capturing subpattern number n+1 matches some part of         can happen when capturing subpattern number n+1 matches  some  part  of
2245         the subject, but subpattern n has not been used at all, they return  an         the  subject, but subpattern n has not been used at all, they return an
2246         empty string. This can be distinguished from a genuine zero-length sub-         empty string. This can be distinguished from a genuine zero-length sub-
2247         string by inspecting the appropriate offset in ovector, which is  nega-         string  by inspecting the appropriate offset in ovector, which is nega-
2248         tive for unset substrings.         tive for unset substrings.
2249    
2250         The  two convenience functions pcre_free_substring() and pcre_free_sub-         The two convenience functions pcre_free_substring() and  pcre_free_sub-
2251         string_list() can be used to free the memory  returned  by  a  previous         string_list()  can  be  used  to free the memory returned by a previous
2252         call  of  pcre_get_substring()  or  pcre_get_substring_list(),  respec-         call  of  pcre_get_substring()  or  pcre_get_substring_list(),  respec-
2253         tively. They do nothing more than  call  the  function  pointed  to  by         tively.  They  do  nothing  more  than  call the function pointed to by
2254         pcre_free,  which  of course could be called directly from a C program.         pcre_free, which of course could be called directly from a  C  program.
2255         However, PCRE is used in some situations where it is linked via a  spe-         However,  PCRE is used in some situations where it is linked via a spe-
2256         cial   interface  to  another  programming  language  that  cannot  use         cial  interface  to  another  programming  language  that  cannot   use
2257         pcre_free directly; it is for these cases that the functions  are  pro-         pcre_free  directly;  it is for these cases that the functions are pro-
2258         vided.         vided.
2259    
2260    
# Line 2229  EXTRACTING CAPTURED SUBSTRINGS BY NAME Line 2273  EXTRACTING CAPTURED SUBSTRINGS BY NAME
2273              int stringcount, const char *stringname,              int stringcount, const char *stringname,
2274              const char **stringptr);              const char **stringptr);
2275    
2276         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-
2277         ber.  For example, for this pattern         ber.  For example, for this pattern
2278    
2279           (a+)b(?<xxx>\d+)...           (a+)b(?<xxx>\d+)...
# Line 2238  EXTRACTING CAPTURED SUBSTRINGS BY NAME Line 2282  EXTRACTING CAPTURED SUBSTRINGS BY NAME
2282         be unique (PCRE_DUPNAMES was not set), you can find the number from the         be unique (PCRE_DUPNAMES was not set), you can find the number from the
2283         name by calling pcre_get_stringnumber(). The first argument is the com-         name by calling pcre_get_stringnumber(). The first argument is the com-
2284         piled pattern, and the second is the name. The yield of the function is         piled pattern, and the second is the name. The yield of the function is
2285         the subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if  there  is  no         the  subpattern  number,  or PCRE_ERROR_NOSUBSTRING (-7) if there is no
2286         subpattern of that name.         subpattern of that name.
2287    
2288         Given the number, you can extract the substring directly, or use one of         Given the number, you can extract the substring directly, or use one of
2289         the functions described in the previous section. For convenience, there         the functions described in the previous section. For convenience, there
2290         are also two functions that do the whole job.         are also two functions that do the whole job.
2291    
2292         Most    of    the    arguments   of   pcre_copy_named_substring()   and         Most   of   the   arguments    of    pcre_copy_named_substring()    and
2293         pcre_get_named_substring() are the same  as  those  for  the  similarly         pcre_get_named_substring()  are  the  same  as  those for the similarly
2294         named  functions  that extract by number. As these are described in the         named functions that extract by number. As these are described  in  the
2295         previous section, they are not re-described here. There  are  just  two         previous  section,  they  are not re-described here. There are just two
2296         differences:         differences:
2297    
2298         First,  instead  of a substring number, a substring name is given. Sec-         First, instead of a substring number, a substring name is  given.  Sec-
2299         ond, there is an extra argument, given at the start, which is a pointer         ond, there is an extra argument, given at the start, which is a pointer
2300         to  the compiled pattern. This is needed in order to gain access to the         to the compiled pattern. This is needed in order to gain access to  the
2301         name-to-number translation table.         name-to-number translation table.
