/[pcre]/code/trunk/doc/html/pcreapi.html

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-revision 142 by ph10,
Fri Mar 30 15:55:18 2007 UTC
+revision 518 by ph10,
Tue May 18 15:47:01 2010 UTC
 Line 164 
 Applications can use these to include su
  The functions <b>pcre_compile()</b>, <b>pcre_compile2()</b>, <b>pcre_study()</b>,
  and <b>pcre_exec()</b> are used for compiling and matching regular expressions
  in a Perl-compatible manner. A sample program that demonstrates the simplest
- way of using them is provided in the file called <i>pcredemo.c</i> in the source
+ way of using them is provided in the file called <i>pcredemo.c</i> in the PCRE
- distribution. The
+ source distribution. A listing of this program is given in the
+ <a href="pcredemo.html"><b>pcredemo</b></a>
+ documentation, and the
  <a href="pcresample.html"><b>pcresample</b></a>
- documentation describes how to run it.
+ documentation describes how to compile and run it.
  </P>
  <P>
  A second matching function, <b>pcre_dfa_exec()</b>, which is not
  Perl-compatible, is also provided. This uses a different algorithm for the
  matching. The alternative algorithm finds all possible matches (at a given
- point in the subject), and scans the subject just once. However, this algorithm
+ point in the subject), and scans the subject just once (unless there are
- does not return captured substrings. A description of the two matching
+ lookbehind assertions). However, this algorithm does not return captured
- algorithms and their advantages and disadvantages is given in the
+ substrings. A description of the two matching algorithms and their advantages
+ and disadvantages is given in the
  <a href="pcrematching.html"><b>pcrematching</b></a>
  documentation.
  </P>
-Line 243 
 by the caller to a "callout" function, w
+Line 246 
 by the caller to a "callout" function, w
  points during a matching operation. Details are given in the
  <a href="pcrecallout.html"><b>pcrecallout</b></a>
  documentation.
- </P>
+ <a name="newlines"></a></P>
  <br><a name="SEC3" href="#TOC1">NEWLINES</a><br>
  <P>
- PCRE supports four different conventions for indicating line breaks in
+ PCRE supports five different conventions for indicating line breaks in
  strings: a single CR (carriage return) character, a single LF (linefeed)
- character, the two-character sequence CRLF, or any Unicode newline sequence.
+ character, the two-character sequence CRLF, any of the three preceding, or any
- The Unicode newline sequences are the three just mentioned, plus the single
+ Unicode newline sequence. The Unicode newline sequences are the three just
- characters VT (vertical tab, U+000B), FF (formfeed, U+000C), NEL (next line,
+ mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,
- U+0085), LS (line separator, U+2028), and PS (paragraph separator, U+2029).
+ U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
+ (paragraph separator, U+2029).
  </P>
  <P>
  Each of the first three conventions is used by at least one operating system as
-Line 261 
 default can be overridden, either when a
+Line 265 
 default can be overridden, either when a
  matched.
  </P>
  <P>
+ At compile time, the newline convention can be specified by the <i>options</i>
+ argument of <b>pcre_compile()</b>, or it can be specified by special text at the
+ start of the pattern itself; this overrides any other settings. See the
+ <a href="pcrepattern.html"><b>pcrepattern</b></a>
+ page for details of the special character sequences.
+ </P>
+ <P>
  In the PCRE documentation the word "newline" is used to mean "the character or
  pair of characters that indicate a line break". The choice of newline
  convention affects the handling of the dot, circumflex, and dollar
  metacharacters, the handling of #-comments in /x mode, and, when CRLF is a
  recognized line ending sequence, the match position advancement for a
- non-anchored pattern. The choice of newline convention does not affect the
+ non-anchored pattern. There is more detail about this in the
- interpretation of the \n or \r escape sequences.
+ <a href="#execoptions">section on <b>pcre_exec()</b> options</a>
+ below.
+ </P>
+ <P>
+ The choice of newline convention does not affect the interpretation of
+ the \n or \r escape sequences, nor does it affect what \R matches, which is
+ controlled in a similar way, but by separate options.
  </P>
  <br><a name="SEC4" href="#TOC1">MULTITHREADING</a><br>
  <P>
-Line 286 
 The compiled form of a regular expressio
+Line 303 
 The compiled form of a regular expressio
  time, possibly by a different program, and even on a host other than the one on
  which it was compiled. Details are given in the
  <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
- documentation.
+ documentation. However, compiling a regular expression with one version of PCRE
+ for use with a different version is not guaranteed to work and may cause
+ crashes.
  </P>
  <br><a name="SEC6" href="#TOC1">CHECKING BUILD-TIME OPTIONS</a><br>
  <P>
-Line 317 
 properties is available; otherwise it is
+Line 336 
 properties is available; otherwise it is
  </pre>
  The output is an integer whose value specifies the default character sequence
  that is recognized as meaning "newline". The four values that are supported
- are: 10 for LF, 13 for CR, 3338 for CRLF, and -1 for ANY. The default should
+ are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF, and -1 for ANY.
- normally be the standard sequence for your operating system.
+ Though they are derived from ASCII, the same values are returned in EBCDIC
+ environments. The default should normally correspond to the standard sequence
+ for your operating system.
+ <pre>
+   PCRE_CONFIG_BSR
+ </pre>
+ The output is an integer whose value indicates what character sequences the \R
+ escape sequence matches by default. A value of 0 means that \R matches any
+ Unicode line ending sequence; a value of 1 means that \R matches only CR, LF,
+ or CRLF. The default can be overridden when a pattern is compiled or matched.
  <pre>
    PCRE_CONFIG_LINK_SIZE
  </pre>
-Line 338 
 documentation.
+Line 366 
 documentation.
  <pre>
    PCRE_CONFIG_MATCH_LIMIT
  </pre>
- The output is an integer that gives the default limit for the number of
+ The output is a long integer that gives the default limit for the number of
  internal matching function calls in a <b>pcre_exec()</b> execution. Further
  details are given with <b>pcre_exec()</b> below.
