Revision: 1014
http://www.exim.org/viewvc/pcre2?view=rev&revision=1014
Author: ph10
Date: 2018-09-19 17:37:59 +0100 (Wed, 19 Sep 2018)
Log Message:
-----------
Documentation update.
Modified Paths:
--------------
code/trunk/doc/html/README.txt
code/trunk/doc/html/pcre2posix.html
code/trunk/doc/pcre2.txt
Modified: code/trunk/doc/html/README.txt
===================================================================
--- code/trunk/doc/html/README.txt 2018-09-19 16:33:09 UTC (rev 1013)
+++ code/trunk/doc/html/README.txt 2018-09-19 16:37:59 UTC (rev 1014)
@@ -42,18 +42,18 @@
32-bit library, which processes strings of 32-bit values. There are no C++
wrappers.
-The distribution does contain a set of C wrapper functions for the 8-bit
-library that are based on the POSIX regular expression API (see the pcre2posix
-man page). These can be found in a library called libpcre2-posix. Note that
-this just provides a POSIX calling interface to PCRE2; the regular expressions
-themselves still follow Perl syntax and semantics. The POSIX API is restricted,
-and does not give full access to all of PCRE2's facilities.
+In addition, the distribution contains a set of C wrapper functions for the
+8-bit library that are based on the POSIX regular expression API (see the
+pcre2posix man page). These are built into a library called libpcre2-posix.
+Note that this just provides a POSIX calling interface to PCRE2; the regular
+expressions themselves still follow Perl syntax and semantics. The POSIX API is
+restricted, and does not give full access to all of PCRE2's facilities.
The header file for the POSIX-style functions is called pcre2posix.h. The
official POSIX name is regex.h, but I did not want to risk possible problems
with existing files of that name by distributing it that way. To use PCRE2 with
an existing program that uses the POSIX API, pcre2posix.h will have to be
-renamed or pointed at by a link.
+renamed or pointed at by a link (or the program modified, of course).
If you are using the POSIX interface to PCRE2 and there is already a POSIX
regex library installed on your system, as well as worrying about the regex.h
@@ -61,12 +61,11 @@
to ensure that they link with PCRE2's libpcre2-posix library. Otherwise they
may pick up the POSIX functions of the same name from the other library.
-One way of avoiding this confusion is to compile PCRE2 with the addition of
--Dregcomp=PCRE2regcomp (and similarly for the other POSIX functions) to the
-compiler flags (CFLAGS if you are using "configure" -- see below). This has the
-effect of renaming the functions so that the names no longer clash. Of course,
-you have to do the same thing for your applications, or write them using the
-new names.
+To help with this issue, the libpcre2-posix library provides alternative names
+for the POSIX functions. These are the POSIX names, prefixed with "pcre2_", for
+example, pcre2_regcomp(). If an application can be compiled to use the
+alternative names (for example by the use of -Dregcomp=pcre2_regcomp etc.) it
+can be sure of linking with the PCRE2 functions.
Documentation for PCRE2
@@ -888,4 +887,4 @@
Philip Hazel
Email local part: ph10
Email domain: cam.ac.uk
-Last updated: 17 June 2018
+Last updated: 19 September 2018
Modified: code/trunk/doc/html/pcre2posix.html
===================================================================
--- code/trunk/doc/html/pcre2posix.html 2018-09-19 16:33:09 UTC (rev 1013)
+++ code/trunk/doc/html/pcre2posix.html 2018-09-19 16:37:59 UTC (rev 1014)
@@ -32,15 +32,30 @@
<b> int <i>cflags</i>);</b>
<br>
<br>
+<b>int pcre2_regcomp(regex_t *<i>preg</i>, const char *<i>pattern</i>,</b>
+<b> int <i>cflags</i>);</b>
+<br>
+<br>
<b>int regexec(const regex_t *<i>preg</i>, const char *<i>string</i>,</b>
<b> size_t <i>nmatch</i>, regmatch_t <i>pmatch</i>[], int <i>eflags</i>);</b>
<br>
<br>
+<b>int pcre2_regexec(const regex_t *<i>preg</i>, const char *<i>string</i>,</b>
+<b> size_t <i>nmatch</i>, regmatch_t <i>pmatch</i>[], int <i>eflags</i>);</b>
+<br>
+<br>
<b>size_t regerror(int <i>errcode</i>, const regex_t *<i>preg</i>,</b>
<b> char *<i>errbuf</i>, size_t <i>errbuf_size</i>);</b>
<br>
<br>
+<b>size_t pcre2_regerror(int <i>errcode</i>, const regex_t *<i>preg</i>,</b>
+<b> char *<i>errbuf</i>, size_t <i>errbuf_size</i>);</b>
+<br>
+<br>
<b>void regfree(regex_t *<i>preg</i>);</b>
+<br>
+<br>
+<b>void pcre2_regfree(regex_t *<i>preg</i>);</b>
</P>
<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
<P>
@@ -60,6 +75,14 @@
call the native ones, it is also necessary to add <b>-lpcre2-8</b>.
