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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
5    
6      ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.gz
7    
8    Please read the NEWS file if you are upgrading from a previous release.
9    The contents of this README file are:
10    
11      The PCRE APIs
12      Documentation for PCRE
13      Contributions by users of PCRE
14      Building PCRE on non-Unix systems
15      Building PCRE on a Unix-like system
16      Retrieving configuration information on a Unix-like system
17      Shared libraries on Unix-like systems
18      Cross-compiling on a Unix-like system
19      Using HP's ANSI C++ compiler (aCC)
20      Testing PCRE
21      Character tables
22      File manifest
23    
24    
25    The PCRE APIs
26    -------------
27    
28    PCRE is written in C, and it has its own API. The distribution now includes a
29    set of C++ wrapper functions, courtesy of Google Inc. (see the pcrecpp man page
30    for details).
31    
32    Also included in the distribution are a set of C wrapper functions that are
33    based on the POSIX API. These end up in the library called libpcreposix. Note
34    that this just provides a POSIX calling interface to PCRE; the regular
35    expressions themselves still follow Perl syntax and semantics. The POSIX API is
36    restricted, and does not give full access to all of PCRE's facilities.
37    
38    The header file for the POSIX-style functions is called pcreposix.h. The
39    official POSIX name is regex.h, but I did not want to risk possible problems
40    with existing files of that name by distributing it that way. To use PCRE with
41    an existing program that uses the POSIX API, pcreposix.h will have to be
42    renamed or pointed at by a link.
43    
44    If you are using the POSIX interface to PCRE and there is already a POSIX regex
45    library installed on your system, as well as worrying about the regex.h header
46    file (as mentioned above), you must also take care when linking programs to
47    ensure that they link with PCRE's libpcreposix library. Otherwise they may pick
48    up the POSIX functions of the same name from the other library.
49    
50    One way of avoiding this confusion is to compile PCRE with the addition of
51    -Dregcomp=PCREregcomp (and similarly for the other functions) to the compiler
52    flags (CFLAGS if you are using "configure" -- see below). This has the effect
53    of renaming the functions so that the names no longer clash. Of course, you
54    have to do the same thing for your applications, or write them using the new
55    names.
56    
57    
58    Documentation for PCRE
59    ----------------------
60    
61    If you install PCRE in the normal way, you will end up with an installed set of
62    man pages whose names all start with "pcre". The one that is just called "pcre"
63    lists all the others. In addition to these man pages, the PCRE documentation is
64    supplied in two other forms:
65    
66      1. There are files called doc/pcre.txt, doc/pcregrep.txt, and
67         doc/pcretest.txt in the source distribution. The first of these is a
68         concatenation of the text forms of all the section 3 man pages except
69         those that summarize individual functions. The other two are the text
70         forms of the section 1 man pages for the pcregrep and pcretest commands.
71         These text forms are provided for ease of scanning with text editors or
72         similar tools.
73    
74      2. A set of files containing all the documentation in HTML form, hyperlinked
75         in various ways, and rooted in a file called index.html, is installed in
76         the directory <prefix>/share/doc/pcre/html, where <prefix> is the
77         installation prefix (defaulting to /usr/local).
78    
79    
80    Contributions by users of PCRE
81    ------------------------------
82    
83    You can find contributions from PCRE users in the directory
84    
85      ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib
86    
87    where there is also a README file giving brief descriptions of what they are.
88    Some are complete in themselves; others are pointers to URLs containing
89    relevant files. Some of this material is likely to be well out-of-date. In
90    particular, several of the contributions provide support for compiling PCRE on
91    various flavours of Windows (I myself do not use Windows), but it is hoped that
92    more Windows support will find its way into the standard distribution.
93    
94    
95    Building PCRE on non-Unix systems
96    ---------------------------------
97    
98    For a non-Unix system, read the comments in the file NON-UNIX-USE, though if
99    the system supports the use of "configure" and "make" you may be able to build
100    PCRE in the same way as for Unix-like systems.
101    
102    PCRE has been compiled on many different operating systems. It should be
103    straightforward to build PCRE on any system that has a Standard C compiler and
104    library, because it uses only Standard C functions.
