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1  README file for PCRE (Perl-compatible regular expressions)  README file for PCRE (Perl-compatible regular expression library)
2  ----------------------------------------------------------  -----------------------------------------------------------------
3    
4  *******************************************************************************  The latest release of PCRE is always available from
 *           IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00           *  
 *                                                                             *  
 * Please note that there has been a change in the API such that a larger      *  
 * ovector is required at matching time, to provide some additional workspace. *  
 * The new man page has details. This change was necessary in order to support *  
 * some of the new functionality in Perl 5.005.                                *  
 *                                                                             *  
 *           IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00                   *  
 *                                                                             *  
 * Another (I hope this is the last!) change has been made to the API for the  *  
 * pcre_compile() function. An additional argument has been added to make it   *  
 * possible to pass over a pointer to character tables built in the current    *  
 * locale by pcre_maketables(). To use the default tables, this new arguement  *  
 * should be passed as NULL.                                                   *  
 *******************************************************************************  
5    
6  The distribution should contain the following files:    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    
10    
11    The PCRE APIs
12    -------------
13    
14    PCRE is written in C, and it has its own API. The distribution now includes a
15    set of C++ wrapper functions, courtesy of Google Inc. (see the pcrecpp man page
16    for details).
17    
18    Also included are a set of C wrapper functions that are based on the POSIX
19    API. These end up in the library called libpcreposix. Note that this just
20    provides a POSIX calling interface to PCRE: the regular expressions themselves
21    still follow Perl syntax and semantics. The header file for the POSIX-style
22    functions is called pcreposix.h. The official POSIX name is regex.h, but I
23    didn't want to risk possible problems with existing files of that name by
24    distributing it that way. To use it with an existing program that uses the
25    POSIX API, it will have to be renamed or pointed at by a link.
26    
27    If you are using the POSIX interface to PCRE and there is already a POSIX regex
28    library installed on your system, you must take care when linking programs to
29    ensure that they link with PCRE's libpcreposix library. Otherwise they may pick
30    up the "real" POSIX functions of the same name.
31    
32    
33    Documentation for PCRE
34    ----------------------
35    
36    If you install PCRE in the normal way, you will end up with an installed set of
37    man pages whose names all start with "pcre". The one that is just called "pcre"
38    lists all the others. In addition to these man pages, the PCRE documentation is
39    supplied in two other forms; however, as there is no standard place to install
40    them, they are left in the doc directory of the unpacked source distribution.
41    These forms are:
42    
43      1. Files called doc/pcre.txt, doc/pcregrep.txt, and doc/pcretest.txt. The
44         first of these is a concatenation of the text forms of all the section 3
45         man pages except those that summarize individual functions. The other two
46         are the text forms of the section 1 man pages for the pcregrep and
47         pcretest commands. Text forms are provided for ease of scanning with text
48         editors or similar tools.
49    
50      2. A subdirectory called doc/html contains all the documentation in HTML
51         form, hyperlinked in various ways, and rooted in a file called
52         doc/index.html.
53    
54    
55    Contributions by users of PCRE
56    ------------------------------
57    
58    You can find contributions from PCRE users in the directory
59    
60      ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib
61    
62    where there is also a README file giving brief descriptions of what they are.
63    Several of them provide support for compiling PCRE on various flavours of
64    Windows systems (I myself do not use Windows). Some are complete in themselves;
65    others are pointers to URLs containing relevant files.
66    
67    
68    Building PCRE on a Unix-like system
69    -----------------------------------
70    
71    If you are using HP's ANSI C++ compiler (aCC), please see the special note
72    in the section entitled "Using HP's ANSI C++ compiler (aCC)" below.