  <pre>
    PCRE_CONFIG_MATCH_LIMIT_RECURSION
  </pre>
- The output is an integer that gives the default limit for the depth of
+ The output is a long integer that gives the default limit for the depth of
  recursion when calling the internal matching function in a <b>pcre_exec()</b>
  execution. Further details are given with <b>pcre_exec()</b> below.
  <pre>
-Line 372 
 avoiding the use of the stack.
+Line 400 
 avoiding the use of the stack.
  Either of the functions <b>pcre_compile()</b> or <b>pcre_compile2()</b> can be
  called to compile a pattern into an internal form. The only difference between
  the two interfaces is that <b>pcre_compile2()</b> has an additional argument,
- <i>errorcodeptr</i>, via which a numerical error code can be returned.
+ <i>errorcodeptr</i>, via which a numerical error code can be returned. To avoid
+ too much repetition, we refer just to <b>pcre_compile()</b> below, but the
+ information applies equally to <b>pcre_compile2()</b>.
  </P>
  <P>
  The pattern is a C string terminated by a binary zero, and is passed in the
-Line 391 
 argument, which is an address (see below
+Line 421 
 argument, which is an address (see below
  <P>
  The <i>options</i> argument contains various bit settings that affect the
  compilation. It should be zero if no options are required. The available
- options are described below. Some of them, in particular, those that are
+ options are described below. Some of them (in particular, those that are
- compatible with Perl, can also be set and unset from within the pattern (see
+ compatible with Perl, but some others as well) can also be set and unset from
- the detailed description in the
+ within the pattern (see the detailed description in the
  <a href="pcrepattern.html"><b>pcrepattern</b></a>
- documentation). For these options, the contents of the <i>options</i> argument
+ documentation). For those options that can be different in different parts of
- specifies their initial settings at the start of compilation and execution. The
+ the pattern, the contents of the <i>options</i> argument specifies their
- PCRE_ANCHORED and PCRE_NEWLINE_<i>xxx</i> options can be set at the time of
+ settings at the start of compilation and execution. The PCRE_ANCHORED,
- matching as well as at compile time.
+ PCRE_BSR_<i>xxx</i>, and PCRE_NEWLINE_<i>xxx</i> options can be set at the time
+ of matching as well as at compile time.
  </P>
  <P>
  If <i>errptr</i> is NULL, <b>pcre_compile()</b> returns NULL immediately.
  Otherwise, if compilation of a pattern fails, <b>pcre_compile()</b> returns
  NULL, and sets the variable pointed to by <i>errptr</i> to point to a textual
  error message. This is a static string that is part of the library. You must
- not try to free it. The offset from the start of the pattern to the character
+ not try to free it. The byte offset from the start of the pattern to the
- where the error was discovered is placed in the variable pointed to by
+ character that was being processed when the error was discovered is placed in
- <i>erroffset</i>, which must not be NULL. If it is, an immediate error is given.
+ the variable pointed to by <i>erroffset</i>, which must not be NULL. If it is,
+ an immediate error is given. Some errors are not detected until checks are
+ carried out when the whole pattern has been scanned; in this case the offset is
+ set to the end of the pattern.
  </P>
  <P>
  If <b>pcre_compile2()</b> is used instead of <b>pcre_compile()</b>, and the
-Line 455 
 facility, see the
+Line 489 
 facility, see the
  <a href="pcrecallout.html"><b>pcrecallout</b></a>
  documentation.
  <pre>
+   PCRE_BSR_ANYCRLF
+   PCRE_BSR_UNICODE
+ </pre>
+ These options (which are mutually exclusive) control what the \R escape
+ sequence matches. The choice is either to match only CR, LF, or CRLF, or to
+ match any Unicode newline sequence. The default is specified when PCRE is
+ built. It can be overridden from within the pattern, or by setting an option
+ when a compiled pattern is matched.
+ <pre>
    PCRE_CASELESS
  </pre>
  If this bit is set, letters in the pattern match both upper and lower case
-Line 517 
 set, any backslash in a pattern that is
+Line 560 
 set, any backslash in a pattern that is
  special meaning causes an error, thus reserving these combinations for future
  expansion. By default, as in Perl, a backslash followed by a letter with no
  special meaning is treated as a literal. (Perl can, however, be persuaded to
- give a warning for this.) There are at present no other features controlled by
+ give an error for this, by running it with the -w option.) There are at present
- this option. It can also be set by a (?X) option setting within a pattern.
+ no other features controlled by this option. It can also be set by a (?X)
+ option setting within a pattern.
  <pre>
    PCRE_FIRSTLINE
  </pre>
-Line 526 
 If this option is set, an unanchored pat
+Line 570 
 If this option is set, an unanchored pat
  the first newline in the subject string, though the matched text may continue
  over the newline.
  <pre>
+   PCRE_JAVASCRIPT_COMPAT
+ </pre>
+ If this option is set, PCRE's behaviour is changed in some ways so that it is
+ compatible with JavaScript rather than Perl. The changes are as follows:
+ </P>
+ <P>
+ (1) A lone closing square bracket in a pattern causes a compile-time error,
+ because this is illegal in JavaScript (by default it is treated as a data
+ character). Thus, the pattern AB]CD becomes illegal when this option is set.
+ </P>
+ <P>
+ (2) At run time, a back reference to an unset subpattern group matches an empty
+ string (by default this causes the current matching alternative to fail). A
+ pattern such as (\1)(a) succeeds when this option is set (assuming it can find
+ an "a" in the subject), whereas it fails by default, for Perl compatibility.
