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authorph10 <ph10@6239d852-aaf2-0410-a92c-79f79f948069>2019-02-12 17:50:19 +0000
committerph10 <ph10@6239d852-aaf2-0410-a92c-79f79f948069>2019-02-12 17:50:19 +0000
commit4e01f37e73ba7afa29fbfbe45a5f923efb0a1c68 (patch)
tree2f92e9bdf9f05dbe278c16ae6162b5dd725f2749 /doc
parent5a5285b1066d191d22eb858cbc9862b6e044ca9e (diff)
downloadpcre2-4e01f37e73ba7afa29fbfbe45a5f923efb0a1c68.tar.gz
Implement PCRE2_EXTRA_ALT_BSUX to support ECMAscript 6's \u{hhh..} syntax.
git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@1070 6239d852-aaf2-0410-a92c-79f79f948069
Diffstat (limited to 'doc')
-rw-r--r--doc/html/pcre2_compile.html7
-rw-r--r--doc/html/pcre2_set_compile_extra_options.html3
-rw-r--r--doc/html/pcre2api.html43
-rw-r--r--doc/html/pcre2compat.html7
-rw-r--r--doc/html/pcre2pattern.html68
-rw-r--r--doc/html/pcre2syntax.html29
-rw-r--r--doc/html/pcre2test.html3
-rw-r--r--doc/pcre2.txt1863
-rw-r--r--doc/pcre2_compile.310
-rw-r--r--doc/pcre2_set_compile_extra_options.37
-rw-r--r--doc/pcre2api.344
-rw-r--r--doc/pcre2compat.39
-rw-r--r--doc/pcre2pattern.363
-rw-r--r--doc/pcre2syntax.329
-rw-r--r--doc/pcre2test.15
-rw-r--r--doc/pcre2test.txt3
16 files changed, 1159 insertions, 1034 deletions
diff --git a/doc/html/pcre2_compile.html b/doc/html/pcre2_compile.html
index d109eeb..23f75e1 100644
--- a/doc/html/pcre2_compile.html
+++ b/doc/html/pcre2_compile.html
@@ -86,7 +86,12 @@ PCRE2 must be built with Unicode support (the default) in order to use
PCRE2_UTF, PCRE2_UCP and related options.
</P>
<P>
-The yield of the function is a pointer to a private data structure that
+Additional options may be set in the compile context via the
+<a href="pcre2_set_compile_extra_options.html"><b>pcre2_set_compile_extra_options</b></a>
+function.
+</P>
+<P>
+The yield of this function is a pointer to a private data structure that
contains the compiled pattern, or NULL if an error was detected.
</P>
<P>
diff --git a/doc/html/pcre2_set_compile_extra_options.html b/doc/html/pcre2_set_compile_extra_options.html
index 336852a..4e342cf 100644
--- a/doc/html/pcre2_set_compile_extra_options.html
+++ b/doc/html/pcre2_set_compile_extra_options.html
@@ -20,7 +20,7 @@ SYNOPSIS
</P>
<P>
<b>int pcre2_set_compile_extra_options(pcre2_compile_context *<i>ccontext</i>,</b>
-<b> PCRE2_SIZE <i>extra_options</i>);</b>
+<b> uint32_t <i>extra_options</i>);</b>
</P>
<br><b>
DESCRIPTION
@@ -31,6 +31,7 @@ housed in a compile context. It completely replaces all the bits. The extra
options are:
<pre>
PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES Allow \x{df800} to \x{dfff} in UTF-8 and UTF-32 modes
+ PCRE2_EXTRA_ALT_BSUX Extended alternate \u, \U, and \x handling
PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL Treat all invalid escapes as a literal following character
PCRE2_EXTRA_ESCAPED_CR_IS_LF Interpret \r as \n
PCRE2_EXTRA_MATCH_LINE Pattern matches whole lines
diff --git a/doc/html/pcre2api.html b/doc/html/pcre2api.html
index bbfaeaa..c045ff5 100644
--- a/doc/html/pcre2api.html
+++ b/doc/html/pcre2api.html
@@ -1298,7 +1298,7 @@ are needed. The <b>pcre2_code_copy_with_tables()</b> provides this facility.
Copies of both the code and the tables are made, with the new code pointing to
the new tables. The memory for the new tables is automatically freed when
<b>pcre2_code_free()</b> is called for the new copy of the compiled code. If
-<b>pcre2_code_copy_withy_tables()</b> is called with a NULL argument, it returns
+<b>pcre2_code_copy_with_tables()</b> is called with a NULL argument, it returns
NULL.
</P>
<P>
@@ -1315,7 +1315,7 @@ PCRE2_COPY_MATCHED_SUBJECT option, which is described in the section entitled
</P>
<P>
The <i>options</i> argument for <b>pcre2_compile()</b> contains various bit
-settings that affect the compilation. It should be zero if no options are
+settings that affect the compilation. It should be zero if none of them are
required. The available options are described below. Some of them (in
particular, those that are compatible with Perl, but some others as well) can
also be set and unset from within the pattern (see the detailed description in
@@ -1330,8 +1330,9 @@ compilation. The PCRE2_ANCHORED, PCRE2_ENDANCHORED, and PCRE2_NO_UTF_CHECK
options can be set at the time of matching as well as at compile time.
</P>
<P>
-Other, less frequently required compile-time parameters (for example, the
-newline setting) can be provided in a compile context (as described
+Some additional options and less frequently required compile-time parameters
+(for example, the newline setting) can be provided in a compile context (as
+described
<a href="#compilecontext">above).</a>
</P>
<P>
@@ -1384,7 +1385,13 @@ This code fragment shows a typical straightforward call to
&errorcode, /* for error code */
&erroffset, /* for error offset */
NULL); /* no compile context */
-</pre>
+
+</PRE>
+</P>
+<br><b>
+Main compile options
+</b><br>
+<P>
The following names for option bits are defined in the <b>pcre2.h</b> header
file:
<pre>
@@ -1424,6 +1431,14 @@ hexadecimal digits, in which case the hexadecimal number defines the code point
to match. By default, as in Perl, a hexadecimal number is always expected after
\x, but it may have zero, one, or two digits (so, for example, \xz matches a
binary zero character followed by z).
+</P>
+<P>
+ECMAscript 6 added additional functionality to \u. This can be accessed using
+the PCRE2_EXTRA_ALT_BSUX extra option (see "Extra compile options"
+<a href="#extracompileoptions">below).</a>
+Note that this alternative escape handling applies only to patterns. Neither of
+these options affects the processing of replacement strings passed to
+<b>pcre2_substitute()</b>.
<pre>
PCRE2_ALT_CIRCUMFLEX
</pre>
@@ -1830,9 +1845,8 @@ characters with code points greater than 127.
Extra compile options
</b><br>
<P>
-Unlike the main compile-time options, the extra options are not saved with the
-compiled pattern. The option bits that can be set in a compile context by
-calling the <b>pcre2_set_compile_extra_options()</b> function are as follows:
+The option bits that can be set in a compile context by calling the
+<b>pcre2_set_compile_extra_options()</b> function are as follows:
<pre>
PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES
</pre>
@@ -1858,6 +1872,14 @@ point values in UTF-8 and UTF-32 patterns no longer provoke errors and are
incorporated in the compiled pattern. However, they can only match subject
characters if the matching function is called with PCRE2_NO_UTF_CHECK set.
<pre>
+ PCRE2_EXTRA_ALT_BSUX
+</pre>
+The original option PCRE2_ALT_BSUX causes PCRE2 to process \U, \u, and \x in
+the way that ECMAscript (aka JavaScript) does. Additional functionality was
+defined by ECMAscript 6; setting PCRE2_EXTRA_ALT_BSUX has the effect of
+PCRE2_ALT_BSUX, but in addition it recognizes \u{hhh..} as a hexadecimal
+character code, where hhh.. is any number of hexadecimal digits.
+<pre>
PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL
</pre>
This is a dangerous option. Use with care. By default, an unrecognized escape
@@ -3382,7 +3404,8 @@ capture groups and letters within \Q...\E quoted sequences.
<P>
Note that case forcing sequences such as \U...\E do not nest. For example,
the result of processing "\Uaa\LBB\Ecc\E" is "AAbbcc"; the final \E has no
-effect.
+effect. Note also that the PCRE2_ALT_BSUX and PCRE2_EXTRA_ALT_BSUX options do
+not apply to not apply to replacement strings.
</P>
<P>
The second effect of setting PCRE2_SUBSTITUTE_EXTENDED is to add more
@@ -3784,7 +3807,7 @@ Cambridge, England.
</P>
<br><a name="SEC42" href="#TOC1">REVISION</a><br>
<P>
-Last updated: 04 February 2019
+Last updated: 12 February 2019
<br>
Copyright &copy; 1997-2019 University of Cambridge.
<br>
diff --git a/doc/html/pcre2compat.html b/doc/html/pcre2compat.html
index f110e33..7d728f5 100644
--- a/doc/html/pcre2compat.html
+++ b/doc/html/pcre2compat.html
@@ -47,8 +47,9 @@ non-newline character, and \N{U+dd..}, matching a Unicode code point, are
supported. The escapes that modify the case of following letters are
implemented by Perl's general string-handling and are not part of its pattern
matching engine. If any of these are encountered by PCRE2, an error is
-generated by default. However, if the PCRE2_ALT_BSUX option is set, \U and \u
-are interpreted as ECMAScript interprets them.
+generated by default. However, if either of the PCRE2_ALT_BSUX or
+PCRE2_EXTRA_ALT_BSUX options is set, \U and \u are interpreted as ECMAScript
+interprets them.
</P>
<P>
5. The Perl escape sequences \p, \P, and \X are supported only if PCRE2 is
@@ -233,7 +234,7 @@ Cambridge, England.
REVISION
</b><br>
<P>
-Last updated: 03 February 2019
+Last updated: 12 February 2019
<br>
Copyright &copy; 1997-2019 University of Cambridge.
<br>
diff --git a/doc/html/pcre2pattern.html b/doc/html/pcre2pattern.html
index d57dcea..d69e6cb 100644
--- a/doc/html/pcre2pattern.html
+++ b/doc/html/pcre2pattern.html
@@ -399,12 +399,33 @@ environment, these escapes are as follows:
\xhh character with hex code hh
\x{hhh..} character with hex code hhh..
\N{U+hhh..} character with Unicode hex code point hhh..
- \uhhhh character with hex code hhhh (when PCRE2_ALT_BSUX is set)
</pre>
-There are some legacy applications where the escape sequence \r is expected to
-match a newline. If the PCRE2_EXTRA_ESCAPED_CR_IS_LF option is set, \r in a
-pattern is converted to \n so that it matches a LF (linefeed) instead of a CR
-(carriage return) character.
+By default, after \x that is not followed by {, from zero to two hexadecimal
+digits are read (letters can be in upper or lower case). Any number of
+hexadecimal digits may appear between \x{ and }. If a character other than a
+hexadecimal digit appears between \x{ and }, or if there is no terminating },
+an error occurs.
+</P>
+<P>
+Characters whose code points are less than 256 can be defined by either of the
+two syntaxes for \x or by an octal sequence. There is no difference in the way
+they are handled. For example, \xdc is exactly the same as \x{dc} or \334.
+However, using the braced versions does make such sequences easier to read.
+</P>
+<P>
+Support is available for some ECMAScript (aka JavaScript) escape sequences via
+two compile-time options. If PCRE2_ALT_BSUX is set, the sequence \x followed
+by { is not recognized. Only if \x is followed by two hexadecimal digits is it
+recognized as a character escape. Otherwise it is interpreted as a literal "x"
+character. In this mode, support for code points greater than 256 is provided
+by \u, which must be followed by four hexadecimal digits; otherwise it is
+interpreted as a literal "u" character.
+</P>
+<P>
+PCRE2_EXTRA_ALT_BSUX has the same effect as PCRE2_ALT_BSUX and, in addition,
+\u{hhh..} is recognized as the character specified by hexadecimal code point.
+There may be any number of hexadecimal digits. This syntax is from ECMAScript
+6.
</P>
<P>
The \N{U+hhh..} escape sequence is recognized only when the PCRE2_UTF option
@@ -414,6 +435,12 @@ Note that when \N is not followed by an opening brace (curly bracket) it has
an entirely different meaning, matching any character that is not a newline.
</P>
<P>
+There are some legacy applications where the escape sequence \r is expected to
+match a newline. If the PCRE2_EXTRA_ESCAPED_CR_IS_LF option is set, \r in a
+pattern is converted to \n so that it matches a LF (linefeed) instead of a CR
+(carriage return) character.
+</P>
+<P>
The precise effect of \cx on ASCII characters is as follows: if x is a lower
case letter, it is converted to upper case. Then bit 6 of the character (hex
40) is inverted. Thus \cA to \cZ become hex 01 to hex 1A (A is 41, Z is 5A),
@@ -500,28 +527,6 @@ Note that octal values of 100 or greater that are specified using this syntax
must not be introduced by a leading zero, because no more than three octal
digits are ever read.
</P>
-<P>
-By default, after \x that is not followed by {, from zero to two hexadecimal
-digits are read (letters can be in upper or lower case). Any number of
-hexadecimal digits may appear between \x{ and }. If a character other than
-a hexadecimal digit appears between \x{ and }, or if there is no terminating
-}, an error occurs.
-</P>
-<P>
-If the PCRE2_ALT_BSUX option is set, the interpretation of \x is as just
-described only when it is followed by two hexadecimal digits. Otherwise, it
-matches a literal "x" character. In this mode, support for code points greater
-than 256 is provided by \u, which must be followed by four hexadecimal digits;
-otherwise it matches a literal "u" character. This syntax makes PCRE2 behave
-like ECMAscript (aka JavaScript). Code points greater than 0xFFFF are not
-supported.
-</P>
-<P>
-Characters whose value is less than 256 can be defined by either of the two
-syntaxes for \x (or by \u in PCRE2_ALT_BSUX mode). There is no difference in
-the way they are handled. For example, \xdc is exactly the same as \x{dc} (or
-\u00dc in PCRE2_ALT_BSUX mode).
-</P>
<br><b>
Constraints on character values
</b><br>
@@ -560,9 +565,10 @@ Unsupported escape sequences
<P>
In Perl, the sequences \F, \l, \L, \u, and \U are recognized by its string
handler and used to modify the case of following characters. By default, PCRE2
-does not support these escape sequences. However, if the PCRE2_ALT_BSUX option
-is set, \U matches a "U" character, and \u can be used to define a character
-by code point, as described above.
+does not support these escape sequences in patterns. However, if either of the
+PCRE2_ALT_BSUX or PCRE2_EXTRA_ALT_BSUX options is set, \U matches a "U"
+character, and \u can be used to define a character by code point, as
+described above.
</P>
<br><b>
Absolute and relative backreferences
@@ -3721,7 +3727,7 @@ Cambridge, England.
</P>
<br><a name="SEC31" href="#TOC1">REVISION</a><br>
<P>
-Last updated: 04 February 2019
+Last updated: 12 February 2019
<br>
Copyright &copy; 1997-2019 University of Cambridge.
<br>
diff --git a/doc/html/pcre2syntax.html b/doc/html/pcre2syntax.html
index 73da500..5022e12 100644
--- a/doc/html/pcre2syntax.html
+++ b/doc/html/pcre2syntax.html
@@ -58,7 +58,8 @@ documentation. This document contains a quick-reference summary of the syntax.
</P>
<br><a name="SEC3" href="#TOC1">ESCAPED CHARACTERS</a><br>
<P>
-This table applies to ASCII and Unicode environments.
+This table applies to ASCII and Unicode environments. An unrecognized escape
+sequence causes an error.
<pre>
\a alarm, that is, the BEL character (hex 07)
\cx "control-x", where x is any ASCII printing character
@@ -70,12 +71,25 @@ This table applies to ASCII and Unicode environments.
\0dd character with octal code 0dd
\ddd character with octal code ddd, or backreference
\o{ddd..} character with octal code ddd..
- \U "U" if PCRE2_ALT_BSUX is set (otherwise is an error)
\N{U+hh..} character with Unicode code point hh.. (Unicode mode only)
- \uhhhh character with hex code hhhh (if PCRE2_ALT_BSUX is set)
\xhh character with hex code hh
\x{hh..} character with hex code hh..
</pre>
+If PCRE2_ALT_BSUX or PCRE2_EXTRA_ALT_BSUX is set ("ALT_BSUX mode"), the
+following are also recognized:
+<pre>
+ \U the character "U"
+ \uhhhh character with hex code hhhh
+ \u{hh..} character with hex code hh.. but only for EXTRA_ALT_BSUX
+</pre>
+When \x is not followed by {, from zero to two hexadecimal digits are read,
+but in ALT_BSUX mode \x must be followed by two hexadecimal digits to be
+recognized as a hexadecimal escape; otherwise it matches a literal "x".
+Likewise, if \u (in ALT_BSUX mode) is not followed by four hexadecimal digits
+or (in EXTRA_ALT_BSUX mode) a sequence of hex digits in curly brackets, it
+matches a literal "u".
+</P>
+<P>
Note that \0dd is always an octal code. The treatment of backslash followed by
a non-zero digit is complicated; for details see the section
<a href="pcre2pattern.html#digitsafterbackslash">"Non-printing characters"</a>
@@ -86,13 +100,6 @@ also given. \N{U+hh..} is synonymous with \x{hh..} in PCRE2 but is not
supported in EBCDIC environments. Note that \N not followed by an opening
curly bracket has a different meaning (see below).
</P>
-<P>
-When \x is not followed by {, from zero to two hexadecimal digits are read,
-but if PCRE2_ALT_BSUX is set, \x must be followed by two hexadecimal digits to
-be recognized as a hexadecimal escape; otherwise it matches a literal "x".
-Likewise, if \u (in ALT_BSUX mode) is not followed by four hexadecimal digits,
-it matches a literal "u".
-</P>
<br><a name="SEC4" href="#TOC1">CHARACTER TYPES</a><br>
<P>
<pre>
@@ -660,7 +667,7 @@ Cambridge, England.
</P>
<br><a name="SEC28" href="#TOC1">REVISION</a><br>
<P>
-Last updated: 03 February 2019
+Last updated: 11 February 2019
<br>
Copyright &copy; 1997-2019 University of Cambridge.
<br>
diff --git a/doc/html/pcre2test.html b/doc/html/pcre2test.html
index db5001f..1eb1553 100644
--- a/doc/html/pcre2test.html
+++ b/doc/html/pcre2test.html
@@ -609,6 +609,7 @@ for a description of the effects of these options.
escaped_cr_is_lf set PCRE2_EXTRA_ESCAPED_CR_IS_LF
/x extended set PCRE2_EXTENDED
/xx extended_more set PCRE2_EXTENDED_MORE
+ extra_alt_bsux set PCRE2_EXTRA_ALT_BSUX
firstline set PCRE2_FIRSTLINE
literal set PCRE2_LITERAL
match_line set PCRE2_EXTRA_MATCH_LINE
@@ -2075,7 +2076,7 @@ Cambridge, England.
</P>
<br><a name="SEC21" href="#TOC1">REVISION</a><br>
<P>
-Last updated: 03 February 2019
+Last updated: 11 February 2019
<br>
Copyright &copy; 1997-2019 University of Cambridge.
<br>
diff --git a/doc/pcre2.txt b/doc/pcre2.txt
index 27cf928..4642e88 100644
--- a/doc/pcre2.txt
+++ b/doc/pcre2.txt
@@ -1296,7 +1296,7 @@ COMPILING A PATTERN
Copies of both the code and the tables are made, with the new code
pointing to the new tables. The memory for the new tables is automati-
cally freed when pcre2_code_free() is called for the new copy of the
- compiled code. If pcre2_code_copy_withy_tables() is called with a NULL
+ compiled code. If pcre2_code_copy_with_tables() is called with a NULL
argument, it returns NULL.
NOTE: When one of the matching functions is called, pointers to the
@@ -1310,7 +1310,7 @@ COMPILING A PATTERN
below.
The options argument for pcre2_compile() contains various bit settings
- that affect the compilation. It should be zero if no options are
+ that affect the compilation. It should be zero if none of them are
required. The available options are described below. Some of them (in
particular, those that are compatible with Perl, but some others as
well) can also be set and unset from within the pattern (see the
@@ -1322,9 +1322,9 @@ COMPILING A PATTERN
PCRE2_NO_UTF_CHECK options can be set at the time of matching as well
as at compile time.
- Other, less frequently required compile-time parameters (for example,
- the newline setting) can be provided in a compile context (as described
- above).
+ Some additional options and less frequently required compile-time
+ parameters (for example, the newline setting) can be provided in a com-
+ pile context (as described above).
If errorcode or erroroffset is NULL, pcre2_compile() returns NULL imme-
diately. Otherwise, the variables to which these point are set to an
@@ -1371,6 +1371,9 @@ COMPILING A PATTERN
&erroffset, /* for error offset */
NULL); /* no compile context */
+
+ Main compile options
+
The following names for option bits are defined in the pcre2.h header
file:
@@ -1409,6 +1412,12 @@ COMPILING A PATTERN
always expected after \x, but it may have zero, one, or two digits (so,
for example, \xz matches a binary zero character followed by z).
+ ECMAscript 6 added additional functionality to \u. This can be accessed
+ using the PCRE2_EXTRA_ALT_BSUX extra option (see "Extra compile
+ options" below). Note that this alternative escape handling applies
+ only to patterns. Neither of these options affects the processing of
+ replacement strings passed to pcre2_substitute().
+
PCRE2_ALT_CIRCUMFLEX
In multiline mode (when PCRE2_MULTILINE is set), the circumflex
@@ -1804,10 +1813,8 @@ COMPILING A PATTERN
Extra compile options
- Unlike the main compile-time options, the extra options are not saved
- with the compiled pattern. The option bits that can be set in a compile
- context by calling the pcre2_set_compile_extra_options() function are
- as follows:
+ The option bits that can be set in a compile context by calling the
+ pcre2_set_compile_extra_options() function are as follows:
PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES
@@ -1834,53 +1841,62 @@ COMPILING A PATTERN
only match subject characters if the matching function is called with
PCRE2_NO_UTF_CHECK set.
+ PCRE2_EXTRA_ALT_BSUX
+
+ The original option PCRE2_ALT_BSUX causes PCRE2 to process \U, \u, and
+ \x in the way that ECMAscript (aka JavaScript) does. Additional func-
+ tionality was defined by ECMAscript 6; setting PCRE2_EXTRA_ALT_BSUX has
+ the effect of PCRE2_ALT_BSUX, but in addition it recognizes \u{hhh..}
+ as a hexadecimal character code, where hhh.. is any number of hexadeci-
+ mal digits.
+
PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL
- This is a dangerous option. Use with care. By default, an unrecognized
- escape such as \j or a malformed one such as \x{2z} causes a compile-
+ This is a dangerous option. Use with care. By default, an unrecognized
+ escape such as \j or a malformed one such as \x{2z} causes a compile-
time error when detected by pcre2_compile(). Perl is somewhat inconsis-
- tent in handling such items: for example, \j is treated as a literal
- "j", and non-hexadecimal digits in \x{} are just ignored, though warn-
- ings are given in both cases if Perl's warning switch is enabled. How-
- ever, a malformed octal number after \o{ always causes an error in
+ tent in handling such items: for example, \j is treated as a literal
+ "j", and non-hexadecimal digits in \x{} are just ignored, though warn-
+ ings are given in both cases if Perl's warning switch is enabled. How-
+ ever, a malformed octal number after \o{ always causes an error in
Perl.
