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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 distribution should contain the following files:  The latest release of PCRE is always available from
5    
6      ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.gz
7    
8    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    Makefile          for building PCRE  
12    Performance       notes on performance  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    Tech.Notes        notes on the encoding  
15    pcre.3            man page for the functions    The PCRE APIs
16    pcreposix.3       man page for the POSIX wrapper API    Documentation for PCRE
17    maketables.c      auxiliary program for building chartables.c    Contributions by users of PCRE
18    study.c           ) source of    Building PCRE on non-Unix systems
19    pcre.c            )   the functions    Building PCRE on Unix-like systems
20    pcreposix.c       )    Retrieving configuration information on Unix-like systems
21    pcre.h            header for the external API    Shared libraries on Unix-like systems
22    pcreposix.h       header for the external POSIX wrapper API    Cross-compiling on Unix-like systems
23    internal.h        header for internal use    Using HP's ANSI C++ compiler (aCC)
24    pcretest.c        test program    Making new tarballs
25    pgrep.1           man page for pgrep    Testing PCRE
26    pgrep.c           source of a grep utility that uses PCRE    Character tables
27    perltest          Perl test program    File manifest
28    testinput         test data, compatible with Perl  
29    testinput2        test data for error messages and non-Perl things  
30    testoutput        test results corresponding to testinput  The PCRE APIs
31    testoutput2       test results corresponding to testinput2  -------------
32    
33  To build PCRE, edit Makefile for your system (it is a fairly simple make file)  PCRE is written in C, and it has its own API. The distribution also includes a
34  and then run it. It builds a two libraries called libpcre.a and libpcreposix.a,  set of C++ wrapper functions (see the pcrecpp man page for details), courtesy
35  a test program called pcretest, and the pgrep command.  of Google Inc.
36    
37  To test PCRE, run pcretest on the file testinput, and compare the output with  In addition, there is a set of C wrapper functions that are based on the POSIX
38  the contents of testoutput. There should be no differences. For example:  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    pcretest testinput /tmp/anything  interface to PCRE; the regular expressions themselves still follow Perl syntax
41    diff /tmp/anything testoutput  and semantics. The POSIX API is restricted, and does not give full access to
42    all of PCRE's facilities.
43  Do the same with testinput2, comparing the output with testoutput2, but this  
44  time using the -i flag for pcretest, i.e.  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    pcretest -i testinput2 /tmp/anything  with existing files of that name by distributing it that way. To use PCRE with
47    diff /tmp/anything testoutput2  an existing program that uses the POSIX API, pcreposix.h will have to be
48    renamed or pointed at by a link.
49  There are two sets of tests because the first set can also be fed directly into  
50  the perltest program to check that Perl gives the same results. The second set  If you are using the POSIX interface to PCRE and there is already a POSIX regex
51  of tests check pcre_info(), pcre_study(), error detection and run-time flags  library installed on your system, as well as worrying about the regex.h header
52  that are specific to PCRE, as well as the POSIX wrapper API.  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  To install PCRE, copy libpcre.a to any suitable library directory (e.g.  up the POSIX functions of the same name from the other library.
55  /usr/local/lib), pcre.h to any suitable include directory (e.g.  
56  /usr/local/include), and pcre.3 to any suitable man directory (e.g.  One way of avoiding this confusion is to compile PCRE with the addition of
57  /usr/local/man/man3).  -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  To install the pgrep command, copy it to any suitable binary directory, (e.g.  effect of renaming the functions so that the names no longer clash. Of course,
60  /usr/local/bin) and pgrep.1 to any suitable man directory (e.g.  you have to do the same thing for your applications, or write them using the
61  /usr/local/man/man1).  new names.
62    
63  PCRE has its own native API, but a set of "wrapper" functions that are based on  
64  the POSIX API are also supplied in the library libpcreposix.a. Note that this  Documentation for PCRE
65  just provides a POSIX calling interface to PCRE: the regular expressions  ----------------------
66  themselves still follow Perl syntax and semantics. The header file  
67  for the POSIX-style functions is called pcreposix.h. The official POSIX name is  If you install PCRE in the normal way on a Unix-like system, you will end up
68  regex.h, but I didn't want to risk possible problems with existing files of  with a set of man pages whose names all start with "pcre". The one that is just
69  that name by distributing it that way. To use it with an existing program that  called "pcre" lists all the others. In addition to these man pages, the PCRE
70  uses the POSIX API it will have to be renamed or pointed at by a link.  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 Unicode newline sequences as indicating the end of a line. Whatever
