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1  README file for PCRE (Perl-compatible regular expressions)  README file for PCRE (Perl-compatible regular expression library)
2  ----------------------------------------------------------  -----------------------------------------------------------------
3    
4  *******************************************************************************  The latest release of PCRE is always available from
 *           IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00           *  
 *                                                                             *  
 * Please note that there has been a change in the API such that a larger      *  
 * ovector is required at matching time, to provide some additional workspace. *  
 * The new man page has details. This change was necessary in order to support *  
 * some of the new functionality in Perl 5.005.                                *  
 *                                                                             *  
 *           IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00                   *  
 *                                                                             *  
 * Another (I hope this is the last!) change has been made to the API for the  *  
 * pcre_compile() function. An additional argument has been added to make it   *  
 * possible to pass over a pointer to character tables built in the current    *  
 * locale by pcre_maketables(). To use the default tables, this new arguement  *  
 * should be passed as NULL.                                                   *  
 *                                                                             *  
 *           IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05                   *  
 *                                                                             *  
 * Yet another (and again I hope this really is the last) change has been made *  
 * to the API for the pcre_exec() function. An additional argument has been    *  
 * added to make it possible to start the match other than at the start of the *  
 * subject string. This is important if there are lookbehinds. The new man     *  
 * page has the details, but you just want to convert existing programs, all   *  
 * you need to do is to stick in a new fifth argument to pcre_exec(), with a   *  
 * value of zero. For example, change                                          *  
 *                                                                             *  
 *   pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)       *  
 * to                                                                          *  
 *   pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)    *  
 *******************************************************************************  
5    
6      ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.gz
7    
8  The distribution should contain the following files:  There is a mailing list for discussion about the development of PCRE at
9    
10    ChangeLog         log of changes to the code    pcre-dev@exim.org
11    LICENCE           conditions for the use of PCRE  
12    Makefile          for building PCRE in Unix systems  Please read the NEWS file if you are upgrading from a previous release.
13    README            this file  The contents of this README file are:
14    RunTest           a Unix shell script for running tests  
15    Tech.Notes        notes on the encoding    The PCRE APIs
16    pcre.3            man page source for the functions    Documentation for PCRE
17    pcre.3.txt        plain text version    Contributions by users of PCRE
18    pcre.3.html       HTML version    Building PCRE on non-Unix systems
19    pcreposix.3       man page source for the POSIX wrapper API    Building PCRE on Unix-like systems
20    pcreposix.3.txt   plain text version    Retrieving configuration information on Unix-like systems
21    pcreposix.3.HTML  HTML version    Shared libraries on Unix-like systems
22    dftables.c        auxiliary program for building chartables.c    Cross-compiling on Unix-like systems
23    get.c             )    Using HP's ANSI C++ compiler (aCC)
24    maketables.c      )    Making new tarballs
25    study.c           ) source of    Testing PCRE
26    pcre.c            )   the functions    Character tables
27    pcreposix.c       )    File manifest
28    pcre.h            header for the external API  
29    pcreposix.h       header for the external POSIX wrapper API  
30    internal.h        header for internal use  The PCRE APIs
31    pcretest.c        test program  -------------
32    pgrep.1           man page source for pgrep  
33    pgrep.1.txt       plain text version  PCRE is written in C, and it has its own API. The distribution also includes a
34    pgrep.1.HTML      HTML version  set of C++ wrapper functions (see the pcrecpp man page for details), courtesy
35    pgrep.c           source of a grep utility that uses PCRE  of Google Inc.
36    perltest          Perl test program  
37    testinput1        test data, compatible with Perl 5.004 and 5.005  In addition, there is a set of C wrapper functions that are based on the POSIX
38    testinput2        test data for error messages and non-Perl things  regular expression API (see the pcreposix man page). These end up in the
39    testinput3        test data, compatible with Perl 5.005  library called libpcreposix. Note that this just provides a POSIX calling
40    testinput4        test data for locale-specific tests  interface to PCRE; the regular expressions themselves still follow Perl syntax
41    testoutput1       test results corresponding to testinput1  and semantics. The POSIX API is restricted, and does not give full access to
42    testoutput2       test results corresponding to testinput2  all of PCRE's facilities.
43    testoutput3       test results corresponding to testinput3  
44    testoutput4       test results corresponding to testinput4  The header file for the POSIX-style functions is called pcreposix.h. The
45    dll.mk            for Win32 DLL  official POSIX name is regex.h, but I did not want to risk possible problems
46    pcre.def          ditto  with existing files of that name by distributing it that way. To use PCRE with
47    an existing program that uses the POSIX API, pcreposix.h will have to be
48  To build PCRE on a Unix system, first edit Makefile for your system. It is a  renamed or pointed at by a link.
49  fairly simple make file, and there are some comments near the top, after the  
50  text "On a Unix system". Then run "make". It builds two libraries called  If you are using the POSIX interface to PCRE and there is already a POSIX regex
51  libpcre.a and libpcreposix.a, a test program called pcretest, and the pgrep  library installed on your system, as well as worrying about the regex.h header
52  command. You can use "make install" to copy these, and the public header file  file (as mentioned above), you must also take care when linking programs to
53  pcre.h, to appropriate live directories on your system. These installation  ensure that they link with PCRE's libpcreposix library. Otherwise they may pick
54  directories are defined at the top of the Makefile, and you should edit them if  up the POSIX functions of the same name from the other library.
55  necessary.  
56    One way of avoiding this confusion is to compile PCRE with the addition of
57  For a non-Unix system, read the comments at the top of Makefile, which give  -Dregcomp=PCREregcomp (and similarly for the other POSIX functions) to the
58  some hints on what needs to be done. PCRE has been compiled on Windows systems  compiler flags (CFLAGS if you are using "configure" -- see below). This has the
59  and on Macintoshes, but I don't know the details as I don't use those systems.  effect of renaming the functions so that the names no longer clash. Of course,
60  It should be straightforward to build PCRE on any system that has a Standard C  you have to do the same thing for your applications, or write them using the