105    
106    
107    Building PCRE on a Unix-like system
108    -----------------------------------
109    
110    If you are using HP's ANSI C++ compiler (aCC), please see the special note
111    in the section entitled "Using HP's ANSI C++ compiler (aCC)" below.
112    
113    To build PCRE on a Unix-like system, first run the "configure" command from the
114    PCRE distribution directory, with your current directory set to the directory
115    where you want the files to be created. This command is a standard GNU
116    "autoconf" configuration script, for which generic instructions are supplied in
117    INSTALL.
118    
119    Most commonly, people build PCRE within its own distribution directory, and in
120    this case, on many systems, just running "./configure" is sufficient. However,
121    the usual methods of changing standard defaults are available. For example:
122    
123    CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
124    
125    specifies that the C compiler should be run with the flags '-O2 -Wall' instead
126    of the default, and that "make install" should install PCRE under /opt/local
127    instead of the default /usr/local.
128    
129    If you want to build in a different directory, just run "configure" with that
130    directory as current. For example, suppose you have unpacked the PCRE source
131    into /source/pcre/pcre-xxx, but you want to build it in /build/pcre/pcre-xxx:
132    
133    cd /build/pcre/pcre-xxx
134    /source/pcre/pcre-xxx/configure
135    
136    PCRE is written in C and is normally compiled as a C library. However, it is
137    possible to build it as a C++ library, though the provided building apparatus
138    does not have any features to support this.
139    
140    There are some optional features that can be included or omitted from the PCRE
141    library. You can read more about them in the pcrebuild man page.
142    
143    . If you want to suppress the building of the C++ wrapper library, you can add
144      --disable-cpp to the "configure" command. Otherwise, when "configure" is run,
145      will try to find a C++ compiler and C++ header files, and if it succeeds, it
146      will try to build the C++ wrapper.
147    
148    . If you want to make use of the support for UTF-8 character strings in PCRE,
149      you must add --enable-utf8 to the "configure" command. Without it, the code
150      for handling UTF-8 is not included in the library. (Even when included, it
151      still has to be enabled by an option at run time.)
152    
153    . If, in addition to support for UTF-8 character strings, you want to include
154      support for the \P, \p, and \X sequences that recognize Unicode character
155      properties, you must add --enable-unicode-properties to the "configure"
156      command. This adds about 30K to the size of the library (in the form of a
157      property table); only the basic two-letter properties such as Lu are
158      supported.
159    
160    . You can build PCRE to recognize either CR or LF or the sequence CRLF or any
161      of the Unicode newline sequences as indicating the end of a line. Whatever
162      you specify at build time is the default; the caller of PCRE can change the
163      selection at run time. The default newline indicator is a single LF character
164      (the Unix standard). You can specify the default newline indicator by adding
165      --newline-is-cr or --newline-is-lf or --newline-is-crlf or --newline-is-any
166      to the "configure" command, respectively.
167    
168      If you specify --newline-is-cr or --newline-is-crlf, some of the standard
169      tests will fail, because the lines in the test files end with LF. Even if
170      the files are edited to change the line endings, there are likely to be some
171      failures. With --newline-is-any, many tests should succeed, but there may be
172      some failures.
173    
174    . When called via the POSIX interface, PCRE uses malloc() to get additional
175      storage for processing capturing parentheses if there are more than 10 of
176      them. You can increase this threshold by setting, for example,
177    
178      --with-posix-malloc-threshold=20
179    
180      on the "configure" command.
181    
182    . PCRE has a counter that can be set to limit the amount of resources it uses.
183      If the limit is exceeded during a match, the match fails. The default is ten
184      million. You can change the default by setting, for example,
185    
186      --with-match-limit=500000
187    
188      on the "configure" command. This is just the default; individual calls to
189      pcre_exec() can supply their own value. There is discussion on the pcreapi
190      man page.