</P>
<P>
+When another POSIX regex library is also installed, there is the possibility of
+linking an application with the wrong library. To help avoid this issue, the
+PCRE2 POSIX library provides alternative names for the functions, all starting
+with "pcre2_". If an application uses these names, possible ambiguity is
+avoided. In the following description, however, the standard POSIX function
+names are used.
+</P>
+<P>
Those POSIX option bits that can reasonably be mapped to PCRE2 native options
have been implemented. In addition, the option REG_EXTENDED is defined with the
value zero. This has no effect, but since programs that are written to the
@@ -322,9 +345,9 @@
</P>
<br><a name="SEC9" href="#TOC1">REVISION</a><br>
<P>
-Last updated: 15 June 2017
+Last updated: 19 September 2018
<br>
-Copyright © 1997-2017 University of Cambridge.
+Copyright © 1997-2018 University of Cambridge.
<br>
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
Modified: code/trunk/doc/pcre2.txt
===================================================================
--- code/trunk/doc/pcre2.txt 2018-09-19 16:33:09 UTC (rev 1013)
+++ code/trunk/doc/pcre2.txt 2018-09-19 16:37:59 UTC (rev 1014)
@@ -9419,15 +9419,26 @@
int regcomp(regex_t *preg, const char *pattern,
int cflags);
+ int pcre2_regcomp(regex_t *preg, const char *pattern,
+ int cflags);
+
int regexec(const regex_t *preg, const char *string,
size_t nmatch, regmatch_t pmatch[], int eflags);
+ int pcre2_regexec(const regex_t *preg, const char *string,
+ size_t nmatch, regmatch_t pmatch[], int eflags);
+
size_t regerror(int errcode, const regex_t *preg,
char *errbuf, size_t errbuf_size);
+ size_t pcre2_regerror(int errcode, const regex_t *preg,
+ char *errbuf, size_t errbuf_size);
+
void regfree(regex_t *preg);
+ void pcre2_regfree(regex_t *preg);
+
DESCRIPTION
This set of functions provides a POSIX-style API for the PCRE2 regular
@@ -9444,42 +9455,49 @@
POSIX functions call the native ones, it is also necessary to add
-lpcre2-8.
- Those POSIX option bits that can reasonably be mapped to PCRE2 native
- options have been implemented. In addition, the option REG_EXTENDED is
- defined with the value zero. This has no effect, but since programs
- that are written to the POSIX interface often use it, this makes it
- easier to slot in PCRE2 as a replacement library. Other POSIX options
+ When another POSIX regex library is also installed, there is the possi-
+ bility of linking an application with the wrong library. To help avoid
+ this issue, the PCRE2 POSIX library provides alternative names for the
+ functions, all starting with "pcre2_". If an application uses these
+ names, possible ambiguity is avoided. In the following description,
+ however, the standard POSIX function names are used.
+
+ Those POSIX option bits that can reasonably be mapped to PCRE2 native
+ options have been implemented. In addition, the option REG_EXTENDED is
+ defined with the value zero. This has no effect, but since programs
+ that are written to the POSIX interface often use it, this makes it
+ easier to slot in PCRE2 as a replacement library. Other POSIX options
are not even defined.