+ <pre>
    PCRE_MULTILINE
  </pre>
  By default, PCRE treats the subject string as consisting of a single line of
-Line 546 
 occurrences of ^ or $ in a pattern, sett
+Line 606 
 occurrences of ^ or $ in a pattern, sett
    PCRE_NEWLINE_CR
    PCRE_NEWLINE_LF
    PCRE_NEWLINE_CRLF
+   PCRE_NEWLINE_ANYCRLF
    PCRE_NEWLINE_ANY
  </pre>
  These options override the default newline definition that was chosen when PCRE
  was built. Setting the first or the second specifies that a newline is
  indicated by a single character (CR or LF, respectively). Setting
  PCRE_NEWLINE_CRLF specifies that a newline is indicated by the two-character
- CRLF sequence. Setting PCRE_NEWLINE_ANY specifies that any Unicode newline
+ CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three
- sequence should be recognized. The Unicode newline sequences are the three just
+ preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
- mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,
+ that any Unicode newline sequence should be recognized. The Unicode newline
- U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
+ sequences are the three just mentioned, plus the single characters VT (vertical
- (paragraph separator, U+2029). The last two are recognized only in UTF-8 mode.
+ tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line
+ separator, U+2028), and PS (paragraph separator, U+2029). The last two are
+ recognized only in UTF-8 mode.
  </P>
  <P>
  The newline setting in the options word uses three bits that are treated
- as a number, giving eight possibilities. Currently only five are used (default
+ as a number, giving eight possibilities. Currently only six are used (default
- plus the four values above). This means that if you set more than one newline
+ plus the five values above). This means that if you set more than one newline
  option, the combination may or may not be sensible. For example,
  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
- other combinations yield unused numbers and cause an error.
+ other combinations may yield unused numbers and cause an error.
  </P>
  <P>
  The only time that a line break is specially recognized when compiling a
-Line 607 
 page.
+Line 670 
 page.
    PCRE_NO_UTF8_CHECK
  </pre>
  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
- automatically checked. If an invalid UTF-8 sequence of bytes is found,
+ automatically checked. There is a discussion about the
- <b>pcre_compile()</b> returns an error. If you already know that your pattern is
+ <a href="pcre.html#utf8strings">validity of UTF-8 strings</a>
- valid, and you want to skip this check for performance reasons, you can set the
+ in the main
- PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid
+ <a href="pcre.html"><b>pcre</b></a>
- UTF-8 string as a pattern is undefined. It may cause your program to crash.
+ page. If an invalid UTF-8 sequence of bytes is found, <b>pcre_compile()</b>
- Note that this option can also be passed to <b>pcre_exec()</b> and
+ returns an error. If you already know that your pattern is valid, and you want
- <b>pcre_dfa_exec()</b>, to suppress the UTF-8 validity checking of subject
+ to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
- strings.
+ option. When it is set, the effect of passing an invalid UTF-8 string as a
+ pattern is undefined. It may cause your program to crash. Note that this option
+ can also be passed to <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>, to suppress
+ the UTF-8 validity checking of subject strings.
  </P>
  <br><a name="SEC8" href="#TOC1">COMPILATION ERROR CODES</a><br>
  <P>
-Line 635 
 out of use. To avoid confusion, they hav
+Line 701 
 out of use. To avoid confusion, they hav
  nothing to repeat
  [this code is not in use]
  internal error: unexpected repeat
- unrecognized character after (?
+ unrecognized character after (? or (?-
  POSIX named classes are supported only within a class
  missing )
  reference to non-existent subpattern
-Line 643 
 out of use. To avoid confusion, they hav
+Line 709 
 out of use. To avoid confusion, they hav
  unknown option bit(s) set
  missing ) after comment
  [this code is not in use]
- regular expression too large
+ regular expression is too large
  failed to get memory
  unmatched parentheses
  internal error: code overflow
-Line 652 
 out of use. To avoid confusion, they hav
+Line 718 
 out of use. To avoid confusion, they hav
  malformed number or name after (?(
  conditional group contains more than two branches
  assertion expected after (?(
- (?R or (?digits must be followed by )
+ (?R or (?[+-]digits must be followed by )
  unknown POSIX class name
  POSIX collating elements are not supported
  this version of PCRE is not compiled with PCRE_UTF8 support
-Line 672 
 out of use. To avoid confusion, they hav
+Line 738 
 out of use. To avoid confusion, they hav
  malformed \P or \p sequence
  unknown property name after \P or \p
  subpattern name is too long (maximum 32 characters)
- too many named subpatterns (maximum 10,000)
+ too many named subpatterns (maximum 10000)
- repeated subpattern is too long
+ [this code is not in use]
  octal value is greater than \377 (not in UTF-8 mode)
  internal error: overran compiling workspace
  internal error: previously-checked referenced subpattern not found
  DEFINE group contains more than one branch
  repeating a DEFINE group is not allowed
- inconsistent NEWLINE options"
+ inconsistent NEWLINE options
- </PRE>
+ \g is not followed by a braced, angle-bracketed, or quoted
+         name/number or by a plain number
+ a numbered reference must not be zero
+ an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
+ (*VERB) not recognized
+ number is too big
+ subpattern name expected
+ digit expected after (?+
+ ] is an invalid data character in JavaScript compatibility mode
+ different names for subpatterns of the same number are not allowed
+ (*MARK) must have an argument
+ </pre>
+ The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
+ be used if the limits were changed when PCRE was built.
  </P>
  <br><a name="SEC9" href="#TOC1">STUDYING A PATTERN</a><br>
  <P>
-Line 698 
 results of the study.
+Line 777 
 results of the study.
  </P>
  <P>
  The returned value from <b>pcre_study()</b> can be passed directly to
- <b>pcre_exec()</b>. However, a <b>pcre_extra</b> block also contains other
+ <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>. However, a <b>pcre_extra</b> block
- fields that can be set by the caller before the block is passed; these are
+ also contains other fields that can be set by the caller before the block is
- described
+ passed; these are described
  <a href="#extradata">below</a>
  in the section on matching a pattern.
  </P>
  <P>
- If studying the pattern does not produce any additional information
+ If studying the pattern does not produce any useful information,
  <b>pcre_study()</b> returns NULL. In that circumstance, if the calling program
- wants to pass any of the other fields to <b>pcre_exec()</b>, it must set up its
+ wants to pass any of the other fields to <b>pcre_exec()</b> or
- own <b>pcre_extra</b> block.
+ <b>pcre_dfa_exec()</b>, it must set up its own <b>pcre_extra</b> block.