73    
74    To build PCRE on a Unix-like system, first run the "configure" command from the
75    PCRE distribution directory, with your current directory set to the directory
76    where you want the files to be created. This command is a standard GNU
77    "autoconf" configuration script, for which generic instructions are supplied in
78    INSTALL.
79    
80    Most commonly, people build PCRE within its own distribution directory, and in
81    this case, on many systems, just running "./configure" is sufficient, but the
82    usual methods of changing standard defaults are available. For example:
83    
84    CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
85    
86    specifies that the C compiler should be run with the flags '-O2 -Wall' instead
87    of the default, and that "make install" should install PCRE under /opt/local
88    instead of the default /usr/local.
89    
90    If you want to build in a different directory, just run "configure" with that
91    directory as current. For example, suppose you have unpacked the PCRE source
92    into /source/pcre/pcre-xxx, but you want to build it in /build/pcre/pcre-xxx:
93    
94    cd /build/pcre/pcre-xxx
95    /source/pcre/pcre-xxx/configure
96    
97    PCRE is written in C and is normally compiled as a C library. However, it is
98    possible to build it as a C++ library, though the provided building apparatus
99    does not have any features to support this.
100    
101    There are some optional features that can be included or omitted from the PCRE
102    library. You can read more about them in the pcrebuild man page.
103    
104    . If you want to suppress the building of the C++ wrapper library, you can add
105      --disable-cpp to the "configure" command. Otherwise, when "configure" is run,
106      will try to find a C++ compiler and C++ header files, and if it succeeds, it
107      will try to build the C++ wrapper.
108    
109    . If you want to make use of the support for UTF-8 character strings in PCRE,
110      you must add --enable-utf8 to the "configure" command. Without it, the code
111      for handling UTF-8 is not included in the library. (Even when included, it
112      still has to be enabled by an option at run time.)
113    
114    . If, in addition to support for UTF-8 character strings, you want to include
115      support for the \P, \p, and \X sequences that recognize Unicode character
116      properties, you must add --enable-unicode-properties to the "configure"
117      command. This adds about 30K to the size of the library (in the form of a
118      property table); only the basic two-letter properties such as Lu are
119      supported.
120    
121    . You can build PCRE to recognize either CR or LF or the sequence CRLF as
122      indicating the end of a line. Whatever you specify at build time is the
123      default; the caller of PCRE can change the selection at run time. The default
124      newline indicator is a single LF character (the Unix standard). You can
125      specify the default newline indicator by adding --newline-is-cr or
126      --newline-is-lf or --newline-is-crlf to the "configure" command,
127      respectively.
128    
129    . When called via the POSIX interface, PCRE uses malloc() to get additional
130      storage for processing capturing parentheses if there are more than 10 of
131      them. You can increase this threshold by setting, for example,
132    
133      --with-posix-malloc-threshold=20
134    
135      on the "configure" command.
136    
137    . PCRE has a counter that can be set to limit the amount of resources it uses.
138      If the limit is exceeded during a match, the match fails. The default is ten
139      million. You can change the default by setting, for example,
140    
141      --with-match-limit=500000
142    
143      on the "configure" command. This is just the default; individual calls to
144      pcre_exec() can supply their own value. There is discussion on the pcreapi
145      man page.
146    
147    . There is a separate counter that limits the depth of recursive function calls
148      during a matching process. This also has a default of ten million, which is
149      essentially "unlimited". You can change the default by setting, for example,
150    
151      --with-match-limit-recursion=500000
152    
153      Recursive function calls use up the runtime stack; running out of stack can
154      cause programs to crash in strange ways. There is a discussion about stack
155      sizes in the pcrestack man page.
156    
157    . The default maximum compiled pattern size is around 64K. You can increase
158      this by adding --with-link-size=3 to the "configure" command. You can
159      increase it even more by setting --with-link-size=4, but this is unlikely
160      ever to be necessary. If you build PCRE with an increased link size, test 2
161      (and 5 if you are using UTF-8) will fail. Part of the output of these tests
162      is a representation of the compiled pattern, and this changes with the link
163      size.