- There are also some options that are not defined by POSIX. These have
- been added at the request of users who want to make use of certain
- PCRE2-specific features via the POSIX calling interface or to add BSD
+ There are also some options that are not defined by POSIX. These have
+ been added at the request of users who want to make use of certain
+ PCRE2-specific features via the POSIX calling interface or to add BSD
or GNU functionality.
- When PCRE2 is called via these functions, it is only the API that is
- POSIX-like in style. The syntax and semantics of the regular expres-
- sions themselves are still those of Perl, subject to the setting of
- various PCRE2 options, as described below. "POSIX-like in style" means
- that the API approximates to the POSIX definition; it is not fully
- POSIX-compatible, and in multi-unit encoding domains it is probably
+ When PCRE2 is called via these functions, it is only the API that is
+ POSIX-like in style. The syntax and semantics of the regular expres-
+ sions themselves are still those of Perl, subject to the setting of
+ various PCRE2 options, as described below. "POSIX-like in style" means
+ that the API approximates to the POSIX definition; it is not fully
+ POSIX-compatible, and in multi-unit encoding domains it is probably
even less compatible.
The header for these functions is supplied as pcre2posix.h to avoid any
- potential clash with other POSIX libraries. It can, of course, be
+ potential clash with other POSIX libraries. It can, of course, be
renamed or aliased as regex.h, which is the "correct" name. It provides
- two structure types, regex_t for compiled internal forms, and reg-
- match_t for returning captured substrings. It also defines some con-
- stants whose names start with "REG_"; these are used for setting
+ two structure types, regex_t for compiled internal forms, and reg-
+ match_t for returning captured substrings. It also defines some con-
+ stants whose names start with "REG_"; these are used for setting
options and identifying error codes.
COMPILING A PATTERN
- The function regcomp() is called to compile a pattern into an internal
+ The function regcomp() is called to compile a pattern into an internal
form. By default, the pattern is a C string terminated by a binary zero
- (but see REG_PEND below). The preg argument is a pointer to a regex_t
+ (but see REG_PEND below). The preg argument is a pointer to a regex_t
structure that is used as a base for storing information about the com-
- piled regular expression. (It is also used for input when REG_PEND is
+ piled regular expression. (It is also used for input when REG_PEND is
set.)
The argument cflags is either zero, or contains one or more of the bits
@@ -9487,84 +9505,84 @@
REG_DOTALL
- The PCRE2_DOTALL option is set when the regular expression is passed
- for compilation to the native function. Note that REG_DOTALL is not
+ The PCRE2_DOTALL option is set when the regular expression is passed
+ for compilation to the native function. Note that REG_DOTALL is not
part of the POSIX standard.
REG_ICASE
- The PCRE2_CASELESS option is set when the regular expression is passed
+ The PCRE2_CASELESS option is set when the regular expression is passed
for compilation to the native function.
REG_NEWLINE
The PCRE2_MULTILINE option is set when the regular expression is passed
- for compilation to the native function. Note that this does not mimic
- the defined POSIX behaviour for REG_NEWLINE (see the following sec-
+ for compilation to the native function. Note that this does not mimic
+ the defined POSIX behaviour for REG_NEWLINE (see the following sec-
tion).
REG_NOSPEC
- The PCRE2_LITERAL option is set when the regular expression is passed
- for compilation to the native function. This disables all meta charac-
- ters in the pattern, causing it to be treated as a literal string. The
- only other options that are allowed with REG_NOSPEC are REG_ICASE,
- REG_NOSUB, REG_PEND, and REG_UTF. Note that REG_NOSPEC is not part of
+ The PCRE2_LITERAL option is set when the regular expression is passed
+ for compilation to the native function. This disables all meta charac-
+ ters in the pattern, causing it to be treated as a literal string. The
+ only other options that are allowed with REG_NOSPEC are REG_ICASE,
+ REG_NOSUB, REG_PEND, and REG_UTF. Note that REG_NOSPEC is not part of
the POSIX standard.