- If the PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL extra option is passed to
- pcre2_compile(), all unrecognized or malformed escape sequences are
- treated as single-character escapes. For example, \j is a literal "j"
- and \x{2z} is treated as the literal string "x{2z}". Setting this
- option means that typos in patterns may go undetected and have unex-
- pected results. Also note that a sequence such as [\N{] is interpreted
- as a malformed attempt at [\N{...}] and so is treated as [N{] whereas
- [\N] gives an error because an unqualified \N is a valid escape
- sequence but is not supported in a character class. To reiterate: this
+ If the PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL extra option is passed to
+ pcre2_compile(), all unrecognized or malformed escape sequences are
+ treated as single-character escapes. For example, \j is a literal "j"
+ and \x{2z} is treated as the literal string "x{2z}". Setting this
+ option means that typos in patterns may go undetected and have unex-
+ pected results. Also note that a sequence such as [\N{] is interpreted
+ as a malformed attempt at [\N{...}] and so is treated as [N{] whereas
+ [\N] gives an error because an unqualified \N is a valid escape
+ sequence but is not supported in a character class. To reiterate: this
is a dangerous option. Use with great care.
PCRE2_EXTRA_ESCAPED_CR_IS_LF
- There are some legacy applications where the escape sequence \r in a
- pattern is expected to match a newline. If this option is set, \r in a
- pattern is converted to \n so that it matches a LF (linefeed) instead
- of a CR (carriage return) character. The option does not affect a lit-
- eral CR in the pattern, nor does it affect CR specified as an explicit
+ There are some legacy applications where the escape sequence \r in a
+ pattern is expected to match a newline. If this option is set, \r in a
+ pattern is converted to \n so that it matches a LF (linefeed) instead
+ of a CR (carriage return) character. The option does not affect a lit-
+ eral CR in the pattern, nor does it affect CR specified as an explicit
code point such as \x{0D}.
PCRE2_EXTRA_MATCH_LINE
- This option is provided for use by the -x option of pcre2grep. It
- causes the pattern only to match complete lines. This is achieved by
- automatically inserting the code for "^(?:" at the start of the com-
- piled pattern and ")$" at the end. Thus, when PCRE2_MULTILINE is set,
- the matched line may be in the middle of the subject string. This
+ This option is provided for use by the -x option of pcre2grep. It
+ causes the pattern only to match complete lines. This is achieved by
+ automatically inserting the code for "^(?:" at the start of the com-
+ piled pattern and ")$" at the end. Thus, when PCRE2_MULTILINE is set,
+ the matched line may be in the middle of the subject string. This
option can be used with PCRE2_LITERAL.
PCRE2_EXTRA_MATCH_WORD
- This option is provided for use by the -w option of pcre2grep. It
- causes the pattern only to match strings that have a word boundary at
- the start and the end. This is achieved by automatically inserting the
- code for "\b(?:" at the start of the compiled pattern and ")\b" at the
- end. The option may be used with PCRE2_LITERAL. However, it is ignored
+ This option is provided for use by the -w option of pcre2grep. It
+ causes the pattern only to match strings that have a word boundary at
+ the start and the end. This is achieved by automatically inserting the
+ code for "\b(?:" at the start of the compiled pattern and ")\b" at the
+ end. The option may be used with PCRE2_LITERAL. However, it is ignored
if PCRE2_EXTRA_MATCH_LINE is also set.
@@ -1903,53 +1919,53 @@ JUST-IN-TIME (JIT) COMPILATION
void pcre2_jit_stack_free(pcre2_jit_stack *jit_stack);
- These functions provide support for JIT compilation, which, if the
- just-in-time compiler is available, further processes a compiled pat-
+ These functions provide support for JIT compilation, which, if the
+ just-in-time compiler is available, further processes a compiled pat-
tern into machine code that executes much faster than the pcre2_match()
- interpretive matching function. Full details are given in the pcre2jit
+ interpretive matching function. Full details are given in the pcre2jit
documentation.
- JIT compilation is a heavyweight optimization. It can take some time
- for patterns to be analyzed, and for one-off matches and simple pat-
- terns the benefit of faster execution might be offset by a much slower
- compilation time. Most (but not all) patterns can be optimized by the
+ JIT compilation is a heavyweight optimization. It can take some time
+ for patterns to be analyzed, and for one-off matches and simple pat-
+ terns the benefit of faster execution might be offset by a much slower
+ compilation time. Most (but not all) patterns can be optimized by the
JIT compiler.
LOCALE SUPPORT
- PCRE2 handles caseless matching, and determines whether characters are
- letters, digits, or whatever, by reference to a set of tables, indexed
- by character code point. This applies only to characters whose code
- points are less than 256. By default, higher-valued code points never
- match escapes such as \w or \d. However, if PCRE2 is built with Uni-
+ PCRE2 handles caseless matching, and determines whether characters are
+ letters, digits, or whatever, by reference to a set of tables, indexed
+ by character code point. This applies only to characters whose code
+ points are less than 256. By default, higher-valued code points never
+ match escapes such as \w or \d. However, if PCRE2 is built with Uni-
code support, all characters can be tested with \p and \P, or, alterna-
- tively, the PCRE2_UCP option can be set when a pattern is compiled;
- this causes \w and friends to use Unicode property support instead of
+ tively, the PCRE2_UCP option can be set when a pattern is compiled;
+ this causes \w and friends to use Unicode property support instead of
the built-in tables.
- The use of locales with Unicode is discouraged. If you are handling
- characters with code points greater than 128, you should either use
+ The use of locales with Unicode is discouraged. If you are handling
+ characters with code points greater than 128, you should either use
Unicode support, or use locales, but not try to mix the two.
- PCRE2 contains an internal set of character tables that are used by
- default. These are sufficient for many applications. Normally, the
+ PCRE2 contains an internal set of character tables that are used by
+ default. These are sufficient for many applications. Normally, the
internal tables recognize only ASCII characters. However, when PCRE2 is
built, it is possible to cause the internal tables to be rebuilt in the
default "C" locale of the local system, which may cause them to be dif-
ferent.
- The internal tables can be overridden by tables supplied by the appli-
- cation that calls PCRE2. These may be created in a different locale
- from the default. As more and more applications change to using Uni-
+ The internal tables can be overridden by tables supplied by the appli-
+ cation that calls PCRE2. These may be created in a different locale
+ from the default. As more and more applications change to using Uni-
code, the need for this locale support is expected to die away.
- External tables are built by calling the pcre2_maketables() function,
- in the relevant locale. The result can be passed to pcre2_compile() as
- often as necessary, by creating a compile context and calling
- pcre2_set_character_tables() to set the tables pointer therein. For
- example, to build and use tables that are appropriate for the French
- locale (where accented characters with values greater than 128 are
+ External tables are built by calling the pcre2_maketables() function,
+ in the relevant locale. The result can be passed to pcre2_compile() as
+ often as necessary, by creating a compile context and calling
+ pcre2_set_character_tables() to set the tables pointer therein. For
+ example, to build and use tables that are appropriate for the French
+ locale (where accented characters with values greater than 128 are
treated as letters), the following code could be used:
setlocale(LC_CTYPE, "fr_FR");
@@ -1958,15 +1974,15 @@ LOCALE SUPPORT
pcre2_set_character_tables(ccontext, tables);
re = pcre2_compile(..., ccontext);
- The locale name "fr_FR" is used on Linux and other Unix-like systems;
- if you are using Windows, the name for the French locale is "french".
- It is the caller's responsibility to ensure that the memory containing
+ The locale name "fr_FR" is used on Linux and other Unix-like systems;
+ if you are using Windows, the name for the French locale is "french".
+ It is the caller's responsibility to ensure that the memory containing
the tables remains available for as long as it is needed.
The pointer that is passed (via the compile context) to pcre2_compile()
- is saved with the compiled pattern, and the same tables are used by
- pcre2_match() and pcre_dfa_match(). Thus, for any single pattern, com-
- pilation and matching both happen in the same locale, but different
+ is saved with the compiled pattern, and the same tables are used by
+ pcre2_match() and pcre_dfa_match(). Thus, for any single pattern, com-
+ pilation and matching both happen in the same locale, but different
patterns can be processed in different locales.
@@ -1974,13 +1990,13 @@ INFORMATION ABOUT A COMPILED PATTERN
int pcre2_pattern_info(const pcre2 *code, uint32_t what, void *where);
- The pcre2_pattern_info() function returns general information about a
+ The pcre2_pattern_info() function returns general information about a
compiled pattern. For information about callouts, see the next section.
- The first argument for pcre2_pattern_info() is a pointer to the com-
+ The first argument for pcre2_pattern_info() is a pointer to the com-
piled pattern. The second argument specifies which piece of information
- is required, and the third argument is a pointer to a variable to
- receive the data. If the third argument is NULL, the first argument is
- ignored, and the function returns the size in bytes of the variable
+ is required, and the third argument is a pointer to a variable to
+ receive the data. If the third argument is NULL, the first argument is
+ ignored, and the function returns the size in bytes of the variable
that is required for the information requested. Otherwise, the yield of
the function is zero for success, or one of the following negative num-
bers:
@@ -1990,9 +2006,9 @@ INFORMATION ABOUT A COMPILED PATTERN
PCRE2_ERROR_BADOPTION the value of what was invalid
PCRE2_ERROR_UNSET the requested field is not set
- The "magic number" is placed at the start of each compiled pattern as
- an simple check against passing an arbitrary memory pointer. Here is a
- typical call of pcre2_pattern_info(), to obtain the length of the com-
+ The "magic number" is placed at the start of each compiled pattern as
+ an simple check against passing an arbitrary memory pointer. Here is a
+ typical call of pcre2_pattern_info(), to obtain the length of the com-
piled pattern:
int rc;
@@ -2010,22 +2026,22 @@ INFORMATION ABOUT A COMPILED PATTERN
PCRE2_INFO_EXTRAOPTIONS
Return copies of the pattern's options. The third argument should point
- to a uint32_t variable. PCRE2_INFO_ARGOPTIONS returns exactly the
- options that were passed to pcre2_compile(), whereas PCRE2_INFO_ALLOP-
- TIONS returns the compile options as modified by any top-level (*XXX)
- option settings such as (*UTF) at the start of the pattern itself.
- PCRE2_INFO_EXTRAOPTIONS returns the extra options that were set in the
- compile context by calling the pcre2_set_compile_extra_options() func-
+ to a uint32_t variable. PCRE2_INFO_ARGOPTIONS returns exactly the
+ options that were passed to pcre2_compile(), whereas PCRE2_INFO_ALLOP-
+ TIONS returns the compile options as modified by any top-level (*XXX)
+ option settings such as (*UTF) at the start of the pattern itself.
+ PCRE2_INFO_EXTRAOPTIONS returns the extra options that were set in the
+ compile context by calling the pcre2_set_compile_extra_options() func-
tion.
- For example, if the pattern /(*UTF)abc/ is compiled with the
- PCRE2_EXTENDED option, the result for PCRE2_INFO_ALLOPTIONS is
- PCRE2_EXTENDED and PCRE2_UTF. Option settings such as (?i) that can
- change within a pattern do not affect the result of PCRE2_INFO_ALLOP-
+ For example, if the pattern /(*UTF)abc/ is compiled with the
+ PCRE2_EXTENDED option, the result for PCRE2_INFO_ALLOPTIONS is
+ PCRE2_EXTENDED and PCRE2_UTF. Option settings such as (?i) that can
+ change within a pattern do not affect the result of PCRE2_INFO_ALLOP-
TIONS, even if they appear right at the start of the pattern. (This was
different in some earlier releases.)
- A pattern compiled without PCRE2_ANCHORED is automatically anchored by
+ A pattern compiled without PCRE2_ANCHORED is automatically anchored by
PCRE2 if the first significant item in every top-level branch is one of
the following:
@@ -2034,7 +2050,7 @@ INFORMATION ABOUT A COMPILED PATTERN
\G always
.* sometimes - see below
- When .* is the first significant item, anchoring is possible only when
+ When .* is the first significant item, anchoring is possible only when
all the following are true:
.* is not in an atomic group
@@ -2044,94 +2060,94 @@ INFORMATION ABOUT A COMPILED PATTERN
Neither (*PRUNE) nor (*SKIP) appears in the pattern
PCRE2_NO_DOTSTAR_ANCHOR is not set
- For patterns that are auto-anchored, the PCRE2_ANCHORED bit is set in
+ For patterns that are auto-anchored, the PCRE2_ANCHORED bit is set in
the options returned for PCRE2_INFO_ALLOPTIONS.
PCRE2_INFO_BACKREFMAX
- Return the number of the highest backreference in the pattern. The
- third argument should point to an uint32_t variable. Named capture
- groups acquire numbers as well as names, and these count towards the
- highest backreference. Backreferences such as \4 or \g{12} match the
+ Return the number of the highest backreference in the pattern. The
+ third argument should point to an uint32_t variable. Named capture
+ groups acquire numbers as well as names, and these count towards the
+ highest backreference. Backreferences such as \4 or \g{12} match the
captured characters of the given group, but in addition, the check that
a capture group is set in a conditional group such as (?(3)a|b) is also
a backreference. Zero is returned if there are no backreferences.
PCRE2_INFO_BSR
- The output is a uint32_t integer whose value indicates what character
- sequences the \R escape sequence matches. A value of PCRE2_BSR_UNICODE
- means that \R matches any Unicode line ending sequence; a value of
+ The output is a uint32_t integer whose value indicates what character
+ sequences the \R escape sequence matches. A value of PCRE2_BSR_UNICODE
+ means that \R matches any Unicode line ending sequence; a value of
PCRE2_BSR_ANYCRLF means that \R matches only CR, LF, or CRLF.
PCRE2_INFO_CAPTURECOUNT
- Return the highest capture group number in the pattern. In patterns
+ Return the highest capture group number in the pattern. In patterns
where (?| is not used, this is also the total number of capture groups.
The third argument should point to an uint32_t variable.
PCRE2_INFO_DEPTHLIMIT
- If the pattern set a backtracking depth limit by including an item of
- the form (*LIMIT_DEPTH=nnnn) at the start, the value is returned. The
+ If the pattern set a backtracking depth limit by including an item of
+ the form (*LIMIT_DEPTH=nnnn) at the start, the value is returned. The
third argument should point to a uint32_t integer. If no such value has
- been set, the call to pcre2_pattern_info() returns the error
+ been set, the call to pcre2_pattern_info() returns the error
PCRE2_ERROR_UNSET. Note that this limit will only be used during match-
- ing if it is less than the limit set or defaulted by the caller of the
+ ing if it is less than the limit set or defaulted by the caller of the
match function.
PCRE2_INFO_FIRSTBITMAP
- In the absence of a single first code unit for a non-anchored pattern,
- pcre2_compile() may construct a 256-bit table that defines a fixed set
- of values for the first code unit in any match. For example, a pattern
- that starts with [abc] results in a table with three bits set. When
- code unit values greater than 255 are supported, the flag bit for 255
- means "any code unit of value 255 or above". If such a table was con-
- structed, a pointer to it is returned. Otherwise NULL is returned. The
+ In the absence of a single first code unit for a non-anchored pattern,
+ pcre2_compile() may construct a 256-bit table that defines a fixed set
+ of values for the first code unit in any match. For example, a pattern
+ that starts with [abc] results in a table with three bits set. When
+ code unit values greater than 255 are supported, the flag bit for 255
+ means "any code unit of value 255 or above". If such a table was con-
+ structed, a pointer to it is returned. Otherwise NULL is returned. The
third argument should point to a const uint8_t * variable.
PCRE2_INFO_FIRSTCODETYPE
Return information about the first code unit of any matched string, for
- a non-anchored pattern. The third argument should point to an uint32_t
- variable. If there is a fixed first value, for example, the letter "c"
- from a pattern such as (cat|cow|coyote), 1 is returned, and the value
- can be retrieved using PCRE2_INFO_FIRSTCODEUNIT. If there is no fixed
- first value, but it is known that a match can occur only at the start
- of the subject or following a newline in the subject, 2 is returned.
+ a non-anchored pattern. The third argument should point to an uint32_t
+ variable. If there is a fixed first value, for example, the letter "c"
+ from a pattern such as (cat|cow|coyote), 1 is returned, and the value
+ can be retrieved using PCRE2_INFO_FIRSTCODEUNIT. If there is no fixed
+ first value, but it is known that a match can occur only at the start
+ of the subject or following a newline in the subject, 2 is returned.
Otherwise, and for anchored patterns, 0 is returned.
PCRE2_INFO_FIRSTCODEUNIT
- Return the value of the first code unit of any matched string for a
- pattern where PCRE2_INFO_FIRSTCODETYPE returns 1; otherwise return 0.
- The third argument should point to an uint32_t variable. In the 8-bit
- library, the value is always less than 256. In the 16-bit library the
- value can be up to 0xffff. In the 32-bit library in UTF-32 mode the
+ Return the value of the first code unit of any matched string for a
+ pattern where PCRE2_INFO_FIRSTCODETYPE returns 1; otherwise return 0.
+ The third argument should point to an uint32_t variable. In the 8-bit
+ library, the value is always less than 256. In the 16-bit library the
+ value can be up to 0xffff. In the 32-bit library in UTF-32 mode the
value can be up to 0x10ffff, and up to 0xffffffff when not using UTF-32
mode.
PCRE2_INFO_FRAMESIZE
Return the size (in bytes) of the data frames that are used to remember
- backtracking positions when the pattern is processed by pcre2_match()
- without the use of JIT. The third argument should point to a size_t
+ backtracking positions when the pattern is processed by pcre2_match()
+ without the use of JIT. The third argument should point to a size_t
variable. The frame size depends on the number of capturing parentheses
in the pattern. Each additional capture group adds two PCRE2_SIZE vari-
ables.
PCRE2_INFO_HASBACKSLASHC
- Return 1 if the pattern contains any instances of \C, otherwise 0. The
+ Return 1 if the pattern contains any instances of \C, otherwise 0. The
third argument should point to an uint32_t variable.
PCRE2_INFO_HASCRORLF
- 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
characters, otherwise 0. The third argument should point to an uint32_t
- variable. An explicit match is either a literal CR or LF character, or
- \r or \n or one of the equivalent hexadecimal or octal escape
+ variable. An explicit match is either a literal CR or LF character, or
+ \r or \n or one of the equivalent hexadecimal or octal escape
sequences.
PCRE2_INFO_HEAPLIMIT
@@ -2139,81 +2155,81 @@ INFORMATION ABOUT A COMPILED PATTERN
If the pattern set a heap memory limit by including an item of the form
(*LIMIT_HEAP=nnnn) at the start, the value is returned. The third argu-
ment should point to a uint32_t integer. If no such value has been set,
- the call to pcre2_pattern_info() returns the error PCRE2_ERROR_UNSET.
- Note that this limit will only be used during matching if it is less
+ the call to pcre2_pattern_info() returns the error PCRE2_ERROR_UNSET.
+ Note that this limit will only be used during matching if it is less
than the limit set or defaulted by the caller of the match function.
PCRE2_INFO_JCHANGED
- Return 1 if the (?J) or (?-J) option setting is used in the pattern,
- otherwise 0. The third argument should point to an uint32_t variable.
- (?J) and (?-J) set and unset the local PCRE2_DUPNAMES option, respec-
+ Return 1 if the (?J) or (?-J) option setting is used in the pattern,
+ otherwise 0. The third argument should point to an uint32_t variable.
+ (?J) and (?-J) set and unset the local PCRE2_DUPNAMES option, respec-
tively.
PCRE2_INFO_JITSIZE
- If the compiled pattern was successfully processed by pcre2_jit_com-
- pile(), return the size of the JIT compiled code, otherwise return
+ If the compiled pattern was successfully processed by pcre2_jit_com-
+ pile(), return the size of the JIT compiled code, otherwise return
zero. The third argument should point to a size_t variable.
PCRE2_INFO_LASTCODETYPE
- Returns 1 if there is a rightmost literal code unit that must exist in
- any matched string, other than at its start. The third argument should
- point to an uint32_t variable. If there is no such value, 0 is
- returned. When 1 is returned, the code unit value itself can be
- retrieved using PCRE2_INFO_LASTCODEUNIT. For anchored patterns, a last
- literal value is recorded only if it follows something of variable
- length. For example, for the pattern /^a\d+z\d+/ the returned value is
- 1 (with "z" returned from PCRE2_INFO_LASTCODEUNIT), but for /^a\dz\d/
+ Returns 1 if there is a rightmost literal code unit that must exist in
+ any matched string, other than at its start. The third argument should
+ point to an uint32_t variable. If there is no such value, 0 is
+ returned. When 1 is returned, the code unit value itself can be
+ retrieved using PCRE2_INFO_LASTCODEUNIT. For anchored patterns, a last
+ literal value is recorded only if it follows something of variable
+ length. For example, for the pattern /^a\d+z\d+/ the returned value is
+ 1 (with "z" returned from PCRE2_INFO_LASTCODEUNIT), but for /^a\dz\d/
the returned value is 0.
PCRE2_INFO_LASTCODEUNIT
- Return the value of the rightmost literal code unit that must exist in
- any matched string, other than at its start, for a pattern where
+ Return the value of the rightmost literal code unit that must exist in
+ any matched string, other than at its start, for a pattern where
PCRE2_INFO_LASTCODETYPE returns 1. Otherwise, return 0. The third argu-
ment should point to an uint32_t variable.
PCRE2_INFO_MATCHEMPTY
- Return 1 if the pattern might match an empty string, otherwise 0. The
- third argument should point to an uint32_t variable. When a pattern
+ Return 1 if the pattern might match an empty string, otherwise 0. The
+ third argument should point to an uint32_t variable. When a pattern
contains recursive subroutine calls it is not always possible to deter-
- mine whether or not it can match an empty string. PCRE2 takes a cau-
+ mine whether or not it can match an empty string. PCRE2 takes a cau-
tious approach and returns 1 in such cases.
PCRE2_INFO_MATCHLIMIT
- If the pattern set a match limit by including an item of the form
- (*LIMIT_MATCH=nnnn) at the start, the value is returned. The third
- argument should point to a uint32_t integer. If no such value has been
- set, the call to pcre2_pattern_info() returns the error
+ If the pattern set a match limit by including an item of the form
+ (*LIMIT_MATCH=nnnn) at the start, the value is returned. The third
+ argument should point to a uint32_t integer. If no such value has been
+ set, the call to pcre2_pattern_info() returns the error
PCRE2_ERROR_UNSET. Note that this limit will only be used during match-
- ing if it is less than the limit set or defaulted by the caller of the
+ ing if it is less than the limit set or defaulted by the caller of the
match function.
PCRE2_INFO_MAXLOOKBEHIND
Return the number of characters (not code units) in the longest lookbe-
- hind assertion in the pattern. The third argument should point to a
- uint32_t integer. This information is useful when doing multi-segment
- matching using the partial matching facilities. Note that the simple
+ hind assertion in the pattern. The third argument should point to a
+ uint32_t integer. This information is useful when doing multi-segment
+ matching using the partial matching facilities. Note that the simple
assertions \b and \B require a one-character lookbehind. \A also regis-
- ters a one-character lookbehind, though it does not actually inspect
- the previous character. This is to ensure that at least one character
- from the old segment is retained when a new segment is processed. Oth-
- erwise, if there are no lookbehinds in the pattern, \A might match
+ ters a one-character lookbehind, though it does not actually inspect
+ the previous character. This is to ensure that at least one character
+ from the old segment is retained when a new segment is processed. Oth-
+ erwise, if there are no lookbehinds in the pattern, \A might match
incorrectly at the start of a second or subsequent segment.
PCRE2_INFO_MINLENGTH
- If a minimum length for matching subject strings was computed, its
- value is returned. Otherwise the returned value is 0. The value is a
- number of characters, which in UTF mode may be different from the num-
- ber of code units. The third argument should point to an uint32_t
- variable. The value is a lower bound to the length of any matching
- string. There may not be any strings of that length that do actually
+ If a minimum length for matching subject strings was computed, its
+ value is returned. Otherwise the returned value is 0. The value is a
+ number of characters, which in UTF mode may be different from the num-
+ ber of code units. The third argument should point to an uint32_t
+ variable. The value is a lower bound to the length of any matching
+ string. There may not be any strings of that length that do actually
match, but every string that does match is at least that long.