2302    
2303         These functions call pcre_get_stringnumber(), and if it succeeds,  they         These  functions call pcre_get_stringnumber(), and if it succeeds, they
2304         then  call  pcre_copy_substring() or pcre_get_substring(), as appropri-         then call pcre_copy_substring() or pcre_get_substring(),  as  appropri-
2305         ate. NOTE: If PCRE_DUPNAMES is set and there are duplicate  names,  the         ate.  NOTE:  If PCRE_DUPNAMES is set and there are duplicate names, the
2306         behaviour may not be what you want (see the next section).         behaviour may not be what you want (see the next section).
2307    
2308    
# Line 2267  DUPLICATE SUBPATTERN NAMES Line 2311  DUPLICATE SUBPATTERN NAMES
2311         int pcre_get_stringtable_entries(const pcre *code,         int pcre_get_stringtable_entries(const pcre *code,
2312              const char *name, char **first, char **last);              const char *name, char **first, char **last);
2313    
2314         When  a  pattern  is  compiled with the PCRE_DUPNAMES option, names for         When a pattern is compiled with the  PCRE_DUPNAMES  option,  names  for
2315         subpatterns are not required to  be  unique.  Normally,  patterns  with         subpatterns  are  not  required  to  be unique. Normally, patterns with
2316         duplicate  names  are such that in any one match, only one of the named         duplicate names are such that in any one match, only one of  the  named
2317         subpatterns participates. An example is shown in the pcrepattern  docu-         subpatterns  participates. An example is shown in the pcrepattern docu-
2318         mentation.         mentation.
2319    
2320         When    duplicates   are   present,   pcre_copy_named_substring()   and         When   duplicates   are   present,   pcre_copy_named_substring()    and
2321         pcre_get_named_substring() return the first substring corresponding  to         pcre_get_named_substring()  return the first substring corresponding to
2322         the  given  name  that  is set. If none are set, PCRE_ERROR_NOSUBSTRING         the given name that is set. If  none  are  set,  PCRE_ERROR_NOSUBSTRING
2323         (-7) is returned; no  data  is  returned.  The  pcre_get_stringnumber()         (-7)  is  returned;  no  data  is returned. The pcre_get_stringnumber()
2324         function  returns one of the numbers that are associated with the name,         function returns one of the numbers that are associated with the  name,
2325         but it is not defined which it is.         but it is not defined which it is.
2326    
2327         If you want to get full details of all captured substrings for a  given         If  you want to get full details of all captured substrings for a given
2328         name,  you  must  use  the pcre_get_stringtable_entries() function. The         name, you must use  the  pcre_get_stringtable_entries()  function.  The
2329         first argument is the compiled pattern, and the second is the name. The         first argument is the compiled pattern, and the second is the name. The
2330         third  and  fourth  are  pointers to variables which are updated by the         third and fourth are pointers to variables which  are  updated  by  the
2331         function. After it has run, they point to the first and last entries in         function. After it has run, they point to the first and last entries in
2332         the  name-to-number  table  for  the  given  name.  The function itself         the name-to-number table  for  the  given  name.  The  function  itself
2333         returns the length of each entry,  or  PCRE_ERROR_NOSUBSTRING  (-7)  if         returns  the  length  of  each entry, or PCRE_ERROR_NOSUBSTRING (-7) if
2334         there  are none. The format of the table is described above in the sec-         there are none. The format of the table is described above in the  sec-
2335         tion entitled Information about a  pattern.   Given  all  the  relevant         tion  entitled  Information  about  a  pattern.  Given all the relevant
2336         entries  for the name, you can extract each of their numbers, and hence         entries for the name, you can extract each of their numbers, and  hence
2337         the captured data, if any.         the captured data, if any.