REG_NOSUB
- When a pattern that is compiled with this flag is passed to regexec()
- for matching, the nmatch and pmatch arguments are ignored, and no cap-
+ When a pattern that is compiled with this flag is passed to regexec()
+ for matching, the nmatch and pmatch arguments are ignored, and no cap-
tured strings are returned. Versions of the PCRE library prior to 10.22
- used to set the PCRE2_NO_AUTO_CAPTURE compile option, but this no
+ used to set the PCRE2_NO_AUTO_CAPTURE compile option, but this no
longer happens because it disables the use of backreferences.
REG_PEND
- If this option is set, the reg_endp field in the preg structure (which
+ If this option is set, the reg_endp field in the preg structure (which
has the type const char *) must be set to point to the character beyond
the end of the pattern before calling regcomp(). The pattern itself may
now contain binary zeros, which are treated as data characters. Without
REG_PEND, a binary zero terminates the pattern and the re_endp field is
- ignored. This is a GNU extension to the POSIX standard and should be
+ ignored. This is a GNU extension to the POSIX standard and should be
used with caution in software intended to be portable to other systems.
REG_UCP
- The PCRE2_UCP option is set when the regular expression is passed for
- compilation to the native function. This causes PCRE2 to use Unicode
- properties when matchine \d, \w, etc., instead of just recognizing
+ The PCRE2_UCP option is set when the regular expression is passed for
+ compilation to the native function. This causes PCRE2 to use Unicode
+ properties when matchine \d, \w, etc., instead of just recognizing
ASCII values. Note that REG_UCP is not part of the POSIX standard.
REG_UNGREEDY
- The PCRE2_UNGREEDY option is set when the regular expression is passed
- for compilation to the native function. Note that REG_UNGREEDY is not
+ The PCRE2_UNGREEDY option is set when the regular expression is passed
+ for compilation to the native function. Note that REG_UNGREEDY is not
part of the POSIX standard.
REG_UTF
- The PCRE2_UTF option is set when the regular expression is passed for
- compilation to the native function. This causes the pattern itself and
- all data strings used for matching it to be treated as UTF-8 strings.
+ The PCRE2_UTF option is set when the regular expression is passed for
+ compilation to the native function. This causes the pattern itself and
+ all data strings used for matching it to be treated as UTF-8 strings.
Note that REG_UTF is not part of the POSIX standard.
- In the absence of these flags, no options are passed to the native
- function. This means the the regex is compiled with PCRE2 default
- semantics. In particular, the way it handles newline characters in the
- subject string is the Perl way, not the POSIX way. Note that setting
+ In the absence of these flags, no options are passed to the native
+ function. This means the the regex is compiled with PCRE2 default
+ semantics. In particular, the way it handles newline characters in the
+ subject string is the Perl way, not the POSIX way. Note that setting
PCRE2_MULTILINE has only some of the effects specified for REG_NEWLINE.
- It does not affect the way newlines are matched by the dot metacharac-
+ It does not affect the way newlines are matched by the dot metacharac-
ter (they are not) or by a negative class such as [^a] (they are).
- The yield of regcomp() is zero on success, and non-zero otherwise. The
- preg structure is filled in on success, and one other member of the
- structure (as well as re_endp) is public: re_nsub contains the number
+ The yield of regcomp() is zero on success, and non-zero otherwise. The
+ preg structure is filled in on success, and one other member of the
+ structure (as well as re_endp) is public: re_nsub contains the number
of capturing subpatterns in the regular expression. Various error codes
are defined in the header file.
- NOTE: If the yield of regcomp() is non-zero, you must not attempt to
+ NOTE: If the yield of regcomp() is non-zero, you must not attempt to
use the contents of the preg structure. If, for example, you pass it to
regexec(), the result is undefined and your program is likely to crash.