PCRE2_INFO_NAMECOUNT
@@ -2221,51 +2237,51 @@ INFORMATION ABOUT A COMPILED PATTERN
PCRE2_INFO_NAMETABLE
PCRE2 supports the use of named as well as numbered capturing parenthe-
- ses. The names are just an additional way of identifying the parenthe-
+ ses. The names are just an additional way of identifying the parenthe-
ses, which still acquire numbers. Several convenience functions such as
- pcre2_substring_get_byname() are provided for extracting captured sub-
- strings by name. It is also possible to extract the data directly, by
- first converting the name to a number in order to access the correct
- pointers in the output vector (described with pcre2_match() below). To
- do the conversion, you need to use the name-to-number map, which is
+ pcre2_substring_get_byname() are provided for extracting captured sub-
+ strings by name. It is also possible to extract the data directly, by
+ first converting the name to a number in order to access the correct
+ pointers in the output vector (described with pcre2_match() below). To
+ do the conversion, you need to use the name-to-number map, which is
described by these three values.
- The map consists of a number of fixed-size entries. PCRE2_INFO_NAME-
- COUNT gives the number of entries, and PCRE2_INFO_NAMEENTRYSIZE gives
- the size of each entry in code units; both of these return a uint32_t
+ The map consists of a number of fixed-size entries. PCRE2_INFO_NAME-
+ COUNT gives the number of entries, and PCRE2_INFO_NAMEENTRYSIZE gives
+ the size of each entry in code units; both of these return a uint32_t
value. The entry size depends on the length of the longest name.
PCRE2_INFO_NAMETABLE returns a pointer to the first entry of the table.
- This is a PCRE2_SPTR pointer to a block of code units. In the 8-bit
- library, the first two bytes of each entry are the number of the cap-
+ This is a PCRE2_SPTR pointer to a block of code units. In the 8-bit
+ library, the first two bytes of each entry are the number of the cap-
turing parenthesis, most significant byte first. In the 16-bit library,
- the pointer points to 16-bit code units, the first of which contains
- the parenthesis number. In the 32-bit library, the pointer points to
- 32-bit code units, the first of which contains the parenthesis number.
+ the pointer points to 16-bit code units, the first of which contains
+ the parenthesis number. In the 32-bit library, the pointer points to
+ 32-bit code units, the first of which contains the parenthesis number.
The rest of the entry is the corresponding name, zero terminated.
- The names are in alphabetical order. If (?| is used to create multiple
- capture groups with the same number, as described in the section on
- duplicate group numbers in the pcre2pattern page, the groups may be
- given the same name, but there is only one entry in the table. Differ-
+ The names are in alphabetical order. If (?| is used to create multiple
+ capture groups with the same number, as described in the section on
+ duplicate group numbers in the pcre2pattern page, the groups may be
+ given the same name, but there is only one entry in the table. Differ-
ent names for groups of the same number are not permitted.
- Duplicate names for capture groups with different numbers are permit-
+ Duplicate names for capture groups with different numbers are permit-
ted, but only if PCRE2_DUPNAMES is set. They appear in the table in the
- order in which they were found in the pattern. In the absence of (?|
- this is the order of increasing number; when (?| is used this is not
- necessarily the case because later capture groups may have lower num-
+ order in which they were found in the pattern. In the absence of (?|
+ this is the order of increasing number; when (?| is used this is not
+ necessarily the case because later capture groups may have lower num-
bers.
- As a simple example of the name/number table, consider the following
- pattern after compilation by the 8-bit library (assume PCRE2_EXTENDED
+ As a simple example of the name/number table, consider the following
+ pattern after compilation by the 8-bit library (assume PCRE2_EXTENDED
is set, so white space - including newlines - is ignored):
(?<date> (?<year>(\d\d)?\d\d) -
(?<month>\d\d) - (?<day>\d\d) )
There are four named capture groups, so the table has four entries, and
- 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,
with non-printing bytes shows in hexadecimal, and undefined bytes shown
as ??:
@@ -2274,8 +2290,8 @@ INFORMATION ABOUT A COMPILED PATTERN
00 04 m o n t h 00
00 02 y e a r 00 ??
- When writing code to extract data from named capture groups using the
- name-to-number map, remember that the length of the entries is likely
+ When writing code to extract data from named capture groups using the
+ name-to-number map, remember that the length of the entries is likely
to be different for each compiled pattern.
PCRE2_INFO_NEWLINE
@@ -2294,14 +2310,14 @@ INFORMATION ABOUT A COMPILED PATTERN
PCRE2_INFO_SIZE
- Return the size of the compiled pattern in bytes (for all three
- libraries). The third argument should point to a size_t variable. This
- value includes the size of the general data block that precedes the
- code units of the compiled pattern itself. The value that is used when
- pcre2_compile() is getting memory in which to place the compiled pat-
- tern may be slightly larger than the value returned by this option,
- because there are cases where the code that calculates the size has to
- over-estimate. Processing a pattern with the JIT compiler does not
+ Return the size of the compiled pattern in bytes (for all three
+ libraries). The third argument should point to a size_t variable. This
+ value includes the size of the general data block that precedes the
+ code units of the compiled pattern itself. The value that is used when
+ pcre2_compile() is getting memory in which to place the compiled pat-
+ tern may be slightly larger than the value returned by this option,
+ because there are cases where the code that calculates the size has to
+ over-estimate. Processing a pattern with the JIT compiler does not
alter the value returned by this option.
@@ -2312,30 +2328,30 @@ INFORMATION ABOUT A PATTERN'S CALLOUTS
void *user_data);
A script language that supports the use of string arguments in callouts
- might like to scan all the callouts in a pattern before running the
+ might like to scan all the callouts in a pattern before running the
match. This can be done by calling pcre2_callout_enumerate(). The first
- argument is a pointer to a compiled pattern, the second points to a
- callback function, and the third is arbitrary user data. The callback
- function is called for every callout in the pattern in the order in
+ argument is a pointer to a compiled pattern, the second points to a
+ callback function, and the third is arbitrary user data. The callback
+ function is called for every callout in the pattern in the order in
which they appear. Its first argument is a pointer to a callout enumer-
- ation block, and its second argument is the user_data value that was
- passed to pcre2_callout_enumerate(). The contents of the callout enu-
- meration block are described in the pcre2callout documentation, which
+ ation block, and its second argument is the user_data value that was
+ passed to pcre2_callout_enumerate(). The contents of the callout enu-
+ meration block are described in the pcre2callout documentation, which
also gives further details about callouts.
SERIALIZATION AND PRECOMPILING
- It is possible to save compiled patterns on disc or elsewhere, and
- reload them later, subject to a number of restrictions. The host on
- which the patterns are reloaded must be running the same version of
+ It is possible to save compiled patterns on disc or elsewhere, and
+ reload them later, subject to a number of restrictions. The host on
+ which the patterns are reloaded must be running the same version of
PCRE2, with the same code unit width, and must also have the same endi-
- anness, pointer width, and PCRE2_SIZE type. Before compiled patterns
- can be saved, they must be converted to a "serialized" form, which in
- the case of PCRE2 is really just a bytecode dump. The functions whose
- names begin with pcre2_serialize_ are used for converting to and from
- the serialized form. They are described in the pcre2serialize documen-
- tation. Note that PCRE2 serialization does not convert compiled pat-
+ anness, pointer width, and PCRE2_SIZE type. Before compiled patterns
+ can be saved, they must be converted to a "serialized" form, which in
+ the case of PCRE2 is really just a bytecode dump. The functions whose
+ names begin with pcre2_serialize_ are used for converting to and from
+ the serialized form. They are described in the pcre2serialize documen-
+ tation. Note that PCRE2 serialization does not convert compiled pat-
terns to an abstract format like Java or .NET serialization.
@@ -2349,60 +2365,60 @@ THE MATCH DATA BLOCK
void pcre2_match_data_free(pcre2_match_data *match_data);
- Information about a successful or unsuccessful match is placed in a
- match data block, which is an opaque structure that is accessed by
- function calls. In particular, the match data block contains a vector
- of offsets into the subject string that define the matched part of the
- subject and any substrings that were captured. This is known as the
+ Information about a successful or unsuccessful match is placed in a
+ match data block, which is an opaque structure that is accessed by
+ function calls. In particular, the match data block contains a vector
+ of offsets into the subject string that define the matched part of the
+ subject and any substrings that were captured. This is known as the
ovector.
- Before calling pcre2_match(), pcre2_dfa_match(), or pcre2_jit_match()
+ Before calling pcre2_match(), pcre2_dfa_match(), or pcre2_jit_match()
you must create a match data block by calling one of the creation func-
- tions above. For pcre2_match_data_create(), the first argument is the
- number of pairs of offsets in the ovector. One pair of offsets is
+ tions above. For pcre2_match_data_create(), the first argument is the
+ number of pairs of offsets in the ovector. One pair of offsets is
required to identify the string that matched the whole pattern, with an
- additional pair for each captured substring. For example, a value of 4
- creates enough space to record the matched portion of the subject plus
- three captured substrings. A minimum of at least 1 pair is imposed by
+ additional pair for each captured substring. For example, a value of 4
+ creates enough space to record the matched portion of the subject plus
+ three captured substrings. A minimum of at least 1 pair is imposed by
pcre2_match_data_create(), so it is always possible to return the over-
all matched string.
The second argument of pcre2_match_data_create() is a pointer to a gen-
- eral context, which can specify custom memory management for obtaining
+ eral context, which can specify custom memory management for obtaining
the memory for the match data block. If you are not using custom memory
management, pass NULL, which causes malloc() to be used.
- For pcre2_match_data_create_from_pattern(), the first argument is a
+ For pcre2_match_data_create_from_pattern(), the first argument is a
pointer to a compiled pattern. The ovector is created to be exactly the
right size to hold all the substrings a pattern might capture. The sec-
- ond argument is again a pointer to a general context, but in this case
+ ond argument is again a pointer to a general context, but in this case
if NULL is passed, the memory is obtained using the same allocator that
was used for the compiled pattern (custom or default).
- A match data block can be used many times, with the same or different
- compiled patterns. You can extract information from a match data block
+ A match data block can be used many times, with the same or different
+ compiled patterns. You can extract information from a match data block
after a match operation has finished, using functions that are
- described in the sections on matched strings and other match data
+ described in the sections on matched strings and other match data
below.
- When a call of pcre2_match() fails, valid data is available in the
- match block only when the error is PCRE2_ERROR_NOMATCH,
- PCRE2_ERROR_PARTIAL, or one of the error codes for an invalid UTF
+ When a call of pcre2_match() fails, valid data is available in the
+ match block only when the error is PCRE2_ERROR_NOMATCH,
+ PCRE2_ERROR_PARTIAL, or one of the error codes for an invalid UTF
string. Exactly what is available depends on the error, and is detailed
below.
- When one of the matching functions is called, pointers to the compiled
- pattern and the subject string are set in the match data block so that
- they can be referenced by the extraction functions after a successful
+ When one of the matching functions is called, pointers to the compiled
+ pattern and the subject string are set in the match data block so that
+ they can be referenced by the extraction functions after a successful
match. After running a match, you must not free a compiled pattern or a
- subject string until after all operations on the match data block (for
- that match) have taken place, unless, in the case of the subject
- string, you have used the PCRE2_COPY_MATCHED_SUBJECT option, which is
- described in the section entitled "Option bits for pcre2_match()"
+ subject string until after all operations on the match data block (for
+ that match) have taken place, unless, in the case of the subject
+ string, you have used the PCRE2_COPY_MATCHED_SUBJECT option, which is
+ described in the section entitled "Option bits for pcre2_match()"
below.
- When a match data block itself is no longer needed, it should be freed
- by calling pcre2_match_data_free(). If this function is called with a
+ When a match data block itself is no longer needed, it should be freed
+ by calling pcre2_match_data_free(). If this function is called with a
NULL argument, it returns immediately, without doing anything.
@@ -2413,15 +2429,15 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION
uint32_t options, pcre2_match_data *match_data,
pcre2_match_context *mcontext);
- The function pcre2_match() is called to match a subject string against
- a compiled pattern, which is passed in the code argument. You can call
+ The function pcre2_match() is called to match a subject string against
+ a compiled pattern, which is passed in the code argument. You can call
pcre2_match() with the same code argument as many times as you like, in
- order to find multiple matches in the subject string or to match dif-
+ order to find multiple matches in the subject string or to match dif-
ferent subject strings with the same pattern.
- This function is the main matching facility of the library, and it
- operates in a Perl-like manner. For specialist use there is also an
- alternative matching function, which is described below in the section
+ This function is the main matching facility of the library, and it
+ operates in a Perl-like manner. For specialist use there is also an
+ alternative matching function, which is described below in the section
about the pcre2_dfa_match() function.
Here is an example of a simple call to pcre2_match():
@@ -2436,205 +2452,205 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION
md, /* the match data block */
NULL); /* a match context; NULL means use defaults */
- If the subject string is zero-terminated, the length can be given as
+ If the subject string is zero-terminated, the length can be given as
PCRE2_ZERO_TERMINATED. A match context must be provided if certain less
common matching parameters are to be changed. For details, see the sec-
tion on the match context above.
The string to be matched by pcre2_match()
- The subject string is passed to pcre2_match() as a pointer in subject,
- a length in length, and a starting offset in startoffset. The length
- and offset are in code units, not characters. That is, they are in
- bytes for the 8-bit library, 16-bit code units for the 16-bit library,
- and 32-bit code units for the 32-bit library, whether or not UTF pro-
+ The subject string is passed to pcre2_match() as a pointer in subject,
+ a length in length, and a starting offset in startoffset. The length
+ and offset are in code units, not characters. That is, they are in
+ bytes for the 8-bit library, 16-bit code units for the 16-bit library,
+ and 32-bit code units for the 32-bit library, whether or not UTF pro-
cessing is enabled.
If startoffset is greater than the length of the subject, pcre2_match()
- returns PCRE2_ERROR_BADOFFSET. When the starting offset is zero, the
- search for a match starts at the beginning of the subject, and this is
+ returns PCRE2_ERROR_BADOFFSET. When the starting offset is zero, the
+ search for a match starts at the beginning of the subject, and this is
by far the most common case. In UTF-8 or UTF-16 mode, the starting off-
- set must point to the start of a character, or to the end of the sub-
- ject (in UTF-32 mode, one code unit equals one character, so all off-
- sets are valid). Like the pattern string, the subject may contain
+ set must point to the start of a character, or to the end of the sub-
+ ject (in UTF-32 mode, one code unit equals one character, so all off-
+ sets are valid). Like the pattern string, the subject may contain
binary zeros.
- A non-zero starting offset is useful when searching for another match
- in the same subject by calling pcre2_match() again after a previous
- success. Setting startoffset differs from passing over a shortened
- string and setting PCRE2_NOTBOL in the case of a pattern that begins
+ A non-zero starting offset is useful when searching for another match
+ in the same subject by calling pcre2_match() again after a previous
+ success. Setting startoffset differs from passing over a shortened
+ string and setting PCRE2_NOTBOL in the case of a pattern that begins
with any kind of lookbehind. For example, consider the pattern
\Biss\B
- which finds occurrences of "iss" in the middle of words. (\B matches
- only if the current position in the subject is not a word boundary.)
+ which finds occurrences of "iss" in the middle of words. (\B matches
+ only if the current position in the subject is not a word boundary.)
When applied to the string "Mississipi" the first call to pcre2_match()
- finds the first occurrence. If pcre2_match() is called again with just
- the remainder of the subject, namely "issipi", it does not match,
+ finds the first occurrence. If pcre2_match() is called again with just
+ the remainder of the subject, namely "issipi", it does not match,
because \B is always false at the start of the subject, which is deemed
- to be a word boundary. However, if pcre2_match() is passed the entire
+ to be a word boundary. However, if pcre2_match() is passed the entire
string again, but with startoffset set to 4, it finds the second occur-
- 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
discover that it is preceded by a letter.
- Finding all the matches in a subject is tricky when the pattern can
+ Finding all the matches in a subject is tricky when the pattern can
match an empty string. It is possible to emulate Perl's /g behaviour by
- first trying the match again at the same offset, with the
- PCRE2_NOTEMPTY_ATSTART and PCRE2_ANCHORED options, and then if that
- fails, advancing the starting offset and trying an ordinary match
- again. There is some code that demonstrates how to do this in the
- pcre2demo sample program. In the most general case, you have to check
- to see if the newline convention recognizes CRLF as a newline, and if
- so, and the current character is CR followed by LF, advance the start-
+ first trying the match again at the same offset, with the
+ PCRE2_NOTEMPTY_ATSTART and PCRE2_ANCHORED options, and then if that
+ fails, advancing the starting offset and trying an ordinary match
+ again. There is some code that demonstrates how to do this in the
+ pcre2demo sample program. In the most general case, you have to check
+ to see if the newline convention recognizes CRLF as a newline, and if
+ so, and the current character is CR followed by LF, advance the start-
ing offset by two characters instead of one.
If a non-zero starting offset is passed when the pattern is anchored, a
single attempt to match at the given offset is made. This can only suc-
- ceed if the pattern does not require the match to be at the start of
- the subject. In other words, the anchoring must be the result of set-
- ting the PCRE2_ANCHORED option or the use of .* with PCRE2_DOTALL, not
+ ceed if the pattern does not require the match to be at the start of
+ the subject. In other words, the anchoring must be the result of set-
+ ting the PCRE2_ANCHORED option or the use of .* with PCRE2_DOTALL, not
by starting the pattern with ^ or \A.
Option bits for pcre2_match()
The unused bits of the options argument for pcre2_match() must be zero.
- The only bits that may be set are PCRE2_ANCHORED,
- PCRE2_COPY_MATCHED_SUBJECT, PCRE2_ENDANCHORED, PCRE2_NOTBOL,
- PCRE2_NOTEOL, PCRE2_NOTEMPTY, PCRE2_NOTEMPTY_ATSTART, PCRE2_NO_JIT,
- PCRE2_NO_UTF_CHECK, PCRE2_PARTIAL_HARD, and PCRE2_PARTIAL_SOFT. Their
+ The only bits that may be set are PCRE2_ANCHORED,
+ PCRE2_COPY_MATCHED_SUBJECT, PCRE2_ENDANCHORED, PCRE2_NOTBOL,
+ PCRE2_NOTEOL, PCRE2_NOTEMPTY, PCRE2_NOTEMPTY_ATSTART, PCRE2_NO_JIT,
+ PCRE2_NO_UTF_CHECK, PCRE2_PARTIAL_HARD, and PCRE2_PARTIAL_SOFT. Their
action is described below.
- Setting PCRE2_ANCHORED or PCRE2_ENDANCHORED at match time is not sup-
- ported by the just-in-time (JIT) compiler. If it is set, JIT matching
- is disabled and the interpretive code in pcre2_match() is run. Apart
- from PCRE2_NO_JIT (obviously), the remaining options are supported for
+ Setting PCRE2_ANCHORED or PCRE2_ENDANCHORED at match time is not sup-
+ ported by the just-in-time (JIT) compiler. If it is set, JIT matching
+ is disabled and the interpretive code in pcre2_match() is run. Apart
+ from PCRE2_NO_JIT (obviously), the remaining options are supported for
JIT matching.
PCRE2_ANCHORED
The PCRE2_ANCHORED option limits pcre2_match() to matching at the first
- matching position. If a pattern was compiled with PCRE2_ANCHORED, or
- turned out to be anchored by virtue of its contents, it cannot be made
- unachored at matching time. Note that setting the option at match time
+ matching position. If a pattern was compiled with PCRE2_ANCHORED, or
+ turned out to be anchored by virtue of its contents, it cannot be made
+ unachored at matching time. Note that setting the option at match time
disables JIT matching.
PCRE2_COPY_MATCHED_SUBJECT
- By default, a pointer to the subject is remembered in the match data
- block so that, after a successful match, it can be referenced by the
- substring extraction functions. This means that the subject's memory
- must not be freed until all such operations are complete. For some
- applications where the lifetime of the subject string is not guaran-
- teed, it may be necessary to make a copy of the subject string, but it
+ By default, a pointer to the subject is remembered in the match data
+ block so that, after a successful match, it can be referenced by the
+ substring extraction functions. This means that the subject's memory
+ must not be freed until all such operations are complete. For some
+ applications where the lifetime of the subject string is not guaran-
+ teed, it may be necessary to make a copy of the subject string, but it
is wasteful to do this unless the match is successful. After a success-
- ful match, if PCRE2_COPY_MATCHED_SUBJECT is set, the subject is copied
- and the new pointer is remembered in the match data block instead of
- the original subject pointer. The memory allocator that was used for
- the match block itself is used. The copy is automatically freed when
- pcre2_match_data_free() is called to free the match data block. It is
+ ful match, if PCRE2_COPY_MATCHED_SUBJECT is set, the subject is copied
+ and the new pointer is remembered in the match data block instead of
+ the original subject pointer. The memory allocator that was used for
+ the match block itself is used. The copy is automatically freed when
+ pcre2_match_data_free() is called to free the match data block. It is
also automatically freed if the match data block is re-used for another
match operation.
PCRE2_ENDANCHORED
- If the PCRE2_ENDANCHORED option is set, any string that pcre2_match()
- matches must be right at the end of the subject string. Note that set-
+ If the PCRE2_ENDANCHORED option is set, any string that pcre2_match()
+ matches must be right at the end of the subject string. Note that set-
ting the option at match time disables JIT matching.
PCRE2_NOTBOL
This option specifies that first character of the subject string is not
- the beginning of a line, so the circumflex metacharacter should not
- match before it. Setting this without having set PCRE2_MULTILINE at
+ the beginning of a line, so the circumflex metacharacter should not
+ match before it. Setting this without having set PCRE2_MULTILINE at
compile time causes circumflex never to match. This option affects only
the behaviour of the circumflex metacharacter. It does not affect \A.
PCRE2_NOTEOL
This option specifies that the end of the subject string is not the end
- of a line, so the dollar metacharacter should not match it nor (except
- in multiline mode) a newline immediately before it. Setting this with-
- out having set PCRE2_MULTILINE at compile time causes dollar never to
+ of a line, so the dollar metacharacter should not match it nor (except
+ in multiline mode) a newline immediately before it. Setting this with-
+ out having set PCRE2_MULTILINE at compile time causes dollar never to
match. This option affects only the behaviour of the dollar metacharac-
ter. It does not affect \Z or \z.
PCRE2_NOTEMPTY
An empty string is not considered to be a valid match if this option is
- set. If there are alternatives in the pattern, they are tried. If all
- the alternatives match the empty string, the entire match fails. For
+ set. If there are alternatives in the pattern, they are tried. If all
+ the alternatives match the empty string, the entire match fails. For
example, if the pattern
a?b?
- is applied to a string not beginning with "a" or "b", it matches an
+ is applied to a string not beginning with "a" or "b", it matches an
empty string at the start of the subject. With PCRE2_NOTEMPTY set, this
- match is not valid, so pcre2_match() searches further into the string
+ match is not valid, so pcre2_match() searches further into the string
for occurrences of "a" or "b".
PCRE2_NOTEMPTY_ATSTART
- This is like PCRE2_NOTEMPTY, except that it locks out an empty string
+ This is like PCRE2_NOTEMPTY, except that it locks out an empty string
match only at the first matching position, that is, at the start of the
- subject plus the starting offset. An empty string match later in the
- subject is permitted. If the pattern is anchored, such a match can
+ subject plus the starting offset. An empty string match later in the
+ subject is permitted. If the pattern is anchored, such a match can
occur only if the pattern contains \K.
PCRE2_NO_JIT
- By default, if a pattern has been successfully processed by
- pcre2_jit_compile(), JIT is automatically used when pcre2_match() is
- called with options that JIT supports. Setting PCRE2_NO_JIT disables
+ By default, if a pattern has been successfully processed by
+ pcre2_jit_compile(), JIT is automatically used when pcre2_match() is
+ called with options that JIT supports. Setting PCRE2_NO_JIT disables
the use of JIT; it forces matching to be done by the interpreter.