2338    
2339    
2340  FINDING ALL POSSIBLE MATCHES  FINDING ALL POSSIBLE MATCHES
2341    
2342         The traditional matching function uses a  similar  algorithm  to  Perl,         The  traditional  matching  function  uses a similar algorithm to Perl,
2343         which stops when it finds the first match, starting at a given point in         which stops when it finds the first match, starting at a given point in
2344         the subject. If you want to find all possible matches, or  the  longest         the  subject.  If you want to find all possible matches, or the longest
2345         possible  match,  consider using the alternative matching function (see         possible match, consider using the alternative matching  function  (see
2346         below) instead. If you cannot use the alternative function,  but  still         below)  instead.  If you cannot use the alternative function, but still
2347         need  to  find all possible matches, you can kludge it up by making use         need to find all possible matches, you can kludge it up by  making  use
2348         of the callout facility, which is described in the pcrecallout documen-         of the callout facility, which is described in the pcrecallout documen-
2349         tation.         tation.
2350    
2351         What you have to do is to insert a callout right at the end of the pat-         What you have to do is to insert a callout right at the end of the pat-
2352         tern.  When your callout function is called, extract and save the  cur-         tern.   When your callout function is called, extract and save the cur-
2353         rent  matched  substring.  Then  return  1, which forces pcre_exec() to         rent matched substring. Then return  1,  which  forces  pcre_exec()  to
2354         backtrack and try other alternatives. Ultimately, when it runs  out  of         backtrack  and  try other alternatives. Ultimately, when it runs out of
2355         matches, pcre_exec() will yield PCRE_ERROR_NOMATCH.         matches, pcre_exec() will yield PCRE_ERROR_NOMATCH.
2356    
2357    
# Line 2318  MATCHING A PATTERN: THE ALTERNATIVE FUNC Line 2362  MATCHING A PATTERN: THE ALTERNATIVE FUNC
2362              int options, int *ovector, int ovecsize,              int options, int *ovector, int ovecsize,
2363              int *workspace, int wscount);              int *workspace, int wscount);
2364    
2365         The  function  pcre_dfa_exec()  is  called  to  match  a subject string         The function pcre_dfa_exec()  is  called  to  match  a  subject  string
2366         against a compiled pattern, using a matching algorithm that  scans  the         against  a  compiled pattern, using a matching algorithm that scans the
2367         subject  string  just  once, and does not backtrack. This has different         subject string just once, and does not backtrack.  This  has  different
2368         characteristics to the normal algorithm, and  is  not  compatible  with         characteristics  to  the  normal  algorithm, and is not compatible with
2369         Perl.  Some  of the features of PCRE patterns are not supported. Never-         Perl. Some of the features of PCRE patterns are not  supported.  Never-
2370         theless, there are times when this kind of matching can be useful.  For         theless,  there are times when this kind of matching can be useful. For
2371         a discussion of the two matching algorithms, see the pcrematching docu-         a discussion of the two matching algorithms, see the pcrematching docu-
2372         mentation.         mentation.
2373    
2374         The arguments for the pcre_dfa_exec() function  are  the  same  as  for         The  arguments  for  the  pcre_dfa_exec()  function are the same as for
2375         pcre_exec(), plus two extras. The ovector argument is used in a differ-         pcre_exec(), plus two extras. The ovector argument is used in a differ-
2376         ent way, and this is described below. The other  common  arguments  are         ent  way,  and  this is described below. The other common arguments are
2377         used  in  the  same way as for pcre_exec(), so their description is not         used in the same way as for pcre_exec(), so their  description  is  not
2378         repeated here.         repeated here.
2379    
2380         The two additional arguments provide workspace for  the  function.  The         The  two  additional  arguments provide workspace for the function. The
2381         workspace  vector  should  contain at least 20 elements. It is used for         workspace vector should contain at least 20 elements. It  is  used  for
2382         keeping  track  of  multiple  paths  through  the  pattern  tree.  More         keeping  track  of  multiple  paths  through  the  pattern  tree.  More
2383         workspace  will  be  needed for patterns and subjects where there are a         workspace will be needed for patterns and subjects where  there  are  a
2384         lot of potential matches.         lot of potential matches.