173      you specify at build time is the default; the caller of PCRE can change the
174      selection at run time. The default newline indicator is a single LF character
175      (the Unix standard). You can specify the default newline indicator by adding
176      --newline-is-cr or --newline-is-lf or --newline-is-crlf or --newline-is-any
177      to the "configure" command, respectively.
178    
179      If you specify --newline-is-cr or --newline-is-crlf, some of the standard
180      tests will fail, because the lines in the test files end with LF. Even if
181      the files are edited to change the line endings, there are likely to be some
182      failures. With --newline-is-any, many tests should succeed, but there may be
183      some failures.
184    
185    . When called via the POSIX interface, PCRE uses malloc() to get additional
186      storage for processing capturing parentheses if there are more than 10 of
187      them in a pattern. You can increase this threshold by setting, for example,
188    
189      --with-posix-malloc-threshold=20
190    
191      on the "configure" command.
192    
193    . PCRE has a counter that can be set to limit the amount of resources it uses.
194      If the limit is exceeded during a match, the match fails. The default is ten
195      million. You can change the default by setting, for example,
196    
197      --with-match-limit=500000
198    
199      on the "configure" command. This is just the default; individual calls to
200      pcre_exec() can supply their own value. There is more discussion on the
201      pcreapi man page.
202    
203    . There is a separate counter that limits the depth of recursive function calls
204      during a matching process. This also has a default of ten million, which is
205      essentially "unlimited". You can change the default by setting, for example,
206    
207      --with-match-limit-recursion=500000
208    
209      Recursive function calls use up the runtime stack; running out of stack can
210      cause programs to crash in strange ways. There is a discussion about stack
211      sizes in the pcrestack man page.
212    
213    . The default maximum compiled pattern size is around 64K. You can increase
214      this by adding --with-link-size=3 to the "configure" command. You can
215      increase it even more by setting --with-link-size=4, but this is unlikely
216      ever to be necessary. Increasing the internal link size will reduce
217      performance.
218    
219    . You can build PCRE so that its internal match() function that is called from
220      pcre_exec() does not call itself recursively. Instead, it uses memory blocks
221      obtained from the heap via the special functions pcre_stack_malloc() and
222      pcre_stack_free() to save data that would otherwise be saved on the stack. To
223      build PCRE like this, use
224    
225      --disable-stack-for-recursion
226    
227      on the "configure" command. PCRE runs more slowly in this mode, but it may be
228      necessary in environments with limited stack sizes. This applies only to the
229      pcre_exec() function; it does not apply to pcre_dfa_exec(), which does not
230      use deeply nested recursion. There is a discussion about stack sizes in the
231      pcrestack man page.
232    
233    . For speed, PCRE uses four tables for manipulating and identifying characters
234      whose code point values are less than 256. By default, it uses a set of
235      tables for ASCII encoding that is part of the distribution. If you specify
236    
237      --enable-rebuild-chartables
238    
239      a program called dftables is compiled and run in the default C locale when
240      you obey "make". It builds a source file called pcre_chartables.c. If you do
241      not specify this option, pcre_chartables.c is created as a copy of
242      pcre_chartables.c.dist. See "Character tables" below for further information.
243    
244    . It is possible to compile PCRE for use on systems that use EBCDIC as their
245      default character code (as opposed to ASCII) by specifying
246    
247      --enable-ebcdic
248    
249      This automatically implies --enable-rebuild-chartables (see above).
250    
251    The "configure" script builds the following files for the basic C library:
252    
253    . Makefile is the makefile that builds the library
254    . config.h contains build-time configuration options for the library
255    . pcre.h is the public PCRE header file
256    . pcre-config is a script that shows the settings of "configure" options
257    . libpcre.pc is data for the pkg-config command
258    . libtool is a script that builds shared and/or static libraries
259    . RunTest is a script for running tests on the basic C library
260    . RunGrepTest is a script for running tests on the pcregrep command
261    
262    Versions of config.h and pcre.h are distributed in the PCRE tarballs under
263    the names config.h.generic and pcre.h.generic. These are provided for the
264    benefit of those who have to built PCRE without the benefit of "configure". If
265    you use "configure", the .generic versions are not used.
266    
267    If a C++ compiler is found, the following files are also built:
268    
269    . libpcrecpp.pc is data for the pkg-config command
270    . pcrecpparg.h is a header file for programs that call PCRE via the C++ wrapper
271    . pcre_stringpiece.h is the header for the C++ "stringpiece" functions
272    