191    
192    . There is a separate counter that limits the depth of recursive function calls
193      during a matching process. This also has a default of ten million, which is
194      essentially "unlimited". You can change the default by setting, for example,
195    
196      --with-match-limit-recursion=500000
197    
198      Recursive function calls use up the runtime stack; running out of stack can
199      cause programs to crash in strange ways. There is a discussion about stack
200      sizes in the pcrestack man page.
201    
202    . The default maximum compiled pattern size is around 64K. You can increase
203      this by adding --with-link-size=3 to the "configure" command. You can
204      increase it even more by setting --with-link-size=4, but this is unlikely
205      ever to be necessary. If you build PCRE with an increased link size, test 2
206      (and 5 if you are using UTF-8) will fail. Part of the output of these tests
207      is a representation of the compiled pattern, and this changes with the link
208      size.
209    
210    . You can build PCRE so that its internal match() function that is called from
211      pcre_exec() does not call itself recursively. Instead, it uses blocks of data
212      from the heap via special functions pcre_stack_malloc() and pcre_stack_free()
213      to save data that would otherwise be saved on the stack. To build PCRE like
214      this, use
215    
216      --disable-stack-for-recursion
217    
218      on the "configure" command. PCRE runs more slowly in this mode, but it may be
219      necessary in environments with limited stack sizes. This applies only to the
220      pcre_exec() function; it does not apply to pcre_dfa_exec(), which does not
221      use deeply nested recursion.
222    
223    The "configure" script builds the following files for the basic C library:
224    
225    . Makefile is the makefile that builds the library
226    . config.h contains build-time configuration options for the library
227    . pcre.h is the public PCRE header file
228    . pcre-config is a script that shows the settings of "configure" options
229    . libpcre.pc is data for the pkg-config command
230    . libtool is a script that builds shared and/or static libraries
231    . RunTest is a script for running tests on the basic C library
232    . RunGrepTest is a script for running tests on the pcregrep command
233    
234    Versions of config.h and pcre.h are distributed in the PCRE tarballs. These are
235    provided for the benefit of those who have to compile PCRE without the benefit
236    of "configure". If you use "configure", the distributed copies are replaced.
237    
238    If a C++ compiler is found, the following files are also built:
239    
240    . libpcrecpp.pc is data for the pkg-config command
241    . pcrecpparg.h is a header file for programs that call PCRE via the C++ wrapper
242    . pcre_stringpiece.h is the header for the C++ "stringpiece" functions
243    
244    The "configure" script also creates config.status, which is an executable
245    script that can be run to recreate the configuration, and config.log, which
246    contains compiler output from tests that "configure" runs.
247    
248    Once "configure" has run, you can run "make". It builds two libraries, called
249    libpcre and libpcreposix, a test program called pcretest, a demonstration
250    program called pcredemo, and the pcregrep command. If a C++ compiler was found
251    on your system, it also builds the C++ wrapper library, which is called
252    libpcrecpp, and some test programs called pcrecpp_unittest,
253    pcre_scanner_unittest, and pcre_stringpiece_unittest.
254    
255    The command "make check" runs all the appropriate tests. Details of the PCRE
256    tests are given below in a separate section of this document.
257    
258    You can use "make install" to install PCRE into live directories on your
259    system. The following are installed (file names are all relative to the
260    <prefix> that is set when "configure" is run):
261    
262      Commands (bin):
263        pcretest
264        pcregrep
265        pcre-config
266    
267      Libraries (lib):
268        libpcre
269        libpcreposix
270        libpcrecpp (if C++ support is enabled)
271    
272      Configuration information (lib/pkgconfig):
273        libpcre.pc
274        libpcrecpp.ps (if C++ support is enabled)
275    
276      Header files (include):
277        pcre.h
278        pcreposix.h
279        pcre_scanner.h      )
280        pcre_stringpiece.h  ) if C++ support is enabled
281        pcrecpp.h           )
282        pcrecpparg.h        )
283    
284      Man pages (share/man/man{1,3}):
285        pcregrep.1
286        pcretest.1
287        pcre.3
288        pcre*.3 (lots more pages, all starting "pcre")
289    
290      HTML documentation (share/doc/pcre/html):
291        index.html
292        *.html (lots more pages, hyperlinked from index.html)
293    
294      Text file documentation (share/doc/pcre):
295        AUTHORS
296        COPYING
297        ChangeLog
298        INSTALL
299        LICENCE
300        NON-UNIX-USE
301        NEWS
302        README
303        pcre.txt       (a concatenation of the man(3) pages)
304        pcretest.txt   the pcretest man page
305        pcregrep.txt   the pcregrep man page
306        perltest.txt   some information about the perltest.pl script
307    
308    Note that the pcredemo program that is built by "configure" is *not* installed
309    anywhere. It is a demonstration for programmers wanting to use PCRE.
