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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      pcre-dev@exim.org
11    
12    Please read the NEWS file if you are upgrading from a previous release.
13    The contents of this README file are:
14    
15      The PCRE APIs
16      Documentation for PCRE
17      Contributions by users of PCRE
18      Building PCRE on non-Unix systems
19      Building PCRE on Unix-like systems
20      Retrieving configuration information on Unix-like systems
21      Shared libraries on Unix-like systems
22      Cross-compiling on Unix-like systems
23      Using HP's ANSI C++ compiler (aCC)
24      Making new tarballs
25      Testing PCRE
26      Character tables
27      File manifest
28    
29    
30    The PCRE APIs
31    -------------
32    
33    PCRE is written in C, and it has its own API. The distribution also includes a
34    set of C++ wrapper functions (see the pcrecpp man page for details), courtesy
35    of Google Inc.
36    
37    In addition, there is a set of C wrapper functions that are based on the POSIX
38    regular expression API (see the pcreposix man page). These end up in the
39    library called libpcreposix. Note that this just provides a POSIX calling
40    interface to PCRE; the regular expressions themselves still follow Perl syntax
41    and semantics. The POSIX API is restricted, and does not give full access to
42    all of PCRE's facilities.
43    
44    The header file for the POSIX-style functions is called pcreposix.h. The
45    official POSIX name is regex.h, but I did not want to risk possible problems
46    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    renamed or pointed at by a link.
49    
50    If you are using the POSIX interface to PCRE and there is already a POSIX regex
51    library installed on your system, as well as worrying about the regex.h header
52    file (as mentioned above), you must also take care when linking programs to
53    ensure that they link with PCRE's libpcreposix library. Otherwise they may pick
54    up the POSIX functions of the same name from the other library.
55    
56    One way of avoiding this confusion is to compile PCRE with the addition of
57    -Dregcomp=PCREregcomp (and similarly for the other POSIX functions) to the
58    compiler flags (CFLAGS if you are using "configure" -- see below). This has the
59    effect of renaming the functions so that the names no longer clash. Of course,
60    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    To build PCRE on a Unix-like system, first run the "configure" command from the
120    PCRE distribution directory, with your current directory set to the directory
121    where you want the files to be created. This command is a standard GNU
122    "autoconf" configuration script, for which generic instructions are supplied in
123    the file INSTALL.
124    
125    Most commonly, people build PCRE within its own distribution directory, and in
126    this case, on many systems, just running "./configure" is sufficient. However,
127    the usual methods of changing standard defaults are available. For example:
128    
129    CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
130    
131    specifies that the C compiler should be run with the flags '-O2 -Wall' instead
132    of the default, and that "make install" should install PCRE under /opt/local
133    instead of the default /usr/local.
134    
135    If you want to build in a different directory, just run "configure" with that
136    directory as current. For example, suppose you have unpacked the PCRE source
137    into /source/pcre/pcre-xxx, but you want to build it in /build/pcre/pcre-xxx:
138    
139    cd /build/pcre/pcre-xxx
140    /source/pcre/pcre-xxx/configure
141    
142    PCRE is written in C and is normally compiled as a C library. However, it is
143    possible to build it as a C++ library, though the provided building apparatus
144    does not have any features to support this.
145    
146    There are some optional features that can be included or omitted from the PCRE
147    library. You can read more about them in the pcrebuild man page.
148    
149    . If you want to suppress the building of the C++ wrapper library, you can add
150      --disable-cpp to the "configure" command. Otherwise, when "configure" is run,
151      it will try to find a C++ compiler and C++ header files, and if it succeeds,
152      it will try to build the C++ wrapper.
153    
154    . If you want to make use of the support for UTF-8 character strings in PCRE,
155      you must add --enable-utf8 to the "configure" command. Without it, the code
156      for handling UTF-8 is not included in the library. (Even when included, it
157      still has to be enabled by an option at run time.)
158    
159    . If, in addition to support for UTF-8 character strings, you want to include
160      support for the \P, \p, and \X sequences that recognize Unicode character
161      properties, you must add --enable-unicode-properties to the "configure"
162      command. This adds about 30K to the size of the library (in the form of a
163      property table); only the basic two-letter properties such as Lu are
164      supported.