2385    
2386         Here is an example of a simple call to pcre_dfa_exec():         Here is an example of a simple call to pcre_dfa_exec():
# Line 2358  MATCHING A PATTERN: THE ALTERNATIVE FUNC Line 2402  MATCHING A PATTERN: THE ALTERNATIVE FUNC
2402    
2403     Option bits for pcre_dfa_exec()     Option bits for pcre_dfa_exec()
2404    
2405         The unused bits of the options argument  for  pcre_dfa_exec()  must  be         The  unused  bits  of  the options argument for pcre_dfa_exec() must be
2406         zero.  The  only  bits  that  may  be  set are PCRE_ANCHORED, PCRE_NEW-         zero. The only bits  that  may  be  set  are  PCRE_ANCHORED,  PCRE_NEW-
2407         LINE_xxx, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY,  PCRE_NO_UTF8_CHECK,         LINE_xxx,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK,
2408         PCRE_PARTIAL, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last         PCRE_PARTIAL, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last
2409         three of these are the same as for pcre_exec(), so their description is         three of these are the same as for pcre_exec(), so their description is
2410         not repeated here.         not repeated here.
2411    
2412           PCRE_PARTIAL           PCRE_PARTIAL
2413    
2414         This  has  the  same general effect as it does for pcre_exec(), but the         This has the same general effect as it does for  pcre_exec(),  but  the
2415         details  are  slightly  different.  When  PCRE_PARTIAL   is   set   for         details   are   slightly   different.  When  PCRE_PARTIAL  is  set  for
2416         pcre_dfa_exec(),  the  return code PCRE_ERROR_NOMATCH is converted into         pcre_dfa_exec(), the return code PCRE_ERROR_NOMATCH is  converted  into
2417         PCRE_ERROR_PARTIAL if the end of the subject  is  reached,  there  have         PCRE_ERROR_PARTIAL  if  the  end  of the subject is reached, there have
2418         been no complete matches, but there is still at least one matching pos-         been no complete matches, but there is still at least one matching pos-
2419         sibility. The portion of the string that provided the partial match  is         sibility.  The portion of the string that provided the partial match is
2420         set as the first matching string.         set as the first matching string.
2421    
2422           PCRE_DFA_SHORTEST           PCRE_DFA_SHORTEST
2423    
2424         Setting  the  PCRE_DFA_SHORTEST option causes the matching algorithm to         Setting the PCRE_DFA_SHORTEST option causes the matching  algorithm  to
2425         stop as soon as it has found one match. Because of the way the alterna-         stop as soon as it has found one match. Because of the way the alterna-
2426         tive  algorithm  works, this is necessarily the shortest possible match         tive algorithm works, this is necessarily the shortest  possible  match
2427         at the first possible matching point in the subject string.         at the first possible matching point in the subject string.
2428    
2429           PCRE_DFA_RESTART           PCRE_DFA_RESTART
2430    
2431         When pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option,  and         When  pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option, and
2432         returns  a  partial  match, it is possible to call it again, with addi-         returns a partial match, it is possible to call it  again,  with  addi-
2433         tional subject characters, and have it continue with  the  same  match.         tional  subject  characters,  and have it continue with the same match.
2434         The  PCRE_DFA_RESTART  option requests this action; when it is set, the         The PCRE_DFA_RESTART option requests this action; when it is  set,  the
2435         workspace and wscount options must reference the same vector as  before         workspace  and wscount options must reference the same vector as before
2436         because  data  about  the  match so far is left in them after a partial         because data about the match so far is left in  them  after  a  partial
2437         match. There is more discussion of this  facility  in  the  pcrepartial         match.  There  is  more  discussion of this facility in the pcrepartial
2438         documentation.         documentation.