310    
311    If you want to remove PCRE from your system, you can run "make uninstall".
312    This removes all the files that "make install" installed. However, it does not
313    remove any directories, because these are often shared with other programs.
314    
315    
316    Retrieving configuration information on a Unix-like system
317  ----------------------------------------------------------  ----------------------------------------------------------
318    
319  *******************************************************************************  Running "make install" installs the command pcre-config, which can be used to
320  *           IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00           *  recall information about the PCRE configuration and installation. For example:
 *                                                                             *  
 * 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.                                                   *  
 *******************************************************************************  
321    
322  The distribution should contain the following files:    pcre-config --version
323    
324    prints the version number, and
325    
326      pcre-config --libs
327    
328    outputs information about where the library is installed. This command can be
329    included in makefiles for programs that use PCRE, saving the programmer from
330    having to remember too many details.
331    
332    The pkg-config command is another system for saving and retrieving information
333    about installed libraries. Instead of separate commands for each library, a
334    single command is used. For example:
335    
336      pkg-config --cflags pcre
337    
338    The data is held in *.pc files that are installed in a directory called
339    <prefix>/lib/pkgconfig.
340    
341    
342    Shared libraries on Unix-like systems
343    -------------------------------------
344    
345    The default distribution builds PCRE as shared libraries and static libraries,
346    as long as the operating system supports shared libraries. Shared library
347    support relies on the "libtool" script which is built as part of the
348    "configure" process.
349    
350    The libtool script is used to compile and link both shared and static
351    libraries. They are placed in a subdirectory called .libs when they are newly
352    built. The programs pcretest and pcregrep are built to use these uninstalled
353    libraries (by means of wrapper scripts in the case of shared libraries). When
354    you use "make install" to install shared libraries, pcregrep and pcretest are
355    automatically re-built to use the newly installed shared libraries before being
356    installed themselves. However, the versions left in the source directory still
357    use the uninstalled libraries.
358    
359    To build PCRE using static libraries only you must use --disable-shared when
360    configuring it. For example:
361    
362    ./configure --prefix=/usr/gnu --disable-shared
363    
364    ChangeLog         log of changes to the code  Then run "make" in the usual way. Similarly, you can use --disable-static to
365    LICENCE           conditions for the use of PCRE  build only shared libraries.
   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  
   testinput         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  
   testoutput        test results corresponding to testinput  
   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.  
366    
367  The fourth set of tests checks pcre_maketables(), the facility for building a  
368    Cross-compiling on a Unix-like system
369    -------------------------------------
370    
371    You can specify CC and CFLAGS in the normal way to the "configure" command, in
372    order to cross-compile PCRE for some other host. However, during the building
373    process, the dftables.c source file is compiled *and run* on the local host, in
374    order to generate the default character tables (the chartables.c file). It
375    therefore needs to be compiled with the local compiler, not the cross compiler.
376    You can do this by specifying CC_FOR_BUILD (and if necessary CFLAGS_FOR_BUILD;
377    there are also CXX_FOR_BUILD and CXXFLAGS_FOR_BUILD for the C++ wrapper)
378    when calling the "configure" command. If they are not specified, they default
379    to the values of CC and CFLAGS.