165    
166    . You can build PCRE to recognize either CR or LF or the sequence CRLF or any
167      of the Unicode newline sequences as indicating the end of a line. Whatever
168      you specify at build time is the default; the caller of PCRE can change the
169      selection at run time. The default newline indicator is a single LF character
170      (the Unix standard). You can specify the default newline indicator by adding
171      --newline-is-cr or --newline-is-lf or --newline-is-crlf or --newline-is-any
172      to the "configure" command, respectively.
173    
174      If you specify --newline-is-cr or --newline-is-crlf, some of the standard
175      tests will fail, because the lines in the test files end with LF. Even if
176      the files are edited to change the line endings, there are likely to be some
177      failures. With --newline-is-any, many tests should succeed, but there may be
178      some failures.
179    
180    . When called via the POSIX interface, PCRE uses malloc() to get additional
181      storage for processing capturing parentheses if there are more than 10 of
182      them in a pattern. You can increase this threshold by setting, for example,
183    
184      --with-posix-malloc-threshold=20
185    
186      on the "configure" command.
187    
188    . PCRE has a counter that can be set to limit the amount of resources it uses.
189      If the limit is exceeded during a match, the match fails. The default is ten
190      million. You can change the default by setting, for example,
191    
192      --with-match-limit=500000
193    
194      on the "configure" command. This is just the default; individual calls to
195      pcre_exec() can supply their own value. There is more discussion on the
196      pcreapi man page.
197    
198    . There is a separate counter that limits the depth of recursive function calls
199      during a matching process. This also has a default of ten million, which is
200      essentially "unlimited". You can change the default by setting, for example,
201    
202      --with-match-limit-recursion=500000
203    
204      Recursive function calls use up the runtime stack; running out of stack can
205      cause programs to crash in strange ways. There is a discussion about stack
206      sizes in the pcrestack man page.
207    
208    . The default maximum compiled pattern size is around 64K. You can increase
209      this by adding --with-link-size=3 to the "configure" command. You can
210      increase it even more by setting --with-link-size=4, but this is unlikely
211      ever to be necessary. Increasing the internal link size will reduce
212      performance.
213    
214    . You can build PCRE so that its internal match() function that is called from
215      pcre_exec() does not call itself recursively. Instead, it uses memory blocks
216      obtained from the heap via the special functions pcre_stack_malloc() and
217      pcre_stack_free() to save data that would otherwise be saved on the stack. To
218      build PCRE like this, use
219    
220      --disable-stack-for-recursion
221    
222      on the "configure" command. PCRE runs more slowly in this mode, but it may be
223      necessary in environments with limited stack sizes. This applies only to the
224      pcre_exec() function; it does not apply to pcre_dfa_exec(), which does not
225      use deeply nested recursion. There is a discussion about stack sizes in the
226      pcrestack man page.
227    
228    . For speed, PCRE uses four tables for manipulating and identifying characters
229      whose code point values are less than 256. By default, it uses a set of
230      tables for ASCII encoding that is part of the distribution. If you specify
231    
232      --enable-rebuild-chartables
233    
234      a program called dftables is compiled and run in the default C locale when
235      you obey "make". It builds a source file called pcre_chartables.c. If you do
236      not specify this option, pcre_chartables.c is created as a copy of
237      pcre_chartables.c.dist. See "Character tables" below for further information.
238    
239    . It is possible to compile PCRE for use on systems that use EBCDIC as their
240      default character code (as opposed to ASCII) by specifying
241    
242      --enable-ebcdic
243    
244      This automatically implies --enable-rebuild-chartables (see above).
245    
246    ChangeLog         log of changes to the code  The "configure" script builds the following files for the basic C library:
   LICENCE           conditions for the use of PCRE  
   Makefile          for building PCRE  
   README            this file  
   RunTest           a shell script for running tests  
   Tech.Notes        notes on the encoding  
   pcre.3            man page for the functions  
   pcreposix.3       man page for the POSIX wrapper API  
   dftables.c        auxiliary program for building chartables.c  
   get.c             )  
   maketables.c      )  
   study.c           ) source of  
   pcre.c            )   the functions  
   pcreposix.c       )  
   pcre.h            header for the external API  
   pcreposix.h       header for the external POSIX wrapper API  
   internal.h        header for internal use  
   pcretest.c        test program  
   pgrep.1           man page for pgrep  
   pgrep.c           source of a grep utility that uses PCRE  
   perltest          Perl test program  
   testinput1        test data, compatible with Perl 5.004 and 5.005  
   testinput2        test data for error messages and non-Perl things  
   testinput3        test data, compatible with Perl 5.005  
   testinput4        test data for locale-specific tests  
   testoutput1       test results corresponding to testinput1  
   testoutput2       test results corresponding to testinput2  
   testoutput3       test results corresponding to testinput3  
   testoutput4       test results corresponding to testinput4  
   
 To build PCRE, edit Makefile for your system (it is a fairly simple make file,  
 and there are some comments at the top) and then run it. It builds two  
 libraries called libpcre.a and libpcreposix.a, a test program called pcretest,  
 and the pgrep command.  