164    
165    . You can build PCRE so that its internal match() function that is called from
166      pcre_exec() does not call itself recursively. Instead, it uses blocks of data
167      from the heap via special functions pcre_stack_malloc() and pcre_stack_free()
168      to save data that would otherwise be saved on the stack. To build PCRE like
169      this, use
170    
171      --disable-stack-for-recursion
172    
173      on the "configure" command. PCRE runs more slowly in this mode, but it may be
174      necessary in environments with limited stack sizes. This applies only to the
175      pcre_exec() function; it does not apply to pcre_dfa_exec(), which does not
176      use deeply nested recursion.
177    
178    The "configure" script builds eight files for the basic C library:
179    
180    . Makefile is the makefile that builds the library
181    . config.h contains build-time configuration options for the library
182    . pcre-config is a script that shows the settings of "configure" options
183    . libpcre.pc is data for the pkg-config command
184    . libtool is a script that builds shared and/or static libraries
185    . RunTest is a script for running tests on the library
186    . RunGrepTest is a script for running tests on the pcregrep command
187    
188    ChangeLog         log of changes to the code  In addition, if a C++ compiler is found, the following are also built:
   LICENCE           conditions for the use of PCRE  
   Makefile          for building PCRE  
   README            this file  
   RunTest           a shell script for running tests  
   Tech.Notes        notes on the encoding  
   pcre.3            man page for the functions  
   pcreposix.3       man page for the POSIX wrapper API  
   dftables.c        auxiliary program for building chartables.c  
   get.c             )  
   maketables.c      )  
   study.c           ) source of  
   pcre.c            )   the functions  
   pcreposix.c       )  
   pcre.h            header for the external API  
   pcreposix.h       header for the external POSIX wrapper API  
   internal.h        header for internal use  
   pcretest.c        test program  
   pgrep.1           man page for pgrep  
   pgrep.c           source of a grep utility that uses PCRE  
   perltest          Perl test program  
   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.  
189    
190  The fourth set of tests checks pcre_maketables(), the facility for building a  . pcrecpp.h is the header file for programs that call PCRE via the C++ wrapper
191    . pcre_stringpiece.h is the header for the C++ "stringpiece" functions
192    
193    The "configure" script also creates config.status, which is an executable
194    script that can be run to recreate the configuration, and config.log, which
195    contains compiler output from tests that "configure" runs.
196    
197    Once "configure" has run, you can run "make". It builds two libraries, called
198    libpcre and libpcreposix, a test program called pcretest, and the pcregrep
199    command. If a C++ compiler was found on your system, it also builds the C++
200    wrapper library, which is called libpcrecpp, and some test programs called
201    pcrecpp_unittest, pcre_scanner_unittest, and pcre_stringpiece_unittest.
202    
203    The command "make test" runs all the appropriate tests. Details of the PCRE
204    tests are given in a separate section of this document, below.
205    
206    You can use "make install" to copy the libraries, the public header files
207    pcre.h, pcreposix.h, pcrecpp.h, and pcre_stringpiece.h (the last two only if
208    the C++ wrapper was built), and the man pages to appropriate live directories
209    on your system, in the normal way.
210    
211    If you want to remove PCRE from your system, you can run "make uninstall".
212    This removes all the files that "make install" installed. However, it does not
213    remove any directories, because these are often shared with other programs.
214    
215    
216    Retrieving configuration information on Unix-like systems
217    ---------------------------------------------------------
218    
219    Running "make install" also installs the command pcre-config, which can be used
220    to recall information about the PCRE configuration and installation. For
221    example:
222    
223      pcre-config --version
224    
225    prints the version number, and
226    
227      pcre-config --libs
228    
229    outputs information about where the library is installed. This command can be
230    included in makefiles for programs that use PCRE, saving the programmer from
231    having to remember too many details.
232    
233    The pkg-config command is another system for saving and retrieving information
234    about installed libraries. Instead of separate commands for each library, a
235    single command is used. For example:
236    
237      pkg-config --cflags pcre
238    
239    The data is held in *.pc files that are installed in a directory called
240    pkgconfig.