  </P>
  <P>
  The second argument of <b>pcre_study()</b> contains option bits. At present, no
-Line 731 
 This is a typical call to pcre_study<
+Line 810 
 This is a typical call to pcre_study<
 ,              /* no options exist */
      &error);        /* set to NULL or points to a message */
  </pre>
- At present, studying a pattern is useful only for non-anchored patterns that do
+ Studying a pattern does two things: first, a lower bound for the length of
- not have a single fixed starting character. A bitmap of possible starting
+ subject string that is needed to match the pattern is computed. This does not
- bytes is created.
+ mean that there are any strings of that length that match, but it does
+ guarantee that no shorter strings match. The value is used by
+ <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b> to avoid wasting time by trying to
+ match strings that are shorter than the lower bound. You can find out the value
+ in a calling program via the <b>pcre_fullinfo()</b> function.
+ </P>
+ <P>
+ Studying a pattern is also useful for non-anchored patterns that do not have a
+ single fixed starting character. A bitmap of possible starting bytes is
+ created. This speeds up finding a position in the subject at which to start
+ matching.
  <a name="localesupport"></a></P>
  <br><a name="SEC10" href="#TOC1">LOCALE SUPPORT</a><br>
  <P>
-Line 882 
 table indicating a fixed set of bytes fo
+Line 971 
 table indicating a fixed set of bytes fo
  string, a pointer to the table is returned. Otherwise NULL is returned. The
  fourth argument should point to an <b>unsigned char *</b> variable.
  <pre>
+   PCRE_INFO_HASCRORLF
+ </pre>
+ Return 1 if the pattern contains any explicit matches for CR or LF characters,
+ otherwise 0. The fourth argument should point to an <b>int</b> variable. An
+ explicit match is either a literal CR or LF character, or \r or \n.
+ <pre>
+   PCRE_INFO_JCHANGED
+ </pre>
+ Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise
+. The fourth argument should point to an <b>int</b> variable. (?J) and
+ (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
+ <pre>
    PCRE_INFO_LASTLITERAL
  </pre>
  Return the value of the rightmost literal byte that must exist in any matched
-Line 892 
 follows something of variable length. Fo
+Line 993 
 follows something of variable length. Fo
  /^a\d+z\d+/ the returned value is "z", but for /^a\dz\d/ the returned value
  is -1.
  <pre>
+   PCRE_INFO_MINLENGTH
+ </pre>
+ If the pattern was studied and a minimum length for matching subject strings
+ was computed, its value is returned. Otherwise the returned value is -1. The
+ value is a number of characters, not bytes (this may be relevant in UTF-8
+ mode). The fourth argument should point to an <b>int</b> variable. A
+ non-negative 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.
+ <pre>
    PCRE_INFO_NAMECOUNT
    PCRE_INFO_NAMEENTRYSIZE
    PCRE_INFO_NAMETABLE
-Line 913 
 entry; both of these return an int
+Line 1024 
 entry; both of these return an int
  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first
  entry of the table (a pointer to <b>char</b>). The first two bytes of each entry
  are the number of the capturing parenthesis, most significant byte first. The
- rest of the entry is the corresponding name, zero terminated. The names are in
+ rest of the entry is the corresponding name, zero terminated.
- alphabetical order. When PCRE_DUPNAMES is set, duplicate names are in order of
+ </P>
- their parentheses numbers. For example, consider the following pattern (assume
+ <P>
- PCRE_EXTENDED is set, so white space - including newlines - is ignored):
+ The names are in alphabetical order. Duplicate names may appear if (?| is used
+ to create multiple groups with the same number, as described in the
+ <a href="pcrepattern.html#dupsubpatternnumber">section on duplicate subpattern numbers</a>
+ in the
+ <a href="pcrepattern.html"><b>pcrepattern</b></a>
+ page. Duplicate names for subpatterns with different numbers are permitted only
+ if PCRE_DUPNAMES is set. In all cases of duplicate names, 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 subpatterns may have lower numbers.
+ </P>
+ <P>
+ As a simple example of the name/number table, consider the following pattern
+ (assume PCRE_EXTENDED is set, so white space - including newlines - is
+ ignored):
  <pre>
    (?&#60;date&#62; (?&#60;year&#62;(\d\d)?\d\d) - (?&#60;month&#62;\d\d) - (?&#60;day&#62;\d\d) )
  </pre>
-Line 933 
 When writing code to extract data from n
+Line 1058 
 When writing code to extract data from n
  name-to-number map, remember that the length of the entries is likely to be
  different for each compiled pattern.
  <pre>
+   PCRE_INFO_OKPARTIAL
+ </pre>
+ Return 1 if the pattern can be used for partial matching with
+ <b>pcre_exec()</b>, otherwise 0. The fourth argument should point to an
+ <b>int</b> variable. From release 8.00, this always returns 1, because the
+ restrictions that previously applied to partial matching have been lifted. The
+ <a href="pcrepartial.html"><b>pcrepartial</b></a>
+ documentation gives details of partial matching.
+ <pre>
    PCRE_INFO_OPTIONS
  </pre>
  Return a copy of the options with which the pattern was compiled. The fourth
  argument should point to an <b>unsigned long int</b> variable. These option bits
  are those specified in the call to <b>pcre_compile()</b>, modified by any
- top-level option settings within the pattern itself.
+ top-level option settings at the start of the pattern itself. In other words,
+ they are the options that will be in force when matching starts. For example,
+ if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
+ result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
  </P>
  <P>
  A pattern is automatically anchored by PCRE if all of its top-level
-Line 964 
 variable.
+Line 1101 
 variable.
  Return the size of the data block pointed to by the <i>study_data</i> field in
  a <b>pcre_extra</b> block. That is, it is the value that was passed to
  <b>pcre_malloc()</b> when PCRE was getting memory into which to place the data
- created by <b>pcre_study()</b>. The fourth argument should point to a
+ created by <b>pcre_study()</b>. If <b>pcre_extra</b> is NULL, or there is no
+ study data, zero is returned. The fourth argument should point to a
  <b>size_t</b> variable.