PCRE2_NO_UTF_CHECK
When PCRE2_UTF is set at compile time, the validity of the subject as a
- UTF string is checked by default when pcre2_match() is subsequently
- called. If a non-zero starting offset is given, the check is applied
- only to that part of the subject that could be inspected during match-
- ing, and there is a check that the starting offset points to the first
- code unit of a character or to the end of the subject. If there are no
- lookbehind assertions in the pattern, the check starts at the starting
- offset. Otherwise, it starts at the length of the longest lookbehind
+ UTF string is checked by default when pcre2_match() is subsequently
+ called. If a non-zero starting offset is given, the check is applied
+ only to that part of the subject that could be inspected during match-
+ ing, and there is a check that the starting offset points to the first
+ code unit of a character or to the end of the subject. If there are no
+ lookbehind assertions in the pattern, the check starts at the starting
+ offset. Otherwise, it starts at the length of the longest lookbehind
before the starting offset, or at the start of the subject if there are
- not that many characters before the starting offset. Note that the
+ not that many characters before the starting offset. Note that the
sequences \b and \B are one-character lookbehinds.
The check is carried out before any other processing takes place, and a
- negative error code is returned if the check fails. There are several
- UTF error codes for each code unit width, corresponding to different
- problems with the code unit sequence. There are discussions about the
- validity of UTF-8 strings, UTF-16 strings, and UTF-32 strings in the
+ negative error code is returned if the check fails. There are several
+ UTF error codes for each code unit width, corresponding to different
+ problems with the code unit sequence. There are discussions about the
+ validity of UTF-8 strings, UTF-16 strings, and UTF-32 strings in the
pcre2unicode page.
- If you know that your subject is valid, and you want to skip these
- checks for performance reasons, you can set the PCRE2_NO_UTF_CHECK
- option when calling pcre2_match(). You might want to do this for the
+ If you know that your subject is valid, and you want to skip these
+ checks for performance reasons, you can set the PCRE2_NO_UTF_CHECK
+ option when calling pcre2_match(). You might want to do this for the
second and subsequent calls to pcre2_match() if you are making repeated
calls to find other matches in the same subject string.
- Warning: When PCRE2_NO_UTF_CHECK is set, the effect of passing an
- invalid string as a subject, or an invalid value of startoffset, is
+ Warning: When PCRE2_NO_UTF_CHECK is set, the effect of passing an
+ invalid string as a subject, or an invalid value of startoffset, is
undefined. Your program may crash or loop indefinitely.
PCRE2_PARTIAL_HARD
PCRE2_PARTIAL_SOFT
- These options turn on the partial matching feature. A partial match
- occurs if the end of the subject string is reached successfully, but
- there are not enough subject characters to complete the match. If this
- happens when PCRE2_PARTIAL_SOFT (but not PCRE2_PARTIAL_HARD) is set,
- matching continues by testing any remaining alternatives. Only if no
- complete match can be found is PCRE2_ERROR_PARTIAL returned instead of
- PCRE2_ERROR_NOMATCH. In other words, PCRE2_PARTIAL_SOFT specifies that
- the caller is prepared to handle a partial match, but only if no com-
+ These options turn on the partial matching feature. A partial match
+ occurs if the end of the subject string is reached successfully, but
+ there are not enough subject characters to complete the match. If this
+ happens when PCRE2_PARTIAL_SOFT (but not PCRE2_PARTIAL_HARD) is set,
+ matching continues by testing any remaining alternatives. Only if no
+ complete match can be found is PCRE2_ERROR_PARTIAL returned instead of
+ PCRE2_ERROR_NOMATCH. In other words, PCRE2_PARTIAL_SOFT specifies that
+ the caller is prepared to handle a partial match, but only if no com-
plete match can be found.
- If PCRE2_PARTIAL_HARD is set, it overrides PCRE2_PARTIAL_SOFT. In this
- case, if a partial match is found, pcre2_match() immediately returns
- PCRE2_ERROR_PARTIAL, without considering any other alternatives. In
+ If PCRE2_PARTIAL_HARD is set, it overrides PCRE2_PARTIAL_SOFT. In this
+ case, if a partial match is found, pcre2_match() immediately returns
+ PCRE2_ERROR_PARTIAL, without considering any other alternatives. In
other words, when PCRE2_PARTIAL_HARD is set, a partial match is consid-
ered to be more important that an alternative complete match.
@@ -2644,38 +2660,38 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION
NEWLINE HANDLING WHEN MATCHING
- When PCRE2 is built, a default newline convention is set; this is usu-
- ally the standard convention for the operating system. The default can
- be overridden in a compile context by calling pcre2_set_newline(). It
- can also be overridden by starting a pattern string with, for example,
- (*CRLF), as described in the section on newline conventions in the
- pcre2pattern page. During matching, the newline choice affects the be-
- haviour of the dot, circumflex, and dollar metacharacters. It may also
- alter the way the match starting position is advanced after a match
+ When PCRE2 is built, a default newline convention is set; this is usu-
+ ally the standard convention for the operating system. The default can
+ be overridden in a compile context by calling pcre2_set_newline(). It
+ can also be overridden by starting a pattern string with, for example,
+ (*CRLF), as described in the section on newline conventions in the
+ pcre2pattern page. During matching, the newline choice affects the be-
+ haviour of the dot, circumflex, and dollar metacharacters. It may also
+ alter the way the match starting position is advanced after a match
failure for an unanchored pattern.
When PCRE2_NEWLINE_CRLF, PCRE2_NEWLINE_ANYCRLF, or PCRE2_NEWLINE_ANY is
- set as the newline convention, and a match attempt for an unanchored
+ set as the newline convention, and a match attempt for an unanchored
pattern fails when the current starting position is at a CRLF sequence,
- and the pattern contains no explicit matches for CR or LF characters,
- the match position is advanced by two characters instead of one, in
+ and the pattern contains no explicit matches for CR or LF characters,
+ the match position is advanced by two characters instead of one, in
other words, to after the CRLF.
The above rule is a compromise that makes the most common cases work as
- expected. For example, if the pattern is .+A (and the PCRE2_DOTALL
+ expected. For example, if the pattern is .+A (and the PCRE2_DOTALL
option is not set), it does not match the string "\r\nA" because, after
- failing at the start, it skips both the CR and the LF before retrying.
- However, the pattern [\r\n]A does match that string, because it con-
+ failing at the start, it skips both the CR and the LF before retrying.
+ However, the pattern [\r\n]A does match that string, because it con-
tains an explicit CR or LF reference, and so advances only by one char-
acter after the first failure.
An explicit match for CR of LF is either a literal appearance of one of
- those characters in the pattern, or one of the \r or \n or equivalent
+ those characters in the pattern, or one of the \r or \n or equivalent
octal or hexadecimal escape sequences. Implicit matches such as [^X] do
- not count, nor does \s, even though it includes CR and LF in the char-
+ not count, nor does \s, even though it includes CR and LF in the char-
acters that it matches.
- Notwithstanding the above, anomalous effects may still occur when CRLF
+ Notwithstanding the above, anomalous effects may still occur when CRLF
is a valid newline sequence and explicit \r or \n escapes appear in the
pattern.
@@ -2686,82 +2702,82 @@ HOW PCRE2_MATCH() RETURNS A STRING AND CAPTURED SUBSTRINGS
PCRE2_SIZE *pcre2_get_ovector_pointer(pcre2_match_data *match_data);
- In general, a pattern matches a certain portion of the subject, and in
- addition, further substrings from the subject may be picked out by
- parenthesized parts of the pattern. Following the usage in Jeffrey
- Friedl's book, this is called "capturing" in what follows, and the
- phrase "capture group" (Perl terminology) is used for a fragment of a
- pattern that picks out a substring. PCRE2 supports several other kinds
+ In general, a pattern matches a certain portion of the subject, and in
+ addition, further substrings from the subject may be picked out by
+ parenthesized parts of the pattern. Following the usage in Jeffrey
+ Friedl's book, this is called "capturing" in what follows, and the
+ phrase "capture group" (Perl terminology) is used for a fragment of a
+ pattern that picks out a substring. PCRE2 supports several other kinds
of parenthesized group that do not cause substrings to be captured. The
- pcre2_pattern_info() function can be used to find out how many capture
+ pcre2_pattern_info() function can be used to find out how many capture
groups there are in a compiled pattern.
- You can use auxiliary functions for accessing captured substrings by
+ You can use auxiliary functions for accessing captured substrings by
number or by name, as described in sections below.
Alternatively, you can make direct use of the vector of PCRE2_SIZE val-
- ues, called the ovector, which contains the offsets of captured
- strings. It is part of the match data block. The function
- pcre2_get_ovector_pointer() returns the address of the ovector, and
+ ues, called the ovector, which contains the offsets of captured
+ strings. It is part of the match data block. The function
+ pcre2_get_ovector_pointer() returns the address of the ovector, and
pcre2_get_ovector_count() returns the number of pairs of values it con-
tains.
Within the ovector, the first in each pair of values is set to the off-
set of the first code unit of a substring, and the second is set to the
- offset of the first code unit after the end of a substring. These val-
- ues are always code unit offsets, not character offsets. That is, they
- are byte offsets in the 8-bit library, 16-bit offsets in the 16-bit
+ offset of the first code unit after the end of a substring. These val-
+ ues are always code unit offsets, not character offsets. That is, they
+ are byte offsets in the 8-bit library, 16-bit offsets in the 16-bit
library, and 32-bit offsets in the 32-bit library.
- After a partial match (error return PCRE2_ERROR_PARTIAL), only the
- first pair of offsets (that is, ovector[0] and ovector[1]) are set.
- They identify the part of the subject that was partially matched. See
+ After a partial match (error return PCRE2_ERROR_PARTIAL), only the
+ first pair of offsets (that is, ovector[0] and ovector[1]) are set.
+ They identify the part of the subject that was partially matched. See
the pcre2partial documentation for details of partial matching.
- After a fully successful match, the first pair of offsets identifies
- the portion of the subject string that was matched by the entire pat-
- tern. The next pair is used for the first captured substring, and so
- on. The value returned by pcre2_match() is one more than the highest
- numbered pair that has been set. For example, if two substrings have
- been captured, the returned value is 3. If there are no captured sub-
+ After a fully successful match, the first pair of offsets identifies
+ the portion of the subject string that was matched by the entire pat-
+ tern. The next pair is used for the first captured substring, and so
+ on. The value returned by pcre2_match() is one more than the highest
+ numbered pair that has been set. For example, if two substrings have
+ been captured, the returned value is 3. If there are no captured sub-
strings, the return value from a successful match is 1, indicating that
just the first pair of offsets has been set.
- If a pattern uses the \K escape sequence within a positive assertion,
+ If a pattern uses the \K escape sequence within a positive assertion,
the reported start of a successful match can be greater than the end of
- the match. For example, if the pattern (?=ab\K) is matched against
+ the match. For example, if the pattern (?=ab\K) is matched against
"ab", the start and end offset values for the match are 2 and 0.
- If a capture group is matched repeatedly within a single match opera-
- tion, it is the last portion of the subject that it matched that is
+ If a capture group is matched repeatedly within a single match opera-
+ tion, it is the last portion of the subject that it matched that is
returned.
If the ovector is too small to hold all the captured substring offsets,
- as much as possible is filled in, and the function returns a value of
- zero. If captured substrings are not of interest, pcre2_match() may be
+ as much as possible is filled in, and the function returns a value of
+ zero. If captured substrings are not of interest, pcre2_match() may be
called with a match data block whose ovector is of minimum length (that
is, one pair).
- It is possible for capture group number n+1 to match some part of the
- subject when group n has not been used at all. For example, if the
+ It is possible for capture group number n+1 to match some part of the
+ subject when group n has not been used at all. For example, if the
string "abc" is matched against the pattern (a|(z))(bc) the return from
- the function is 4, and groups 1 and 3 are matched, but 2 is not. When
- this happens, both values in the offset pairs corresponding to unused
+ the function is 4, and groups 1 and 3 are matched, but 2 is not. When
+ this happens, both values in the offset pairs corresponding to unused
groups are set to PCRE2_UNSET.
- Offset values that correspond to unused groups at the end of the
- expression are also set to PCRE2_UNSET. For example, if the string
- "abc" is matched against the pattern (abc)(x(yz)?)? groups 2 and 3 are
- not matched. The return from the function is 2, because the highest
- used capture group number is 1. The offsets for for the second and
- third capture groupss (assuming the vector is large enough, of course)
+ Offset values that correspond to unused groups at the end of the
+ expression are also set to PCRE2_UNSET. For example, if the string
+ "abc" is matched against the pattern (abc)(x(yz)?)? groups 2 and 3 are
+ not matched. The return from the function is 2, because the highest
+ used capture group number is 1. The offsets for for the second and
+ third capture groupss (assuming the vector is large enough, of course)
are set to PCRE2_UNSET.
Elements in the ovector that do not correspond to capturing parentheses
in the pattern are never changed. That is, if a pattern contains n cap-
turing parentheses, no more than ovector[0] to ovector[2n+1] are set by
- pcre2_match(). The other elements retain whatever values they previ-
- ously had. After a failed match attempt, the contents of the ovector
+ pcre2_match(). The other elements retain whatever values they previ-
+ ously had. After a failed match attempt, the contents of the ovector
are unchanged.
@@ -2771,69 +2787,69 @@ OTHER INFORMATION ABOUT A MATCH
PCRE2_SIZE pcre2_get_startchar(pcre2_match_data *match_data);
- As well as the offsets in the ovector, other information about a match
- is retained in the match data block and can be retrieved by the above
- functions in appropriate circumstances. If they are called at other
+ As well as the offsets in the ovector, other information about a match
+ is retained in the match data block and can be retrieved by the above
+ functions in appropriate circumstances. If they are called at other
times, the result is undefined.
- After a successful match, a partial match (PCRE2_ERROR_PARTIAL), or a
- failure to match (PCRE2_ERROR_NOMATCH), a mark name may be available.
- The function pcre2_get_mark() can be called to access this name, which
- can be specified in the pattern by any of the backtracking control
+ After a successful match, a partial match (PCRE2_ERROR_PARTIAL), or a
+ failure to match (PCRE2_ERROR_NOMATCH), a mark name may be available.
+ The function pcre2_get_mark() can be called to access this name, which
+ can be specified in the pattern by any of the backtracking control
verbs, not just (*MARK). The same function applies to all the verbs. It
returns a pointer to the zero-terminated name, which is within the com-
piled pattern. If no name is available, NULL is returned. The length of
- the name (excluding the terminating zero) is stored in the code unit
- that precedes the name. You should use this length instead of relying
+ the name (excluding the terminating zero) is stored in the code unit
+ that precedes the name. You should use this length instead of relying
on the terminating zero if the name might contain a binary zero.
- After a successful match, the name that is returned is the last mark
+ After a successful match, the name that is returned is the last mark
name encountered on the matching path through the pattern. Instances of
- backtracking verbs without names do not count. Thus, for example, if
+ backtracking verbs without names do not count. Thus, for example, if
the matching path contains (*MARK:A)(*PRUNE), the name "A" is returned.
- After a "no match" or a partial match, the last encountered name is
+ After a "no match" or a partial match, the last encountered name is
returned. For example, consider this pattern:
^(*MARK:A)((*MARK:B)a|b)c
- When it matches "bc", the returned name is A. The B mark is "seen" in
- the first branch of the group, but it is not on the matching path. On
- the other hand, when this pattern fails to match "bx", the returned
+ When it matches "bc", the returned name is A. The B mark is "seen" in
+ the first branch of the group, but it is not on the matching path. On
+ the other hand, when this pattern fails to match "bx", the returned
name is B.
- Warning: By default, certain start-of-match optimizations are used to
- give a fast "no match" result in some situations. For example, if the
- anchoring is removed from the pattern above, there is an initial check
- for the presence of "c" in the subject before running the matching
+ Warning: By default, certain start-of-match optimizations are used to
+ give a fast "no match" result in some situations. For example, if the
+ anchoring is removed from the pattern above, there is an initial check
+ for the presence of "c" in the subject before running the matching
engine. This check fails for "bx", causing a match failure without see-
ing any marks. You can disable the start-of-match optimizations by set-
- ting the PCRE2_NO_START_OPTIMIZE option for pcre2_compile() or by
+ ting the PCRE2_NO_START_OPTIMIZE option for pcre2_compile() or by
starting the pattern with (*NO_START_OPT).
- After a successful match, a partial match, or one of the invalid UTF
- errors (for example, PCRE2_ERROR_UTF8_ERR5), pcre2_get_startchar() can
+ After a successful match, a partial match, or one of the invalid UTF
+ errors (for example, PCRE2_ERROR_UTF8_ERR5), pcre2_get_startchar() can
be called. After a successful or partial match it returns the code unit
- offset of the character at which the match started. For a non-partial
- match, this can be different to the value of ovector[0] if the pattern
- contains the \K escape sequence. After a partial match, however, this
- value is always the same as ovector[0] because \K does not affect the
+ offset of the character at which the match started. For a non-partial
+ match, this can be different to the value of ovector[0] if the pattern
+ contains the \K escape sequence. After a partial match, however, this
+ value is always the same as ovector[0] because \K does not affect the
result of a partial match.
- After a UTF check failure, pcre2_get_startchar() can be used to obtain
+ After a UTF check failure, pcre2_get_startchar() can be used to obtain
the code unit offset of the invalid UTF character. Details are given in
the pcre2unicode page.
ERROR RETURNS FROM pcre2_match()
- If pcre2_match() fails, it returns a negative number. This can be con-
- verted to a text string by calling the pcre2_get_error_message() func-
- tion (see "Obtaining a textual error message" below). Negative error
- codes are also returned by other functions, and are documented with
- them. The codes are given names in the header file. If UTF checking is
+ If pcre2_match() fails, it returns a negative number. This can be con-
+ verted to a text string by calling the pcre2_get_error_message() func-
+ tion (see "Obtaining a textual error message" below). Negative error
+ codes are also returned by other functions, and are documented with
+ them. The codes are given names in the header file. If UTF checking is
in force and an invalid UTF subject string is detected, one of a number
- of UTF-specific negative error codes is returned. Details are given in
- the pcre2unicode page. The following are the other errors that may be
+ of UTF-specific negative error codes is returned. Details are given in
+ the pcre2unicode page. The following are the other errors that may be
returned by pcre2_match():
PCRE2_ERROR_NOMATCH
@@ -2842,20 +2858,20 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_PARTIAL
- The subject string did not match, but it did match partially. See the
+ The subject string did not match, but it did match partially. See the
pcre2partial documentation for details of partial matching.
PCRE2_ERROR_BADMAGIC
PCRE2 stores a 4-byte "magic number" at the start of the compiled code,
- to catch the case when it is passed a junk pointer. This is the error
+ to catch the case when it is passed a junk pointer. This is the error
that is returned when the magic number is not present.
PCRE2_ERROR_BADMODE
- This error is given when a compiled pattern is passed to a function in
- a library of a different code unit width, for example, a pattern com-
- piled by the 8-bit library is passed to a 16-bit or 32-bit library
+ This error is given when a compiled pattern is passed to a function in
+ a library of a different code unit width, for example, a pattern com-
+ piled by the 8-bit library is passed to a 16-bit or 32-bit library
function.
PCRE2_ERROR_BADOFFSET
@@ -2869,15 +2885,15 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_BADUTFOFFSET
The UTF code unit sequence that was passed as a subject was checked and
- found to be valid (the PCRE2_NO_UTF_CHECK option was not set), but the
- value of startoffset did not point to the beginning of a UTF character
+ found to be valid (the PCRE2_NO_UTF_CHECK option was not set), but the
+ value of startoffset did not point to the beginning of a UTF character
or the end of the subject.
PCRE2_ERROR_CALLOUT
- This error is never generated by pcre2_match() itself. It is provided
- for use by callout functions that want to cause pcre2_match() or
- pcre2_callout_enumerate() to return a distinctive error code. See the
+ This error is never generated by pcre2_match() itself. It is provided
+ for use by callout functions that want to cause pcre2_match() or
+ pcre2_callout_enumerate() to return a distinctive error code. See the
pcre2callout documentation for details.
PCRE2_ERROR_DEPTHLIMIT
@@ -2890,14 +2906,14 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_INTERNAL
- An unexpected internal error has occurred. This error could be caused
+ An unexpected internal error has occurred. This error could be caused
by a bug in PCRE2 or by overwriting of the compiled pattern.
PCRE2_ERROR_JIT_STACKLIMIT
- This error is returned when a pattern that was successfully studied
- using JIT is being matched, but the memory available for the just-in-
- time processing stack is not large enough. See the pcre2jit documenta-
+ This error is returned when a pattern that was successfully studied
+ using JIT is being matched, but the memory available for the just-in-
+ time processing stack is not large enough. See the pcre2jit documenta-
tion for more details.
PCRE2_ERROR_MATCHLIMIT
@@ -2906,11 +2922,11 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_NOMEMORY
- If a pattern contains many nested backtracking points, heap memory is
- used to remember them. This error is given when the memory allocation
- function (default or custom) fails. Note that a different error,
- PCRE2_ERROR_HEAPLIMIT, is given if the amount of memory needed exceeds
- the heap limit. PCRE2_ERROR_NOMEMORY is also returned if
+ If a pattern contains many nested backtracking points, heap memory is
+ used to remember them. This error is given when the memory allocation
+ function (default or custom) fails. Note that a different error,
+ PCRE2_ERROR_HEAPLIMIT, is given if the amount of memory needed exceeds
+ the heap limit. PCRE2_ERROR_NOMEMORY is also returned if
PCRE2_COPY_MATCHED_SUBJECT is set and memory allocation fails.
PCRE2_ERROR_NULL
@@ -2919,12 +2935,12 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_RECURSELOOP
- This error is returned when pcre2_match() detects a recursion loop
- within the pattern. Specifically, it means that either the whole pat-
+ This error is returned when pcre2_match() detects a recursion loop
+ within the pattern. Specifically, it means that either the whole pat-
tern or a capture group has been called recursively for the second time
- at the same position in the subject string. Some simple patterns that
- might do this are detected and faulted at compile time, but more com-
- plicated cases, in particular mutual recursions between two different
+ at the same position in the subject string. Some simple patterns that
+ might do this are detected and faulted at compile time, but more com-
+ plicated cases, in particular mutual recursions between two different
groups, cannot be detected until matching is attempted.
@@ -2933,20 +2949,20 @@ OBTAINING A TEXTUAL ERROR MESSAGE
int pcre2_get_error_message(int errorcode, PCRE2_UCHAR *buffer,
PCRE2_SIZE bufflen);
- A text message for an error code from any PCRE2 function (compile,
- match, or auxiliary) can be obtained by calling pcre2_get_error_mes-
- sage(). The code is passed as the first argument, with the remaining
- two arguments specifying a code unit buffer and its length in code
- units, into which the text message is placed. The message is returned
- in code units of the appropriate width for the library that is being
+ A text message for an error code from any PCRE2 function (compile,
+ match, or auxiliary) can be obtained by calling pcre2_get_error_mes-
+ sage(). The code is passed as the first argument, with the remaining
+ two arguments specifying a code unit buffer and its length in code
+ units, into which the text message is placed. The message is returned
+ in code units of the appropriate width for the library that is being
used.
- The returned message is terminated with a trailing zero, and the func-
- tion returns the number of code units used, excluding the trailing
+ The returned message is terminated with a trailing zero, and the func-
+ tion returns the number of code units used, excluding the trailing
zero. If the error number is unknown, the negative error code
- PCRE2_ERROR_BADDATA is returned. If the buffer is too small, the mes-
- sage is truncated (but still with a trailing zero), and the negative
- error code PCRE2_ERROR_NOMEMORY is returned. None of the messages are
+ PCRE2_ERROR_BADDATA is returned. If the buffer is too small, the mes-
+ sage is truncated (but still with a trailing zero), and the negative
+ error code PCRE2_ERROR_NOMEMORY is returned. None of the messages are
very long; a buffer size of 120 code units is ample.