61    new names.
62    
63    
64    Documentation for PCRE
65    ----------------------
66    
67    If you install PCRE in the normal way on a Unix-like system, you will end up
68    with a set of man pages whose names all start with "pcre". The one that is just
69    called "pcre" lists all the others. In addition to these man pages, the PCRE
70    documentation is supplied in two other forms:
71    
72      1. There are files called doc/pcre.txt, doc/pcregrep.txt, and
73         doc/pcretest.txt in the source distribution. The first of these is a
74         concatenation of the text forms of all the section 3 man pages except
75         those that summarize individual functions. The other two are the text
76         forms of the section 1 man pages for the pcregrep and pcretest commands.
77         These text forms are provided for ease of scanning with text editors or
78         similar tools. They are installed in <prefix>/share/doc/pcre, where
79         <prefix> is the installation prefix (defaulting to /usr/local).
80    
81      2. A set of files containing all the documentation in HTML form, hyperlinked
82         in various ways, and rooted in a file called index.html, is distributed in
83         doc/html and installed in <prefix>/share/doc/pcre/html.
84    
85    
86    Contributions by users of PCRE
87    ------------------------------
88    
89    You can find contributions from PCRE users in the directory
90    
91      ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib
92    
93    There is a README file giving brief descriptions of what they are. Some are
94    complete in themselves; others are pointers to URLs containing relevant files.
95    Some of this material is likely to be well out-of-date. Several of the earlier
96    contributions provided support for compiling PCRE on various flavours of
97    Windows (I myself do not use Windows). Nowadays there is more Windows support
98    in the standard distribution, so these contibutions have been archived.
99    
100    
101    Building PCRE on non-Unix systems
102    ---------------------------------
103    
104    For a non-Unix system, please read the comments in the file NON-UNIX-USE,
105    though if your system supports the use of "configure" and "make" you may be
106    able to build PCRE in the same way as for Unix-like systems.
107    
108    PCRE has been compiled on many different operating systems. It should be
109    straightforward to build PCRE on any system that has a Standard C compiler and
110    library, because it uses only Standard C functions.
111    
112    
113    Building PCRE on Unix-like systems
114    ----------------------------------
115    
116    If you are using HP's ANSI C++ compiler (aCC), please see the special note
117    in the section entitled "Using HP's ANSI C++ compiler (aCC)" below.
118    
119    The following instructions assume the use of the widely used "configure, make,
120    make install" process. There is also some experimental support for "cmake" in
121    the PCRE distribution, but it is incomplete and not documented. However, if you
122    are a "cmake" user, you might want to try it.
123    
124    To build PCRE on a Unix-like system, first run the "configure" command from the
125    PCRE distribution directory, with your current directory set to the directory
126    where you want the files to be created. This command is a standard GNU
127    "autoconf" configuration script, for which generic instructions are supplied in
128    the file INSTALL.
129    
130    Most commonly, people build PCRE within its own distribution directory, and in
131    this case, on many systems, just running "./configure" is sufficient. However,
132    the usual methods of changing standard defaults are available. For example:
133    
134    CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
135    
136    specifies that the C compiler should be run with the flags '-O2 -Wall' instead
137    of the default, and that "make install" should install PCRE under /opt/local
138    instead of the default /usr/local.
139    
140    If you want to build in a different directory, just run "configure" with that
141    directory as current. For example, suppose you have unpacked the PCRE source
142    into /source/pcre/pcre-xxx, but you want to build it in /build/pcre/pcre-xxx:
143    
144    cd /build/pcre/pcre-xxx
145    /source/pcre/pcre-xxx/configure
146    
147    PCRE is written in C and is normally compiled as a C library. However, it is
148    possible to build it as a C++ library, though the provided building apparatus
149    does not have any features to support this.
150    
151    There are some optional features that can be included or omitted from the PCRE
152    library. You can read more about them in the pcrebuild man page.
153    
154    . If you want to suppress the building of the C++ wrapper library, you can add
155      --disable-cpp to the "configure" command. Otherwise, when "configure" is run,
156      it will try to find a C++ compiler and C++ header files, and if it succeeds,
157      it will try to build the C++ wrapper.
158    
159    . If you want to make use of the support for UTF-8 character strings in PCRE,
160      you must add --enable-utf8 to the "configure" command. Without it, the code
161      for handling UTF-8 is not included in the library. (Even when included, it
162      still has to be enabled by an option at run time.)
163    
164    . If, in addition to support for UTF-8 character strings, you want to include
165      support for the \P, \p, and \X sequences that recognize Unicode character
166      properties, you must add --enable-unicode-properties to the "configure"
167      command. This adds about 30K to the size of the library (in the form of a
168      property table); only the basic two-letter properties such as Lu are
169      supported.
170    
171    . You can build PCRE to recognize either CR or LF or the sequence CRLF or any
172      of the preceding, or any of the Unicode newline sequences as indicating the
173      end of a line. Whatever you specify at build time is the default; the caller
174      of PCRE can change the selection at run time. The default newline indicator
175      is a single LF character (the Unix standard). You can specify the default
176      newline indicator by adding --enable-newline-is-cr or --enable-newline-is-lf
177      or --enable-newline-is-crlf or --enable-newline-is-anycrlf or
178      --enable-newline-is-any to the "configure" command, respectively.
179    
180      If you specify --enable-newline-is-cr or --enable-newline-is-crlf, some of
181      the standard tests will fail, because the lines in the test files end with
182      LF. Even if the files are edited to change the line endings, there are likely
183      to be some failures. With --enable-newline-is-anycrlf or
184      --enable-newline-is-any, many tests should succeed, but there may be some
185      failures.
186    
187    . When called via the POSIX interface, PCRE uses malloc() to get additional
188      storage for processing capturing parentheses if there are more than 10 of
189      them in a pattern. You can increase this threshold by setting, for example,
190    
191      --with-posix-malloc-threshold=20
192    
193      on the "configure" command.
194    
195    . PCRE has a counter that can be set to limit the amount of resources it uses.
196      If the limit is exceeded during a match, the match fails. The default is ten
197      million. You can change the default by setting, for example,
198    
199      --with-match-limit=500000
200    
201      on the "configure" command. This is just the default; individual calls to
202      pcre_exec() can supply their own value. There is more discussion on the
203      pcreapi man page.
204    
205    . There is a separate counter that limits the depth of recursive function calls