241    
242    
243    Shared libraries on Unix-like systems
244    -------------------------------------
245    
246    The default distribution builds PCRE as shared libraries and static libraries,
247    as long as the operating system supports shared libraries. Shared library
248    support relies on the "libtool" script which is built as part of the
249    "configure" process.
250    
251    The libtool script is used to compile and link both shared and static
252    libraries. They are placed in a subdirectory called .libs when they are newly
253    built. The programs pcretest and pcregrep are built to use these uninstalled
254    libraries (by means of wrapper scripts in the case of shared libraries). When
255    you use "make install" to install shared libraries, pcregrep and pcretest are
256    automatically re-built to use the newly installed shared libraries before being
257    installed themselves. However, the versions left in the source directory still
258    use the uninstalled libraries.
259    
260    To build PCRE using static libraries only you must use --disable-shared when
261    configuring it. For example:
262    
263    ./configure --prefix=/usr/gnu --disable-shared
264    
265    Then run "make" in the usual way. Similarly, you can use --disable-static to
266    build only shared libraries.
267    
268    
269    Cross-compiling on a Unix-like system
270    -------------------------------------
271    
272    You can specify CC and CFLAGS in the normal way to the "configure" command, in
273    order to cross-compile PCRE for some other host. However, during the building
274    process, the dftables.c source file is compiled *and run* on the local host, in
275    order to generate the default character tables (the chartables.c file). It
276    therefore needs to be compiled with the local compiler, not the cross compiler.
277    You can do this by specifying CC_FOR_BUILD (and if necessary CFLAGS_FOR_BUILD;
278    there are also CXX_FOR_BUILD and CXXFLAGS_FOR_BUILD for the C++ wrapper)
279    when calling the "configure" command. If they are not specified, they default
280    to the values of CC and CFLAGS.
281    
282    
283    Using HP's ANSI C++ compiler (aCC)
284    ----------------------------------
285    
286    Unless C++ support is disabled by specifiying the "--disable-cpp" option of the
287    "configure" script, you *must* include the "-AA" option in the CXXFLAGS
288    environment variable in order for the C++ components to compile correctly.
289    
290    Also, note that the aCC compiler on PA-RISC platforms may have a defect whereby
291    needed libraries fail to get included when specifying the "-AA" compiler
292    option. If you experience unresolved symbols when linking the C++ programs,
293    use the workaround of specifying the following environment variable prior to
294    running the "configure" script:
295    
296      CXXLDFLAGS="-lstd_v2 -lCsup_v2"
297    
298    
299    Building on non-Unix systems
300    ----------------------------
301    
302    For a non-Unix system, read the comments in the file NON-UNIX-USE, though if
303    the system supports the use of "configure" and "make" you may be able to build
304    PCRE in the same way as for Unix systems.
305    
306    PCRE has been compiled on Windows systems and on Macintoshes, but I don't know
307    the details because I don't use those systems. It should be straightforward to
308    build PCRE on any system that has a Standard C compiler, because it uses only
309    Standard C functions.
310    
311    
312    Testing PCRE
313    ------------
314    
315    To test PCRE on a Unix system, run the RunTest script that is created by the
316    configuring process. There is also a script called RunGrepTest that tests the
317    options of the pcregrep command. If the C++ wrapper library is build, three
318    test programs called pcrecpp_unittest, pcre_scanner_unittest, and
319    pcre_stringpiece_unittest are provided.
320    
321    Both the scripts and all the program tests are run if you obey "make runtest",
322    "make check", or "make test". For other systems, see the instructions in
323    NON-UNIX-USE.
324    
325    The RunTest script runs the pcretest test program (which is documented in its
326    own man page) on each of the testinput files (in the testdata directory) in
327    turn, and compares the output with the contents of the corresponding testoutput
328    file. A file called testtry is used to hold the main output from pcretest
329    (testsavedregex is also used as a working file). To run pcretest on just one of
330    the test files, give its number as an argument to RunTest, for example:
331    
332      RunTest 2
333    
334    The first file can also be fed directly into the perltest script to check that
335    Perl gives the same results. The only difference you should see is in the first
336    few lines, where the Perl version is given instead of the PCRE version.