  </P>
  <br><a name="SEC12" href="#TOC1">OBSOLETE INFO FUNCTION</a><br>
-Line 1024 
 is different. (This seems a highly unlik
+Line 1162 
 is different. (This seems a highly unlik
  <P>
  The function <b>pcre_exec()</b> is called to match a subject string against a
  compiled pattern, which is passed in the <i>code</i> argument. If the
- pattern has been studied, the result of the study should be passed in the
+ pattern was studied, the result of the study should be passed in the
  <i>extra</i> argument. 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
-Line 1072 
 fields (not necessarily in this order):
+Line 1210 
 fields (not necessarily in this order):
    unsigned long int <i>match_limit_recursion</i>;
    void *<i>callout_data</i>;
    const unsigned char *<i>tables</i>;
+   unsigned char **<i>mark</i>;
  </pre>
  The <i>flags</i> field is a bitmap that specifies which of the other fields
  are set. The flag bits are:
-Line 1081 
 are set. The flag bits are:
+Line 1220 
 are set. The flag bits are:
    PCRE_EXTRA_MATCH_LIMIT_RECURSION
    PCRE_EXTRA_CALLOUT_DATA
    PCRE_EXTRA_TABLES
+   PCRE_EXTRA_MARK
  </pre>
  Other flag bits should be set to zero. The <i>study_data</i> field is set in the
  <b>pcre_extra</b> block that is returned by <b>pcre_study()</b>, together with
-Line 1091 
 the block by setting the other fields an
+Line 1231 
 the block by setting the other fields an
  The <i>match_limit</i> field provides a means of preventing PCRE from using up a
  vast amount of resources when running patterns that are not going to match,
  but which have a very large number of possibilities in their search trees. The
- classic example is the use of nested unlimited repeats.
+ classic example is a pattern that uses nested unlimited repeats.
  </P>
  <P>
  Internally, PCRE uses a function called <b>match()</b> which it calls repeatedly
-Line 1130 
 PCRE_EXTRA_MATCH_LIMIT_RECURSION is set
+Line 1270 
 PCRE_EXTRA_MATCH_LIMIT_RECURSION is set
  is exceeded, <b>pcre_exec()</b> returns PCRE_ERROR_RECURSIONLIMIT.
  </P>
  <P>
- The <i>pcre_callout</i> field is used in conjunction with the "callout" feature,
+ The <i>callout_data</i> field is used in conjunction with the "callout" feature,
- which is described in the
+ and is described in the
  <a href="pcrecallout.html"><b>pcrecallout</b></a>
  documentation.
  </P>
-Line 1148 
 called. See the
+Line 1288 
 called. See the
  <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
  documentation for a discussion of saving compiled patterns for later use.
  </P>
+ <P>
+ If PCRE_EXTRA_MARK is set in the <i>flags</i> field, the <i>mark</i> field must
+ be set to point to a <b>char *</b> variable. If the pattern contains any
+ backtracking control verbs such as (*MARK:NAME), and the execution ends up with
+ a name to pass back, a pointer to the name string (zero terminated) is placed
+ in the variable pointed to by the <i>mark</i> field. The names are within the
+ compiled pattern; if you wish to retain such a name you must copy it before
+ freeing the memory of a compiled pattern. If there is no name to pass back, the
+ variable pointed to by the <i>mark</i> field set to NULL. For details of the
+ backtracking control verbs, see the section entitled
+ <a href="pcrepattern#backtrackcontrol">"Backtracking control"</a>
+ in the
+ <a href="pcrepattern.html"><b>pcrepattern</b></a>
+ documentation.
+ <a name="execoptions"></a></P>
  <br><b>
  Option bits for <b>pcre_exec()</b>
  </b><br>
  <P>
  The unused bits of the <i>options</i> argument for <b>pcre_exec()</b> must be
  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_<i>xxx</i>,
- PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.
+ PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
+ PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
+ PCRE_PARTIAL_HARD.
  <pre>
    PCRE_ANCHORED
  </pre>
-Line 1163 
 matching position. If a pattern was comp
+Line 1320 
 matching position. If a pattern was comp
  to be anchored by virtue of its contents, it cannot be made unachored at
  matching time.
  <pre>
+   PCRE_BSR_ANYCRLF
+   PCRE_BSR_UNICODE
+ </pre>
+ These options (which are mutually exclusive) control what the \R escape
+ sequence matches. The choice is either to match only CR, LF, or CRLF, or to
+ match any Unicode newline sequence. These options override the choice that was
+ made or defaulted when the pattern was compiled.
+ <pre>
    PCRE_NEWLINE_CR
    PCRE_NEWLINE_LF
    PCRE_NEWLINE_CRLF
+   PCRE_NEWLINE_ANYCRLF
    PCRE_NEWLINE_ANY
  </pre>
  These options override the newline definition that was chosen or defaulted when
-Line 1173 
 the pattern was compiled. For details, s
+Line 1339 
 the pattern was compiled. For details, s
  <b>pcre_compile()</b> above. During matching, the newline choice affects the
  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
  the way the match position is advanced after a match failure for an unanchored
- pattern. When PCRE_NEWLINE_CRLF or PCRE_NEWLINE_ANY is set, and a match attempt
+ pattern.
- fails when the current position is at a CRLF sequence, the match position is
+ </P>
- advanced by two characters instead of one, in other words, to after the CRLF.
+ <P>
+ When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a
+ match attempt for an unanchored pattern fails when the current 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
+ other words, to after the CRLF.
+ </P>
+ <P>
+ The above rule is a compromise that makes the most common cases work as
+ expected. For example, if the pattern is .+A (and the PCRE_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 contains an explicit CR or LF
+ reference, and so advances only by one character after the first failure.
+ </P>
+ <P>
+ An explicit match for CR of LF is either a literal appearance of one of those
+ characters, or one of the \r or \n escape sequences. Implicit matches such as
+ [^X] do not count, nor does \s (which includes CR and LF in the characters
+ that it matches).
+ </P>
+ <P>
+ 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.