206      during a matching process. This also has a default of ten million, which is
207      essentially "unlimited". You can change the default by setting, for example,
208    
209      --with-match-limit-recursion=500000
210    
211      Recursive function calls use up the runtime stack; running out of stack can
212      cause programs to crash in strange ways. There is a discussion about stack
213      sizes in the pcrestack man page.
214    
215    . The default maximum compiled pattern size is around 64K. You can increase
216      this by adding --with-link-size=3 to the "configure" command. You can
217      increase it even more by setting --with-link-size=4, but this is unlikely
218      ever to be necessary. Increasing the internal link size will reduce
219      performance.
220    
221    . You can build PCRE so that its internal match() function that is called from
222      pcre_exec() does not call itself recursively. Instead, it uses memory blocks
223      obtained from the heap via the special functions pcre_stack_malloc() and
224      pcre_stack_free() to save data that would otherwise be saved on the stack. To
225      build PCRE like this, use
226    
227      --disable-stack-for-recursion
228    
229      on the "configure" command. PCRE runs more slowly in this mode, but it may be
230      necessary in environments with limited stack sizes. This applies only to the
231      pcre_exec() function; it does not apply to pcre_dfa_exec(), which does not
232      use deeply nested recursion. There is a discussion about stack sizes in the
233      pcrestack man page.
234    
235    . For speed, PCRE uses four tables for manipulating and identifying characters
236      whose code point values are less than 256. By default, it uses a set of
237      tables for ASCII encoding that is part of the distribution. If you specify
238    
239      --enable-rebuild-chartables
240    
241      a program called dftables is compiled and run in the default C locale when
242      you obey "make". It builds a source file called pcre_chartables.c. If you do
243      not specify this option, pcre_chartables.c is created as a copy of
244      pcre_chartables.c.dist. See "Character tables" below for further information.
245    
246    . It is possible to compile PCRE for use on systems that use EBCDIC as their
247      default character code (as opposed to ASCII) by specifying
248    
249      --enable-ebcdic
250    
251      This automatically implies --enable-rebuild-chartables (see above).
252    
253    The "configure" script builds the following files for the basic C library:
254    
255    . Makefile is the makefile that builds the library
256    . config.h contains build-time configuration options for the library
257    . pcre.h is the public PCRE header file
258    . pcre-config is a script that shows the settings of "configure" options
259    . libpcre.pc is data for the pkg-config command
260    . libtool is a script that builds shared and/or static libraries
261    . RunTest is a script for running tests on the basic C library
262    . RunGrepTest is a script for running tests on the pcregrep command
263    
264    Versions of config.h and pcre.h are distributed in the PCRE tarballs under
265    the names config.h.generic and pcre.h.generic. These are provided for the
266    benefit of those who have to built PCRE without the benefit of "configure". If
267    you use "configure", the .generic versions are not used.
268    
269    If a C++ compiler is found, the following files are also built:
270    
271    . libpcrecpp.pc is data for the pkg-config command
272    . pcrecpparg.h is a header file for programs that call PCRE via the C++ wrapper
273    . pcre_stringpiece.h is the header for the C++ "stringpiece" functions
274    
275    The "configure" script also creates config.status, which is an executable
276    script that can be run to recreate the configuration, and config.log, which
277    contains compiler output from tests that "configure" runs.
278    
279    Once "configure" has run, you can run "make". It builds two libraries, called
280    libpcre and libpcreposix, a test program called pcretest, a demonstration
281    program called pcredemo, and the pcregrep command. If a C++ compiler was found
282    on your system, "make" also builds the C++ wrapper library, which is called
283    libpcrecpp, and some test programs called pcrecpp_unittest,
284    pcre_scanner_unittest, and pcre_stringpiece_unittest. Building the C++ wrapper
285    can be disabled by adding --disable-cpp to the "configure" command.
286    
287    The command "make check" runs all the appropriate tests. Details of the PCRE
288    tests are given below in a separate section of this document.
289    
290    You can use "make install" to install PCRE into live directories on your
291    system. The following are installed (file names are all relative to the
292    <prefix> that is set when "configure" is run):
293    
294      Commands (bin):
295        pcretest
296        pcregrep
297        pcre-config
298    
299      Libraries (lib):
300        libpcre
301        libpcreposix
302        libpcrecpp (if C++ support is enabled)
303    
304      Configuration information (lib/pkgconfig):
305        libpcre.pc
306        libpcrecpp.pc (if C++ support is enabled)
307    
308      Header files (include):
309        pcre.h
310        pcreposix.h
311        pcre_scanner.h      )
312        pcre_stringpiece.h  ) if C++ support is enabled
313        pcrecpp.h           )
314        pcrecpparg.h        )
315    
316      Man pages (share/man/man{1,3}):
317        pcregrep.1
318        pcretest.1
319        pcre.3
320        pcre*.3 (lots more pages, all starting "pcre")
321    
322      HTML documentation (share/doc/pcre/html):
323        index.html
324        *.html (lots more pages, hyperlinked from index.html)
325    
326      Text file documentation (share/doc/pcre):
327        AUTHORS
328        COPYING
329        ChangeLog
330        LICENCE
331        NEWS
332        README
333        pcre.txt       (a concatenation of the man(3) pages)
334        pcretest.txt   the pcretest man page
335        pcregrep.txt   the pcregrep man page
336    
337    Note that the pcredemo program that is built by "configure" is *not* installed
338    anywhere. It is a demonstration for programmers wanting to use PCRE.
339    
340    If you want to remove PCRE from your system, you can run "make uninstall".
341    This removes all the files that "make install" installed. However, it does not
342    remove any directories, because these are often shared with other programs.
343    
344    
345    Retrieving configuration information on Unix-like systems
346    ---------------------------------------------------------
347    
348    Running "make install" installs the command pcre-config, which can be used to
349    recall information about the PCRE configuration and installation. For example:
350    
351      pcre-config --version
352    
353    prints the version number, and
354    
355      pcre-config --libs
356    
357    outputs information about where the library is installed. This command can be
358    included in makefiles for programs that use PCRE, saving the programmer from
359    having to remember too many details.
360    
361    The pkg-config command is another system for saving and retrieving information
362    about installed libraries. Instead of separate commands for each library, a
363    single command is used. For example:
364    
365      pkg-config --cflags pcre
366    
367    The data is held in *.pc files that are installed in a directory called
368    <prefix>/lib/pkgconfig.
369    
370    
371    Shared libraries on Unix-like systems
372    -------------------------------------
373    
374    The default distribution builds PCRE as shared libraries and static libraries,
375    as long as the operating system supports shared libraries. Shared library
376    support relies on the "libtool" script which is built as part of the
377    "configure" process.