337    
338    The second set of tests check pcre_fullinfo(), pcre_info(), pcre_study(),
339    pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error
340    detection, and run-time flags that are specific to PCRE, as well as the POSIX
341    wrapper API. It also uses the debugging flag to check some of the internals of
342    pcre_compile().
343    
344    If you build PCRE with a locale setting that is not the standard C locale, the
345    character tables may be different (see next paragraph). In some cases, this may
346    cause failures in the second set of tests. For example, in a locale where the
347    isprint() function yields TRUE for characters in the range 128-255, the use of
348    [:isascii:] inside a character class defines a different set of characters, and
349    this shows up in this test as a difference in the compiled code, which is being
350    listed for checking. Where the comparison test output contains [\x00-\x7f] the
351    test will contain [\x00-\xff], and similarly in some other cases. This is not a
352    bug in PCRE.
353    
354    The third set of tests checks pcre_maketables(), the facility for building a
355  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
356  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
357  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
358  "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"
359  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
360  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
361    
362    ** Failed to set locale "fr"    ** Failed to set locale "fr_FR"
363    
364  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,
365  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.
366    
367  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
368  /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
369  /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,
370  /usr/local/man/man3).  provided you are running Perl 5.8 or higher. (For Perl 5.6, a small patch,
371    commented in the script, can be be used.)
372  To install the pgrep command, copy it to any suitable binary directory, (e.g.  
373  /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
374  /usr/local/man/man1).  features of PCRE that are not relevant to Perl.
375    
376  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
377  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
378  just provides a POSIX calling interface to PCRE: the regular expressions  this you must set --enable-unicode-properties when running "configure".
379  themselves still follow Perl syntax and semantics. The header file  
380  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
381  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
382  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
383  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.
384    
385    
386  Character tables  Character tables
387  ----------------  ----------------
388    
389  PCRE uses four tables for manipulating and identifying characters. The final  PCRE uses four tables for manipulating and identifying characters whose values
390  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
391  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
392  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
393  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
394  used.  default tables that is built into the binary is used.
395    
396  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
397  not supplied in the distribution, but is built by the program dftables  not supplied in the distribution, but is built by the program dftables
398  (compiled from dftables.c), which uses the ANSI C character handling functions  (compiled from dftables.c), which uses the ANSI C character handling functions
399  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table
400  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
401  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
402  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
403  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
404    re-generated.
405    
406  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,
407  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
# Line 145  You should not alter the set of characte Line 422  You should not alter the set of characte
422  will cause PCRE to malfunction.  will cause PCRE to malfunction.
423    
424    
425  The pcretest program  Manifest
426  --------------------  --------
427    
428    The distribution should contain the following files:
429    
430  This program is intended for testing PCRE, but it can also be used for  (A) The actual source files of the PCRE library functions and their
431  experimenting with regular expressions.      headers:
432    
433  If it is given two filename arguments, it reads from the first and writes to    dftables.c            auxiliary program for building chartables.c
 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.  
   
 The /M option causes information about the size of memory block used to hold  
 the compile pattern to be output.  
   
 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 -m is given to pcretest, it outputs the size of each compiled  
 pattern after it has been compiled. It is equivalent to adding /M to each  
 regular expression. For compatibility with earlier versions of pcretest, -s is  
 a synonym for -m.  
   
 If the -t option is given, each compile, study, and match is run 20000 times  
 while being timed, and the resulting time per compile or match is output in  
 milliseconds. Do not set -t with -s, because you will then get the size output  
 20000 times and the timing will be distorted. If you want to change the number  
 of repetitions used for timing, edit the definition of LOOPREPEAT at the top of  
 pcretest.c  
   
   
   
 The perltest program  
 --------------------  
   
 The perltest program tests Perl's regular expressions; it has the same  
 specification as pcretest, and so can be given identical input, except that  
 input patterns can be followed only by Perl's lower case 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.  