   
 To test PCRE, run the RunTest script in the pcre directory. This runs pcretest  
 on each of the testinput files in turn, and compares the output with the  
 contents of the corresponding testoutput file. A file called testtry is used to  
 hold the output from pcretest (which is documented below).  
   
 To run pcretest on just one of the test files, give its number as an argument  
 to RunTest, for example:  
   
   RunTest 3  
   
 The first and third test files can also be fed directly into the perltest  
 program to check that Perl gives the same results. The third file requires the  
 additional features of release 5.005, which is why it is kept separate from the  
 main test input, which needs only Perl 5.004. In the long run, when 5.005 is  
 widespread, these two test files may get amalgamated.  
   
 The second set of tests check pcre_info(), pcre_study(), pcre_copy_substring(),  
 pcre_get_substring(), pcre_get_substring_list(), error detection and run-time  
 flags that are specific to PCRE, as well as the POSIX wrapper API.  
247    
248  The fourth set of tests checks pcre_maketables(), the facility for building a  . Makefile is the makefile that builds the library
249    . config.h contains build-time configuration options for the library
250    . pcre.h is the public PCRE header file
251    . pcre-config is a script that shows the settings of "configure" options
252    . libpcre.pc is data for the pkg-config command
253    . libtool is a script that builds shared and/or static libraries
254    . RunTest is a script for running tests on the basic C library
255    . RunGrepTest is a script for running tests on the pcregrep command
256    
257    Versions of config.h and pcre.h are distributed in the PCRE tarballs under
258    the names config.h.generic and pcre.h.generic. These are provided for the
259    benefit of those who have to built PCRE without the benefit of "configure". If
260    you use "configure", the .generic versions are not used.
261    
262    If a C++ compiler is found, the following files are also built:
263    
264    . libpcrecpp.pc is data for the pkg-config command
265    . pcrecpparg.h is a header file for programs that call PCRE via the C++ wrapper
266    . pcre_stringpiece.h is the header for the C++ "stringpiece" functions
267    
268    The "configure" script also creates config.status, which is an executable
269    script that can be run to recreate the configuration, and config.log, which
270    contains compiler output from tests that "configure" runs.
271    
272    Once "configure" has run, you can run "make". It builds two libraries, called
273    libpcre and libpcreposix, a test program called pcretest, a demonstration
274    program called pcredemo, and the pcregrep command. If a C++ compiler was found
275    on your system, "make" also builds the C++ wrapper library, which is called
276    libpcrecpp, and some test programs called pcrecpp_unittest,
277    pcre_scanner_unittest, and pcre_stringpiece_unittest. Building the C++ wrapper
278    can be disabled by adding --disable-cpp to the "configure" command.
279    
280    The command "make check" runs all the appropriate tests. Details of the PCRE
281    tests are given below in a separate section of this document.
282    
283    You can use "make install" to install PCRE into live directories on your
284    system. The following are installed (file names are all relative to the
285    <prefix> that is set when "configure" is run):
286    
287      Commands (bin):
288        pcretest
289        pcregrep
290        pcre-config
291    
292      Libraries (lib):
293        libpcre
294        libpcreposix
295        libpcrecpp (if C++ support is enabled)
296    
297      Configuration information (lib/pkgconfig):
298        libpcre.pc
299        libpcrecpp.pc (if C++ support is enabled)
300    
301      Header files (include):
302        pcre.h
303        pcreposix.h
304        pcre_scanner.h      )
305        pcre_stringpiece.h  ) if C++ support is enabled
306        pcrecpp.h           )
307        pcrecpparg.h        )
308    
309      Man pages (share/man/man{1,3}):
310        pcregrep.1
311        pcretest.1
312        pcre.3
313        pcre*.3 (lots more pages, all starting "pcre")
314    
315      HTML documentation (share/doc/pcre/html):
316        index.html
317        *.html (lots more pages, hyperlinked from index.html)
318    
319      Text file documentation (share/doc/pcre):
320        AUTHORS
321        COPYING
322        ChangeLog
323        LICENCE
324        NEWS
325        README
326        pcre.txt       (a concatenation of the man(3) pages)
327        pcretest.txt   the pcretest man page
328        pcregrep.txt   the pcregrep man page
329    
330    Note that the pcredemo program that is built by "configure" is *not* installed
331    anywhere. It is a demonstration for programmers wanting to use PCRE.