2439    
2440     Successful returns from pcre_dfa_exec()     Successful returns from pcre_dfa_exec()
2441    
2442         When  pcre_dfa_exec()  succeeds, it may have matched more than one sub-         When pcre_dfa_exec() succeeds, it may have matched more than  one  sub-
2443         string in the subject. Note, however, that all the matches from one run         string in the subject. Note, however, that all the matches from one run
2444         of  the  function  start  at the same point in the subject. The shorter         of the function start at the same point in  the  subject.  The  shorter
2445         matches are all initial substrings of the longer matches. For  example,         matches  are all initial substrings of the longer matches. For example,
2446         if the pattern         if the pattern
2447    
2448           <.*>           <.*>
# Line 2413  MATCHING A PATTERN: THE ALTERNATIVE FUNC Line 2457  MATCHING A PATTERN: THE ALTERNATIVE FUNC
2457           <something> <something else>           <something> <something else>
2458           <something> <something else> <something further>           <something> <something else> <something further>
2459    
2460         On  success,  the  yield of the function is a number greater than zero,         On success, the yield of the function is a number  greater  than  zero,
2461         which is the number of matched substrings.  The  substrings  themselves         which  is  the  number of matched substrings. The substrings themselves
2462         are  returned  in  ovector. Each string uses two elements; the first is         are returned in ovector. Each string uses two elements;  the  first  is
2463         the offset to the start, and the second is the offset to  the  end.  In         the  offset  to  the start, and the second is the offset to the end. In
2464         fact,  all  the  strings  have the same start offset. (Space could have         fact, all the strings have the same start  offset.  (Space  could  have
2465         been saved by giving this only once, but it was decided to retain  some         been  saved by giving this only once, but it was decided to retain some
2466         compatibility  with  the  way pcre_exec() returns data, even though the         compatibility with the way pcre_exec() returns data,  even  though  the
2467         meaning of the strings is different.)         meaning of the strings is different.)
2468    
2469         The strings are returned in reverse order of length; that is, the long-         The strings are returned in reverse order of length; that is, the long-
2470         est  matching  string is given first. If there were too many matches to         est matching string is given first. If there were too many  matches  to
2471         fit into ovector, the yield of the function is zero, and the vector  is         fit  into ovector, the yield of the function is zero, and the vector is
2472         filled with the longest matches.         filled with the longest matches.
2473    
2474     Error returns from pcre_dfa_exec()     Error returns from pcre_dfa_exec()
2475    
2476         The  pcre_dfa_exec()  function returns a negative number when it fails.         The pcre_dfa_exec() function returns a negative number when  it  fails.
2477         Many of the errors are the same  as  for  pcre_exec(),  and  these  are         Many  of  the  errors  are  the  same as for pcre_exec(), and these are
2478         described  above.   There are in addition the following errors that are         described above.  There are in addition the following errors  that  are
2479         specific to pcre_dfa_exec():         specific to pcre_dfa_exec():
2480    
2481           PCRE_ERROR_DFA_UITEM      (-16)           PCRE_ERROR_DFA_UITEM      (-16)
2482    
2483         This return is given if pcre_dfa_exec() encounters an item in the  pat-         This  return is given if pcre_dfa_exec() encounters an item in the pat-
2484         tern  that  it  does not support, for instance, the use of \C or a back         tern that it does not support, for instance, the use of \C  or  a  back
2485         reference.         reference.
2486    
2487           PCRE_ERROR_DFA_UCOND      (-17)           PCRE_ERROR_DFA_UCOND      (-17)
2488    
2489         This return is given if pcre_dfa_exec()  encounters  a  condition  item         This  return  is  given  if pcre_dfa_exec() encounters a condition item
2490         that  uses  a back reference for the condition, or a test for recursion         that uses a back reference for the condition, or a test  for  recursion
2491         in a specific group. These are not supported.         in a specific group. These are not supported.
2492    
2493           PCRE_ERROR_DFA_UMLIMIT    (-18)           PCRE_ERROR_DFA_UMLIMIT    (-18)
2494    
2495         This return is given if pcre_dfa_exec() is called with an  extra  block         This  return  is given if pcre_dfa_exec() is called with an extra block
2496         that contains a setting of the match_limit field. This is not supported         that contains a setting of the match_limit field. This is not supported
2497         (it is meaningless).         (it is meaningless).