  <pre>
    PCRE_NOTBOL
  </pre>
-Line 1201 
 match the empty string, the entire match
+Line 1390 
 match the empty string, the entire match
  <pre>
    a?b?
  </pre>
- is applied to a string not beginning with "a" or "b", it matches the empty
+ is applied to a string not beginning with "a" or "b", it matches an empty
  string at the start of the subject. With PCRE_NOTEMPTY set, this match is not
  valid, so PCRE searches further into the string for occurrences of "a" or "b".
+ <pre>
+   PCRE_NOTEMPTY_ATSTART
+ </pre>
+ This is like PCRE_NOTEMPTY, except that an empty string match that is not at
+ the start of the subject is permitted. If the pattern is anchored, such a match
+ can occur only if the pattern contains \K.
  </P>
  <P>
- Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case
+ Perl has no direct equivalent of PCRE_NOTEMPTY or PCRE_NOTEMPTY_ATSTART, but it
- of a pattern match of the empty string within its <b>split()</b> function, and
+ does make a special case of a pattern match of the empty string within its
- when using the /g modifier. It is possible to emulate Perl's behaviour after
+ <b>split()</b> function, and when using the /g modifier. It is possible to
- matching a null string by first trying the match again at the same offset with
+ emulate Perl's behaviour after matching a null string by first trying the match
- PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the
+ again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then
- starting offset (see below) and trying an ordinary match again. There is some
+ if that fails, by advancing the starting offset (see below) and trying an
- code that demonstrates how to do this in the <i>pcredemo.c</i> sample program.
+ ordinary match again. There is some code that demonstrates how to do this in
+ the
+ <a href="pcredemo.html"><b>pcredemo</b></a>
+ sample program.
+ <pre>
+   PCRE_NO_START_OPTIMIZE
+ </pre>
+ There are a number of optimizations that <b>pcre_exec()</b> uses at the start of
+ a match, in order to speed up the process. For example, if it is known that a
+ match must start with a specific character, it searches the subject for that
+ character, and fails immediately if it cannot find it, without actually running
+ the main matching function. When callouts are in use, these optimizations can
+ cause them to be skipped. This option disables the "start-up" optimizations,
+ causing performance to suffer, but ensuring that the callouts do occur.
  <pre>
    PCRE_NO_UTF8_CHECK
  </pre>
  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8
  string is automatically checked when <b>pcre_exec()</b> is subsequently called.
  The value of <i>startoffset</i> is also checked to ensure that it points to the
- start of a UTF-8 character. If an invalid UTF-8 sequence of bytes is found,
+ start of a UTF-8 character. There is a discussion about the validity of UTF-8
- <b>pcre_exec()</b> returns the error PCRE_ERROR_BADUTF8. If <i>startoffset</i>
+ strings in the
- contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.
+ <a href="pcre.html#utf8strings">section on UTF-8 support</a>
+ in the main
+ <a href="pcre.html"><b>pcre</b></a>
+ page. If an invalid UTF-8 sequence of bytes is found, <b>pcre_exec()</b> returns
+ the error PCRE_ERROR_BADUTF8. If <i>startoffset</i> contains an invalid value,
+ PCRE_ERROR_BADUTF8_OFFSET is returned.
  </P>
  <P>
  If you already know that your subject is valid, and you want to skip these
-Line 1234 
 PCRE_NO_UTF8_CHECK is set, the effect of
+Line 1447 
 PCRE_NO_UTF8_CHECK is set, the effect of
  subject, or a value of <i>startoffset</i> that does not point to the start of a
  UTF-8 character, is undefined. Your program may crash.
  <pre>
-   PCRE_PARTIAL
+   PCRE_PARTIAL_HARD
+   PCRE_PARTIAL_SOFT
  </pre>
- This option turns on the partial matching feature. If the subject string fails
+ These options turn on the partial matching feature. For backwards
- to match the pattern, but at some point during the matching process the end of
+ compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match
- the subject was reached (that is, the subject partially matches the pattern and
+ occurs if the end of the subject string is reached successfully, but there are
- the failure to match occurred only because there were not enough subject
+ not enough subject characters to complete the match. If this happens when
- characters), <b>pcre_exec()</b> returns PCRE_ERROR_PARTIAL instead of
+ PCRE_PARTIAL_HARD is set, <b>pcre_exec()</b> immediately returns
- PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is used, there are restrictions on what
+ PCRE_ERROR_PARTIAL. Otherwise, if PCRE_PARTIAL_SOFT is set, matching continues
- may appear in the pattern. These are discussed in the
+ by testing any other alternatives. Only if they all fail is PCRE_ERROR_PARTIAL
+ returned (instead of PCRE_ERROR_NOMATCH). The portion of the string that
+ was inspected when the partial match was found is set as the first matching
+ string. There is a more detailed discussion in the
  <a href="pcrepartial.html"><b>pcrepartial</b></a>
  documentation.
  </P>
-Line 1251 
 The string to be matched by pcre_exec
+Line 1468 
 The string to be matched by pcre_exec
  </b><br>
  <P>
  The subject string is passed to <b>pcre_exec()</b> as a pointer in
- <i>subject</i>, a length in <i>length</i>, and a starting byte offset in
+ <i>subject</i>, a length (in bytes) in <i>length</i>, and a starting byte offset
- <i>startoffset</i>. In UTF-8 mode, the byte offset must point to the start of a
+ in <i>startoffset</i>. In UTF-8 mode, the byte offset must point to the start of
- UTF-8 character. Unlike the pattern string, the subject may contain binary zero
+ a UTF-8 character. Unlike the pattern string, the subject may contain binary
- bytes. When the starting offset is zero, the search for a match starts at the
+ zero bytes. When the starting offset is zero, the search for a match starts at
- beginning of the subject, and this is by far the most common case.
+ the beginning of the subject, and this is by far the most common case.
  </P>
  <P>
  A non-zero starting offset is useful when searching for another match in the
-Line 1293 
 a fragment of a pattern that picks out a
+Line 1510 
 a fragment of a pattern that picks out a
  kinds of parenthesized subpattern that do not cause substrings to be captured.