378    
379    The libtool script is used to compile and link both shared and static
380    libraries. They are placed in a subdirectory called .libs when they are newly
381    built. The programs pcretest and pcregrep are built to use these uninstalled
382    libraries (by means of wrapper scripts in the case of shared libraries). When
383    you use "make install" to install shared libraries, pcregrep and pcretest are
384    automatically re-built to use the newly installed shared libraries before being
385    installed themselves. However, the versions left in the build directory still
386    use the uninstalled libraries.
387    
388    To build PCRE using static libraries only you must use --disable-shared when
389    configuring it. For example:
390    
391    ./configure --prefix=/usr/gnu --disable-shared
392    
393    Then run "make" in the usual way. Similarly, you can use --disable-static to
394    build only shared libraries.
395    
396    
397    Cross-compiling on Unix-like systems
398    ------------------------------------
399    
400    You can specify CC and CFLAGS in the normal way to the "configure" command, in
401    order to cross-compile PCRE for some other host. However, you should NOT
402    specify --enable-rebuild-chartables, because if you do, the dftables.c source
403    file is compiled and run on the local host, in order to generate the inbuilt
404    character tables (the pcre_chartables.c file). This will probably not work,
405    because dftables.c needs to be compiled with the local compiler, not the cross
406  compiler.  compiler.
407    
408  Some help in building a Win32 DLL of PCRE in GnuWin32 environments was  When --enable-rebuild-chartables is not specified, pcre_chartables.c is created
409  contributed by Paul.Sokolovsky@technologist.com. These environments are  by making a copy of pcre_chartables.c.dist, which is a default set of tables
410  Mingw32 (http://www.xraylith.wisc.edu/~khan/software/gnu-win32/) and  that assumes ASCII code. Cross-compiling with the default tables should not be
411  CygWin  (http://sourceware.cygnus.com/cygwin/). Paul comments:  a problem.
412    
413    For CygWin, set CFLAGS=-mno-cygwin, and do 'make dll'. You'll get  If you need to modify the character tables when cross-compiling, you should
414    pcre.dll (containing pcreposix also), libpcre.dll.a, and dynamically  move pcre_chartables.c.dist out of the way, then compile dftables.c by hand and
415    linked pgrep and pcretest. If you have /bin/sh, run RunTest (three  run it on the local host to make a new version of pcre_chartables.c.dist.
416    main test go ok, locale not supported).  Then when you cross-compile PCRE this new version of the tables will be used.
417    
418  To test PCRE, run the RunTest script in the pcre directory. This can also be  
419  run by "make runtest". It runs the pcretest test program (which is documented  Using HP's ANSI C++ compiler (aCC)
420  below) on each of the testinput files in turn, and compares the output with the  ----------------------------------
421  contents of the corresponding testoutput file. A file called testtry is used to  
422  hold the output from pcretest. To run pcretest on just one of the test files,  Unless C++ support is disabled by specifying the "--disable-cpp" option of the
423  give its number as an argument to RunTest, for example:  "configure" script, you must include the "-AA" option in the CXXFLAGS
424    environment variable in order for the C++ components to compile correctly.
425    RunTest 3  
426    Also, note that the aCC compiler on PA-RISC platforms may have a defect whereby
427  The first and third test files can also be fed directly into the perltest  needed libraries fail to get included when specifying the "-AA" compiler
428  script to check that Perl gives the same results. The third file requires the  option. If you experience unresolved symbols when linking the C++ programs,
429  additional features of release 5.005, which is why it is kept separate from the  use the workaround of specifying the following environment variable prior to
430  main test input, which needs only Perl 5.004. In the long run, when 5.005 is  running the "configure" script:
431  widespread, these two test files may get amalgamated.  
432      CXXLDFLAGS="-lstd_v2 -lCsup_v2"
433  The second set of tests check pcre_info(), pcre_study(), pcre_copy_substring(),  
434  pcre_get_substring(), pcre_get_substring_list(), error detection and run-time  
435  flags that are specific to PCRE, as well as the POSIX wrapper API.  Making new tarballs
436    -------------------
437    
438    The command "make dist" creates three PCRE tarballs, in tar.gz, tar.bz2, and
439    zip formats. The command "make distcheck" does the same, but then does a trial
440    build of the new distribution to ensure that it works.
441    
442    If you have modified any of the man page sources in the doc directory, you
443    should first run the PrepareRelease script before making a distribution. This
444    script creates the .txt and HTML forms of the documentation from the man pages.
445    
446    
447    Testing PCRE
448    ------------
449    
450    To test the basic PCRE library on a Unix system, run the RunTest script that is
451    created by the configuring process. There is also a script called RunGrepTest
452    that tests the options of the pcregrep command. If the C++ wrapper library is
453    built, three test programs called pcrecpp_unittest, pcre_scanner_unittest, and
454    pcre_stringpiece_unittest are also built.
455    
456    Both the scripts and all the program tests are run if you obey "make check" or
457    "make test". For other systems, see the instructions in NON-UNIX-USE.
458    
459    The RunTest script runs the pcretest test program (which is documented in its
460    own man page) on each of the testinput files in the testdata directory in
461    turn, and compares the output with the contents of the corresponding testoutput
462    files. A file called testtry is used to hold the main output from pcretest
463    (testsavedregex is also used as a working file). To run pcretest on just one of
464    the test files, give its number as an argument to RunTest, for example:
465    
466      RunTest 2
467    
468    The first test file can also be fed directly into the perltest.pl script to
469    check that Perl gives the same results. The only difference you should see is
470    in the first few lines, where the Perl version is given instead of the PCRE
471    version.
472    
473    The second set of tests check pcre_fullinfo(), pcre_info(), pcre_study(),
474    pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error
475    detection, and run-time flags that are specific to PCRE, as well as the POSIX
476    wrapper API. It also uses the debugging flags to check some of the internals of
477    pcre_compile().
478    
479    If you build PCRE with a locale setting that is not the standard C locale, the
480    character tables may be different (see next paragraph). In some cases, this may
481    cause failures in the second set of tests. For example, in a locale where the
482    isprint() function yields TRUE for characters in the range 128-255, the use of
483    [:isascii:] inside a character class defines a different set of characters, and
484    this shows up in this test as a difference in the compiled code, which is being
485    listed for checking. Where the comparison test output contains [\x00-\x7f] the
486    test will contain [\x00-\xff], and similarly in some other cases. This is not a
487    bug in PCRE.
488    
489  The fourth set of tests checks pcre_maketables(), the facility for building a  The third set of tests checks pcre_maketables(), the facility for building a
490  set of character tables for a specific locale and using them instead of the  set of character tables for a specific locale and using them instead of the
491  default tables. The tests make use of the "fr" (French) locale. Before running  default tables. The tests make use of the "fr_FR" (French) locale. Before