273    The "configure" script also creates config.status, which is an executable
274    script that can be run to recreate the configuration, and config.log, which
275    contains compiler output from tests that "configure" runs.
276    
277    Once "configure" has run, you can run "make". It builds two libraries, called
278    libpcre and libpcreposix, a test program called pcretest, a demonstration
279    program called pcredemo, and the pcregrep command. If a C++ compiler was found
280    on your system, "make" also builds the C++ wrapper library, which is called
281    libpcrecpp, and some test programs called pcrecpp_unittest,
282    pcre_scanner_unittest, and pcre_stringpiece_unittest. Building the C++ wrapper
283    can be disabled by adding --disable-cpp to the "configure" command.
284    
285    The command "make check" runs all the appropriate tests. Details of the PCRE
286    tests are given below in a separate section of this document.
287    
288    You can use "make install" to install PCRE into live directories on your
289    system. The following are installed (file names are all relative to the
290    <prefix> that is set when "configure" is run):
291    
292      Commands (bin):
293        pcretest
294        pcregrep
295        pcre-config
296    
297      Libraries (lib):
298        libpcre
299        libpcreposix
300        libpcrecpp (if C++ support is enabled)
301    
302      Configuration information (lib/pkgconfig):
303        libpcre.pc
304        libpcrecpp.pc (if C++ support is enabled)
305    
306      Header files (include):
307        pcre.h
308        pcreposix.h
309        pcre_scanner.h      )
310        pcre_stringpiece.h  ) if C++ support is enabled
311        pcrecpp.h           )
312        pcrecpparg.h        )
313    
314      Man pages (share/man/man{1,3}):
315        pcregrep.1
316        pcretest.1
317        pcre.3
318        pcre*.3 (lots more pages, all starting "pcre")
319    
320      HTML documentation (share/doc/pcre/html):
321        index.html
322        *.html (lots more pages, hyperlinked from index.html)
323    
324      Text file documentation (share/doc/pcre):
325        AUTHORS
326        COPYING
327        ChangeLog
328        LICENCE
329        NEWS
330        README
331        pcre.txt       (a concatenation of the man(3) pages)
332        pcretest.txt   the pcretest man page
333        pcregrep.txt   the pcregrep man page
334    
335    Note that the pcredemo program that is built by "configure" is *not* installed
336    anywhere. It is a demonstration for programmers wanting to use PCRE.
337    
338    If you want to remove PCRE from your system, you can run "make uninstall".
339    This removes all the files that "make install" installed. However, it does not
340    remove any directories, because these are often shared with other programs.
341    
342    
343    Retrieving configuration information on Unix-like systems
344    ---------------------------------------------------------
345    
346    Running "make install" installs the command pcre-config, which can be used to
347    recall information about the PCRE configuration and installation. For example:
348    
349      pcre-config --version
350    
351    prints the version number, and
352    
353      pcre-config --libs
354    
355    outputs information about where the library is installed. This command can be
356    included in makefiles for programs that use PCRE, saving the programmer from
357    having to remember too many details.
358    
359    The pkg-config command is another system for saving and retrieving information
360    about installed libraries. Instead of separate commands for each library, a
361    single command is used. For example:
362    
363      pkg-config --cflags pcre
364    
365    The data is held in *.pc files that are installed in a directory called
366    <prefix>/lib/pkgconfig.
367    
368    
369    Shared libraries on Unix-like systems
370    -------------------------------------
371    
372    The default distribution builds PCRE as shared libraries and static libraries,
373    as long as the operating system supports shared libraries. Shared library
374    support relies on the "libtool" script which is built as part of the
375    "configure" process.
376    
377    The libtool script is used to compile and link both shared and static
378    libraries. They are placed in a subdirectory called .libs when they are newly
379    built. The programs pcretest and pcregrep are built to use these uninstalled
380    libraries (by means of wrapper scripts in the case of shared libraries). When
381    you use "make install" to install shared libraries, pcregrep and pcretest are
382    automatically re-built to use the newly installed shared libraries before being
383    installed themselves. However, the versions left in the build directory still
384    use the uninstalled libraries.
385    
386    To build PCRE using static libraries only you must use --disable-shared when
387    configuring it. For example:
388    
389    ./configure --prefix=/usr/gnu --disable-shared
390    
391    Then run "make" in the usual way. Similarly, you can use --disable-static to
392    build only shared libraries.
393    
394    
395    Cross-compiling on Unix-like systems
396    ------------------------------------
397    
398    You can specify CC and CFLAGS in the normal way to the "configure" command, in
399    order to cross-compile PCRE for some other host. However, you should NOT
400    specify --enable-rebuild-chartables, because if you do, the dftables.c source