@@ -2965,39 +2981,39 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
void pcre2_substring_free(PCRE2_UCHAR *buffer);
- Captured substrings can be accessed directly by using the ovector as
+ Captured substrings can be accessed directly by using the ovector as
described above. For convenience, auxiliary functions are provided for
- extracting captured substrings as new, separate, zero-terminated
+ extracting captured substrings as new, separate, zero-terminated
strings. A substring that contains a binary zero is correctly extracted
- and has a further zero added on the end, but the result is not, of
+ and has a further zero added on the end, but the result is not, of
course, a C string.
The functions in this section identify substrings by number. The number
zero refers to the entire matched substring, with higher numbers refer-
- ring to substrings captured by parenthesized groups. After a partial
- match, only substring zero is available. An attempt to extract any
- other substring gives the error PCRE2_ERROR_PARTIAL. The next section
+ ring to substrings captured by parenthesized groups. After a partial
+ match, only substring zero is available. An attempt to extract any
+ other substring gives the error PCRE2_ERROR_PARTIAL. The next section
describes similar functions for extracting captured substrings by name.
- If a pattern uses the \K escape sequence within a positive assertion,
+ If a pattern uses the \K escape sequence within a positive assertion,
the reported start of a successful match can be greater than the end of
- the match. For example, if the pattern (?=ab\K) is matched against
- "ab", the start and end offset values for the match are 2 and 0. In
- this situation, calling these functions with a zero substring number
+ the match. For example, if the pattern (?=ab\K) is matched against
+ "ab", the start and end offset values for the match are 2 and 0. In
+ this situation, calling these functions with a zero substring number
extracts a zero-length empty string.
- You can find the length in code units of a captured substring without
- extracting it by calling pcre2_substring_length_bynumber(). The first
- argument is a pointer to the match data block, the second is the group
- number, and the third is a pointer to a variable into which the length
- is placed. If you just want to know whether or not the substring has
+ You can find the length in code units of a captured substring without
+ extracting it by calling pcre2_substring_length_bynumber(). The first
+ argument is a pointer to the match data block, the second is the group
+ number, and the third is a pointer to a variable into which the length
+ is placed. If you just want to know whether or not the substring has
been captured, you can pass the third argument as NULL.
- The pcre2_substring_copy_bynumber() function copies a captured sub-
- string into a supplied buffer, whereas pcre2_substring_get_bynumber()
- copies it into new memory, obtained using the same memory allocation
- function that was used for the match data block. The first two argu-
- ments of these functions are a pointer to the match data block and a
+ The pcre2_substring_copy_bynumber() function copies a captured sub-
+ string into a supplied buffer, whereas pcre2_substring_get_bynumber()
+ copies it into new memory, obtained using the same memory allocation
+ function that was used for the match data block. The first two argu-
+ ments of these functions are a pointer to the match data block and a
capture group number.
The final arguments of pcre2_substring_copy_bynumber() are a pointer to
@@ -3006,25 +3022,25 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
for the extracted substring, excluding the terminating zero.
For pcre2_substring_get_bynumber() the third and fourth arguments point
- to variables that are updated with a pointer to the new memory and the
- number of code units that comprise the substring, again excluding the
- terminating zero. When the substring is no longer needed, the memory
+ to variables that are updated with a pointer to the new memory and the
+ number of code units that comprise the substring, again excluding the
+ terminating zero. When the substring is no longer needed, the memory
should be freed by calling pcre2_substring_free().
- The return value from all these functions is zero for success, or a
- negative error code. If the pattern match failed, the match failure
- code is returned. If a substring number greater than zero is used
- after a partial match, PCRE2_ERROR_PARTIAL is returned. Other possible
+ The return value from all these functions is zero for success, or a
+ negative error code. If the pattern match failed, the match failure
+ code is returned. If a substring number greater than zero is used
+ after a partial match, PCRE2_ERROR_PARTIAL is returned. Other possible
error codes are:
PCRE2_ERROR_NOMEMORY
- The buffer was too small for pcre2_substring_copy_bynumber(), or the
+ The buffer was too small for pcre2_substring_copy_bynumber(), or the
attempt to get memory failed for pcre2_substring_get_bynumber().
PCRE2_ERROR_NOSUBSTRING
- There is no substring with that number in the pattern, that is, the
+ There is no substring with that number in the pattern, that is, the
number is greater than the number of capturing parentheses.
PCRE2_ERROR_UNAVAILABLE
@@ -3035,8 +3051,8 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
PCRE2_ERROR_UNSET
- The substring did not participate in the match. For example, if the
- pattern is (abc)|(def) and the subject is "def", and the ovector con-
+ The substring did not participate in the match. For example, if the
+ pattern is (abc)|(def) and the subject is "def", and the ovector con-
tains at least two capturing slots, substring number 1 is unset.
@@ -3047,31 +3063,31 @@ EXTRACTING A LIST OF ALL CAPTURED SUBSTRINGS
void pcre2_substring_list_free(PCRE2_SPTR *list);
- The pcre2_substring_list_get() function extracts all available sub-
- strings and builds a list of pointers to them. It also (optionally)
- builds a second list that contains their lengths (in code units),
+ The pcre2_substring_list_get() function extracts all available sub-
+ strings and builds a list of pointers to them. It also (optionally)
+ builds a second list that contains their lengths (in code units),
excluding a terminating zero that is added to each of them. All this is
done in a single block of memory that is obtained using the same memory
allocation function that was used to get the match data block.
- This function must be called only after a successful match. If called
+ This function must be called only after a successful match. If called
after a partial match, the error code PCRE2_ERROR_PARTIAL is returned.
- The address of the memory block is returned via listptr, which is also
+ The address of the memory block is returned via listptr, which is also
the start of the list of string pointers. The end of the list is marked
- by a NULL pointer. The address of the list of lengths is returned via
- lengthsptr. If your strings do not contain binary zeros and you do not
+ by a NULL pointer. The address of the list of lengths is returned via
+ lengthsptr. If your strings do not contain binary zeros and you do not
therefore need the lengths, you may supply NULL as the lengthsptr argu-
- ment to disable the creation of a list of lengths. The yield of the
- function is zero if all went well, or PCRE2_ERROR_NOMEMORY if the mem-
- ory block could not be obtained. When the list is no longer needed, it
+ ment to disable the creation of a list of lengths. The yield of the
+ function is zero if all went well, or PCRE2_ERROR_NOMEMORY if the mem-
+ ory block could not be obtained. When the list is no longer needed, it
should be freed by calling pcre2_substring_list_free().
If this function encounters a substring that is unset, which can happen
- when capture group number n+1 matches some part of the subject, but
- group n has not been used at all, it returns an empty string. This can
+ when capture group number n+1 matches some part of the subject, but
+ group n has not been used at all, it returns an empty string. This can
be distinguished from a genuine zero-length substring by inspecting the
- appropriate offset in the ovector, which contain PCRE2_UNSET for unset
+ appropriate offset in the ovector, which contain PCRE2_UNSET for unset
substrings, or by calling pcre2_substring_length_bynumber().
@@ -3091,7 +3107,7 @@ EXTRACTING CAPTURED SUBSTRINGS BY NAME
void pcre2_substring_free(PCRE2_UCHAR *buffer);
- To extract a substring by name, you first have to find associated num-
+ To extract a substring by name, you first have to find associated num-
ber. For example, for this pattern:
(a+)b(?<xxx>\d+)...
@@ -3099,32 +3115,32 @@ EXTRACTING CAPTURED SUBSTRINGS BY NAME
the number of the capture group called "xxx" is 2. If the name is known
to be unique (PCRE2_DUPNAMES was not set), you can find the number from
the name by calling pcre2_substring_number_from_name(). The first argu-
- ment is the compiled pattern, and the second is the name. The yield of
- the function is the group number, PCRE2_ERROR_NOSUBSTRING if there is
- no group with that name, or PCRE2_ERROR_NOUNIQUESUBSTRING if there is
- more than one group with that name. Given the number, you can extract
- the substring directly from the ovector, or use one of the "bynumber"
+ ment is the compiled pattern, and the second is the name. The yield of
+ the function is the group number, PCRE2_ERROR_NOSUBSTRING if there is
+ no group with that name, or PCRE2_ERROR_NOUNIQUESUBSTRING if there is
+ more than one group with that name. Given the number, you can extract
+ the substring directly from the ovector, or use one of the "bynumber"
functions described above.
- For convenience, there are also "byname" functions that correspond to
- the "bynumber" functions, the only difference being that the second
- argument is a name instead of a number. If PCRE2_DUPNAMES is set and
+ For convenience, there are also "byname" functions that correspond to
+ the "bynumber" functions, the only difference being that the second
+ argument is a name instead of a number. If PCRE2_DUPNAMES is set and
there are duplicate names, these functions scan all the groups with the
- given name, and return the captured substring from the first named
+ given name, and return the captured substring from the first named
group that is set.
- If there are no groups with the given name, PCRE2_ERROR_NOSUBSTRING is
- returned. If all groups with the name have numbers that are greater
- than the number of slots in the ovector, PCRE2_ERROR_UNAVAILABLE is
- returned. If there is at least one group with a slot in the ovector,
+ If there are no groups with the given name, PCRE2_ERROR_NOSUBSTRING is
+ returned. If all groups with the name have numbers that are greater
+ than the number of slots in the ovector, PCRE2_ERROR_UNAVAILABLE is
+ returned. If there is at least one group with a slot in the ovector,
but no group is found to be set, PCRE2_ERROR_UNSET is returned.
Warning: If the pattern uses the (?| feature to set up multiple capture
- groups with the same number, as described in the section on duplicate
+ groups with the same number, as described in the section on duplicate
group numbers in the pcre2pattern page, you cannot use names to distin-
- guish the different capture groups, because names are not included in
- the compiled code. The matching process uses only numbers. For this
- reason, the use of different names for groups with the same number
+ guish the different capture groups, because names are not included in
+ the compiled code. The matching process uses only numbers. For this
+ reason, the use of different names for groups with the same number
causes an error at compile time.
@@ -3137,91 +3153,91 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
PCRE2_SIZE rlength, PCRE2_UCHAR *outputbuffer,
PCRE2_SIZE *outlengthptr);
- This function calls pcre2_match() and then makes a copy of the subject
- string in outputbuffer, replacing one or more parts that were matched
+ This function calls pcre2_match() and then makes a copy of the subject
+ string in outputbuffer, replacing one or more parts that were matched
with the replacement string, whose length is supplied in rlength. This
- can be given as PCRE2_ZERO_TERMINATED for a zero-terminated string.
- The default is to perform just one replacement, but there is an option
- that requests multiple replacements (see PCRE2_SUBSTITUTE_GLOBAL below
+ can be given as PCRE2_ZERO_TERMINATED for a zero-terminated string.
+ The default is to perform just one replacement, but there is an option
+ that requests multiple replacements (see PCRE2_SUBSTITUTE_GLOBAL below
for details).
- Matches in which a \K item in a lookahead in the pattern causes the
- match to end before it starts are not supported, and give rise to an
+ Matches in which a \K item in a lookahead in the pattern causes the
+ match to end before it starts are not supported, and give rise to an
error return. For global replacements, matches in which \K in a lookbe-
- hind causes the match to start earlier than the point that was reached
+ hind causes the match to start earlier than the point that was reached
in the previous iteration are also not supported.
- The first seven arguments of pcre2_substitute() are the same as for
+ The first seven arguments of pcre2_substitute() are the same as for
pcre2_match(), except that the partial matching options are not permit-
- ted, and match_data may be passed as NULL, in which case a match data
- block is obtained and freed within this function, using memory manage-
- ment functions from the match context, if provided, or else those that
+ ted, and match_data may be passed as NULL, in which case a match data
+ block is obtained and freed within this function, using memory manage-
+ ment functions from the match context, if provided, or else those that
were used to allocate memory for the compiled code.
- If an external match_data block is provided, its contents afterwards
- are those set by the final call to pcre2_match(). For global changes,
- this will have ended in a matching error. The contents of the ovector
+ If an external match_data block is provided, its contents afterwards
+ are those set by the final call to pcre2_match(). For global changes,
+ this will have ended in a matching error. The contents of the ovector
within the match data block may or may not have been changed.
- The outlengthptr argument must point to a variable that contains the
- length, in code units, of the output buffer. If the function is suc-
- cessful, the value is updated to contain the length of the new string,
+ The outlengthptr argument must point to a variable that contains the
+ length, in code units, of the output buffer. If the function is suc-
+ cessful, the value is updated to contain the length of the new string,
excluding the trailing zero that is automatically added.
- If the function is not successful, the value set via outlengthptr
- depends on the type of error. For syntax errors in the replacement
- string, the value is the offset in the replacement string where the
- error was detected. For other errors, the value is PCRE2_UNSET by
- default. This includes the case of the output buffer being too small,
- unless PCRE2_SUBSTITUTE_OVERFLOW_LENGTH is set (see below), in which
- case the value is the minimum length needed, including space for the
- trailing zero. Note that in order to compute the required length,
- pcre2_substitute() has to simulate all the matching and copying,
+ If the function is not successful, the value set via outlengthptr
+ depends on the type of error. For syntax errors in the replacement
+ string, the value is the offset in the replacement string where the
+ error was detected. For other errors, the value is PCRE2_UNSET by
+ default. This includes the case of the output buffer being too small,
+ unless PCRE2_SUBSTITUTE_OVERFLOW_LENGTH is set (see below), in which
+ case the value is the minimum length needed, including space for the
+ trailing zero. Note that in order to compute the required length,
+ pcre2_substitute() has to simulate all the matching and copying,
instead of giving an error return as soon as the buffer overflows. Note
also that the length is in code units, not bytes.
- In the replacement string, which is interpreted as a UTF string in UTF
- mode, and is checked for UTF validity unless the PCRE2_NO_UTF_CHECK
+ In the replacement string, which is interpreted as a UTF string in UTF
+ mode, and is checked for UTF validity unless the PCRE2_NO_UTF_CHECK
option is set, a dollar character is an escape character that can spec-
- ify the insertion of characters from capture groups or names from
- (*MARK) or other control verbs in the pattern. The following forms are
+ ify the insertion of characters from capture groups or names from
+ (*MARK) or other control verbs in the pattern. The following forms are
always recognized:
$$ insert a dollar character
$<n> or ${<n>} insert the contents of group <n>
$*MARK or ${*MARK} insert a control verb name
- Either a group number or a group name can be given for <n>. Curly
- brackets are required only if the following character would be inter-
+ Either a group number or a group name can be given for <n>. Curly
+ brackets are required only if the following character would be inter-
preted as part of the number or name. The number may be zero to include
- the entire matched string. For example, if the pattern a(b)c is
- matched with "=abc=" and the replacement string "+$1$0$1+", the result
+ the entire matched string. For example, if the pattern a(b)c is
+ matched with "=abc=" and the replacement string "+$1$0$1+", the result
is "=+babcb+=".
- $*MARK inserts the name from the last encountered backtracking control
- verb on the matching path that has a name. (*MARK) must always include
- a name, but the other verbs need not. For example, in the case of
+ $*MARK inserts the name from the last encountered backtracking control
+ verb on the matching path that has a name. (*MARK) must always include
+ a name, but the other verbs need not. For example, in the case of
(*MARK:A)(*PRUNE) the name inserted is "A", but for (*MARK:A)(*PRUNE:B)
- the relevant name is "B". This facility can be used to perform simple
+ the relevant name is "B". This facility can be used to perform simple
simultaneous substitutions, as this pcre2test example shows:
/(*MARK:pear)apple|(*MARK:orange)lemon/g,replace=${*MARK}
apple lemon
2: pear orange
- As well as the usual options for pcre2_match(), a number of additional
+ As well as the usual options for pcre2_match(), a number of additional
options can be set in the options argument of pcre2_substitute().
PCRE2_SUBSTITUTE_GLOBAL causes the function to iterate over the subject
- string, replacing every matching substring. If this option is not set,
- only the first matching substring is replaced. The search for matches
- takes place in the original subject string (that is, previous replace-
- ments do not affect it). Iteration is implemented by advancing the
- startoffset value for each search, which is always passed the entire
+ string, replacing every matching substring. If this option is not set,
+ only the first matching substring is replaced. The search for matches
+ takes place in the original subject string (that is, previous replace-
+ ments do not affect it). Iteration is implemented by advancing the
+ startoffset value for each search, which is always passed the entire
subject string. If an offset limit is set in the match context, search-
ing stops when that limit is reached.
- You can restrict the effect of a global substitution to a portion of
+ You can restrict the effect of a global substitution to a portion of
the subject string by setting either or both of startoffset and an off-
set limit. Here is a pcre2test example:
@@ -3229,86 +3245,88 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
ABC ABC ABC ABC\=offset=3,offset_limit=12
2: ABC A!C A!C ABC
- When continuing with global substitutions after matching a substring
+ When continuing with global substitutions after matching a substring
with zero length, an attempt to find a non-empty match at the same off-
set is performed. If this is not successful, the offset is advanced by
one character except when CRLF is a valid newline sequence and the next
- two characters are CR, LF. In this case, the offset is advanced by two
+ two characters are CR, LF. In this case, the offset is advanced by two
characters.
- PCRE2_SUBSTITUTE_OVERFLOW_LENGTH changes what happens when the output
+ PCRE2_SUBSTITUTE_OVERFLOW_LENGTH changes what happens when the output
buffer is too small. The default action is to return PCRE2_ERROR_NOMEM-
- ORY immediately. If this option is set, however, pcre2_substitute()
+ ORY immediately. If this option is set, however, pcre2_substitute()
continues to go through the motions of matching and substituting (with-
- out, of course, writing anything) in order to compute the size of buf-
- fer that is needed. This value is passed back via the outlengthptr
- variable, with the result of the function still being
+ out, of course, writing anything) in order to compute the size of buf-
+ fer that is needed. This value is passed back via the outlengthptr
+ variable, with the result of the function still being
PCRE2_ERROR_NOMEMORY.
- Passing a buffer size of zero is a permitted way of finding out how
- much memory is needed for given substitution. However, this does mean
+ Passing a buffer size of zero is a permitted way of finding out how
+ much memory is needed for given substitution. However, this does mean
that the entire operation is carried out twice. Depending on the appli-
- cation, it may be more efficient to allocate a large buffer and free
- the excess afterwards, instead of using PCRE2_SUBSTITUTE_OVER-
+ cation, it may be more efficient to allocate a large buffer and free
+ the excess afterwards, instead of using PCRE2_SUBSTITUTE_OVER-
FLOW_LENGTH.
PCRE2_SUBSTITUTE_UNKNOWN_UNSET causes references to capture groups that
do not appear in the pattern to be treated as unset groups. This option
- should be used with care, because it means that a typo in a group name
+ should be used with care, because it means that a typo in a group name
or number no longer causes the PCRE2_ERROR_NOSUBSTRING error.
- PCRE2_SUBSTITUTE_UNSET_EMPTY causes unset capture groups (including
+ PCRE2_SUBSTITUTE_UNSET_EMPTY causes unset capture groups (including
unknown groups when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set) to be
- treated as empty strings when inserted as described above. If this
- option is not set, an attempt to insert an unset group causes the
- PCRE2_ERROR_UNSET error. This option does not influence the extended
+ treated as empty strings when inserted as described above. If this
+ option is not set, an attempt to insert an unset group causes the
+ PCRE2_ERROR_UNSET error. This option does not influence the extended
substitution syntax described below.
- PCRE2_SUBSTITUTE_EXTENDED causes extra processing to be applied to the
- replacement string. Without this option, only the dollar character is
- special, and only the group insertion forms listed above are valid.
+ PCRE2_SUBSTITUTE_EXTENDED causes extra processing to be applied to the
+ replacement string. Without this option, only the dollar character is
+ special, and only the group insertion forms listed above are valid.
When PCRE2_SUBSTITUTE_EXTENDED is set, two things change:
- Firstly, backslash in a replacement string is interpreted as an escape
+ Firstly, backslash in a replacement string is interpreted as an escape
character. The usual forms such as \n or \x{ddd} can be used to specify
- particular character codes, and backslash followed by any non-alphanu-
- meric character quotes that character. Extended quoting can be coded
+ particular character codes, and backslash followed by any non-alphanu-
+ meric character quotes that character. Extended quoting can be coded
using \Q...\E, exactly as in pattern strings.
- There are also four escape sequences for forcing the case of inserted
- letters. The insertion mechanism has three states: no case forcing,
+ There are also four escape sequences for forcing the case of inserted
+ letters. The insertion mechanism has three states: no case forcing,
force upper case, and force lower case. The escape sequences change the
current state: \U and \L change to upper or lower case forcing, respec-
- tively, and \E (when not terminating a \Q quoted sequence) reverts to
- no case forcing. The sequences \u and \l force the next character (if
- it is a letter) to upper or lower case, respectively, and then the
+ tively, and \E (when not terminating a \Q quoted sequence) reverts to
+ no case forcing. The sequences \u and \l force the next character (if
+ it is a letter) to upper or lower case, respectively, and then the
state automatically reverts to no case forcing. Case forcing applies to
- all inserted characters, including those from capture groups and let-
+ all inserted characters, including those from capture groups and let-
ters within \Q...\E quoted sequences.
Note that case forcing sequences such as \U...\E do not nest. For exam-
- ple, the result of processing "\Uaa\LBB\Ecc\E" is "AAbbcc"; the final
- \E has no effect.
+ ple, the result of processing "\Uaa\LBB\Ecc\E" is "AAbbcc"; the final
+ \E has no effect. Note also that the PCRE2_ALT_BSUX and
+ PCRE2_EXTRA_ALT_BSUX options do not apply to not apply to replacement
+ strings.
- The second effect of setting PCRE2_SUBSTITUTE_EXTENDED is to add more
- flexibility to capture group substitution. The syntax is similar to
+ The second effect of setting PCRE2_SUBSTITUTE_EXTENDED is to add more
+ flexibility to capture group substitution. The syntax is similar to
that used by Bash:
${<n>:-<string>}
${<n>:+<string1>:<string2>}
- As before, <n> may be a group number or a name. The first form speci-
- fies a default value. If group <n> is set, its value is inserted; if
- not, <string> is expanded and the result inserted. The second form
- specifies strings that are expanded and inserted when group <n> is set
- or unset, respectively. The first form is just a convenient shorthand
+ As before, <n> may be a group number or a name. The first form speci-
+ fies a default value. If group <n> is set, its value is inserted; if
+ not, <string> is expanded and the result inserted. The second form
+ specifies strings that are expanded and inserted when group <n> is set
+ or unset, respectively. The first form is just a convenient shorthand
for
${<n>:+${<n>}:<string>}
- Backslash can be used to escape colons and closing curly brackets in
- the replacement strings. A change of the case forcing state within a
- replacement string remains in force afterwards, as shown in this
+ Backslash can be used to escape colons and closing curly brackets in
+ the replacement strings. A change of the case forcing state within a
+ replacement string remains in force afterwards, as shown in this
pcre2test example:
/(some)?(body)/substitute_extended,replace=${1:+\U:\L}HeLLo
@@ -3317,42 +3335,42 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
somebody
1: HELLO
- The PCRE2_SUBSTITUTE_UNSET_EMPTY option does not affect these extended
- substitutions. However, PCRE2_SUBSTITUTE_UNKNOWN_UNSET does cause
+ The PCRE2_SUBSTITUTE_UNSET_EMPTY option does not affect these extended
+ substitutions. However, PCRE2_SUBSTITUTE_UNKNOWN_UNSET does cause
unknown groups in the extended syntax forms to be treated as unset.
- If successful, pcre2_substitute() returns the number of successful
- matches. This may be zero if no matches were found, and is never
+ If successful, pcre2_substitute() returns the number of successful
+ matches. This may be zero if no matches were found, and is never
greater than 1 unless PCRE2_SUBSTITUTE_GLOBAL is set.
In the event of an error, a negative error code is returned. Except for
- PCRE2_ERROR_NOMATCH (which is never returned), errors from
+ PCRE2_ERROR_NOMATCH (which is never returned), errors from
pcre2_match() are passed straight back.
PCRE2_ERROR_NOSUBSTRING is returned for a non-existent substring inser-
tion, unless PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set.