2498    
2499           PCRE_ERROR_DFA_WSSIZE     (-19)           PCRE_ERROR_DFA_WSSIZE     (-19)
2500    
2501         This return is given if  pcre_dfa_exec()  runs  out  of  space  in  the         This  return  is  given  if  pcre_dfa_exec()  runs  out of space in the
2502         workspace vector.         workspace vector.
2503    
2504           PCRE_ERROR_DFA_RECURSE    (-20)           PCRE_ERROR_DFA_RECURSE    (-20)
2505    
2506         When  a  recursive subpattern is processed, the matching function calls         When a recursive subpattern is processed, the matching  function  calls
2507         itself recursively, using private vectors for  ovector  and  workspace.         itself  recursively,  using  private vectors for ovector and workspace.
2508         This  error  is  given  if  the output vector is not large enough. This         This error is given if the output vector  is  not  large  enough.  This
2509         should be extremely rare, as a vector of size 1000 is used.         should be extremely rare, as a vector of size 1000 is used.
2510    
2511    
2512  SEE ALSO  SEE ALSO
2513    
2514         pcrebuild(3), pcrecallout(3), pcrecpp(3)(3), pcrematching(3),  pcrepar-         pcrebuild(3),  pcrecallout(3), pcrecpp(3)(3), pcrematching(3), pcrepar-
2515         tial(3),  pcreposix(3), pcreprecompile(3), pcresample(3), pcrestack(3).         tial(3), pcreposix(3), pcreprecompile(3), pcresample(3),  pcrestack(3).
2516    
2517    
2518  AUTHOR  AUTHOR
# Line 2480  AUTHOR Line 2524  AUTHOR
2524    
2525  REVISION  REVISION
2526    
2527         Last updated: 21 August 2007         Last updated: 11 September 2007
2528         Copyright (c) 1997-2007 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.
2529  ------------------------------------------------------------------------------  ------------------------------------------------------------------------------
2530    
# Line 2765  DIFFERENCES BETWEEN PCRE AND PERL Line 2809  DIFFERENCES BETWEEN PCRE AND PERL
2809         (f)  The PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NO_AUTO_CAP-         (f)  The PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NO_AUTO_CAP-
2810         TURE options for pcre_exec() have no Perl equivalents.         TURE options for pcre_exec() have no Perl equivalents.
2811    
2812         (g) The callout facility is PCRE-specific.         (g) The \R escape sequence can be restricted to match only CR,  LF,  or
2813           CRLF by the PCRE_BSR_ANYCRLF option.
2814    
2815           (h) The callout facility is PCRE-specific.
2816    
2817         (h) The partial matching facility is PCRE-specific.         (i) The partial matching facility is PCRE-specific.
2818    
2819         (i) Patterns compiled by PCRE can be saved and re-used at a later time,         (j) Patterns compiled by PCRE can be saved and re-used at a later time,
2820         even on different hosts that have the other endianness.         even on different hosts that have the other endianness.
2821    
2822         (j)  The  alternative  matching function (pcre_dfa_exec()) matches in a         (k) The alternative matching function (pcre_dfa_exec())  matches  in  a
2823         different way and is not Perl-compatible.         different way and is not Perl-compatible.
2824    
2825           (l)  PCRE  recognizes some special sequences such as (*CR) at the start
2826           of a pattern that set overall options that cannot be changed within the
2827           pattern.
2828    
2829    
2830  AUTHOR  AUTHOR
2831    
# Line 2785  AUTHOR Line 2836  AUTHOR
2836    
2837  REVISION  REVISION
2838    
2839         Last updated: 08 August 2007         Last updated: 11 September 2007
2840         Copyright (c) 1997-2007 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.
2841  ------------------------------------------------------------------------------  ------------------------------------------------------------------------------
2842    
# Line 2853  NEWLINE CONVENTIONS Line 2904  NEWLINE CONVENTIONS
2904         changes the convention to CR. That pattern matches "a\nb" because LF is         changes the convention to CR. That pattern matches "a\nb" because LF is
2905         no longer a newline. Note that these special settings,  which  are  not         no longer a newline. Note that these special settings,  which  are  not
2906         Perl-compatible,  are  recognized  only at the very start of a pattern,         Perl-compatible,  are  recognized  only at the very start of a pattern,
2907         and that they must be in upper case.         and that they must be in upper case.  If  more  than  one  of  them  is
2908           present, the last one is used.