332    
333    If you want to remove PCRE from your system, you can run "make uninstall".
334    This removes all the files that "make install" installed. However, it does not
335    remove any directories, because these are often shared with other programs.
336    
337    
338    Retrieving configuration information on Unix-like systems
339    ---------------------------------------------------------
340    
341    Running "make install" installs the command pcre-config, which can be used to
342    recall information about the PCRE configuration and installation. For example:
343    
344      pcre-config --version
345    
346    prints the version number, and
347    
348      pcre-config --libs
349    
350    outputs information about where the library is installed. This command can be
351    included in makefiles for programs that use PCRE, saving the programmer from
352    having to remember too many details.
353    
354    The pkg-config command is another system for saving and retrieving information
355    about installed libraries. Instead of separate commands for each library, a
356    single command is used. For example:
357    
358      pkg-config --cflags pcre
359    
360    The data is held in *.pc files that are installed in a directory called
361    <prefix>/lib/pkgconfig.
362    
363    
364    Shared libraries on Unix-like systems
365    -------------------------------------
366    
367    The default distribution builds PCRE as shared libraries and static libraries,
368    as long as the operating system supports shared libraries. Shared library
369    support relies on the "libtool" script which is built as part of the
370    "configure" process.
371    
372    The libtool script is used to compile and link both shared and static
373    libraries. They are placed in a subdirectory called .libs when they are newly
374    built. The programs pcretest and pcregrep are built to use these uninstalled
375    libraries (by means of wrapper scripts in the case of shared libraries). When
376    you use "make install" to install shared libraries, pcregrep and pcretest are
377    automatically re-built to use the newly installed shared libraries before being
378    installed themselves. However, the versions left in the build directory still
379    use the uninstalled libraries.
380    
381    To build PCRE using static libraries only you must use --disable-shared when
382    configuring it. For example:
383    
384    ./configure --prefix=/usr/gnu --disable-shared
385    
386    Then run "make" in the usual way. Similarly, you can use --disable-static to
387    build only shared libraries.
388    
389    
390    Cross-compiling on Unix-like systems
391    ------------------------------------
392    
393    You can specify CC and CFLAGS in the normal way to the "configure" command, in
394    order to cross-compile PCRE for some other host. However, you should NOT
395    specify --enable-rebuild-chartables, because if you do, the dftables.c source
396    file is compiled and run on the local host, in order to generate the inbuilt
397    character tables (the pcre_chartables.c file). This will probably not work,
398    because dftables.c needs to be compiled with the local compiler, not the cross
399    compiler.
400    
401    When --enable-rebuild-chartables is not specified, pcre_chartables.c is created
402    by making a copy of pcre_chartables.c.dist, which is a default set of tables
403    that assumes ASCII code. Cross-compiling with the default tables should not be
404    a problem.
405    
406    If you need to modify the character tables when cross-compiling, you should
407    move pcre_chartables.c.dist out of the way, then compile dftables.c by hand and
408    run it on the local host to make a new version of pcre_chartables.c.dist.
409    Then when you cross-compile PCRE this new version of the tables will be used.
410    
411    
412    Using HP's ANSI C++ compiler (aCC)
413    ----------------------------------
414    
415    Unless C++ support is disabled by specifying the "--disable-cpp" option of the
416    "configure" script, you must include the "-AA" option in the CXXFLAGS
417    environment variable in order for the C++ components to compile correctly.