401    file is compiled and run on the local host, in order to generate the inbuilt
402    character tables (the pcre_chartables.c file). This will probably not work,
403    because dftables.c needs to be compiled with the local compiler, not the cross
404    compiler.
405    
406    When --enable-rebuild-chartables is not specified, pcre_chartables.c is created
407    by making a copy of pcre_chartables.c.dist, which is a default set of tables
408    that assumes ASCII code. Cross-compiling with the default tables should not be
409    a problem.
410    
411    If you need to modify the character tables when cross-compiling, you should
412    move pcre_chartables.c.dist out of the way, then compile dftables.c by hand and
413    run it on the local host to make a new version of pcre_chartables.c.dist.
414    Then when you cross-compile PCRE this new version of the tables will be used.
415    
416    
417    Using HP's ANSI C++ compiler (aCC)
418    ----------------------------------
419    
420    Unless C++ support is disabled by specifying the "--disable-cpp" option of the
421    "configure" script, you must include the "-AA" option in the CXXFLAGS
422    environment variable in order for the C++ components to compile correctly.
423    
424    Also, note that the aCC compiler on PA-RISC platforms may have a defect whereby
425    needed libraries fail to get included when specifying the "-AA" compiler
426    option. If you experience unresolved symbols when linking the C++ programs,
427    use the workaround of specifying the following environment variable prior to
428    running the "configure" script:
429    
430      CXXLDFLAGS="-lstd_v2 -lCsup_v2"
431    
432    
433    Making new tarballs
434    -------------------
435    
436    The command "make dist" creates three PCRE tarballs, in tar.gz, tar.bz2, and
437    zip formats. However, if you have modified any of the man page sources in the
438    doc directory, you should first run the PrepareRelease script. This re-creates
439    the .txt and HTML forms of the documentation from the man pages.
440    
441    
442    Testing PCRE
443    ------------
444    
445    To test the basic PCRE library on a Unix system, run the RunTest script that is
446    created by the configuring process. There is also a script called RunGrepTest
447    that tests the options of the pcregrep command. If the C++ wrapper library is
448    built, three test programs called pcrecpp_unittest, pcre_scanner_unittest, and
449    pcre_stringpiece_unittest are also built.
450    
451    Both the scripts and all the program tests are run if you obey "make check" or
452    "make test". For other systems, see the instructions in NON-UNIX-USE.
453    
454    The RunTest script runs the pcretest test program (which is documented in its
455    own man page) on each of the testinput files in the testdata directory in
456    turn, and compares the output with the contents of the corresponding testoutput
457    files. A file called testtry is used to hold the main output from pcretest
458    (testsavedregex is also used as a working file). To run pcretest on just one of
459    the test files, give its number as an argument to RunTest, for example:
460    
461      RunTest 2
462    
463    The first test file can also be fed directly into the perltest.pl script to
464    check that Perl gives the same results. The only difference you should see is
465    in the first few lines, where the Perl version is given instead of the PCRE
466    version.
467    
468    The second set of tests check pcre_fullinfo(), pcre_info(), pcre_study(),
469    pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error
470    detection, and run-time flags that are specific to PCRE, as well as the POSIX
471    wrapper API. It also uses the debugging flags to check some of the internals of
472    pcre_compile().
473    
474    If you build PCRE with a locale setting that is not the standard C locale, the
475    character tables may be different (see next paragraph). In some cases, this may
476    cause failures in the second set of tests. For example, in a locale where the
477    isprint() function yields TRUE for characters in the range 128-255, the use of
478    [:isascii:] inside a character class defines a different set of characters, and
479    this shows up in this test as a difference in the compiled code, which is being
480    listed for checking. Where the comparison test output contains [\x00-\x7f] the
481    test will contain [\x00-\xff], and similarly in some other cases. This is not a
482    bug in PCRE.
483    
484    The third set of tests checks pcre_maketables(), the facility for building a
485    set of character tables for a specific locale and using them instead of the
486    default tables. The tests make use of the "fr_FR" (French) locale. Before
487    running the test, the script checks for the presence of this locale by running
488    the "locale" command. If that command fails, or if it doesn't include "fr_FR"
489    in the list of available locales, the third test cannot be run, and a comment
490    is output to say why. If running this test produces instances of the error
491    
492      ** Failed to set locale "fr_FR"
493    
494    in the comparison output, it means that locale is not available on your system,
495    despite being listed by "locale". This does not mean that PCRE is broken.
496    
497    [If you are trying to run this test on Windows, you may be able to get it to
498    work by changing "fr_FR" to "french" everywhere it occurs.]
499    