492  the test, the script checks for the presence of this locale by running the  running the test, the script checks for the presence of this locale by running
493  "locale" command. If that command fails, or if it doesn't include "fr" in the  the "locale" command. If that command fails, or if it doesn't include "fr_FR"
494  list of available locales, the fourth test cannot be run, and a comment is  in the list of available locales, the third test cannot be run, and a comment
495  output to say why. If running this test produces instances of the error  is output to say why. If running this test produces instances of the error
496    
497    ** Failed to set locale "fr"    ** Failed to set locale "fr_FR"
498    
499  in the comparison output, it means that locale is not available on your system,  in the comparison output, it means that locale is not available on your system,
500  despite being listed by "locale". This does not mean that PCRE is broken.  despite being listed by "locale". This does not mean that PCRE is broken.
501    
502  PCRE has its own native API, but a set of "wrapper" functions that are based on  [If you are trying to run this test on Windows, you may be able to get it to
503  the POSIX API are also supplied in the library libpcreposix.a. Note that this  work by changing "fr_FR" to "french" everywhere it occurs.]
504  just provides a POSIX calling interface to PCRE: the regular expressions  
505  themselves still follow Perl syntax and semantics. The header file  The fourth test checks the UTF-8 support. It is not run automatically unless
506  for the POSIX-style functions is called pcreposix.h. The official POSIX name is  PCRE is built with UTF-8 support. To do this you must set --enable-utf8 when
507  regex.h, but I didn't want to risk possible problems with existing files of  running "configure". This file can be also fed directly to the perltest script,
508  that name by distributing it that way. To use it with an existing program that  provided you are running Perl 5.8 or higher. (For Perl 5.6, a small patch,
509  uses the POSIX API, it will have to be renamed or pointed at by a link.  commented in the script, can be be used.)
510    
511    The fifth test checks error handling with UTF-8 encoding, and internal UTF-8
512    features of PCRE that are not relevant to Perl.
513    
514    The sixth test checks the support for Unicode character properties. It it not
515    run automatically unless PCRE is built with Unicode property support. To to
516    this you must set --enable-unicode-properties when running "configure".
517    
518    The seventh, eighth, and ninth tests check the pcre_dfa_exec() alternative
519    matching function, in non-UTF-8 mode, UTF-8 mode, and UTF-8 mode with Unicode
520    property support, respectively. The eighth and ninth tests are not run
521    automatically unless PCRE is build with the relevant support.
522    
523    
524  Character tables  Character tables
525  ----------------  ----------------
526    
527  PCRE uses four tables for manipulating and identifying characters. The final  For speed, PCRE uses four tables for manipulating and identifying characters
528  argument of the pcre_compile() function is a pointer to a block of memory  whose code point values are less than 256. The final argument of the
529  containing the concatenated tables. A call to pcre_maketables() can be used to  pcre_compile() function is a pointer to a block of memory containing the
530  generate a set of tables in the current locale. If the final argument for  concatenated tables. A call to pcre_maketables() can be used to generate a set
531  pcre_compile() is passed as NULL, a set of default tables that is built into  of tables in the current locale. If the final argument for pcre_compile() is
532  the binary is used.  passed as NULL, a set of default tables that is built into the binary is used.
533    
534  The source file called chartables.c contains the default set of tables. This is  The source file called pcre_chartables.c contains the default set of tables. By
535  not supplied in the distribution, but is built by the program dftables  default, this is created as a copy of pcre_chartables.c.dist, which contains
536  (compiled from dftables.c), which uses the ANSI C character handling functions  tables for ASCII coding. However, if --enable-rebuild-chartables is specified
537  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table  for ./configure, a different version of pcre_chartables.c is built by the
538  sources. This means that the default C locale which is set for your system will  program dftables (compiled from dftables.c), which uses the ANSI C character
539  control the contents of these default tables. You can change the default tables  handling functions such as isalnum(), isalpha(), isupper(), islower(), etc. to
540  by editing chartables.c and then re-building PCRE. If you do this, you should  build the table sources. This means that the default C locale which is set for
541  probably also edit Makefile to ensure that the file doesn't ever get  your system will control the contents of these default tables. You can change
542  re-generated.  the default tables by editing pcre_chartables.c and then re-building PCRE. If
543    you do this, you should take care to ensure that the file does not get
544    automatically re-generated. The best way to do this is to move
545    pcre_chartables.c.dist out of the way and replace it with your customized
546    tables.
547    
548    When the dftables program is run as a result of --enable-rebuild-chartables,
549    it uses the default C locale that is set on your system. It does not pay
550    attention to the LC_xxx environment variables. In other words, it uses the
551    system's default locale rather than whatever the compiling user happens to have
552    set. If you really do want to build a source set of character tables in a
553    locale that is specified by the LC_xxx variables, you can run the dftables
554    program by hand with the -L option. For example:
555    
556      ./dftables -L pcre_chartables.c.special
557    
558  The first two 256-byte tables provide lower casing and case flipping functions,  The first two 256-byte tables provide lower casing and case flipping functions,
559  respectively. The next table consists of three 32-byte bit maps which identify  respectively. The next table consists of three 32-byte bit maps which identify
560  digits, "word" characters, and white space, respectively. These are used when  digits, "word" characters, and white space, respectively. These are used when
561  building 32-byte bit maps that represent character classes.  building 32-byte bit maps that represent character classes for code points less
562    than 256.
563    
564  The final 256-byte table has bits indicating various character types, as  The final 256-byte table has bits indicating various character types, as
565  follows:  follows:
# Line 179  You should not alter the set of characte Line 575  You should not alter the set of characte
575  will cause PCRE to malfunction.  will cause PCRE to malfunction.
576    
577    
578  The pcretest program  File manifest
579  --------------------  -------------
580    
581    The distribution should contain the following files:
582    
583  This program is intended for testing PCRE, but it can also be used for  (A) Source files of the PCRE library functions and their headers:
 experimenting with regular expressions.  
584    
585  If it is given two filename arguments, it reads from the first and writes to    dftables.c              auxiliary program for building pcre_chartables.c
586  the second. If it is given only one filename argument, it reads from that file                              when --enable-rebuild-chartables is specified
 and writes to stdout. Otherwise, it reads from stdin and writes to stdout, and  
 prompts for each line of input.  
   