2909    
2910           The  newline  convention  does  not  affect what the \R escape sequence
2911           matches. By default, this is any Unicode  newline  sequence,  for  Perl
2912           compatibility.  However, this can be changed; see the description of \R
2913           in the section entitled "Newline sequences" below.
2914    
2915    
2916  CHARACTERS AND METACHARACTERS  CHARACTERS AND METACHARACTERS
# Line 3128  BACKSLASH Line 3185  BACKSLASH
3185    
3186     Newline sequences     Newline sequences
3187    
3188         Outside  a  character class, the escape sequence \R matches any Unicode         Outside  a  character class, by default, the escape sequence \R matches
3189         newline sequence. This is a Perl 5.10 feature. In non-UTF-8 mode \R  is         any Unicode newline sequence. This is a Perl 5.10 feature. In non-UTF-8
3190         equivalent to the following:         mode \R is equivalent to the following:
3191    
3192           (?>\r\n|\n|\x0b|\f|\r|\x85)           (?>\r\n|\n|\x0b|\f|\r|\x85)
3193    
# Line 3146  BACKSLASH Line 3203  BACKSLASH
3203         rator, U+2029).  Unicode character property support is not  needed  for         rator, U+2029).  Unicode character property support is not  needed  for
3204         these characters to be recognized.         these characters to be recognized.
3205    
3206           It is possible to restrict \R to match only CR, LF, or CRLF (instead of
3207           the complete set  of  Unicode  line  endings)  by  setting  the  option
3208           PCRE_BSR_ANYCRLF either at compile time or when the pattern is matched.
3209           This can be made the default when PCRE is built; if this is  the  case,
3210           the  other  behaviour can be requested via the PCRE_BSR_UNICODE option.
3211           It is also possible to specify these settings  by  starting  a  pattern
3212           string with one of the following sequences:
3213    
3214             (*BSR_ANYCRLF)   CR, LF, or CRLF only
3215             (*BSR_UNICODE)   any Unicode newline sequence
3216    
3217           These override the default and the options given to pcre_compile(), but
3218           they can be overridden by options given to pcre_exec(). Note that these
3219           special settings, which are not Perl-compatible, are recognized only at
3220           the very start of a pattern, and that they must be in  upper  case.  If
3221           more than one of them is present, the last one is used.
3222    
3223         Inside a character class, \R matches the letter "R".         Inside a character class, \R matches the letter "R".
3224    
3225     Unicode character properties     Unicode character properties
# Line 4775  AUTHOR Line 4849  AUTHOR
4849    
4850  REVISION  REVISION
4851    
4852         Last updated: 21 August 2007         Last updated: 11 September 2007
4853         Copyright (c) 1997-2007 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.
4854  ------------------------------------------------------------------------------  ------------------------------------------------------------------------------
4855    
# Line 5083  NEWLINE CONVENTIONS Line 5157  NEWLINE CONVENTIONS
5157           (*ANY)           (*ANY)
5158    
5159    
5160    WHAT \R MATCHES
5161    
5162           These are recognized only at the very start of a pattern.
5163    
5164             (*BSR_ANYCRLF)
5165             (*BSR_UNICODE)
5166    
5167    
5168  CALLOUTS  CALLOUTS
5169    
5170           (?C)      callout           (?C)      callout
# Line 5103  AUTHOR Line 5185  AUTHOR
5185    
5186  REVISION  REVISION
5187    
5188         Last updated: 21 August 2007         Last updated: 11 September 2007
5189         Copyright (c) 1997-2007 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.
5190  ------------------------------------------------------------------------------  ------------------------------------------------------------------------------
5191    

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