  </P>
  <P>
- Captured substrings are returned to the caller via a vector of integer offsets
+ Captured substrings are returned to the caller via a vector of integers whose
- whose address is passed in <i>ovector</i>. The number of elements in the vector
+ address is passed in <i>ovector</i>. The number of elements in the vector is
- is passed in <i>ovecsize</i>, which must be a non-negative number. <b>Note</b>:
+ passed in <i>ovecsize</i>, which must be a non-negative number. <b>Note</b>: this
- this argument is NOT the size of <i>ovector</i> in bytes.
+ argument is NOT the size of <i>ovector</i> in bytes.
  </P>
  <P>
  The first two-thirds of the vector is used to pass back captured substrings,
  each substring using a pair of integers. The remaining third of the vector is
  used as workspace by <b>pcre_exec()</b> while matching capturing subpatterns,
- and is not available for passing back information. The length passed in
+ and is not available for passing back information. The number passed in
  <i>ovecsize</i> should always be a multiple of three. If it is not, it is
  rounded down.
  </P>
  <P>
  When a match is successful, information about captured substrings is returned
  in pairs of integers, starting at the beginning of <i>ovector</i>, and
- continuing up to two-thirds of its length at the most. The first element of a
+ continuing up to two-thirds of its length at the most. The first element of
- pair is set to the offset of the first character in a substring, and the second
+ each pair is set to the byte offset of the first character in a substring, and
- is set to the offset of the first character after the end of a substring. The
+ the second is set to the byte offset of the first character after the end of a
- first pair, <i>ovector[0]</i> and <i>ovector[1]</i>, identify the portion of the
+ substring. <b>Note</b>: these values are always byte offsets, even in UTF-8
- subject string matched by the entire pattern. The next pair is used for the
+ mode. They are not character counts.
- first capturing subpattern, and so on. The value returned by <b>pcre_exec()</b>
+ </P>
- is one more than the highest numbered pair that has been set. For example, if
+ <P>
- two substrings have been captured, the returned value is 3. If there are no
+ The first pair of integers, <i>ovector[0]</i> and <i>ovector[1]</i>, identify the
- capturing subpatterns, the return value from a successful match is 1,
+ portion of the subject string matched by the entire pattern. The next pair is
- indicating that just the first pair of offsets has been set.
+ used for the first capturing subpattern, and so on. The value returned by
+ <b>pcre_exec()</b> 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 capturing subpatterns, the return value from a successful match is
+, indicating that just the first pair of offsets has been set.
  </P>
  <P>
  If a capturing subpattern is matched repeatedly, it is the last portion of the
-Line 1327 
 string that it matched that is returned.
+Line 1548 
 string that it matched that is returned.
  <P>
  If the vector is too small to hold all the captured substring offsets, it is
  used as far as possible (up to two-thirds of its length), and the function
- returns a value of zero. In particular, if the substring offsets are not of
+ returns a value of zero. If the substring offsets are not of interest,
- interest, <b>pcre_exec()</b> may be called with <i>ovector</i> passed as NULL and
+ <b>pcre_exec()</b> may be called with <i>ovector</i> passed as NULL and
  <i>ovecsize</i> as zero. However, if the pattern contains back references and
  the <i>ovector</i> is not big enough to remember the related substrings, PCRE
  has to get additional memory for use during matching. Thus it is usually
  advisable to supply an <i>ovector</i>.
  </P>
  <P>
- The <b>pcre_info()</b> function can be used to find out how many capturing
+ The <b>pcre_fullinfo()</b> function can be used to find out how many capturing
  subpatterns there are in a compiled pattern. The smallest size for
  <i>ovector</i> that will allow for <i>n</i> captured substrings, in addition to
  the offsets of the substring matched by the whole pattern, is (<i>n</i>+1)*3.
-Line 1439 
 documentation for details of partial mat
+Line 1660 
 documentation for details of partial mat
  <pre>
    PCRE_ERROR_BADPARTIAL     (-13)
  </pre>
- The PCRE_PARTIAL option was used with a compiled pattern containing items that
+ This code is no longer in use. It was formerly returned when the PCRE_PARTIAL
- are not supported for partial matching. See the
+ option was used with a compiled pattern containing items that were not
- <a href="pcrepartial.html"><b>pcrepartial</b></a>
+ supported for partial matching. From release 8.00 onwards, there are no
- documentation for details of partial matching.
+ restrictions on partial matching.
  <pre>
    PCRE_ERROR_INTERNAL       (-14)
  </pre>
-Line 1459 
 The internal recursion limit, as specifi
+Line 1680 
 The internal recursion limit, as specifi
  field in a <b>pcre_extra</b> structure (or defaulted) was reached. See the
  description above.
  <pre>
-   PCRE_ERROR_NULLWSLIMIT    (-22)
- </pre>
- When a group that can match an empty substring is repeated with an unbounded
- upper limit, the subject position at the start of the group must be remembered,
- so that a test for an empty string can be made when the end of the group is
- reached. Some workspace is required for this; if it runs out, this error is
- given.
- <pre>
    PCRE_ERROR_BADNEWLINE     (-23)
  </pre>
  An invalid combination of PCRE_NEWLINE_<i>xxx</i> options was given.
  </P>
  <P>
- Error numbers -16 to -20 are not used by <b>pcre_exec()</b>.
+ Error numbers -16 to -20 and -22 are not used by <b>pcre_exec()</b>.
  </P>
  <br><a name="SEC15" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a><br>
  <P>
-Line 1622 
 then call pcre_copy_substring() o
+Line 1835 
 then call pcre_copy_substring() o
  appropriate. <b>NOTE:</b> If PCRE_DUPNAMES is set and there are duplicate names,
  the behaviour may not be what you want (see the next section).
  </P>
+ <P>
+ <b>Warning:</b> If the pattern uses the (?| feature to set up multiple
+ subpatterns with the same number, as described in the
+ <a href="pcrepattern.html#dupsubpatternnumber">section on duplicate subpattern numbers</a>
+ in the
+ <a href="pcrepattern.html"><b>pcrepattern</b></a>
+ page, you cannot use names to distinguish the different subpatterns, because
+ names are not included in the compiled code. The matching process uses only
+ numbers. For this reason, the use of different names for subpatterns of the
+ same number causes an error at compile time.