 The program handles any number of sets of input on a single input file. Each  
 set starts with a regular expression, and continues with any number of data  
 lines to be matched against the pattern. An empty line signals the end of the  
 set. The regular expressions are given enclosed in any non-alphameric  
 delimiters other than backslash, for example  
   
   /(a|bc)x+yz/  
   
 White space before the initial delimiter is ignored. A regular expression may  
 be continued over several input lines, in which case the newline characters are  
 included within it. See the testinput files for many examples. It is possible  
 to include the delimiter within the pattern by escaping it, for example  
   
   /abc\/def/  
   
 If you do so, the escape and the delimiter form part of the pattern, but since  
 delimiters are always non-alphameric, this does not affect its interpretation.  
 If the terminating delimiter is immediately followed by a backslash, for  
 example,  
   
   /abc/\  
   
 then a backslash is added to the end of the pattern. This is done to provide a  
 way of testing the error condition that arises if a pattern finishes with a  
 backslash, because  
   
   /abc\/  
   
 is interpreted as the first line of a pattern that starts with "abc/", causing  
 pcretest to read the next line as a continuation of the regular expression.  
   
 The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS,  
 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. For  
 example:  
   
   /caseless/i  
   
 These modifier letters have the same effect as they do in Perl. There are  
 others which set PCRE options that do not correspond to anything in Perl: /A,  
 /E, and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively.  
   
 Searching for all possible matches within each subject string can be requested  
 by the /g or /G modifier. After finding a match, PCRE is called again to search  
 the remainder of the subject string. The difference between /g and /G is that  
 the former uses the startoffset argument to pcre_exec() to start searching at  
 a new point within the entire string (which is in effect what Perl does),  
 whereas the latter passes over a shortened substring. This makes a difference  
 to the matching process if the pattern begins with a lookbehind assertion  
 (including \b or \B).  
   
 If any call to pcre_exec() in a /g or /G sequence matches an empty string, the  
 next call is done with the PCRE_NOTEMPTY flag set so that it cannot match an  
 empty string again. This imitates the way Perl handles such cases when using  
 the /g modifier or the split() function.  
   
 There are a number of other modifiers for controlling the way pcretest  
 operates.  
   
 The /+ modifier requests that as well as outputting the substring that matched  
 the entire pattern, pcretest should in addition output the remainder of the  
 subject string. This is useful for tests where the subject contains multiple  
 copies of the same substring.  
   
 The /L modifier must be followed directly by the name of a locale, for example,  
   
   /pattern/Lfr  
   
 For this reason, it must be the last modifier letter. The given locale is set,  
 pcre_maketables() is called to build a set of character tables for the locale,  
 and this is then passed to pcre_compile() when compiling the regular  
 expression. Without an /L modifier, NULL is passed as the tables pointer; that  
 is, /L applies only to the expression on which it appears.  
   