@@ -9572,9 +9590,9 @@
MATCHING NEWLINE CHARACTERS
This area is not simple, because POSIX and Perl take different views of
- things. It is not possible to get PCRE2 to obey POSIX semantics, but
+ things. It is not possible to get PCRE2 to obey POSIX semantics, but
then PCRE2 was never intended to be a POSIX engine. The following table
- lists the different possibilities for matching newline characters in
+ lists the different possibilities for matching newline characters in
Perl and PCRE2:
Default Change with
@@ -9595,25 +9613,25 @@
$ matches \n in middle no REG_NEWLINE
^ matches \n in middle no REG_NEWLINE
- This behaviour is not what happens when PCRE2 is called via its POSIX
- API. By default, PCRE2's behaviour is the same as Perl's, except that
- there is no equivalent for PCRE2_DOLLAR_ENDONLY in Perl. In both PCRE2
+ This behaviour is not what happens when PCRE2 is called via its POSIX
+ API. By default, PCRE2's behaviour is the same as Perl's, except that
+ there is no equivalent for PCRE2_DOLLAR_ENDONLY in Perl. In both PCRE2
and Perl, there is no way to stop newline from matching [^a].
- Default POSIX newline handling can be obtained by setting PCRE2_DOTALL
- and PCRE2_DOLLAR_ENDONLY when calling pcre2_compile() directly, but
- there is no way to make PCRE2 behave exactly as for the REG_NEWLINE
- action. When using the POSIX API, passing REG_NEWLINE to PCRE2's reg-
+ Default POSIX newline handling can be obtained by setting PCRE2_DOTALL
+ and PCRE2_DOLLAR_ENDONLY when calling pcre2_compile() directly, but
+ there is no way to make PCRE2 behave exactly as for the REG_NEWLINE
+ action. When using the POSIX API, passing REG_NEWLINE to PCRE2's reg-
comp() function causes PCRE2_MULTILINE to be passed to pcre2_compile(),
- and REG_DOTALL passes PCRE2_DOTALL. There is no way to pass PCRE2_DOL-
+ and REG_DOTALL passes PCRE2_DOTALL. There is no way to pass PCRE2_DOL-
LAR_ENDONLY.
MATCHING A PATTERN
- The function regexec() is called to match a compiled pattern preg
- against a given string, which is by default terminated by a zero byte
- (but see REG_STARTEND below), subject to the options in eflags. These
+ The function regexec() is called to match a compiled pattern preg
+ against a given string, which is by default terminated by a zero byte
+ (but see REG_STARTEND below), subject to the options in eflags. These
can be:
REG_NOTBOL
@@ -9623,9 +9641,9 @@
REG_NOTEMPTY
- The PCRE2_NOTEMPTY option is set when calling the underlying PCRE2
- matching function. Note that REG_NOTEMPTY is not part of the POSIX
- standard. However, setting this option can give more POSIX-like behav-
+ The PCRE2_NOTEMPTY option is set when calling the underlying PCRE2
+ matching function. Note that REG_NOTEMPTY is not part of the POSIX
+ standard. However, setting this option can give more POSIX-like behav-
iour in some situations.
REG_NOTEOL
@@ -9635,46 +9653,46 @@
REG_STARTEND
- When this option is set, the subject string starts at string +
- pmatch[0].rm_so and ends at string + pmatch[0].rm_eo, which should
- point to the first character beyond the string. There may be binary
- zeros within the subject string, and indeed, using REG_STARTEND is the
+ When this option is set, the subject string starts at string +
+ pmatch[0].rm_so and ends at string + pmatch[0].rm_eo, which should
+ point to the first character beyond the string. There may be binary
+ zeros within the subject string, and indeed, using REG_STARTEND is the
only way to pass a subject string that contains a binary zero.
- Whatever the value of pmatch[0].rm_so, the offsets of the matched
- string and any captured substrings are still given relative to the
- start of string itself. (Before PCRE2 release 10.30 these were given
- relative to string + pmatch[0].rm_so, but this differs from other
+ Whatever the value of pmatch[0].rm_so, the offsets of the matched
+ string and any captured substrings are still given relative to the
+ start of string itself. (Before PCRE2 release 10.30 these were given
+ relative to string + pmatch[0].rm_so, but this differs from other
implementations.)