418    
419    Also, note that the aCC compiler on PA-RISC platforms may have a defect whereby
420    needed libraries fail to get included when specifying the "-AA" compiler
421    option. If you experience unresolved symbols when linking the C++ programs,
422    use the workaround of specifying the following environment variable prior to
423    running the "configure" script:
424    
425      CXXLDFLAGS="-lstd_v2 -lCsup_v2"
426    
427    
428    Making new tarballs
429    -------------------
430    
431    The command "make dist" creates three PCRE tarballs, in tar.gz, tar.bz2, and
432    zip formats. However, if you have modified any of the man page sources in the
433    doc directory, you should first run the PrepareRelease script. This re-creates
434    the .txt and HTML forms of the documentation from the man pages.
435    
436    
437    Testing PCRE
438    ------------
439    
440    To test the basic PCRE library on a Unix system, run the RunTest script that is
441    created by the configuring process. There is also a script called RunGrepTest
442    that tests the options of the pcregrep command. If the C++ wrapper library is
443    built, three test programs called pcrecpp_unittest, pcre_scanner_unittest, and
444    pcre_stringpiece_unittest are also built.
445    
446    Both the scripts and all the program tests are run if you obey "make check" or
447    "make test". For other systems, see the instructions in NON-UNIX-USE.
448    
449    The RunTest script runs the pcretest test program (which is documented in its
450    own man page) on each of the testinput files in the testdata directory in
451    turn, and compares the output with the contents of the corresponding testoutput
452    files. A file called testtry is used to hold the main output from pcretest
453    (testsavedregex is also used as a working file). To run pcretest on just one of
454    the test files, give its number as an argument to RunTest, for example:
455    
456      RunTest 2
457    
458    The first test file can also be fed directly into the perltest.pl script to
459    check that Perl gives the same results. The only difference you should see is
460    in the first few lines, where the Perl version is given instead of the PCRE
461    version.
462    
463    The second set of tests check pcre_fullinfo(), pcre_info(), pcre_study(),
464    pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error
465    detection, and run-time flags that are specific to PCRE, as well as the POSIX
466    wrapper API. It also uses the debugging flags to check some of the internals of
467    pcre_compile().
468    
469    If you build PCRE with a locale setting that is not the standard C locale, the
470    character tables may be different (see next paragraph). In some cases, this may
471    cause failures in the second set of tests. For example, in a locale where the
472    isprint() function yields TRUE for characters in the range 128-255, the use of
473    [:isascii:] inside a character class defines a different set of characters, and
474    this shows up in this test as a difference in the compiled code, which is being
475    listed for checking. Where the comparison test output contains [\x00-\x7f] the
476    test will contain [\x00-\xff], and similarly in some other cases. This is not a
477    bug in PCRE.
478    
479    The third set of tests checks pcre_maketables(), the facility for building a
480  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
481  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
482  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
483  "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"
484  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
485  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
486    
487    ** Failed to set locale "fr"    ** Failed to set locale "fr_FR"
488    
489  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,
490  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.
491    
492  To install PCRE, copy libpcre.a to any suitable library directory (e.g.  The fourth test checks the UTF-8 support. It is not run automatically unless
493  /usr/local/lib), pcre.h to any suitable include directory (e.g.  PCRE is built with UTF-8 support. To do this you must set --enable-utf8 when
494  /usr/local/include), and pcre.3 to any suitable man directory (e.g.  running "configure". This file can be also fed directly to the perltest script,
495  /usr/local/man/man3).  provided you are running Perl 5.8 or higher. (For Perl 5.6, a small patch,
496    commented in the script, can be be used.)
497  To install the pgrep command, copy it to any suitable binary directory, (e.g.  
498  /usr/local/bin) and pgrep.1 to any suitable man directory (e.g.  The fifth test checks error handling with UTF-8 encoding, and internal UTF-8
499  /usr/local/man/man1).  features of PCRE that are not relevant to Perl.
500    
501  PCRE has its own native API, but a set of "wrapper" functions that are based on  The sixth test checks the support for Unicode character properties. It it not
502  the POSIX API are also supplied in the library libpcreposix.a. Note that this  run automatically unless PCRE is built with Unicode property support. To to
503  just provides a POSIX calling interface to PCRE: the regular expressions  this you must set --enable-unicode-properties when running "configure".