 The /I modifier requests that pcretest output information about the compiled  
 expression (whether it is anchored, has a fixed first character, and so on). It  
 does this by calling pcre_info() after compiling an expression, and outputting  
 the information it gets back. If the pattern is studied, the results of that  
 are also output.  
   
 The /D modifier is a PCRE debugging feature, which also assumes /I. It causes  
 the internal form of compiled regular expressions to be output after  
 compilation.  
   
 The /S modifier causes pcre_study() to be called after the expression has been  
 compiled, and the results used when the expression is matched.  
   
 The /M modifier causes the size of memory block used to hold the compiled  
 pattern to be output.  
   
 Finally, the /P modifier causes pcretest to call PCRE via the POSIX wrapper API  
 rather than its native API. When this is done, all other modifiers except /i,  
 /m, and /+ are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is  
 set if /m is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always,  
 and PCRE_DOTALL unless REG_NEWLINE is set.  
   
 Before each data line is passed to pcre_exec(), leading and trailing whitespace  
 is removed, and it is then scanned for \ escapes. The following are recognized:  
   
   \a     alarm (= BEL)  
   \b     backspace  
   \e     escape  
   \f     formfeed  
   \n     newline  
   \r     carriage return  
   \t     tab  
   \v     vertical tab  
   \nnn   octal character (up to 3 octal digits)  
   \xhh   hexadecimal character (up to 2 hex digits)  
   
   \A     pass the PCRE_ANCHORED option to pcre_exec()  
   \B     pass the PCRE_NOTBOL option to pcre_exec()  
   \Cdd   call pcre_copy_substring() for substring dd after a successful match  
            (any decimal number less than 32)  
   \Gdd   call pcre_get_substring() for substring dd after a successful match  
            (any decimal number less than 32)  
   \L     call pcre_get_substringlist() after a successful match  
   \N     pass the PCRE_NOTEMPTY option to pcre_exec()  
   \Odd   set the size of the output vector passed to pcre_exec() to dd  
            (any number of decimal digits)  
   \Z     pass the PCRE_NOTEOL option to pcre_exec()  
   
 A backslash followed by anything else just escapes the anything else. If the  
 very last character is a backslash, it is ignored. This gives a way of passing  
 an empty line as data, since a real empty line terminates the data input.  
   
 If /P was present on the regex, causing the POSIX wrapper API to be used, only  
 \B, and \Z have any effect, causing REG_NOTBOL and REG_NOTEOL to be passed to  
 regexec() respectively.  
   
 When a match succeeds, pcretest outputs the list of captured substrings that  
 pcre_exec() returns, starting with number 0 for the string that matched the  
 whole pattern. Here is an example of an interactive pcretest run.  
   
   $ pcretest  
   PCRE version 2.06 08-Jun-1999  
   
     re> /^abc(\d+)/  
   data> abc123  
    0: abc123  
    1: 123  
   data> xyz  
   No match  
   
 If the strings contain any non-printing characters, they are output as \0x  
 escapes. If the pattern has the /+ modifier, then the output for substring 0 is  
 followed by the the rest of the subject string, identified by "0+" like this:  
   
     re> /cat/+  
   data> cataract  
    0: cat  
    0+ aract  
   
 If the pattern has the /g or /G modifier, the results of successive matching  
 attempts are output in sequence, like this:  
   
     re> /\Bi(\w\w)/g  
   data> Mississippi  
    0: iss  
    1: ss  
    0: iss  
    1: ss  
    0: ipp  
    1: pp  
   
 "No match" is output only if the first match attempt fails.  
   
 If any of \C, \G, or \L are present in a data line that is successfully  
 matched, the substrings extracted by the convenience functions are output with  
 C, G, or L after the string number instead of a colon. This is in addition to  
 the normal full list. The string length (that is, the return from the  
 extraction function) is given in parentheses after each string for \C and \G.  
   
 Note that while patterns can be continued over several lines (a plain ">"  
 prompt is used for continuations), data lines may not. However newlines can be  
 included in data by means of the \n escape.  
   
 If the -p option is given to pcretest, it is equivalent to adding /P to each  
 regular expression: the POSIX wrapper API is used to call PCRE. None of the  
 following flags has any effect in this case.  
   
 If the option -d is given to pcretest, it is equivalent to adding /D to each  
 regular expression: the internal form is output after compilation.  
   
 If the option -i is given to pcretest, it is equivalent to adding /I to each  
 regular expression: information about the compiled pattern is given after  
 compilation.  
   
 If the option -m is given to pcretest, it outputs the size of each compiled  
 pattern after it has been compiled. It is equivalent to adding /M to each  
 regular expression. For compatibility with earlier versions of pcretest, -s is  
 a synonym for -m.  
   
 If the -t option is given, each compile, study, and match is run 20000 times  
 while being timed, and the resulting time per compile or match is output in  
 milliseconds. Do not set -t with -s, because you will then get the size output  
 20000 times and the timing will be distorted. If you want to change the number  
 of repetitions used for timing, edit the definition of LOOPREPEAT at the top of  
 pcretest.c  
   
   
   
 The perltest program  
 --------------------  
   
 The perltest program tests Perl's regular expressions; it has the same  
 specification as pcretest, and so can be given identical input, except that  
 input patterns can be followed only by Perl's lower case modifiers. The  
 contents of testinput1 and testinput3 meet this condition.  
   
 The data lines are processed as Perl double-quoted strings, so if they contain  
 " \ $ or @ characters, these have to be escaped. For this reason, all such  
 characters in testinput1 and testinput3 are escaped so that they can be used  
 for perltest as well as for pcretest, and the special upper case modifiers such  
 as /A that pcretest recognizes are not used in these files. The output should  
 be identical, apart from the initial identifying banner.  
   