380    
381    
382    Using HP's ANSI C++ compiler (aCC)
383    ----------------------------------
384    
385    Unless C++ support is disabled by specifying the "--disable-cpp" option of the
386    "configure" script, you *must* include the "-AA" option in the CXXFLAGS
387    environment variable in order for the C++ components to compile correctly.
388    
389    Also, note that the aCC compiler on PA-RISC platforms may have a defect whereby
390    needed libraries fail to get included when specifying the "-AA" compiler
391    option. If you experience unresolved symbols when linking the C++ programs,
392    use the workaround of specifying the following environment variable prior to
393    running the "configure" script:
394    
395      CXXLDFLAGS="-lstd_v2 -lCsup_v2"
396    
397    
398    Testing PCRE
399    ------------
400    
401    To test PCRE on a Unix system, run the RunTest script that is created by the
402    configuring process. There is also a script called RunGrepTest that tests the
403    options of the pcregrep command. If the C++ wrapper library is build, three
404    test programs called pcrecpp_unittest, pcre_scanner_unittest, and
405    pcre_stringpiece_unittest are also built.
406    
407    Both the scripts and all the program tests are run if you obey "make check" or
408    "make test". For other systems, see the instructions in NON-UNIX-USE.
409    
410    The RunTest script runs the pcretest test program (which is documented in its
411    own man page) on each of the testinput files (in the testdata directory) in
412    turn, and compares the output with the contents of the corresponding testoutput
413    files. A file called testtry is used to hold the main output from pcretest
414    (testsavedregex is also used as a working file). To run pcretest on just one of
415    the test files, give its number as an argument to RunTest, for example:
416    
417      RunTest 2
418    
419    The first test file can also be fed directly into the perltest.pl script to
420    check that Perl gives the same results. The only difference you should see is
421    in the first few lines, where the Perl version is given instead of the PCRE
422    version.
423    
424    The second set of tests check pcre_fullinfo(), pcre_info(), pcre_study(),
425    pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error
426    detection, and run-time flags that are specific to PCRE, as well as the POSIX
427    wrapper API. It also uses the debugging flag to check some of the internals of
428    pcre_compile().
429    
430    If you build PCRE with a locale setting that is not the standard C locale, the
431    character tables may be different (see next paragraph). In some cases, this may
432    cause failures in the second set of tests. For example, in a locale where the
433    isprint() function yields TRUE for characters in the range 128-255, the use of
434    [:isascii:] inside a character class defines a different set of characters, and
435    this shows up in this test as a difference in the compiled code, which is being
436    listed for checking. Where the comparison test output contains [\x00-\x7f] the
437    test will contain [\x00-\xff], and similarly in some other cases. This is not a
438    bug in PCRE.
439    
440    The third set of tests checks pcre_maketables(), the facility for building a
441  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
442  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
443  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
444  "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"
445  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
446  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
447    
448    ** Failed to set locale "fr"    ** Failed to set locale "fr_FR"
449    
450  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,
451  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.
452    
453  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
454  /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
455  /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,
456  /usr/local/man/man3).  provided you are running Perl 5.8 or higher. (For Perl 5.6, a small patch,
457    commented in the script, can be be used.)
458  To install the pgrep command, copy it to any suitable binary directory, (e.g.  
459  /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
460  /usr/local/man/man1).  features of PCRE that are not relevant to Perl.
461    
462  PCRE has its own native API, but a set of "wrapper" functions that are based on  The sixth and test checks the support for Unicode character properties. It it
463  the POSIX API are also supplied in the library libpcreposix.a. Note that this  not run automatically unless PCRE is built with Unicode property support. To to
464  just provides a POSIX calling interface to PCRE: the regular expressions  this you must set --enable-unicode-properties when running "configure".
465  themselves still follow Perl syntax and semantics. The header file  
466  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
467  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
468  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
469  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.