+ </P>
  <br><a name="SEC17" href="#TOC1">DUPLICATE SUBPATTERN NAMES</a><br>
  <P>
  <b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b>
-Line 1629 
 the behaviour may not be what you want (
+Line 1853 
 the behaviour may not be what you want (
  </P>
  <P>
  When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns
- are not required to be unique. Normally, patterns with duplicate names are such
+ are not required to be unique. (Duplicate names are always allowed for
- that in any one match, only one of the named subpatterns participates. An
+ subpatterns with the same number, created by using the (?| feature. Indeed, if
- example is shown in the
+ such subpatterns are named, they are required to use the same names.)
+ </P>
+ <P>
+ Normally, patterns with duplicate names are such that in any one match, only
+ one of the named subpatterns participates. An example is shown in the
  <a href="pcrepattern.html"><b>pcrepattern</b></a>
- documentation. When duplicates are present, <b>pcre_copy_named_substring()</b>
+ documentation.
- and <b>pcre_get_named_substring()</b> return the first substring corresponding
+ </P>
- to the given name that is set. If none are set, an empty string is returned.
+ <P>
- The <b>pcre_get_stringnumber()</b> function returns one of the numbers that are
+ When duplicates are present, <b>pcre_copy_named_substring()</b> and
- associated with the name, but it is not defined which it is.
+ <b>pcre_get_named_substring()</b> return the first substring corresponding to
- <br>
+ the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
- <br>
+ returned; no data is returned. The <b>pcre_get_stringnumber()</b> function
+ returns one of the numbers that are associated with the name, but it is not
+ defined which it is.
+ </P>
+ <P>
  If you want to get full details of all captured substrings for a given name,
  you must use the <b>pcre_get_stringtable_entries()</b> function. The first
  argument is the compiled pattern, and the second is the name. The third and
-Line 1683 
 a compiled pattern, using a matching alg
+Line 1915 
 a compiled pattern, using a matching alg
  just once, and does not backtrack. This has different characteristics to the
  normal algorithm, and is not compatible with Perl. Some of the features of PCRE
  patterns are not supported. Nevertheless, there are times when this kind of
- matching can be useful. For a discussion of the two matching algorithms, see
+ matching can be useful. For a discussion of the two matching algorithms, and a
- the
+ list of features that <b>pcre_dfa_exec()</b> does not support, see the
  <a href="pcrematching.html"><b>pcrematching</b></a>
  documentation.
  </P>
-Line 1726 
 Option bits for pcre_dfa_exec()
+Line 1958 
 Option bits for pcre_dfa_exec()
  <P>
  The unused bits of the <i>options</i> argument for <b>pcre_dfa_exec()</b> must be
  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_<i>xxx</i>,
- PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,
+ PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
- PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last three of these are
+ PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST,
- the same as for <b>pcre_exec()</b>, so their description is not repeated here.
+ and PCRE_DFA_RESTART. All but the last four of these are exactly the same as
- <pre>
+ for <b>pcre_exec()</b>, so their description is not repeated here.
-   PCRE_PARTIAL
+ <pre>
- </pre>
+   PCRE_PARTIAL_HARD
- This has the same general effect as it does for <b>pcre_exec()</b>, but the
+   PCRE_PARTIAL_SOFT
- details are slightly different. When PCRE_PARTIAL is set for
+ </pre>
- <b>pcre_dfa_exec()</b>, the return code PCRE_ERROR_NOMATCH is converted into
+ These have the same general effect as they do for <b>pcre_exec()</b>, but the
- PCRE_ERROR_PARTIAL if the end of the subject is reached, there have been no
+ details are slightly different. When PCRE_PARTIAL_HARD is set for
- complete matches, but there is still at least one matching possibility. The
+ <b>pcre_dfa_exec()</b>, it returns PCRE_ERROR_PARTIAL if the end of the subject
- portion of the string that provided the partial match is set as the first
+ is reached and there is still at least one matching possibility that requires
- matching string.
+ additional characters. This happens even if some complete matches have also
+ been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
+ is converted into PCRE_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 portion of the string that was inspected when the longest
+ partial match was found is set as the first matching string in both cases.
  <pre>
    PCRE_DFA_SHORTEST
  </pre>
-Line 1749 
 matching point in the subject string.
+Line 1986 
 matching point in the subject string.
  <pre>
    PCRE_DFA_RESTART
  </pre>
- When <b>pcre_dfa_exec()</b> is called with the PCRE_PARTIAL option, and returns
+ When <b>pcre_dfa_exec()</b> returns a partial match, it is possible to call it
- a partial match, it is possible to call it again, with additional subject
+ again, with additional subject characters, and have it continue with the same
- characters, and have it continue with the same match. The PCRE_DFA_RESTART
+ match. The PCRE_DFA_RESTART option requests this action; when it is set, the
- option requests this action; when it is set, the <i>workspace</i> and
+ <i>workspace</i> and <i>wscount</i> options must reference the same vector as
- <i>wscount</i> options must reference the same vector as before because data
+ before because data about the match so far is left in them after a partial
- about the match so far is left in them after a partial match. There is more
+ match. There is more discussion of this facility in the
- discussion of this facility in the
  <a href="pcrepartial.html"><b>pcrepartial</b></a>
  documentation.
  </P>
-Line 1851 
 Cambridge CB2 3QH, England.
+Line 2087 
 Cambridge CB2 3QH, England.
  </P>
  <br><a name="SEC22" href="#TOC1">REVISION</a><br>
  <P>
- Last updated: 06 March 2007
+ Last updated: 03 May 2010
  <br>
- Copyright &copy; 1997-2007 University of Cambridge.
+ Copyright &copy; 1997-2010 University of Cambridge.
  <br>
  <p>
  Return to the <a href="index.html">PCRE index page</a>.

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