 The testinput2 and testinput4 files are not suitable for feeding to perltest,  
 since they do make use of the special upper case modifiers and escapes that  
 pcretest uses to test some features of PCRE. The first of these files also  
 contains malformed regular expressions, in order to check that PCRE diagnoses  
 them correctly.  
587    
588  Philip Hazel <ph10@cam.ac.uk>    pcre_chartables.c.dist  a default set of character tables that assume ASCII
589  July 1999                              coding; used, unless --enable-rebuild-chartables is
590                                specified, by copying to pcre_chartables.c
591    
592      pcreposix.c             )
593      pcre_compile.c          )
594      pcre_config.c           )
595      pcre_dfa_exec.c         )
596      pcre_exec.c             )
597      pcre_fullinfo.c         )
598      pcre_get.c              ) sources for the functions in the library,
599      pcre_globals.c          )   and some internal functions that they use
600      pcre_info.c             )
601      pcre_maketables.c       )
602      pcre_newline.c          )
603      pcre_ord2utf8.c         )
604      pcre_refcount.c         )
605      pcre_study.c            )
606      pcre_tables.c           )
607      pcre_try_flipped.c      )
608      pcre_ucp_searchfuncs.c  )
609      pcre_valid_utf8.c       )
610      pcre_version.c          )
611      pcre_xclass.c           )
612      pcre_printint.src       ) debugging function that is #included in pcretest,
613                              )   and can also be #included in pcre_compile()
614      pcre.h.in               template for pcre.h when built by "configure"
615      pcreposix.h             header for the external POSIX wrapper API
616      pcre_internal.h         header for internal use
617      ucp.h                   ) headers concerned with
618      ucpinternal.h           )   Unicode property handling
619      ucptable.h              ) (this one is the data table)
620    
621      config.h.in             template for config.h, which is built by "configure"
622    
623      pcrecpp.h               public header file for the C++ wrapper
624      pcrecpparg.h.in         template for another C++ header file
625      pcre_scanner.h          public header file for C++ scanner functions
626      pcrecpp.cc              )
627      pcre_scanner.cc         ) source for the C++ wrapper library
628    
629      pcre_stringpiece.h.in   template for pcre_stringpiece.h, the header for the
630                                C++ stringpiece functions
631      pcre_stringpiece.cc     source for the C++ stringpiece functions
632    
633    (B) Source files for programs that use PCRE:
634    
635      pcredemo.c              simple demonstration of coding calls to PCRE
636      pcregrep.c              source of a grep utility that uses PCRE
637      pcretest.c              comprehensive test program
638    
639    (C) Auxiliary files:
640    
641      132html                 script to turn "man" pages into HTML
642      AUTHORS                 information about the author of PCRE
643      ChangeLog               log of changes to the code
644      CleanTxt                script to clean nroff output for txt man pages
645      Detrail                 script to remove trailing spaces
646      HACKING                 some notes about the internals of PCRE
647      INSTALL                 generic installation instructions
648      LICENCE                 conditions for the use of PCRE
649      COPYING                 the same, using GNU's standard name
650      Makefile.in             ) template for Unix Makefile, which is built by
651                              )   "configure"
652      Makefile.am             ) the automake input that was used to create
653                              )   Makefile.in
654      NEWS                    important changes in this release
655      NON-UNIX-USE            notes on building PCRE on non-Unix systems
656      PrepareRelease          script to make preparations for "make dist"
657      README                  this file
658      RunTest                 a Unix shell script for running tests
659      RunGrepTest             a Unix shell script for pcregrep tests
660      aclocal.m4              m4 macros (generated by "aclocal")
661      config.guess            ) files used by libtool,
662      config.sub              )   used only when building a shared library
663      configure               a configuring shell script (built by autoconf)
664      configure.ac            ) the autoconf input that was used to build
665                              )   "configure" and config.h
666      depcomp                 ) script to find program dependencies, generated by
667                              )   automake
668      doc/*.3                 man page sources for the PCRE functions
669      doc/*.1                 man page sources for pcregrep and pcretest
670      doc/index.html.src      the base HTML page
671      doc/html/*              HTML documentation
672      doc/pcre.txt            plain text version of the man pages
673      doc/pcretest.txt        plain text documentation of test program
674      doc/perltest.txt        plain text documentation of Perl test program
675      install-sh              a shell script for installing files
676      libpcre.pc.in           template for libpcre.pc for pkg-config
677      libpcrecpp.pc.in        template for libpcrecpp.pc for pkg-config
678      ltmain.sh               file used to build a libtool script
679      missing                 ) common stub for a few missing GNU programs while
680                              )   installing, generated by automake
681      mkinstalldirs           script for making install directories
682      perltest.pl             Perl test program
683      pcre-config.in          source of script which retains PCRE information
684      pcrecpp_unittest.cc          )
685      pcre_scanner_unittest.cc     ) test programs for the C++ wrapper
686      pcre_stringpiece_unittest.cc )
687      testdata/testinput*     test data for main library tests
688      testdata/testoutput*    expected test results
689      testdata/grep*          input and output for pcregrep tests
690    
691    (D) Auxiliary files for cmake support
692    
693      CMakeLists.txt
694      config-cmake.h.in
695    
696    (E) Auxiliary files for VPASCAL
697    
698      makevp.bat
699      makevp_c.txt
700      makevp_l.txt
701      pcregexp.pas
702    
703    (F) Auxiliary files for building PCRE "by hand"
704    
705      pcre.h.generic          ) a version of the public PCRE header file
706                              )   for use in non-"configure" environments
707      config.h.generic        ) a version of config.h for use in non-"configure"
708                              )   environments
709    
710    (F) Miscellaneous
711    
712      RunTest.bat            a script for running tests under Windows
713    
714    Philip Hazel
715    Email local part: ph10
716    Email domain: cam.ac.uk
717    Last updated: 24 April 2007

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