470    
471    
472  Character tables  Character tables
473  ----------------  ----------------
474    
475  PCRE uses four tables for manipulating and identifying characters. The final  PCRE uses four tables for manipulating and identifying characters whose values
476  argument of the pcre_compile() function is a pointer to a block of memory  are less than 256. The final argument of the pcre_compile() function is a
477  containing the concatenated tables. A call to pcre_maketables() is used to  pointer to a block of memory containing the concatenated tables. A call to
478  generate a set of tables in the current locale. However, if the final argument  pcre_maketables() can be used to generate a set of tables in the current
479  is passed as NULL, a set of default tables that is built into the binary is  locale. If the final argument for pcre_compile() is passed as NULL, a set of
480  used.  default tables that is built into the binary is used.
481    
482  The source file called chartables.c contains the default set of tables. This is  The source file called chartables.c contains the default set of tables. This is
483  not supplied in the distribution, but is built by the program dftables  not supplied in the distribution, but is built by the program dftables
484  (compiled from dftables.c), which uses the ANSI C character handling functions  (compiled from dftables.c), which uses the ANSI C character handling functions
485  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table
486  sources. This means that the default C locale set your system will control the  sources. This means that the default C locale which is set for your system will
487  contents of the tables. You can change the default tables by editing  control the contents of these default tables. You can change the default tables
488  chartables.c and then re-building PCRE. If you do this, you should probably  by editing chartables.c and then re-building PCRE. If you do this, you should
489  also edit Makefile to ensure that the file doesn't ever get re-generated.  probably also edit Makefile to ensure that the file doesn't ever get
490    re-generated.
491    
492  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,
493  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
494  digits, "word" characters, and white space, respectively. These are used when  digits, "word" characters, and white space, respectively. These are used when
495  building 32-byte bit maps that represent character classes.  building 32-byte bit maps that represent character classes for code points less
496    than 256.
497    
498  The final 256-byte table has bits indicating various character types, as  The final 256-byte table has bits indicating various character types, as
499  follows:  follows:
# Line 145  You should not alter the set of characte Line 509  You should not alter the set of characte
509  will cause PCRE to malfunction.  will cause PCRE to malfunction.
510    
511    
512  The pcretest program  File manifest
513  --------------------  -------------
514    
515  This program is intended for testing PCRE, but it can also be used for  The distribution should contain the following files:
 experimenting with regular expressions.  
516    
517  If it is given two filename arguments, it reads from the first and writes to  (A) Source files of the PCRE library functions and their headers:
 the second. If it is given only one filename argument, it reads from that file  
 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 provides 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. 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 /L option must be followed directly by the name of a locale, for example,  
   
   /pattern/Lfr  
   
 For this reason, it must be the last option 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 option, NULL is passed as the tables pointer; that  
 is, /L applies only to the expression on which it appears.  
   
 The /I option 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 option 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 option causes pcre_study() to be called after the expression has been  
 compiled, and the results used when the expression is matched.  
   
 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.  
   
 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  
   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  
   
 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 -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 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 options. The contents  
 of testinput 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  
 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 and testinput4 files are not suitable for feeding to Perltest,  
 since they do make use of the special upper case options 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.  