500    The fourth test checks the UTF-8 support. It is not run automatically unless
501    PCRE is built with UTF-8 support. To do this you must set --enable-utf8 when
502    running "configure". This file can be also fed directly to the perltest script,
503    provided you are running Perl 5.8 or higher. (For Perl 5.6, a small patch,
504    commented in the script, can be be used.)
505    
506    The fifth test checks error handling with UTF-8 encoding, and internal UTF-8
507    features of PCRE that are not relevant to Perl.
508    
509    The sixth test checks the support for Unicode character properties. It it not
510    run automatically unless PCRE is built with Unicode property support. To to
511    this you must set --enable-unicode-properties when running "configure".
512    
513    The seventh, eighth, and ninth tests check the pcre_dfa_exec() alternative
514    matching function, in non-UTF-8 mode, UTF-8 mode, and UTF-8 mode with Unicode
515    property support, respectively. The eighth and ninth tests are not run
516    automatically unless PCRE is build with the relevant support.
517    
518    
519  Character tables  Character tables
520  ----------------  ----------------
521    
522  PCRE uses four tables for manipulating and identifying characters. These are  For speed, PCRE uses four tables for manipulating and identifying characters
523  compiled from a source file called chartables.c. This is not supplied in  whose code point values are less than 256. The final argument of the
524  the distribution, but is built by the program maketables (compiled from  pcre_compile() function is a pointer to a block of memory containing the
525  maketables.c), which uses the ANSI C character handling functions such as  concatenated tables. A call to pcre_maketables() can be used to generate a set
526  isalnum(), isalpha(), isupper(), islower(), etc. to build the table sources.  of tables in the current locale. If the final argument for pcre_compile() is
527  This means that the default C locale set in your system may affect the contents  passed as NULL, a set of default tables that is built into the binary is used.
528  of the tables. You can change the tables by editing chartables.c and then  
529  re-building PCRE. If you do this, you should probably also edit Makefile to  The source file called pcre_chartables.c contains the default set of tables. By
530  ensure that the file doesn't ever get re-generated.  default, this is created as a copy of pcre_chartables.c.dist, which contains
531    tables for ASCII coding. However, if --enable-rebuild-chartables is specified
532  The first two tables pcre_lcc[] and pcre_fcc[] provide lower casing and a  for ./configure, a different version of pcre_chartables.c is built by the
533  case flipping functions, respectively. The pcre_cbits[] table consists of four  program dftables (compiled from dftables.c), which uses the ANSI C character
534  32-byte bit maps which identify digits, letters, "word" characters, and white  handling functions such as isalnum(), isalpha(), isupper(), islower(), etc. to
535  space, respectively. These are used when building 32-byte bit maps that  build the table sources. This means that the default C locale which is set for
536  represent character classes.  your system will control the contents of these default tables. You can change
537    the default tables by editing pcre_chartables.c and then re-building PCRE. If
538    you do this, you should take care to ensure that the file does not get
539    automatically re-generated. The best way to do this is to move
540    pcre_chartables.c.dist out of the way and replace it with your customized
541    tables.
542    
543    When the dftables program is run as a result of --enable-rebuild-chartables,
544    it uses the default C locale that is set on your system. It does not pay
545    attention to the LC_xxx environment variables. In other words, it uses the
546    system's default locale rather than whatever the compiling user happens to have
547    set. If you really do want to build a source set of character tables in a
548    locale that is specified by the LC_xxx variables, you can run the dftables
549    program by hand with the -L option. For example:
550    
551      ./dftables -L pcre_chartables.c.special
552    
553    The first two 256-byte tables provide lower casing and case flipping functions,
554    respectively. The next table consists of three 32-byte bit maps which identify
555    digits, "word" characters, and white space, respectively. These are used when
556    building 32-byte bit maps that represent character classes for code points less
557    than 256.
558    
559  The pcre_ctypes[] table has bits indicating various character types, as  The final 256-byte table has bits indicating various character types, as
560  follows:  follows:
561    
562      1   white space character      1   white space character
# Line 99  You should not alter the set of characte Line 570  You should not alter the set of characte
570  will cause PCRE to malfunction.  will cause PCRE to malfunction.
571    
572    
573  The pcretest program  File manifest
574  --------------------  -------------
575    
576    The distribution should contain the following files:
577    
578  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.  
579    
580  If it is given two filename arguments, it reads from the first and writes to    dftables.c              auxiliary program for building pcre_chartables.c
581  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, for example  
   