PCRE2_ERROR_UNSET is returned for an unset substring insertion (includ-
- ing an unknown substring when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set)
+ ing an unknown substring when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set)
when the simple (non-extended) syntax is used and PCRE2_SUBSTI-
TUTE_UNSET_EMPTY is not set.
- PCRE2_ERROR_NOMEMORY is returned if the output buffer is not big
+ PCRE2_ERROR_NOMEMORY is returned if the output buffer is not big
enough. If the PCRE2_SUBSTITUTE_OVERFLOW_LENGTH option is set, the size
- of buffer that is needed is returned via outlengthptr. Note that this
+ of buffer that is needed is returned via outlengthptr. Note that this
does not happen by default.
- PCRE2_ERROR_BADREPLACEMENT is used for miscellaneous syntax errors in
+ PCRE2_ERROR_BADREPLACEMENT is used for miscellaneous syntax errors in
the replacement string, with more particular errors being
- PCRE2_ERROR_BADREPESCAPE (invalid escape sequence), PCRE2_ERROR_REP-
- MISSINGBRACE (closing curly bracket not found), PCRE2_ERROR_BADSUBSTI-
+ PCRE2_ERROR_BADREPESCAPE (invalid escape sequence), PCRE2_ERROR_REP-
+ MISSINGBRACE (closing curly bracket not found), PCRE2_ERROR_BADSUBSTI-
TUTION (syntax error in extended group substitution), and
- PCRE2_ERROR_BADSUBSPATTERN (the pattern match ended before it started
- or the match started earlier than the current position in the subject,
+ PCRE2_ERROR_BADSUBSPATTERN (the pattern match ended before it started
+ or the match started earlier than the current position in the subject,
which can happen if \K is used in an assertion).
As for all PCRE2 errors, a text message that describes the error can be
- obtained by calling the pcre2_get_error_message() function (see
+ obtained by calling the pcre2_get_error_message() function (see
"Obtaining a textual error message" above).
Substitution callouts
@@ -3361,15 +3379,15 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
int (*callout_function)(pcre2_substitute_callout_block *, void *),
void *callout_data);
- The pcre2_set_substitution_callout() function can be used to specify a
- callout function for pcre2_substitute(). This information is passed in
+ The pcre2_set_substitution_callout() function can be used to specify a
+ callout function for pcre2_substitute(). This information is passed in
a match context. The callout function is called after each substitution
has been processed, but it can cause the replacement not to happen. The
- callout function is not called for simulated substitutions that happen
+ callout function is not called for simulated substitutions that happen
as a result of the PCRE2_SUBSTITUTE_OVERFLOW_LENGTH option.
The first argument of the callout function is a pointer to a substitute
- callout block structure, which contains the following fields, not nec-
+ callout block structure, which contains the following fields, not nec-
essarily in this order:
uint32_t version;
@@ -3380,34 +3398,34 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
uint32_t oveccount;
PCRE2_SIZE output_offsets[2];
- The version field contains the version number of the block format. The
- current version is 0. The version number will increase in future if
- more fields are added, but the intention is never to remove any of the
+ The version field contains the version number of the block format. The
+ current version is 0. The version number will increase in future if
+ more fields are added, but the intention is never to remove any of the
existing fields.
The subscount field is the number of the current match. It is 1 for the
first callout, 2 for the second, and so on. The input and output point-
ers are copies of the values passed to pcre2_substitute().
- The ovector field points to the ovector, which contains the result of
+ The ovector field points to the ovector, which contains the result of
the most recent match. The oveccount field contains the number of pairs
that are set in the ovector, and is always greater than zero.
- The output_offsets vector contains the offsets of the replacement in
- the output string. This has already been processed for dollar and (if
+ The output_offsets vector contains the offsets of the replacement in
+ the output string. This has already been processed for dollar and (if
requested) backslash substitutions as described above.
- The second argument of the callout function is the value passed as
- callout_data when the function was registered. The value returned by
+ The second argument of the callout function is the value passed as
+ callout_data when the function was registered. The value returned by
the callout function is interpreted as follows:
- If the value is zero, the replacement is accepted, and, if PCRE2_SUB-
- STITUTE_GLOBAL is set, processing continues with a search for the next
- match. If the value is not zero, the current replacement is not
- accepted. If the value is greater than zero, processing continues when
- PCRE2_SUBSTITUTE_GLOBAL is set. Otherwise (the value is less than zero
- or PCRE2_SUBSTITUTE_GLOBAL is not set), the the rest of the input is
- copied to the output and the call to pcre2_substitute() exits, return-
+ If the value is zero, the replacement is accepted, and, if PCRE2_SUB-
+ STITUTE_GLOBAL is set, processing continues with a search for the next
+ match. If the value is not zero, the current replacement is not
+ accepted. If the value is greater than zero, processing continues when
+ PCRE2_SUBSTITUTE_GLOBAL is set. Otherwise (the value is less than zero
+ or PCRE2_SUBSTITUTE_GLOBAL is not set), the the rest of the input is
+ copied to the output and the call to pcre2_substitute() exits, return-
ing the number of matches so far.
@@ -3416,56 +3434,56 @@ DUPLICATE CAPTURE GROUP NAMES
int pcre2_substring_nametable_scan(const pcre2_code *code,
PCRE2_SPTR name, PCRE2_SPTR *first, PCRE2_SPTR *last);
- When a pattern is compiled with the PCRE2_DUPNAMES option, names for
- capture groups are not required to be unique. Duplicate names are
- always allowed for groups with the same number, created by using the
+ When a pattern is compiled with the PCRE2_DUPNAMES option, names for
+ capture groups are not required to be unique. Duplicate names are
+ always allowed for groups with the same number, created by using the
(?| feature. Indeed, if such groups are named, they are required to use
the same names.
- Normally, patterns that use duplicate names are such that in any one
- match, only one of each set of identically-named groups participates.
+ Normally, patterns that use duplicate names are such that in any one
+ match, only one of each set of identically-named groups participates.
An example is shown in the pcre2pattern documentation.
- When duplicates are present, pcre2_substring_copy_byname() and
- pcre2_substring_get_byname() return the first substring corresponding
- to the given name that is set. Only if none are set is
- PCRE2_ERROR_UNSET is returned. The pcre2_substring_number_from_name()
+ When duplicates are present, pcre2_substring_copy_byname() and
+ pcre2_substring_get_byname() return the first substring corresponding
+ to the given name that is set. Only if none are set is
+ PCRE2_ERROR_UNSET is returned. The pcre2_substring_number_from_name()
function returns the error PCRE2_ERROR_NOUNIQUESUBSTRING when there are
duplicate names.
- If you want to get full details of all captured substrings for a given
- name, you must use the pcre2_substring_nametable_scan() function. The
- first argument is the compiled pattern, and the second is the name. If
- the third and fourth arguments are NULL, the function returns a group
+ If you want to get full details of all captured substrings for a given
+ name, you must use the pcre2_substring_nametable_scan() function. The
+ first argument is the compiled pattern, and the second is the name. If
+ the third and fourth arguments are NULL, the function returns a group
number for a unique name, or PCRE2_ERROR_NOUNIQUESUBSTRING otherwise.
When the third and fourth arguments are not NULL, they must be pointers
- to variables that are updated by the function. After it has run, they
+ to variables that are updated by the function. After it has run, they
point to the first and last entries in the name-to-number table for the
- given name, and the function returns the length of each entry in code
- units. In both cases, PCRE2_ERROR_NOSUBSTRING is returned if there are
+ given name, and the function returns the length of each entry in code
+ units. In both cases, PCRE2_ERROR_NOSUBSTRING is returned if there are
no entries for the given name.
The format of the name table is described above in the section entitled
- Information about a pattern. Given all the relevant entries for the
- name, you can extract each of their numbers, and hence the captured
+ Information about a pattern. Given all the relevant entries for the
+ name, you can extract each of their numbers, and hence the captured
data.
FINDING ALL POSSIBLE MATCHES AT ONE POSITION
- The traditional matching function uses a similar algorithm to Perl,
- which stops when it finds the first match at a given point in the sub-
+ The traditional matching function uses a similar algorithm to Perl,
+ which stops when it finds the first match at a given point in the sub-
ject. If you want to find all possible matches, or the longest possible
- match at a given position, consider using the alternative matching
- function (see below) instead. If you cannot use the alternative func-
+ match at a given position, consider using the alternative matching
+ function (see below) instead. If you cannot use the alternative func-
tion, you can kludge it up by making use of the callout facility, which
is described in the pcre2callout documentation.
What you have to do is to insert a callout right at the end of the pat-
- tern. When your callout function is called, extract and save the cur-
- rent matched substring. Then return 1, which forces pcre2_match() to
- backtrack and try other alternatives. Ultimately, when it runs out of
+ tern. When your callout function is called, extract and save the cur-
+ rent matched substring. Then return 1, which forces pcre2_match() to
+ backtrack and try other alternatives. Ultimately, when it runs out of
matches, pcre2_match() will yield PCRE2_ERROR_NOMATCH.
@@ -3477,26 +3495,26 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
pcre2_match_context *mcontext,
int *workspace, PCRE2_SIZE wscount);
- The function pcre2_dfa_match() is called to match a subject string
- against a compiled pattern, using a matching algorithm that scans the
+ The function pcre2_dfa_match() is called to match a subject string
+ against a compiled pattern, using a matching algorithm that scans the
subject string just once (not counting lookaround assertions), and does
- not backtrack. This has different characteristics to the normal algo-
- rithm, and is not compatible with Perl. Some of the features of PCRE2
- patterns are not supported. Nevertheless, there are times when this
- kind of matching can be useful. For a discussion of the two matching
+ not backtrack. This has different characteristics to the normal algo-
+ rithm, and is not compatible with Perl. Some of the features of PCRE2
+ patterns are not supported. Nevertheless, there are times when this
+ kind of matching can be useful. For a discussion of the two matching
algorithms, and a list of features that pcre2_dfa_match() does not sup-
port, see the pcre2matching documentation.
- The arguments for the pcre2_dfa_match() function are the same as for
+ The arguments for the pcre2_dfa_match() function are the same as for
pcre2_match(), plus two extras. The ovector within the match data block
is used in a different way, and this is described below. The other com-
- mon arguments are used in the same way as for pcre2_match(), so their
+ mon arguments are used in the same way as for pcre2_match(), so their
description is not repeated here.
- The two additional arguments provide workspace for the function. The
- workspace vector should contain at least 20 elements. It is used for
+ The two additional arguments provide workspace for the function. The
+ workspace vector should contain at least 20 elements. It is used for
keeping track of multiple paths through the pattern tree. More
- workspace is needed for patterns and subjects where there are a lot of
+ workspace is needed for patterns and subjects where there are a lot of
potential matches.
Here is an example of a simple call to pcre2_dfa_match():
@@ -3516,46 +3534,46 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
Option bits for pcre_dfa_match()
- The unused bits of the options argument for pcre2_dfa_match() must be
- zero. The only bits that may be set are PCRE2_ANCHORED,
- PCRE2_COPY_MATCHED_SUBJECT, PCRE2_ENDANCHORED, PCRE2_NOTBOL,
+ The unused bits of the options argument for pcre2_dfa_match() must be
+ zero. The only bits that may be set are PCRE2_ANCHORED,
+ PCRE2_COPY_MATCHED_SUBJECT, PCRE2_ENDANCHORED, PCRE2_NOTBOL,
PCRE2_NOTEOL, PCRE2_NOTEMPTY, PCRE2_NOTEMPTY_ATSTART,
PCRE2_NO_UTF_CHECK, PCRE2_PARTIAL_HARD, PCRE2_PARTIAL_SOFT,
- PCRE2_DFA_SHORTEST, and PCRE2_DFA_RESTART. All but the last four of
- these are exactly the same as for pcre2_match(), so their description
+ PCRE2_DFA_SHORTEST, and PCRE2_DFA_RESTART. All but the last four of
+ these are exactly the same as for pcre2_match(), so their description
is not repeated here.
PCRE2_PARTIAL_HARD
PCRE2_PARTIAL_SOFT
- These have the same general effect as they do for pcre2_match(), but
- the details are slightly different. When PCRE2_PARTIAL_HARD is set for
- pcre2_dfa_match(), it returns PCRE2_ERROR_PARTIAL if the end of the
+ These have the same general effect as they do for pcre2_match(), but
+ the details are slightly different. When PCRE2_PARTIAL_HARD is set for
+ pcre2_dfa_match(), it returns PCRE2_ERROR_PARTIAL if the end of the
subject is reached and there is still at least one matching possibility
that requires additional characters. This happens even if some complete
- matches have already been found. When PCRE2_PARTIAL_SOFT is set, the
- return code PCRE2_ERROR_NOMATCH is converted into PCRE2_ERROR_PARTIAL
- if the end of the subject is reached, there have been no complete
+ matches have already been found. When PCRE2_PARTIAL_SOFT is set, the
+ return code PCRE2_ERROR_NOMATCH is converted into PCRE2_ERROR_PARTIAL
+ if the end of the subject is reached, there have been no complete
matches, but there is still at least one matching possibility. The por-
- tion of the string that was inspected when the longest partial match
+ tion of the string that was inspected when the longest partial match
was found is set as the first matching string in both cases. There is a
- more detailed discussion of partial and multi-segment matching, with
+ more detailed discussion of partial and multi-segment matching, with
examples, in the pcre2partial documentation.
PCRE2_DFA_SHORTEST
- Setting the PCRE2_DFA_SHORTEST option causes the matching algorithm to
+ Setting the PCRE2_DFA_SHORTEST option causes the matching algorithm to
stop as soon as it has found one match. Because of the way the alterna-
- tive algorithm works, this is necessarily the shortest possible match
+ tive algorithm works, this is necessarily the shortest possible match
at the first possible matching point in the subject string.
PCRE2_DFA_RESTART
- When pcre2_dfa_match() returns a partial match, it is possible to call
+ When pcre2_dfa_match() returns a partial match, it is possible to call
it again, with additional subject characters, and have it continue with
the same match. The PCRE2_DFA_RESTART option requests this action; when
- it is set, the workspace and wscount options must reference the same
- vector as before because data about the match so far is left in them
+ it is set, the workspace and wscount options must reference the same
+ vector as before because data about the match so far is left in them
after a partial match. There is more discussion of this facility in the
pcre2partial documentation.
@@ -3563,8 +3581,8 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
When pcre2_dfa_match() succeeds, it may have matched more than one sub-
string in the subject. Note, however, that all the matches from one run
- of the function start at the same point in the subject. The shorter
- matches are all initial substrings of the longer matches. For example,
+ of the function start at the same point in the subject. The shorter
+ matches are all initial substrings of the longer matches. For example,
if the pattern
<.*>
@@ -3579,74 +3597,74 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
<something> <something else>
<something>
- On success, the yield of the function is a number greater than zero,
- which is the number of matched substrings. The offsets of the sub-
- strings are returned in the ovector, and can be extracted by number in
- the same way as for pcre2_match(), but the numbers bear no relation to
- any capture groups that may exist in the pattern, because DFA matching
+ On success, the yield of the function is a number greater than zero,
+ which is the number of matched substrings. The offsets of the sub-
+ strings are returned in the ovector, and can be extracted by number in
+ the same way as for pcre2_match(), but the numbers bear no relation to
+ any capture groups that may exist in the pattern, because DFA matching
does not support capturing.
- Calls to the convenience functions that extract substrings by name
- return the error PCRE2_ERROR_DFA_UFUNC (unsupported function) if used
+ Calls to the convenience functions that extract substrings by name
+ return the error PCRE2_ERROR_DFA_UFUNC (unsupported function) if used
after a DFA match. The convenience functions that extract substrings by
number never return PCRE2_ERROR_NOSUBSTRING.
- The matched strings are stored in the ovector in reverse order of
- length; that is, the longest matching string is first. If there were
- too many matches to fit into the ovector, the yield of the function is
+ The matched strings are stored in the ovector in reverse order of
+ length; that is, the longest matching string is first. If there were
+ too many matches to fit into the ovector, the yield of the function is
zero, and the vector is filled with the longest matches.
- NOTE: PCRE2's "auto-possessification" optimization usually applies to
- character repeats at the end of a pattern (as well as internally). For
- example, the pattern "a\d+" is compiled as if it were "a\d++". For DFA
- matching, this means that only one possible match is found. If you
- really do want multiple matches in such cases, either use an ungreedy
- repeat such as "a\d+?" or set the PCRE2_NO_AUTO_POSSESS option when
+ NOTE: PCRE2's "auto-possessification" optimization usually applies to
+ character repeats at the end of a pattern (as well as internally). For
+ example, the pattern "a\d+" is compiled as if it were "a\d++". For DFA
+ matching, this means that only one possible match is found. If you
+ really do want multiple matches in such cases, either use an ungreedy
+ repeat such as "a\d+?" or set the PCRE2_NO_AUTO_POSSESS option when
compiling.
Error returns from pcre2_dfa_match()
The pcre2_dfa_match() function returns a negative number when it fails.
- Many of the errors are the same as for pcre2_match(), as described
+ Many of the errors are the same as for pcre2_match(), as described
above. There are in addition the following errors that are specific to
pcre2_dfa_match():
PCRE2_ERROR_DFA_UITEM
- This return is given if pcre2_dfa_match() encounters an item in the
- pattern that it does not support, for instance, the use of \C in a UTF
+ This return is given if pcre2_dfa_match() encounters an item in the
+ pattern that it does not support, for instance, the use of \C in a UTF
mode or a backreference.
PCRE2_ERROR_DFA_UCOND
- This return is given if pcre2_dfa_match() encounters a condition item
+ This return is given if pcre2_dfa_match() encounters a condition item
that uses a backreference for the condition, or a test for recursion in
a specific capture group. These are not supported.
PCRE2_ERROR_DFA_WSSIZE
- This return is given if pcre2_dfa_match() runs out of space in the
+ This return is given if pcre2_dfa_match() runs out of space in the
workspace vector.
PCRE2_ERROR_DFA_RECURSE
When a recursion or subroutine call is processed, the matching function
- calls itself recursively, using private memory for the ovector and
- workspace. This error is given if the internal ovector is not large
- enough. This should be extremely rare, as a vector of size 1000 is
+ calls itself recursively, using private memory for the ovector and
+ workspace. This error is given if the internal ovector is not large
+ enough. This should be extremely rare, as a vector of size 1000 is
used.
PCRE2_ERROR_DFA_BADRESTART
- When pcre2_dfa_match() is called with the PCRE2_DFA_RESTART option,
- some plausibility checks are made on the contents of the workspace,
- which should contain data about the previous partial match. If any of
+ When pcre2_dfa_match() is called with the PCRE2_DFA_RESTART option,
+ some plausibility checks are made on the contents of the workspace,
+ which should contain data about the previous partial match. If any of
these checks fail, this error is given.
SEE ALSO
- pcre2build(3), pcre2callout(3), pcre2demo(3), pcre2matching(3),
+ pcre2build(3), pcre2callout(3), pcre2demo(3), pcre2matching(3),
pcre2partial(3), pcre2posix(3), pcre2sample(3), pcre2unicode(3).
@@ -3659,7 +3677,7 @@ AUTHOR
REVISION
- Last updated: 04 February 2019
+ Last updated: 12 February 2019
Copyright (c) 1997-2019 University of Cambridge.
------------------------------------------------------------------------------
@@ -4701,27 +4719,28 @@ DIFFERENCES BETWEEN PCRE2 AND PERL
point, are supported. The escapes that modify the case of following
letters are implemented by Perl's general string-handling and are not
part of its pattern matching engine. If any of these are encountered by
- PCRE2, an error is generated by default. However, if the PCRE2_ALT_BSUX
- option is set, \U and \u are interpreted as ECMAScript interprets them.
+ PCRE2, an error is generated by default. However, if either of the
+ PCRE2_ALT_BSUX or PCRE2_EXTRA_ALT_BSUX options is set, \U and \u are
+ interpreted as ECMAScript interprets them.
5. The Perl escape sequences \p, \P, and \X are supported only if PCRE2
is built with Unicode support (the default). The properties that can be
- tested with \p and \P are limited to the general category properties
- such as Lu and Nd, script names such as Greek or Han, and the derived
+ tested with \p and \P are limited to the general category properties
+ such as Lu and Nd, script names such as Greek or Han, and the derived
properties Any and L&. PCRE2 does support the Cs (surrogate) property,
- which Perl does not; the Perl documentation says "Because Perl hides
+ which Perl does not; the Perl documentation says "Because Perl hides
the need for the user to understand the internal representation of Uni-
- code characters, there is no need to implement the somewhat messy con-
+ code characters, there is no need to implement the somewhat messy con-
cept of surrogates."
6. PCRE2 supports the \Q...\E escape for quoting substrings. Characters
in between are treated as literals. However, this is slightly different
- from Perl in that $ and @ are also handled as literals inside the
+ from Perl in that $ and @ are also handled as literals inside the
quotes. In Perl, they cause variable interpolation (but of course PCRE2
- does not have variables). Also, Perl does "double-quotish backslash
+ does not have variables). Also, Perl does "double-quotish backslash
interpolation" on any backslashes between \Q and \E which, its documen-
- tation says, "may lead to confusing results". PCRE2 treats a backslash
- between \Q and \E just like any other character. Note the following
+ tation says, "may lead to confusing results". PCRE2 treats a backslash
+ between \Q and \E just like any other character. Note the following
examples:
Pattern PCRE2 matches Perl matches
@@ -4733,125 +4752,125 @@ DIFFERENCES BETWEEN PCRE2 AND PERL
\QA\B\E A\B A\B
\Q\\E \ \\E
- The \Q...\E sequence is recognized both inside and outside character
+ The \Q...\E sequence is recognized both inside and outside character
classes.
- 7. Fairly obviously, PCRE2 does not support the (?{code}) and
+ 7. Fairly obviously, PCRE2 does not support the (?{code}) and
(??{code}) constructions. However, PCRE2 does have a "callout" feature,
which allows an external function to be called during pattern matching.
See the pcre2callout documentation for details.
- 8. Subroutine calls (whether recursive or not) were treated as atomic
- groups up to PCRE2 release 10.23, but from release 10.30 this changed,
+ 8. Subroutine calls (whether recursive or not) were treated as atomic
+ groups up to PCRE2 release 10.23, but from release 10.30 this changed,
and backtracking into subroutine calls is now supported, as in Perl.
9. If any of the backtracking control verbs are used in a group that is
- called as a subroutine (whether or not recursively), their effect is
- confined to that group; it does not extend to the surrounding pattern.
- This is not always the case in Perl. In particular, if (*THEN) is
- present in a group that is called as a subroutine, its action is lim-
- ited to that group, even if the group does not contain any | charac-
- ters. Note that such groups are processed as anchored at the point
+ called as a subroutine (whether or not recursively), their effect is
+ confined to that group; it does not extend to the surrounding pattern.
+ This is not always the case in Perl. In particular, if (*THEN) is
+ present in a group that is called as a subroutine, its action is lim-
+ ited to that group, even if the group does not contain any | charac-
+ ters. Note that such groups are processed as anchored at the point
where they are tested.
- 10. If a pattern contains more than one backtracking control verb, the
- first one that is backtracked onto acts. For example, in the pattern
- A(*COMMIT)B(*PRUNE)C a failure in B triggers (*COMMIT), but a failure
+ 10. If a pattern contains more than one backtracking control verb, the
+ first one that is backtracked onto acts. For example, in the pattern
+ A(*COMMIT)B(*PRUNE)C a failure in B triggers (*COMMIT), but a failure
in C triggers (*PRUNE). Perl's behaviour is more complex; in many cases
it is the same as PCRE2, but there are cases where it differs.
- 11. Most backtracking verbs in assertions have their normal actions.
+ 11. Most backtracking verbs in assertions have their normal actions.
They are not confined to the assertion.