518    
519  Philip Hazel <ph10@cam.ac.uk>    dftables.c             auxiliary program for building chartables.c
520  February 1999  
521      pcreposix.c            )
522      pcre_compile.c         )
523      pcre_config.c          )
524      pcre_dfa_exec.c        )
525      pcre_exec.c            )
526      pcre_fullinfo.c        )
527      pcre_get.c             ) sources for the functions in the library,
528      pcre_globals.c         )   and some internal functions that they use
529      pcre_info.c            )
530      pcre_maketables.c      )
531      pcre_newline.c         )
532      pcre_ord2utf8.c        )
533      pcre_refcount.c        )
534      pcre_study.c           )
535      pcre_tables.c          )
536      pcre_try_flipped.c     )
537      pcre_ucp_searchfuncs.c )
538      pcre_valid_utf8.c      )
539      pcre_version.c         )
540      pcre_xclass.c          )
541      pcre_printint.src      ) debugging function that is #included in pcretest,
542                             )   and can also be #included in pcre_compile()
543      pcre.h                 ) a version of the public PCRE header file
544                             )   for use in non-"configure" environments
545      pcre.h.in              template for pcre.h when built by "configure"
546      pcreposix.h            header for the external POSIX wrapper API
547      pcre_internal.h        header for internal use
548      ucp.h                  ) headers concerned with
549      ucpinternal.h          )   Unicode property handling
550      ucptable.h             ) (this one is the data table)
551    
552      config.h               ) a version of config.h for use in non-"configure"
553                             )   environments
554      config.h.in            template for config.h when built by "configure"
555    
556      pcrecpp.h              public header file for the C++ wrapper
557      pcrecpparg.h.in        template for another C++ header file
558      pcre_scanner.h         public header file for C++ scanner functions
559      pcrecpp.cc             )
560      pcre_scanner.cc        ) source for the C++ wrapper library
561    
562      pcre_stringpiece.h.in  template for pcre_stringpiece.h, the header for the
563                               C++ stringpiece functions
564      pcre_stringpiece.cc    source for the C++ stringpiece functions
565    
566    (B) Source files for programs that use PCRE:
567    
568      pcredemo.c             simple demonstration of coding calls to PCRE
569      pcregrep.c             source of a grep utility that uses PCRE
570      pcretest.c             comprehensive test program
571    
572    (C) Auxiliary files:
573    
574      AUTHORS                information about the author of PCRE
575      ChangeLog              log of changes to the code
576      INSTALL                generic installation instructions
577      LICENCE                conditions for the use of PCRE
578      COPYING                the same, using GNU's standard name
579      Makefile.in            ) template for Unix Makefile, which is built by
580                             )   "configure"
581      Makefile.am            ) the automake input that was used to create
582                             )   Makefile.in
583      NEWS                   important changes in this release
584      NON-UNIX-USE           notes on building PCRE on non-Unix systems
585      README                 this file
586      RunTest.in             template for a Unix shell script for running tests
587      RunGrepTest.in         template for a Unix shell script for pcregrep tests
588      aclocal.m4             m4 macros (generated by "aclocal")
589      config.guess           ) files used by libtool,
590      config.sub             )   used only when building a shared library
591      configure              a configuring shell script (built by autoconf)
592      configure.ac           ) the autoconf input that was used to build
593                             )   "configure" and config.h
594      depcomp                ) script to find program dependencies, generated by
595                             )   automake
596      doc/*.3                man page sources for the PCRE functions
597      doc/*.1                man page sources for pcregrep and pcretest
598      doc/html/*             HTML documentation
599      doc/pcre.txt           plain text version of the man pages
600      doc/pcretest.txt       plain text documentation of test program
601      doc/perltest.txt       plain text documentation of Perl test program
602      install-sh             a shell script for installing files
603      libpcre.pc.in          template for libpcre.pc for pkg-config
604      libpcrecpp.pc.in       template for libpcrecpp.pc for pkg-config
605      ltmain.sh              file used to build a libtool script
606      missing                ) common stub for a few missing GNU programs while
607                             )   installing, generated by automake
608      mkinstalldirs          script for making install directories
609      perltest.pl            Perl test program
610      pcre-config.in         source of script which retains PCRE information
611      pcrecpp_unittest.c           )
612      pcre_scanner_unittest.c      ) test programs for the C++ wrapper
613      pcre_stringpiece_unittest.c  )
614      testdata/testinput*    test data for main library tests
615      testdata/testoutput*   expected test results
616      testdata/grep*         input and output for pcregrep tests
617    
618    (D) Auxiliary files for cmake support
619    
620      CMakeLists.txt
621      config-cmake.h.in
622    
623    (E) Auxiliary files for VPASCAL
624    
625      makevp.bat
626      !compile.txt
627      !linklib.txt
628      pcregexp.pas
629    
630    (F) Miscellaneous
631    
632      RunTest.bat            a script for running tests under Windows
633    
634    Philip Hazel
635    Email local part: ph10
636    Email domain: cam.ac.uk
637    Last updated: March 2007

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