   /(a|bc)x+yz/  
   
 and may be followed by i, m, s, or x to set the PCRE_CASELESS, PCRE_MULTILINE,  
 PCRE_DOTALL, or PCRE_EXTENDED options, respectively. These options have the  
 same effect as they do in Perl.  
   
 There are also some upper case options that do not match Perl options: /A, /E,  
 and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively.  
 The /D option is a PCRE debugging feature. It causes the internal form of  
 compiled regular expressions to be output after compilation. The /S option  
 causes pcre_study() to be called after the expression has been compiled, and  
 the results used when the expression is matched. If /I is present as well as  
 /S, then pcre_study() is called with the PCRE_CASELESS option.  
   
 Finally, the /P option causes pcretest to call PCRE via the POSIX wrapper API  
 rather than its native API. When this is done, all other options except /i and  
 /m 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.  
   
 A regular expression can extend over several lines of input; the newlines are  
 included in it. See the testinput file for many examples.  
   
 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()  
   \E     pass the PCRE_DOLLAR_ENDONLY option to pcre_exec()  
   \I     pass the PCRE_CASELESS option to pcre_exec()  
   \M     pass the PCRE_MULTILINE option to pcre_exec()  
   \S     pass the PCRE_DOTALL 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 identified 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  
   Testing Perl-Compatible Regular Expressions  
   PCRE version 0.90 08-Sep-1997  
   
       re> /^abc(\d+)/  
     data> abc123  
    0: abc123  
    1: 123  
     data> xyz  
   No match  
   
 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 (for "information") is given to pcretest, it calls pcre_info()  
 after compiling an expression, and outputs the information it gets back. If the  
 pattern is studied, the results of that are also output.  
   
 If the option -s is given to pcretest, it outputs the size of each compiled  
 pattern after it has been compiled.  
   
 If the -t option is given, each compile, study, and match is run 2000 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  
 2000 times and the timing will be distorted.  
   
   
   
 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 options.  
   
 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  
 the testinput file are escaped so that it can be used for perltest as well as  
 for pcretest, and the special upper case options such as /A that pcretest  
 recognizes are not used in this file. The output should be identical, apart  
 from the initial identifying banner.  
   