504  themselves still follow Perl syntax and semantics. The header file  
505  for the POSIX-style functions is called pcreposix.h. The official POSIX name is  The seventh, eighth, and ninth tests check the pcre_dfa_exec() alternative
506  regex.h, but I didn't want to risk possible problems with existing files of  matching function, in non-UTF-8 mode, UTF-8 mode, and UTF-8 mode with Unicode
507  that name by distributing it that way. To use it with an existing program that  property support, respectively. The eighth and ninth tests are not run
508  uses the POSIX API, it will have to be renamed or pointed at by a link.  automatically unless PCRE is build with the relevant support.
509    
510    
511  Character tables  Character tables
512  ----------------  ----------------
513    
514  PCRE uses four tables for manipulating and identifying characters. The final  For speed, PCRE uses four tables for manipulating and identifying characters
515  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
516  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
517  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
518  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
519  the binary is used.  passed as NULL, a set of default tables that is built into the binary is used.
520    
521  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
522  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
523  (compiled from dftables.c), which uses the ANSI C character handling functions  tables for ASCII coding. However, if --enable-rebuild-chartables is specified
524  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table  for ./configure, a different version of pcre_chartables.c is built by the
525  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
526  control the contents of these default tables. You can change the default tables  handling functions such as isalnum(), isalpha(), isupper(), islower(), etc. to
527  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
528  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
529  re-generated.  the default tables by editing pcre_chartables.c and then re-building PCRE. If
530    you do this, you should take care to ensure that the file does not get
531    automatically re-generated. The best way to do this is to move
532    pcre_chartables.c.dist out of the way and replace it with your customized
533    tables.
534    
535    When the dftables program is run as a result of --enable-rebuild-chartables,
536    it uses the default C locale that is set on your system. It does not pay
537    attention to the LC_xxx environment variables. In other words, it uses the
538    system's default locale rather than whatever the compiling user happens to have
539    set. If you really do want to build a source set of character tables in a
540    locale that is specified by the LC_xxx variables, you can run the dftables
541    program by hand with the -L option. For example:
542    
543      ./dftables -L pcre_chartables.c.special
544    
545  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,
546  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
547  digits, "word" characters, and white space, respectively. These are used when  digits, "word" characters, and white space, respectively. These are used when
548  building 32-byte bit maps that represent character classes.  building 32-byte bit maps that represent character classes for code points less
549    than 256.
550    
551  The final 256-byte table has bits indicating various character types, as  The final 256-byte table has bits indicating various character types, as
552  follows:  follows:
# Line 161  You should not alter the set of characte Line 562  You should not alter the set of characte
562  will cause PCRE to malfunction.  will cause PCRE to malfunction.
563    
564    
565  The pcretest program  File manifest
566  --------------------  -------------
567    
568    The distribution should contain the following files:
569    
570  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.  
571    
572  If it is given two filename arguments, it reads from the first and writes to    dftables.c              auxiliary program for building pcre_chartables.c
573  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. The /g modifier behaves similarly to the way it does  
 in Perl. 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 start_offset argument to pcre_exec() to start searching at a new point  
 within the entire string, 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).  
   
 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 information about the size of memory block used to hold  
 the compile 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  
   \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 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.  
574    
575  Philip Hazel <ph10@cam.ac.uk>    pcre_chartables.c.dist  a default set of character tables that assume ASCII
576  June 1999                              coding; used, unless --enable-rebuild-chartables is
577                                specified, by copying to pcre_chartables.c
578    
579      pcreposix.c             )
580      pcre_compile.c          )
581      pcre_config.c           )
582      pcre_dfa_exec.c         )
583      pcre_exec.c             )
584      pcre_fullinfo.c         )
585      pcre_get.c              ) sources for the functions in the library,
586      pcre_globals.c          )   and some internal functions that they use
587      pcre_info.c             )
588      pcre_maketables.c       )
589      pcre_newline.c          )
590      pcre_ord2utf8.c         )
591      pcre_refcount.c         )
592      pcre_study.c            )
593      pcre_tables.c           )
594      pcre_try_flipped.c      )
595      pcre_ucp_searchfuncs.c  )