- 12. There are some differences that are concerned with the settings of
- captured strings when part of a pattern is repeated. For example,
- matching "aba" against the pattern /^(a(b)?)+$/ in Perl leaves $2
+ 12. There are some differences that are concerned with the settings of
+ captured strings when part of a pattern is repeated. For example,
+ matching "aba" against the pattern /^(a(b)?)+$/ in Perl leaves $2
unset, but in PCRE2 it is set to "b".
- 13. PCRE2's handling of duplicate capture group numbers and names is
- not as general as Perl's. This is a consequence of the fact the PCRE2
- works internally just with numbers, using an external table to trans-
- late between numbers and names. In particular, a pattern such as
- (?|(?<a>A)|(?<b>B), where the two capture groups have the same number
- but different names, is not supported, and causes an error at compile
+ 13. PCRE2's handling of duplicate capture group numbers and names is
+ not as general as Perl's. This is a consequence of the fact the PCRE2
+ works internally just with numbers, using an external table to trans-
+ late between numbers and names. In particular, a pattern such as
+ (?|(?<a>A)|(?<b>B), where the two capture groups have the same number
+ but different names, is not supported, and causes an error at compile
time. If it were allowed, it would not be possible to distinguish which
- group matched, because both names map to capture group number 1. To
+ group matched, because both names map to capture group number 1. To
avoid this confusing situation, an error is given at compile time.
14. Perl used to recognize comments in some places that PCRE2 does not,
- for example, between the ( and ? at the start of a group. If the /x
- modifier is set, Perl allowed white space between ( and ? though the
- latest Perls give an error (for a while it was just deprecated). There
+ for example, between the ( and ? at the start of a group. If the /x
+ modifier is set, Perl allowed white space between ( and ? though the
+ latest Perls give an error (for a while it was just deprecated). There
may still be some cases where Perl behaves differently.
- 15. Perl, when in warning mode, gives warnings for character classes
- such as [A-\d] or [a-[:digit:]]. It then treats the hyphens as liter-
+ 15. Perl, when in warning mode, gives warnings for character classes
+ such as [A-\d] or [a-[:digit:]]. It then treats the hyphens as liter-
als. PCRE2 has no warning features, so it gives an error in these cases
because they are almost certainly user mistakes.
- 16. In PCRE2, the upper/lower case character properties Lu and Ll are
- not affected when case-independent matching is specified. For example,
+ 16. In PCRE2, the upper/lower case character properties Lu and Ll are
+ not affected when case-independent matching is specified. For example,
\p{Lu} always matches an upper case letter. I think Perl has changed in
- this respect; in the release at the time of writing (5.24), \p{Lu} and
+ this respect; in the release at the time of writing (5.24), \p{Lu} and
\p{Ll} match all letters, regardless of case, when case independence is
specified.
- 17. PCRE2 provides some extensions to the Perl regular expression
- facilities. Perl 5.10 includes new features that are not in earlier
- versions of Perl, some of which (such as named parentheses) were in
+ 17. PCRE2 provides some extensions to the Perl regular expression
+ facilities. Perl 5.10 includes new features that are not in earlier
+ versions of Perl, some of which (such as named parentheses) were in
PCRE2 for some time before. This list is with respect to Perl 5.26:
- (a) Although lookbehind assertions in PCRE2 must match fixed length
- strings, each alternative branch of a lookbehind assertion can match a
- different length of string. Perl requires them all to have the same
+ (a) Although lookbehind assertions in PCRE2 must match fixed length
+ strings, each alternative branch of a lookbehind assertion can match a
+ different length of string. Perl requires them all to have the same
length.
(b) From PCRE2 10.23, backreferences to groups of fixed length are sup-
- ported in lookbehinds, provided that there is no possibility of refer-
- encing a non-unique number or name. Perl does not support backrefer-
+ ported in lookbehinds, provided that there is no possibility of refer-
+ encing a non-unique number or name. Perl does not support backrefer-
ences in lookbehinds.
- (c) If PCRE2_DOLLAR_ENDONLY is set and PCRE2_MULTILINE is not set, the
+ (c) If PCRE2_DOLLAR_ENDONLY is set and PCRE2_MULTILINE is not set, the
$ meta-character matches only at the very end of the string.
- (d) A backslash followed by a letter with no special meaning is
+ (d) A backslash followed by a letter with no special meaning is
faulted. (Perl can be made to issue a warning.)
- (e) If PCRE2_UNGREEDY is set, the greediness of the repetition quanti-
+ (e) If PCRE2_UNGREEDY is set, the greediness of the repetition quanti-
fiers is inverted, that is, by default they are not greedy, but if fol-
lowed by a question mark they are.
- (f) PCRE2_ANCHORED can be used at matching time to force a pattern to
+ (f) PCRE2_ANCHORED can be used at matching time to force a pattern to
be tried only at the first matching position in the subject string.
- (g) The PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY and
+ (g) The PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY and
PCRE2_NOTEMPTY_ATSTART options have no Perl equivalents.
- (h) The \R escape sequence can be restricted to match only CR, LF, or
+ (h) The \R escape sequence can be restricted to match only CR, LF, or
CRLF by the PCRE2_BSR_ANYCRLF option.
- (i) The callout facility is PCRE2-specific. Perl supports codeblocks
+ (i) The callout facility is PCRE2-specific. Perl supports codeblocks
and variable interpolation, but not general hooks on every match.
(j) The partial matching facility is PCRE2-specific.
- (k) The alternative matching function (pcre2_dfa_match() matches in a
+ (k) The alternative matching function (pcre2_dfa_match() matches in a
different way and is not Perl-compatible.
- (l) PCRE2 recognizes some special sequences such as (*CR) or (*NO_JIT)
- at the start of a pattern that set overall options that cannot be
+ (l) PCRE2 recognizes some special sequences such as (*CR) or (*NO_JIT)
+ at the start of a pattern that set overall options that cannot be
changed within the pattern.
- 18. The Perl /a modifier restricts /d numbers to pure ascii, and the
- /aa modifier restricts /i case-insensitive matching to pure ascii,
- ignoring Unicode rules. This separation cannot be represented with
+ 18. The Perl /a modifier restricts /d numbers to pure ascii, and the
+ /aa modifier restricts /i case-insensitive matching to pure ascii,
+ ignoring Unicode rules. This separation cannot be represented with
PCRE2_UCP.
19. Perl has different limits than PCRE2. See the pcre2limit documenta-
tion for details. Perl went with 5.10 from recursion to iteration keep-
ing the intermediate matches on the heap, which is ~10% slower but does
- not fall into any stack-overflow limit. PCRE2 made a similar change at
- release 10.30, and also has many build-time and run-time customizable
+ not fall into any stack-overflow limit. PCRE2 made a similar change at
+ release 10.30, and also has many build-time and run-time customizable
limits.
@@ -4864,7 +4883,7 @@ AUTHOR
REVISION
- Last updated: 03 February 2019
+ Last updated: 12 February 2019
Copyright (c) 1997-2019 University of Cambridge.
------------------------------------------------------------------------------
@@ -6333,20 +6352,45 @@ BACKSLASH
\xhh character with hex code hh
\x{hhh..} character with hex code hhh..
\N{U+hhh..} character with Unicode hex code point hhh..
- \uhhhh character with hex code hhhh (when PCRE2_ALT_BSUX is set)
- There are some legacy applications where the escape sequence \r is
- expected to match a newline. If the PCRE2_EXTRA_ESCAPED_CR_IS_LF option
- is set, \r in a pattern is converted to \n so that it matches a LF
- (linefeed) instead of a CR (carriage return) character.
+ By default, after \x that is not followed by {, from zero to two hexa-
+ decimal digits are read (letters can be in upper or lower case). Any
+ number of hexadecimal digits may appear between \x{ and }. If a charac-
+ ter other than a hexadecimal digit appears between \x{ and }, or if
+ there is no terminating }, an error occurs.
- The \N{U+hhh..} escape sequence is recognized only when the PCRE2_UTF
+ Characters whose code points are less than 256 can be defined by either
+ of the two syntaxes for \x or by an octal sequence. There is no differ-
+ ence in the way they are handled. For example, \xdc is exactly the same
+ as \x{dc} or \334. However, using the braced versions does make such
+ sequences easier to read.
+
+ Support is available for some ECMAScript (aka JavaScript) escape
+ sequences via two compile-time options. If PCRE2_ALT_BSUX is set, the
+ sequence \x followed by { is not recognized. Only if \x is followed by
+ two hexadecimal digits is it recognized as a character escape. Other-
+ wise it is interpreted as a literal "x" character. In this mode, sup-
+ port for code points greater than 256 is provided by \u, which must be
+ followed by four hexadecimal digits; otherwise it is interpreted as a
+ literal "u" character.
+
+ PCRE2_EXTRA_ALT_BSUX has the same effect as PCRE2_ALT_BSUX and, in
+ addition, \u{hhh..} is recognized as the character specified by hexa-
+ decimal code point. There may be any number of hexadecimal digits.
+ This syntax is from ECMAScript 6.
+
+ The \N{U+hhh..} escape sequence is recognized only when the PCRE2_UTF
option is set, that is, when PCRE2 is operating in a Unicode mode. Perl
- also uses \N{name} to specify characters by Unicode name; PCRE2 does
- not support this. Note that when \N is not followed by an opening
- brace (curly bracket) it has an entirely different meaning, matching
+ also uses \N{name} to specify characters by Unicode name; PCRE2 does
+ not support this. Note that when \N is not followed by an opening
+ brace (curly bracket) it has an entirely different meaning, matching
any character that is not a newline.
+ There are some legacy applications where the escape sequence \r is
+ expected to match a newline. If the PCRE2_EXTRA_ESCAPED_CR_IS_LF option
+ is set, \r in a pattern is converted to \n so that it matches a LF
+ (linefeed) instead of a CR (carriage return) character.
+
The precise effect of \cx on ASCII characters is as follows: if x is a
lower case letter, it is converted to upper case. Then bit 6 of the
character (hex 40) is inverted. Thus \cA to \cZ become hex 01 to hex 1A
@@ -6429,28 +6473,9 @@ BACKSLASH
syntax must not be introduced by a leading zero, because no more than
three octal digits are ever read.
- By default, after \x that is not followed by {, from zero to two hexa-
- decimal digits are read (letters can be in upper or lower case). Any
- number of hexadecimal digits may appear between \x{ and }. If a charac-
- ter other than a hexadecimal digit appears between \x{ and }, or if
- there is no terminating }, an error occurs.
-
- If the PCRE2_ALT_BSUX option is set, the interpretation of \x is as
- just described only when it is followed by two hexadecimal digits. Oth-
- erwise, it matches a literal "x" character. In this mode, support for
- code points greater than 256 is provided by \u, which must be followed
- by four hexadecimal digits; otherwise it matches a literal "u" charac-
- ter. This syntax makes PCRE2 behave like ECMAscript (aka JavaScript).
- Code points greater than 0xFFFF are not supported.
-
- Characters whose value is less than 256 can be defined by either of the
- two syntaxes for \x (or by \u in PCRE2_ALT_BSUX mode). There is no dif-
- ference in the way they are handled. For example, \xdc is exactly the
- same as \x{dc} (or \u00dc in PCRE2_ALT_BSUX mode).
-
Constraints on character values
- Characters that are specified using octal or hexadecimal numbers are
+ Characters that are specified using octal or hexadecimal numbers are
limited to certain values, as follows:
8-bit non-UTF mode no greater than 0xff
@@ -6459,30 +6484,31 @@ BACKSLASH
All UTF modes no greater than 0x10ffff and a valid code point
Invalid Unicode code points are all those in the range 0xd800 to 0xdfff
- (the so-called "surrogate" code points). The check for these can be
- disabled by the caller of pcre2_compile() by setting the option
- PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES. However, this is possible only in
- UTF-8 and UTF-32 modes, because these values are not representable in
+ (the so-called "surrogate" code points). The check for these can be
+ disabled by the caller of pcre2_compile() by setting the option
+ PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES. However, this is possible only in
+ UTF-8 and UTF-32 modes, because these values are not representable in
UTF-16.
Escape sequences in character classes
All the sequences that define a single character value can be used both
- inside and outside character classes. In addition, inside a character
+ inside and outside character classes. In addition, inside a character
class, \b is interpreted as the backspace character (hex 08).
When not followed by an opening brace, \N is not allowed in a character
- class. \B, \R, and \X are not special inside a character class. Like
- other unrecognized alphabetic escape sequences, they cause an error.
+ class. \B, \R, and \X are not special inside a character class. Like
+ other unrecognized alphabetic escape sequences, they cause an error.
Outside a character class, these sequences have different meanings.
Unsupported escape sequences
- In Perl, the sequences \F, \l, \L, \u, and \U are recognized by its
- string handler and used to modify the case of following characters. By
- default, PCRE2 does not support these escape sequences. However, if the
- PCRE2_ALT_BSUX option is set, \U matches a "U" character, and \u can be
- used to define a character by code point, as described above.
+ In Perl, the sequences \F, \l, \L, \u, and \U are recognized by its
+ string handler and used to modify the case of following characters. By
+ default, PCRE2 does not support these escape sequences in patterns.
+ However, if either of the PCRE2_ALT_BSUX or PCRE2_EXTRA_ALT_BSUX
+ options is set, \U matches a "U" character, and \u can be used to
+ define a character by code point, as described above.
Absolute and relative backreferences
@@ -9332,7 +9358,7 @@ AUTHOR
REVISION
- Last updated: 04 February 2019
+ Last updated: 12 February 2019
Copyright (c) 1997-2019 University of Cambridge.
------------------------------------------------------------------------------
@@ -10203,7 +10229,8 @@ QUOTING
ESCAPED CHARACTERS
- This table applies to ASCII and Unicode environments.
+ This table applies to ASCII and Unicode environments. An unrecognized
+ escape sequence causes an error.
\a alarm, that is, the BEL character (hex 07)
\cx "control-x", where x is any ASCII printing character
@@ -10215,26 +10242,32 @@ ESCAPED CHARACTERS
\0dd character with octal code 0dd
\ddd character with octal code ddd, or backreference
\o{ddd..} character with octal code ddd..
- \U "U" if PCRE2_ALT_BSUX is set (otherwise is an error)
\N{U+hh..} character with Unicode code point hh.. (Unicode mode only)
- \uhhhh character with hex code hhhh (if PCRE2_ALT_BSUX is set)
\xhh character with hex code hh
\x{hh..} character with hex code hh..
+ If PCRE2_ALT_BSUX or PCRE2_EXTRA_ALT_BSUX is set ("ALT_BSUX mode"), the
+ following are also recognized:
+
+ \U the character "U"
+ \uhhhh character with hex code hhhh
+ \u{hh..} character with hex code hh.. but only for EXTRA_ALT_BSUX
+
+ When \x is not followed by {, from zero to two hexadecimal digits are
+ read, but in ALT_BSUX mode \x must be followed by two hexadecimal dig-
+ its to be recognized as a hexadecimal escape; otherwise it matches a
+ literal "x". Likewise, if \u (in ALT_BSUX mode) is not followed by
+ four hexadecimal digits or (in EXTRA_ALT_BSUX mode) a sequence of hex
+ digits in curly brackets, it matches a literal "u".
+
Note that \0dd is always an octal code. The treatment of backslash fol-
- lowed by a non-zero digit is complicated; for details see the section
- "Non-printing characters" in the pcre2pattern documentation, where
- details of escape processing in EBCDIC environments are also given.
+ lowed by a non-zero digit is complicated; for details see the section
+ "Non-printing characters" in the pcre2pattern documentation, where
+ details of escape processing in EBCDIC environments are also given.
\N{U+hh..} is synonymous with \x{hh..} in PCRE2 but is not supported in
- EBCDIC environments. Note that \N not followed by an opening curly
+ EBCDIC environments. Note that \N not followed by an opening curly
bracket has a different meaning (see below).
- When \x is not followed by {, from zero to two hexadecimal digits are
- read, but if PCRE2_ALT_BSUX is set, \x must be followed by two hexadec-
- imal digits to be recognized as a hexadecimal escape; otherwise it
- matches a literal "x". Likewise, if \u (in ALT_BSUX mode) is not fol-
- lowed by four hexadecimal digits, it matches a literal "u".
-
CHARACTER TYPES
@@ -10257,14 +10290,14 @@ CHARACTER TYPES
\W a "non-word" character
\X a Unicode extended grapheme cluster
- \C is dangerous because it may leave the current matching point in the
+ \C is dangerous because it may leave the current matching point in the
middle of a UTF-8 or UTF-16 character. The application can lock out the
- use of \C by setting the PCRE2_NEVER_BACKSLASH_C option. It is also
+ use of \C by setting the PCRE2_NEVER_BACKSLASH_C option. It is also
possible to build PCRE2 with the use of \C permanently disabled.
- By default, \d, \s, and \w match only ASCII characters, even in UTF-8
+ By default, \d, \s, and \w match only ASCII characters, even in UTF-8
mode or in the 16-bit and 32-bit libraries. However, if locale-specific
- matching is happening, \s and \w may also match characters with code
+ matching is happening, \s and \w may also match characters with code
points in the range 128-255. If the PCRE2_UCP option is set, the behav-
iour of these escape sequences is changed to use Unicode properties and
they match many more characters.
@@ -10333,28 +10366,28 @@ PCRE2 SPECIAL CATEGORY PROPERTIES FOR \p and \P
SCRIPT NAMES FOR \p AND \P
- Adlam, Ahom, Anatolian_Hieroglyphs, Arabic, Armenian, Avestan, Bali-
- nese, Bamum, Bassa_Vah, Batak, Bengali, Bhaiksuki, Bopomofo, Brahmi,
- Braille, Buginese, Buhid, Canadian_Aboriginal, Carian, Caucasian_Alba-
- nian, Chakma, Cham, Cherokee, Common, Coptic, Cuneiform, Cypriot,
- Cyrillic, Deseret, Devanagari, Dogra, Duployan, Egyptian_Hieroglyphs,
- Elbasan, Ethiopic, Georgian, Glagolitic, Gothic, Grantha, Greek,
- Gujarati, Gunjala_Gondi, Gurmukhi, Han, Hangul, Hanifi_Rohingya,
- Hanunoo, Hatran, Hebrew, Hiragana, Imperial_Aramaic, Inherited,
- Inscriptional_Pahlavi, Inscriptional_Parthian, Javanese, Kaithi, Kan-
- nada, Katakana, Kayah_Li, Kharoshthi, Khmer, Khojki, Khudawadi, Lao,
- Latin, Lepcha, Limbu, Linear_A, Linear_B, Lisu, Lycian, Lydian, Maha-
- jani, Makasar, Malayalam, Mandaic, Manichaean, Marchen, Masaram_Gondi,
+ Adlam, Ahom, Anatolian_Hieroglyphs, Arabic, Armenian, Avestan, Bali-
+ nese, Bamum, Bassa_Vah, Batak, Bengali, Bhaiksuki, Bopomofo, Brahmi,
+ Braille, Buginese, Buhid, Canadian_Aboriginal, Carian, Caucasian_Alba-
+ nian, Chakma, Cham, Cherokee, Common, Coptic, Cuneiform, Cypriot,
+ Cyrillic, Deseret, Devanagari, Dogra, Duployan, Egyptian_Hieroglyphs,
+ Elbasan, Ethiopic, Georgian, Glagolitic, Gothic, Grantha, Greek,
+ Gujarati, Gunjala_Gondi, Gurmukhi, Han, Hangul, Hanifi_Rohingya,
+ Hanunoo, Hatran, Hebrew, Hiragana, Imperial_Aramaic, Inherited,
+ Inscriptional_Pahlavi, Inscriptional_Parthian, Javanese, Kaithi, Kan-
+ nada, Katakana, Kayah_Li, Kharoshthi, Khmer, Khojki, Khudawadi, Lao,
+ Latin, Lepcha, Limbu, Linear_A, Linear_B, Lisu, Lycian, Lydian, Maha-
+ jani, Makasar, Malayalam, Mandaic, Manichaean, Marchen, Masaram_Gondi,
Medefaidrin, Meetei_Mayek, Mende_Kikakui, Meroitic_Cursive,
- Meroitic_Hieroglyphs, Miao, Modi, Mongolian, Mro, Multani, Myanmar,
- Nabataean, New_Tai_Lue, Newa, Nko, Nushu, Ogham, Ol_Chiki, Old_Hungar-
- ian, Old_Italic, Old_North_Arabian, Old_Permic, Old_Persian, Old_Sog-
- dian, Old_South_Arabian, Old_Turkic, Oriya, Osage, Osmanya,
+ Meroitic_Hieroglyphs, Miao, Modi, Mongolian, Mro, Multani, Myanmar,
+ Nabataean, New_Tai_Lue, Newa, Nko, Nushu, Ogham, Ol_Chiki, Old_Hungar-
+ ian, Old_Italic, Old_North_Arabian, Old_Permic, Old_Persian, Old_Sog-
+ dian, Old_South_Arabian, Old_Turkic, Oriya, Osage, Osmanya,
Pahawh_Hmong, Palmyrene, Pau_Cin_Hau, Phags_Pa, Phoenician,
- Psalter_Pahlavi, Rejang, Runic, Samaritan, Saurashtra, Sharada, Sha-
- vian, Siddham, SignWriting, Sinhala, Sogdian, Sora_Sompeng, Soyombo,
- Sundanese, Syloti_Nagri, Syriac, Tagalog, Tagbanwa, Tai_Le, Tai_Tham,
- Tai_Viet, Takri, Tamil, Tangut, Telugu, Thaana, Thai, Tibetan, Tifi-
+ Psalter_Pahlavi, Rejang, Runic, Samaritan, Saurashtra, Sharada, Sha-
+ vian, Siddham, SignWriting, Sinhala, Sogdian, Sora_Sompeng, Soyombo,
+ Sundanese, Syloti_Nagri, Syriac, Tagalog, Tagbanwa, Tai_Le, Tai_Tham,
+ Tai_Viet, Takri, Tamil, Tangut, Telugu, Thaana, Thai, Tibetan, Tifi-
nagh, Tirhuta, Ugaritic, Vai, Warang_Citi, Yi, Zanabazar_Square.
@@ -10381,8 +10414,8 @@ CHARACTER CLASSES
word same as \w
xdigit hexadecimal digit
- In PCRE2, POSIX character set names recognize only ASCII characters by
- default, but some of them use Unicode properties if PCRE2_UCP is set.
+ In PCRE2, POSIX character set names recognize only ASCII characters by
+ default, but some of them use Unicode properties if PCRE2_UCP is set.
You can use \Q...\E inside a character class.
@@ -10445,8 +10478,8 @@ CAPTURING
(?|...) non-capture group; reset group numbers for
capture groups in each alternative
- In non-UTF modes, names may contain underscores and ASCII letters and
- digits; in UTF modes, any Unicode letters and Unicode decimal digits
+ In non-UTF modes, names may contain underscores and ASCII letters and
+ digits; in UTF modes, any Unicode letters and Unicode decimal digits
are permitted. In both cases, a name must not start with a digit.
@@ -10462,7 +10495,7 @@ COMMENT
OPTION SETTING
- Changes of these options within a group are automatically cancelled at
+ Changes of these options within a group are automatically cancelled at
the end of the group.
(?i) caseless
@@ -10476,14 +10509,14 @@ OPTION SETTING
(?-...) unset option(s)
(?^) unset imnsx options
- Unsetting x or xx unsets both. Several options may be set at once, and
+ Unsetting x or xx unsets both. Several options may be set at once, and
a mixture of setting and unsetting such as (?i-x) is allowed, but there
may be only one hyphen. Setting (but no unsetting) is allowed after (?^
for example (?^in). An option setting may appear at the start of a non-
capture group, for example (?i:...).
- The following are recognized only at the very start of a pattern or
- after one of the newline or \R options with similar syntax. More than
+ The following are recognized only at the very start of a pattern or
+ after one of the newline or \R options with similar syntax. More than
one of them may appear. For the first three, d is a decimal number.