- This is a BSD extension, compatible with but not specified by IEEE
- Standard 1003.2 (POSIX.2), and should be used with caution in software
- intended to be portable to other systems. Note that a non-zero rm_so
- does not imply REG_NOTBOL; REG_STARTEND affects only the location and
- length of the string, not how it is matched. Setting REG_STARTEND and
- passing pmatch as NULL are mutually exclusive; the error REG_INVARG is
+ This is a BSD extension, compatible with but not specified by IEEE
+ Standard 1003.2 (POSIX.2), and should be used with caution in software
+ intended to be portable to other systems. Note that a non-zero rm_so
+ does not imply REG_NOTBOL; REG_STARTEND affects only the location and
+ length of the string, not how it is matched. Setting REG_STARTEND and
+ passing pmatch as NULL are mutually exclusive; the error REG_INVARG is
returned.
- If the pattern was compiled with the REG_NOSUB flag, no data about any
- matched strings is returned. The nmatch and pmatch arguments of
+ If the pattern was compiled with the REG_NOSUB flag, no data about any
+ matched strings is returned. The nmatch and pmatch arguments of
regexec() are ignored (except possibly as input for REG_STARTEND).
- The value of nmatch may be zero, and the value pmatch may be NULL
- (unless REG_STARTEND is set); in both these cases no data about any
+ The value of nmatch may be zero, and the value pmatch may be NULL
+ (unless REG_STARTEND is set); in both these cases no data about any
matched strings is returned.
- Otherwise, the portion of the string that was matched, and also any
+ Otherwise, the portion of the string that was matched, and also any
captured substrings, are returned via the pmatch argument, which points
- to an array of nmatch structures of type regmatch_t, containing the
- members rm_so and rm_eo. These contain the byte offset to the first
+ to an array of nmatch structures of type regmatch_t, containing the
+ members rm_so and rm_eo. These contain the byte offset to the first
character of each substring and the offset to the first character after
- the end of each substring, respectively. The 0th element of the vector
- relates to the entire portion of string that was matched; subsequent
+ the end of each substring, respectively. The 0th element of the vector
+ relates to the entire portion of string that was matched; subsequent
elements relate to the capturing subpatterns of the regular expression.
Unused entries in the array have both structure members set to -1.
- A successful match yields a zero return; various error codes are
- defined in the header file, of which REG_NOMATCH is the "expected"
+ A successful match yields a zero return; various error codes are
+ defined in the header file, of which REG_NOMATCH is the "expected"
failure code.
@@ -9681,20 +9699,20 @@
ERROR MESSAGES
The regerror() function maps a non-zero errorcode from either regcomp()
- or regexec() to a printable message. If preg is not NULL, the error
+ or regexec() to a printable message. If preg is not NULL, the error
should have arisen from the use of that structure. A message terminated
- by a binary zero is placed in errbuf. If the buffer is too short, only
+ by a binary zero is placed in errbuf. If the buffer is too short, only
the first errbuf_size - 1 characters of the error message are used. The
- yield of the function is the size of buffer needed to hold the whole
- message, including the terminating zero. This value is greater than
+ yield of the function is the size of buffer needed to hold the whole
+ message, including the terminating zero. This value is greater than
errbuf_size if the message was truncated.
MEMORY USAGE
- Compiling a regular expression causes memory to be allocated and asso-
- ciated with the preg structure. The function regfree() frees all such
- memory, after which preg may no longer be used as a compiled expres-
+ Compiling a regular expression causes memory to be allocated and asso-
+ ciated with the preg structure. The function regfree() frees all such
+ memory, after which preg may no longer be used as a compiled expres-
sion.
@@ -9707,8 +9725,8 @@
REVISION
- Last updated: 15 June 2017
- Copyright (c) 1997-2017 University of Cambridge.
+ Last updated: 19 September 2018
+ Copyright (c) 1997-2018 University of Cambridge.
------------------------------------------------------------------------------