596      pcre_valid_utf8.c       )
597      pcre_version.c          )
598      pcre_xclass.c           )
599      pcre_printint.src       ) debugging function that is #included in pcretest,
600                              )   and can also be #included in pcre_compile()
601      pcre.h.in               template for pcre.h when built by "configure"
602      pcreposix.h             header for the external POSIX wrapper API
603      pcre_internal.h         header for internal use
604      ucp.h                   ) headers concerned with
605      ucpinternal.h           )   Unicode property handling
606      ucptable.h              ) (this one is the data table)
607    
608      config.h.in             template for config.h, which is built by "configure"
609    
610      pcrecpp.h               public header file for the C++ wrapper
611      pcrecpparg.h.in         template for another C++ header file
612      pcre_scanner.h          public header file for C++ scanner functions
613      pcrecpp.cc              )
614      pcre_scanner.cc         ) source for the C++ wrapper library
615    
616      pcre_stringpiece.h.in   template for pcre_stringpiece.h, the header for the
617                                C++ stringpiece functions
618      pcre_stringpiece.cc     source for the C++ stringpiece functions
619    
620    (B) Source files for programs that use PCRE:
621    
622      pcredemo.c              simple demonstration of coding calls to PCRE
623      pcregrep.c              source of a grep utility that uses PCRE
624      pcretest.c              comprehensive test program
625    
626    (C) Auxiliary files:
627    
628      132html                 script to turn "man" pages into HTML
629      AUTHORS                 information about the author of PCRE
630      ChangeLog               log of changes to the code
631      CleanTxt                script to clean nroff output for txt man pages
632      Detrail                 script to remove trailing spaces
633      HACKING                 some notes about the internals of PCRE
634      INSTALL                 generic installation instructions
635      LICENCE                 conditions for the use of PCRE
636      COPYING                 the same, using GNU's standard name
637      Makefile.in             ) template for Unix Makefile, which is built by
638                              )   "configure"
639      Makefile.am             ) the automake input that was used to create
640                              )   Makefile.in
641      NEWS                    important changes in this release
642      NON-UNIX-USE            notes on building PCRE on non-Unix systems
643      PrepareRelease          script to make preparations for "make dist"
644      README                  this file
645      RunTest.in              template for a Unix shell script for running tests
646      RunGrepTest.in          template for a Unix shell script for pcregrep tests
647      aclocal.m4              m4 macros (generated by "aclocal")
648      config.guess            ) files used by libtool,
649      config.sub              )   used only when building a shared library
650      configure               a configuring shell script (built by autoconf)
651      configure.ac            ) the autoconf input that was used to build
652                              )   "configure" and config.h
653      depcomp                 ) script to find program dependencies, generated by
654                              )   automake
655      doc/*.3                 man page sources for the PCRE functions
656      doc/*.1                 man page sources for pcregrep and pcretest
657      doc/index.html.src      the base HTML page
658      doc/html/*              HTML documentation
659      doc/pcre.txt            plain text version of the man pages
660      doc/pcretest.txt        plain text documentation of test program
661      doc/perltest.txt        plain text documentation of Perl test program
662      install-sh              a shell script for installing files
663      libpcre.pc.in           template for libpcre.pc for pkg-config
664      libpcrecpp.pc.in        template for libpcrecpp.pc for pkg-config
665      ltmain.sh               file used to build a libtool script
666      missing                 ) common stub for a few missing GNU programs while
667                              )   installing, generated by automake
668      mkinstalldirs           script for making install directories
669      perltest.pl             Perl test program
670      pcre-config.in          source of script which retains PCRE information
671      pcrecpp_unittest.cc          )
672      pcre_scanner_unittest.cc     ) test programs for the C++ wrapper
673      pcre_stringpiece_unittest.cc )
674      testdata/testinput*     test data for main library tests
675      testdata/testoutput*    expected test results
676      testdata/grep*          input and output for pcregrep tests
677    
678    (D) Auxiliary files for cmake support
679    
680      CMakeLists.txt
681      config-cmake.h.in
682    
683    (E) Auxiliary files for VPASCAL
684    
685      makevp.bat
686      makevp-compile.txt
687      makevp-linklib.txt
688      pcregexp.pas
689    
690    (F) Auxiliary files for building PCRE "by hand"
691    
692      pcre.h.generic          ) a version of the public PCRE header file
693                              )   for use in non-"configure" environments
694      config.h.generic        ) a version of config.h for use in non-"configure"
695                              )   environments
696    
697    (F) Miscellaneous
698    
699      RunTest.bat            a script for running tests under Windows
700    
701    Philip Hazel
702    Email local part: ph10
703    Email domain: cam.ac.uk
704    Last updated: 20 March 2007

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