| 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 |
| 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 |
|
|
| 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 |
|
|
| 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 |
|
|
| 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 |
|
|
| 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; |
| 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 |
| 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 |
| 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 |
| 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(): |
| 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 |
|
|
| 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 |
| 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; |
| 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 |
|
|
| 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 |
|
|
| 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 |
| 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. |
| 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 |
|
|
| 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 |
|
|
| 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 |
|
|
| 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(): |
| 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; |
| 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 |
| 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 |
| 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 |
|
|
| 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) |
| 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) |
| 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) |
| 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 |
|
|
| 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+)... |
| 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 |
|
|
| 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 |
|
|
| 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(): |
| 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 |
<.*> |
<.*> |
| 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 |
| 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 |
|
|
| 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 |
|
|
| 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 |
|
|
| 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 |
| 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 |
|
|
| 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 |
| 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 |
|
|
| 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 |
| 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 |
|
|