(*LIMIT_DEPTH=d) set the backtracking limit to d
@@ -10498,17 +10531,17 @@ OPTION SETTING
(*UTF) set appropriate UTF mode for the library in use
(*UCP) set PCRE2_UCP (use Unicode properties for \d etc)
- Note that LIMIT_DEPTH, LIMIT_HEAP, and LIMIT_MATCH can only reduce the
- value of the limits set by the caller of pcre2_match() or
- pcre2_dfa_match(), not increase them. LIMIT_RECURSION is an obsolete
+ Note that LIMIT_DEPTH, LIMIT_HEAP, and LIMIT_MATCH can only reduce the
+ value of the limits set by the caller of pcre2_match() or
+ pcre2_dfa_match(), not increase them. LIMIT_RECURSION is an obsolete
synonym for LIMIT_DEPTH. The application can lock out the use of (*UTF)
- and (*UCP) by setting the PCRE2_NEVER_UTF or PCRE2_NEVER_UCP options,
+ and (*UCP) by setting the PCRE2_NEVER_UTF or PCRE2_NEVER_UCP options,
respectively, at compile time.
NEWLINE CONVENTION
- These are recognized only at the very start of the pattern or after
+ These are recognized only at the very start of the pattern or after
option settings with a similar syntax.
(*CR) carriage return only
@@ -10521,7 +10554,7 @@ NEWLINE CONVENTION
WHAT \R MATCHES
- These are recognized only at the very start of the pattern or after
+ These are recognized only at the very start of the pattern or after
option setting with a similar syntax.
(*BSR_ANYCRLF) CR, LF, or CRLF
@@ -10610,16 +10643,16 @@ CONDITIONAL PATTERNS
(?(VERSION[>]=n.m) test PCRE2 version
(?(assert) assertion condition
- Note the ambiguity of (?(R) and (?(Rn) which might be named reference
- conditions or recursion tests. Such a condition is interpreted as a
+ Note the ambiguity of (?(R) and (?(Rn) which might be named reference
+ conditions or recursion tests. Such a condition is interpreted as a
reference condition if the relevant named group exists.
BACKTRACKING CONTROL
- All backtracking control verbs may be in the form (*VERB:NAME). For
- (*MARK) the name is mandatory, for the others it is optional. (*SKIP)
- changes its behaviour if :NAME is present. The others just set a name
+ All backtracking control verbs may be in the form (*VERB:NAME). For
+ (*MARK) the name is mandatory, for the others it is optional. (*SKIP)
+ changes its behaviour if :NAME is present. The others just set a name
for passing back to the caller, but this is not a name that (*SKIP) can
see. The following act immediately they are reached:
@@ -10627,7 +10660,7 @@ BACKTRACKING CONTROL
(*FAIL) force backtrack; synonym (*F)
(*MARK:NAME) set name to be passed back; synonym (*:NAME)
- The following act only when a subsequent match failure causes a back-
+ The following act only when a subsequent match failure causes a back-
track to reach them. They all force a match failure, but they differ in
what happens afterwards. Those that advance the start-of-match point do
so only if the pattern is not anchored.
@@ -10639,7 +10672,7 @@ BACKTRACKING CONTROL
(*MARK:NAME); if not found, the (*SKIP) is ignored
(*THEN) local failure, backtrack to next alternation
- The effect of one of these verbs in a group called as a subroutine is
+ The effect of one of these verbs in a group called as a subroutine is
confined to the subroutine call.
@@ -10650,14 +10683,14 @@ CALLOUTS
(?C"text") callout with string data
The allowed string delimiters are ` ' " ^ % # $ (which are the same for
- the start and the end), and the starting delimiter { matched with the
- ending delimiter }. To encode the ending delimiter within the string,
+ the start and the end), and the starting delimiter { matched with the
+ ending delimiter }. To encode the ending delimiter within the string,
double it.
SEE ALSO
- pcre2pattern(3), pcre2api(3), pcre2callout(3), pcre2matching(3),
+ pcre2pattern(3), pcre2api(3), pcre2callout(3), pcre2matching(3),
pcre2(3).
@@ -10670,7 +10703,7 @@ AUTHOR
REVISION
- Last updated: 03 February 2019
+ Last updated: 11 February 2019
Copyright (c) 1997-2019 University of Cambridge.
------------------------------------------------------------------------------
diff --git a/doc/pcre2_compile.3 b/doc/pcre2_compile.3
index a5e8269..c212355 100644
--- a/doc/pcre2_compile.3
+++ b/doc/pcre2_compile.3
@@ -1,4 +1,4 @@
-.TH PCRE2_COMPILE 3 "16 June 2017" "PCRE2 10.30"
+.TH PCRE2_COMPILE 3 "11 February 2019" "PCRE2 10.33"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -73,7 +73,13 @@ The option bits are:
PCRE2 must be built with Unicode support (the default) in order to use
PCRE2_UTF, PCRE2_UCP and related options.
.P
-The yield of the function is a pointer to a private data structure that
+Additional options may be set in the compile context via the
+.\" HREF
+\fBpcre2_set_compile_extra_options\fP
+.\"
+function.
+.P
+The yield of this function is a pointer to a private data structure that
contains the compiled pattern, or NULL if an error was detected.
.P
There is a complete description of the PCRE2 native API, with more detail on
diff --git a/doc/pcre2_set_compile_extra_options.3 b/doc/pcre2_set_compile_extra_options.3
index a724af9..26d1e33 100644
--- a/doc/pcre2_set_compile_extra_options.3
+++ b/doc/pcre2_set_compile_extra_options.3
@@ -1,4 +1,4 @@
-.TH PCRE2_SET_COMPILE_EXTRA_OPTIONS 3 "21 September 2018" "PCRE2 10.33"
+.TH PCRE2_SET_COMPILE_EXTRA_OPTIONS 3 "11 February 2019" "PCRE2 10.33"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -8,7 +8,7 @@ PCRE2 - Perl-compatible regular expressions (revised API)
.PP
.nf
.B int pcre2_set_compile_extra_options(pcre2_compile_context *\fIccontext\fP,
-.B " PCRE2_SIZE \fIextra_options\fP);"
+.B " uint32_t \fIextra_options\fP);"
.fi
.
.SH DESCRIPTION
@@ -22,6 +22,9 @@ options are:
PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES Allow \ex{df800} to \ex{dfff}
in UTF-8 and UTF-32 modes
.\" JOIN
+ PCRE2_EXTRA_ALT_BSUX Extended alternate \eu, \eU, and \ex
+ handling
+.\" JOIN
PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL Treat all invalid escapes as
a literal following character
PCRE2_EXTRA_ESCAPED_CR_IS_LF Interpret \er as \en
diff --git a/doc/pcre2api.3 b/doc/pcre2api.3
index 5c9fe82..0ab60f5 100644
--- a/doc/pcre2api.3
+++ b/doc/pcre2api.3
@@ -1,4 +1,4 @@
-.TH PCRE2API 3 "04 February 2019" "PCRE2 10.33"
+.TH PCRE2API 3 "12 February 2019" "PCRE2 10.33"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.sp
@@ -1231,7 +1231,7 @@ are needed. The \fBpcre2_code_copy_with_tables()\fP provides this facility.
Copies of both the code and the tables are made, with the new code pointing to
the new tables. The memory for the new tables is automatically freed when
\fBpcre2_code_free()\fP is called for the new copy of the compiled code. If
-\fBpcre2_code_copy_withy_tables()\fP is called with a NULL argument, it returns
+\fBpcre2_code_copy_with_tables()\fP is called with a NULL argument, it returns
NULL.
.P
NOTE: When one of the matching functions is called, pointers to the compiled
@@ -1252,7 +1252,7 @@ below.
.\"
.P
The \fIoptions\fP argument for \fBpcre2_compile()\fP contains various bit
-settings that affect the compilation. It should be zero if no options are
+settings that affect the compilation. It should be zero if none of them are
required. The available options are described below. Some of them (in
particular, those that are compatible with Perl, but some others as well) can
also be set and unset from within the pattern (see the detailed description in
@@ -1267,8 +1267,9 @@ contents of the \fIoptions\fP argument specifies their settings at the start of
compilation. The PCRE2_ANCHORED, PCRE2_ENDANCHORED, and PCRE2_NO_UTF_CHECK
options can be set at the time of matching as well as at compile time.
.P
-Other, less frequently required compile-time parameters (for example, the
-newline setting) can be provided in a compile context (as described
+Some additional options and less frequently required compile-time parameters
+(for example, the newline setting) can be provided in a compile context (as
+described
.\" HTML <a href="#compilecontext">
.\" </a>
above).
@@ -1325,6 +1326,11 @@ This code fragment shows a typical straightforward call to
&erroffset, /* for error offset */
NULL); /* no compile context */
.sp
+.
+.
+.SS "Main compile options"
+.rs
+.sp
The following names for option bits are defined in the \fBpcre2.h\fP header
file:
.sp
@@ -1361,6 +1367,16 @@ hexadecimal digits, in which case the hexadecimal number defines the code point
to match. By default, as in Perl, a hexadecimal number is always expected after
\ex, but it may have zero, one, or two digits (so, for example, \exz matches a
binary zero character followed by z).
+.P
+ECMAscript 6 added additional functionality to \eu. This can be accessed using
+the PCRE2_EXTRA_ALT_BSUX extra option (see "Extra compile options"
+.\" HTML <a href="#extracompileoptions">
+.\" </a>
+below).
+.\"
+Note that this alternative escape handling applies only to patterns. Neither of
+these options affects the processing of replacement strings passed to
+\fBpcre2_substitute()\fP.
.sp
PCRE2_ALT_CIRCUMFLEX
.sp
@@ -1788,9 +1804,8 @@ characters with code points greater than 127.
.SS "Extra compile options"
.rs
.sp
-Unlike the main compile-time options, the extra options are not saved with the
-compiled pattern. The option bits that can be set in a compile context by
-calling the \fBpcre2_set_compile_extra_options()\fP function are as follows:
+The option bits that can be set in a compile context by calling the
+\fBpcre2_set_compile_extra_options()\fP function are as follows:
.sp
PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES
.sp
@@ -1814,6 +1829,14 @@ point values in UTF-8 and UTF-32 patterns no longer provoke errors and are
incorporated in the compiled pattern. However, they can only match subject
characters if the matching function is called with PCRE2_NO_UTF_CHECK set.
.sp
+ PCRE2_EXTRA_ALT_BSUX
+.sp
+The original option PCRE2_ALT_BSUX causes PCRE2 to process \eU, \eu, and \ex in
+the way that ECMAscript (aka JavaScript) does. Additional functionality was
+defined by ECMAscript 6; setting PCRE2_EXTRA_ALT_BSUX has the effect of
+PCRE2_ALT_BSUX, but in addition it recognizes \eu{hhh..} as a hexadecimal
+character code, where hhh.. is any number of hexadecimal digits.
+.sp
PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL
.sp
This is a dangerous option. Use with care. By default, an unrecognized escape
@@ -3383,7 +3406,8 @@ capture groups and letters within \eQ...\eE quoted sequences.
.P
Note that case forcing sequences such as \eU...\eE do not nest. For example,
the result of processing "\eUaa\eLBB\eEcc\eE" is "AAbbcc"; the final \eE has no
-effect.
+effect. Note also that the PCRE2_ALT_BSUX and PCRE2_EXTRA_ALT_BSUX options do
+not apply to not apply to replacement strings.
.P
The second effect of setting PCRE2_SUBSTITUTE_EXTENDED is to add more
flexibility to capture group substitution. The syntax is similar to that used
@@ -3792,6 +3816,6 @@ Cambridge, England.
.rs
.sp
.nf
-Last updated: 04 February 2019
+Last updated: 12 February 2019
Copyright (c) 1997-2019 University of Cambridge.
.fi
diff --git a/doc/pcre2compat.3 b/doc/pcre2compat.3
index a2fbf48..39ccc2e 100644
--- a/doc/pcre2compat.3
+++ b/doc/pcre2compat.3
@@ -1,4 +1,4 @@
-.TH PCRE2COMPAT 3 "03 February 2019" "PCRE2 10.33"
+.TH PCRE2COMPAT 3 "12 February 2019" "PCRE2 10.33"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH "DIFFERENCES BETWEEN PCRE2 AND PERL"
@@ -33,8 +33,9 @@ non-newline character, and \eN{U+dd..}, matching a Unicode code point, are
supported. The escapes that modify the case of following letters are
implemented by Perl's general string-handling and are not part of its pattern
matching engine. If any of these are encountered by PCRE2, an error is
-generated by default. However, if the PCRE2_ALT_BSUX option is set, \eU and \eu
-are interpreted as ECMAScript interprets them.
+generated by default. However, if either of the PCRE2_ALT_BSUX or
+PCRE2_EXTRA_ALT_BSUX options is set, \eU and \eu are interpreted as ECMAScript
+interprets them.
.P
5. The Perl escape sequences \ep, \eP, and \eX are supported only if PCRE2 is
built with Unicode support (the default). The properties that can be tested
@@ -198,6 +199,6 @@ Cambridge, England.
.rs
.sp
.nf
-Last updated: 03 February 2019
+Last updated: 12 February 2019
Copyright (c) 1997-2019 University of Cambridge.
.fi
diff --git a/doc/pcre2pattern.3 b/doc/pcre2pattern.3
index f26117f..0576f0b 100644
--- a/doc/pcre2pattern.3
+++ b/doc/pcre2pattern.3
@@ -1,4 +1,4 @@
-.TH PCRE2PATTERN 3 "04 February 2019" "PCRE2 10.33"
+.TH PCRE2PATTERN 3 "12 February 2019" "PCRE2 10.33"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH "PCRE2 REGULAR EXPRESSION DETAILS"
@@ -373,12 +373,30 @@ environment, these escapes are as follows:
\exhh character with hex code hh
\ex{hhh..} character with hex code hhh..
\eN{U+hhh..} character with Unicode hex code point hhh..
- \euhhhh character with hex code hhhh (when PCRE2_ALT_BSUX is set)
.sp
-There are some legacy applications where the escape sequence \er is expected to
-match a newline. If the PCRE2_EXTRA_ESCAPED_CR_IS_LF option is set, \er in a
-pattern is converted to \en so that it matches a LF (linefeed) instead of a CR
-(carriage return) character.
+By default, after \ex that is not followed by {, from zero to two hexadecimal
+digits are read (letters can be in upper or lower case). Any number of
+hexadecimal digits may appear between \ex{ and }. If a character other than a
+hexadecimal digit appears between \ex{ and }, or if there is no terminating },
+an error occurs.
+.P
+Characters whose code points are less than 256 can be defined by either of the
+two syntaxes for \ex or by an octal sequence. There is no difference in the way
+they are handled. For example, \exdc is exactly the same as \ex{dc} or \e334.
+However, using the braced versions does make such sequences easier to read.
+.P
+Support is available for some ECMAScript (aka JavaScript) escape sequences via
+two compile-time options. If PCRE2_ALT_BSUX is set, the sequence \ex followed
+by { is not recognized. Only if \ex is followed by two hexadecimal digits is it
+recognized as a character escape. Otherwise it is interpreted as a literal "x"
+character. In this mode, support for code points greater than 256 is provided
+by \eu, which must be followed by four hexadecimal digits; otherwise it is
+interpreted as a literal "u" character.
+.P
+PCRE2_EXTRA_ALT_BSUX has the same effect as PCRE2_ALT_BSUX and, in addition,
+\eu{hhh..} is recognized as the character specified by hexadecimal code point.
+There may be any number of hexadecimal digits. This syntax is from ECMAScript
+6.
.P
The \eN{U+hhh..} escape sequence is recognized only when the PCRE2_UTF option
is set, that is, when PCRE2 is operating in a Unicode mode. Perl also uses
@@ -386,6 +404,11 @@ is set, that is, when PCRE2 is operating in a Unicode mode. Perl also uses
Note that when \eN is not followed by an opening brace (curly bracket) it has
an entirely different meaning, matching any character that is not a newline.
.P
+There are some legacy applications where the escape sequence \er is expected to
+match a newline. If the PCRE2_EXTRA_ESCAPED_CR_IS_LF option is set, \er in a
+pattern is converted to \en so that it matches a LF (linefeed) instead of a CR
+(carriage return) character.
+.P
The precise effect of \ecx on ASCII characters is as follows: if x is a lower
case letter, it is converted to upper case. Then bit 6 of the character (hex
40) is inverted. Thus \ecA to \ecZ become hex 01 to hex 1A (A is 41, Z is 5A),
@@ -477,25 +500,6 @@ for themselves. For example, outside a character class:
Note that octal values of 100 or greater that are specified using this syntax
must not be introduced by a leading zero, because no more than three octal
digits are ever read.
-.P
-By default, after \ex that is not followed by {, from zero to two hexadecimal
-digits are read (letters can be in upper or lower case). Any number of
-hexadecimal digits may appear between \ex{ and }. If a character other than
-a hexadecimal digit appears between \ex{ and }, or if there is no terminating
-}, an error occurs.
-.P
-If the PCRE2_ALT_BSUX option is set, the interpretation of \ex is as just
-described only when it is followed by two hexadecimal digits. Otherwise, it
-matches a literal "x" character. In this mode, support for code points greater
-than 256 is provided by \eu, which must be followed by four hexadecimal digits;
-otherwise it matches a literal "u" character. This syntax makes PCRE2 behave
-like ECMAscript (aka JavaScript). Code points greater than 0xFFFF are not
-supported.
-.P
-Characters whose value is less than 256 can be defined by either of the two
-syntaxes for \ex (or by \eu in PCRE2_ALT_BSUX mode). There is no difference in
-the way they are handled. For example, \exdc is exactly the same as \ex{dc} (or
-\eu00dc in PCRE2_ALT_BSUX mode).
.
.
.SS "Constraints on character values"
@@ -534,9 +538,10 @@ character class, these sequences have different meanings.
.sp
In Perl, the sequences \eF, \el, \eL, \eu, and \eU are recognized by its string
handler and used to modify the case of following characters. By default, PCRE2
-does not support these escape sequences. However, if the PCRE2_ALT_BSUX option
-is set, \eU matches a "U" character, and \eu can be used to define a character
-by code point, as described above.
+does not support these escape sequences in patterns. However, if either of the
+PCRE2_ALT_BSUX or PCRE2_EXTRA_ALT_BSUX options is set, \eU matches a "U"
+character, and \eu can be used to define a character by code point, as
+described above.
.
.
.SS "Absolute and relative backreferences"
@@ -3758,6 +3763,6 @@ Cambridge, England.
.rs
.sp
.nf
-Last updated: 04 February 2019
+Last updated: 12 February 2019
Copyright (c) 1997-2019 University of Cambridge.
.fi
diff --git a/doc/pcre2syntax.3 b/doc/pcre2syntax.3
index ff1b2b8..b6dd33c 100644
--- a/doc/pcre2syntax.3
+++ b/doc/pcre2syntax.3
@@ -1,4 +1,4 @@
-.TH PCRE2SYNTAX 3 "03 February 2019" "PCRE2 10.33"
+.TH PCRE2SYNTAX 3 "11 February 2019" "PCRE2 10.33"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH "PCRE2 REGULAR EXPRESSION SYNTAX SUMMARY"
@@ -22,7 +22,8 @@ documentation. This document contains a quick-reference summary of the syntax.
.SH "ESCAPED CHARACTERS"
.rs
.sp
-This table applies to ASCII and Unicode environments.
+This table applies to ASCII and Unicode environments. An unrecognized escape
+sequence causes an error.
.sp
\ea alarm, that is, the BEL character (hex 07)
\ecx "control-x", where x is any ASCII printing character
@@ -34,12 +35,24 @@ This table applies to ASCII and Unicode environments.
\e0dd character with octal code 0dd
\eddd character with octal code ddd, or backreference
\eo{ddd..} character with octal code ddd..
- \eU "U" if PCRE2_ALT_BSUX is set (otherwise is an error)
\eN{U+hh..} character with Unicode code point hh.. (Unicode mode only)
- \euhhhh character with hex code hhhh (if PCRE2_ALT_BSUX is set)
\exhh character with hex code hh
\ex{hh..} character with hex code hh..
.sp
+If PCRE2_ALT_BSUX or PCRE2_EXTRA_ALT_BSUX is set ("ALT_BSUX mode"), the
+following are also recognized:
+.sp
+ \eU the character "U"
+ \euhhhh character with hex code hhhh
+ \eu{hh..} character with hex code hh.. but only for EXTRA_ALT_BSUX
+.sp
+When \ex is not followed by {, from zero to two hexadecimal digits are read,
+but in ALT_BSUX mode \ex must be followed by two hexadecimal digits to be
+recognized as a hexadecimal escape; otherwise it matches a literal "x".
+Likewise, if \eu (in ALT_BSUX mode) is not followed by four hexadecimal digits
+or (in EXTRA_ALT_BSUX mode) a sequence of hex digits in curly brackets, it
+matches a literal "u".
+.P
Note that \e0dd is always an octal code. The treatment of backslash followed by
a non-zero digit is complicated; for details see the section
.\" HTML <a href="pcre2pattern.html#digitsafterbackslash">
@@ -54,12 +67,6 @@ documentation, where details of escape processing in EBCDIC environments are
also given. \eN{U+hh..} is synonymous with \ex{hh..} in PCRE2 but is not
supported in EBCDIC environments. Note that \eN not followed by an opening
curly bracket has a different meaning (see below).
-.P
-When \ex is not followed by {, from zero to two hexadecimal digits are read,
-but if PCRE2_ALT_BSUX is set, \ex must be followed by two hexadecimal digits to
-be recognized as a hexadecimal escape; otherwise it matches a literal "x".
-Likewise, if \eu (in ALT_BSUX mode) is not followed by four hexadecimal digits,
-it matches a literal "u".
.
.
.SH "CHARACTER TYPES"
@@ -647,6 +654,6 @@ Cambridge, England.
.rs
.sp
.nf
-Last updated: 03 February 2019
+Last updated: 11 February 2019
Copyright (c) 1997-2019 University of Cambridge.
.fi
diff --git a/doc/pcre2test.1 b/doc/pcre2test.1
index fdde2ff..b4b8eca 100644
--- a/doc/pcre2test.1
+++ b/doc/pcre2test.1
@@ -1,4 +1,4 @@
-.TH PCRE2TEST 1 "03 February 2019" "PCRE 10.33"
+.TH PCRE2TEST 1 "11 February 2019" "PCRE 10.33"
.SH NAME
pcre2test - a program for testing Perl-compatible regular expressions.
.SH SYNOPSIS
@@ -568,6 +568,7 @@ for a description of the effects of these options.
escaped_cr_is_lf set PCRE2_EXTRA_ESCAPED_CR_IS_LF
/x extended set PCRE2_EXTENDED
/xx extended_more set PCRE2_EXTENDED_MORE
+ extra_alt_bsux set PCRE2_EXTRA_ALT_BSUX
firstline set PCRE2_FIRSTLINE
literal set PCRE2_LITERAL
match_line set PCRE2_EXTRA_MATCH_LINE
@@ -2056,6 +2057,6 @@ Cambridge, England.
.rs
.sp
.nf
-Last updated: 03 February 2019
+Last updated: 11 February 2019
Copyright (c) 1997-2019 University of Cambridge.
.fi
diff --git a/doc/pcre2test.txt b/doc/pcre2test.txt
index dfc5651..ca3b7e3 100644
--- a/doc/pcre2test.txt
+++ b/doc/pcre2test.txt
@@ -547,6 +547,7 @@ PATTERN MODIFIERS
escaped_cr_is_lf set PCRE2_EXTRA_ESCAPED_CR_IS_LF
/x extended set PCRE2_EXTENDED
/xx extended_more set PCRE2_EXTENDED_MORE
+ extra_alt_bsux set PCRE2_EXTRA_ALT_BSUX
firstline set PCRE2_FIRSTLINE
literal set PCRE2_LITERAL
match_line set PCRE2_EXTRA_MATCH_LINE
@@ -1887,5 +1888,5 @@ AUTHOR
REVISION
- Last updated: 03 February 2019
+ Last updated: 11 February 2019
Copyright (c) 1997-2019 University of Cambridge.
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