 The testinput2 file is not suitable for feeding to Perltest, since it does  
 make use of the special upper case options and escapes that pcretest uses to  
 test additional features of PCRE.  
582    
583  Philip Hazel <ph10@cam.ac.uk>    pcre_chartables.c.dist  a default set of character tables that assume ASCII
584  October 1997                              coding; used, unless --enable-rebuild-chartables is
585                                specified, by copying to pcre_chartables.c
586    
587      pcreposix.c             )
588      pcre_compile.c          )
589      pcre_config.c           )
590      pcre_dfa_exec.c         )
591      pcre_exec.c             )
592      pcre_fullinfo.c         )
593      pcre_get.c              ) sources for the functions in the library,
594      pcre_globals.c          )   and some internal functions that they use
595      pcre_info.c             )
596      pcre_maketables.c       )
597      pcre_newline.c          )
598      pcre_ord2utf8.c         )
599      pcre_refcount.c         )
600      pcre_study.c            )
601      pcre_tables.c           )
602      pcre_try_flipped.c      )
603      pcre_ucp_searchfuncs.c  )
604      pcre_valid_utf8.c       )
605      pcre_version.c          )
606      pcre_xclass.c           )
607      pcre_printint.src       ) debugging function that is #included in pcretest,
608                              )   and can also be #included in pcre_compile()
609      pcre.h.in               template for pcre.h when built by "configure"
610      pcreposix.h             header for the external POSIX wrapper API
611      pcre_internal.h         header for internal use
612      ucp.h                   ) headers concerned with
613      ucpinternal.h           )   Unicode property handling
614      ucptable.h              ) (this one is the data table)
615    
616      config.h.in             template for config.h, which is built by "configure"
617    
618      pcrecpp.h               public header file for the C++ wrapper
619      pcrecpparg.h.in         template for another C++ header file
620      pcre_scanner.h          public header file for C++ scanner functions
621      pcrecpp.cc              )
622      pcre_scanner.cc         ) source for the C++ wrapper library
623    
624      pcre_stringpiece.h.in   template for pcre_stringpiece.h, the header for the
625                                C++ stringpiece functions
626      pcre_stringpiece.cc     source for the C++ stringpiece functions
627    
628    (B) Source files for programs that use PCRE:
629    
630      pcredemo.c              simple demonstration of coding calls to PCRE
631      pcregrep.c              source of a grep utility that uses PCRE
632      pcretest.c              comprehensive test program
633    
634    (C) Auxiliary files:
635    
636      132html                 script to turn "man" pages into HTML
637      AUTHORS                 information about the author of PCRE
638      ChangeLog               log of changes to the code
639      CleanTxt                script to clean nroff output for txt man pages
640      Detrail                 script to remove trailing spaces
641      HACKING                 some notes about the internals of PCRE
642      INSTALL                 generic installation instructions
643      LICENCE                 conditions for the use of PCRE
644      COPYING                 the same, using GNU's standard name
645      Makefile.in             ) template for Unix Makefile, which is built by
646                              )   "configure"
647      Makefile.am             ) the automake input that was used to create
648                              )   Makefile.in
649      NEWS                    important changes in this release
650      NON-UNIX-USE            notes on building PCRE on non-Unix systems
651      PrepareRelease          script to make preparations for "make dist"
652      README                  this file
653      RunTest                 a Unix shell script for running tests
654      RunGrepTest             a Unix shell script for pcregrep tests
655      aclocal.m4              m4 macros (generated by "aclocal")
656      config.guess            ) files used by libtool,
657      config.sub              )   used only when building a shared library
658      configure               a configuring shell script (built by autoconf)
659      configure.ac            ) the autoconf input that was used to build
660                              )   "configure" and config.h
661      depcomp                 ) script to find program dependencies, generated by
662                              )   automake
663      doc/*.3                 man page sources for the PCRE functions
664      doc/*.1                 man page sources for pcregrep and pcretest
665      doc/index.html.src      the base HTML page
666      doc/html/*              HTML documentation
667      doc/pcre.txt            plain text version of the man pages
668      doc/pcretest.txt        plain text documentation of test program
669      doc/perltest.txt        plain text documentation of Perl test program
670      install-sh              a shell script for installing files
671      libpcre.pc.in           template for libpcre.pc for pkg-config
672      libpcrecpp.pc.in        template for libpcrecpp.pc for pkg-config
673      ltmain.sh               file used to build a libtool script
674      missing                 ) common stub for a few missing GNU programs while
675                              )   installing, generated by automake
676      mkinstalldirs           script for making install directories
677      perltest.pl             Perl test program
678      pcre-config.in          source of script which retains PCRE information
679      pcrecpp_unittest.cc          )
680      pcre_scanner_unittest.cc     ) test programs for the C++ wrapper
681      pcre_stringpiece_unittest.cc )
682      testdata/testinput*     test data for main library tests
683      testdata/testoutput*    expected test results
684      testdata/grep*          input and output for pcregrep tests
685    
686    (D) Auxiliary files for cmake support
687    
688      CMakeLists.txt
689      config-cmake.h.in
690    
691    (E) Auxiliary files for VPASCAL
692    
693      makevp.bat
694      makevp_c.txt
695      makevp_l.txt
696      pcregexp.pas
697    
698    (F) Auxiliary files for building PCRE "by hand"
699    
700      pcre.h.generic          ) a version of the public PCRE header file
701                              )   for use in non-"configure" environments
702      config.h.generic        ) a version of config.h for use in non-"configure"
703                              )   environments
704    
705    (F) Miscellaneous
706    
707      RunTest.bat            a script for running tests under Windows
708    
709    Philip Hazel
710    Email local part: ph10
711    Email domain: cam.ac.uk
712    Last updated: 29 March 2007

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