434    
435  Philip Hazel <ph10@cam.ac.uk>    pcreposix.c           )
436  February 1999    pcre_compile.c        )
437      pcre_config.c         )
438      pcre_dfa_exec.c       )
439      pcre_exec.c           )
440      pcre_fullinfo.c       )
441      pcre_get.c            ) sources for the functions in the library,
442      pcre_globals.c        )   and some internal functions that they use
443      pcre_info.c           )
444      pcre_maketables.c     )
445      pcre_ord2utf8.c       )
446      pcre_refcount.c       )
447      pcre_study.c          )
448      pcre_tables.c         )
449      pcre_try_flipped.c    )
450      pcre_ucp_searchfuncs.c)
451      pcre_valid_utf8.c     )
452      pcre_version.c        )
453      pcre_xclass.c         )
454      ucptable.c            )
455    
456      pcre_printint.src     ) debugging function that is #included in pcretest, and
457                            )   can also be #included in pcre_compile()
458    
459      pcre.h                the public PCRE header file
460      pcreposix.h           header for the external POSIX wrapper API
461      pcre_internal.h       header for internal use
462      ucp.h                 ) headers concerned with
463      ucpinternal.h         )   Unicode property handling
464      config.in             template for config.h, which is built by configure
465    
466      pcrecpp.h             the header file for the C++ wrapper
467      pcrecpparg.h.in       "source" for another C++ header file
468      pcrecpp.cc            )
469      pcre_scanner.cc       ) source for the C++ wrapper library
470    
471      pcre_stringpiece.h.in "source" for pcre_stringpiece.h, the header for the
472                              C++ stringpiece functions
473      pcre_stringpiece.cc   source for the C++ stringpiece functions
474    
475    (B) Auxiliary files:
476    
477      AUTHORS               information about the author of PCRE
478      ChangeLog             log of changes to the code
479      INSTALL               generic installation instructions
480      LICENCE               conditions for the use of PCRE
481      COPYING               the same, using GNU's standard name
482      Makefile.in           template for Unix Makefile, which is built by configure
483      NEWS                  important changes in this release
484      NON-UNIX-USE          notes on building PCRE on non-Unix systems
485      README                this file
486      RunTest.in            template for a Unix shell script for running tests
487      RunGrepTest.in        template for a Unix shell script for pcregrep tests
488      config.guess          ) files used by libtool,
489      config.sub            )   used only when building a shared library
490      config.h.in           "source" for the config.h header file
491      configure             a configuring shell script (built by autoconf)
492      configure.ac          the autoconf input used to build configure
493      doc/Tech.Notes        notes on the encoding
494      doc/*.3               man page sources for the PCRE functions
495      doc/*.1               man page sources for pcregrep and pcretest
496      doc/html/*            HTML documentation
497      doc/pcre.txt          plain text version of the man pages
498      doc/pcretest.txt      plain text documentation of test program
499      doc/perltest.txt      plain text documentation of Perl test program
500      install-sh            a shell script for installing files
501      libpcre.pc.in         "source" for libpcre.pc for pkg-config
502      ltmain.sh             file used to build a libtool script
503      mkinstalldirs         script for making install directories
504      pcretest.c            comprehensive test program
505      pcredemo.c            simple demonstration of coding calls to PCRE
506      perltest              Perl test program
507      pcregrep.c            source of a grep utility that uses PCRE
508      pcre-config.in        source of script which retains PCRE information
509      pcrecpp_unittest.c           )
510      pcre_scanner_unittest.c      ) test programs for the C++ wrapper
511      pcre_stringpiece_unittest.c  )
512      testdata/testinput*   test data for main library tests
513      testdata/testoutput*  expected test results
514      testdata/grep*        input and output for pcregrep tests
515    
516    (C) Auxiliary files for Win32 DLL
517    
518      libpcre.def
519      libpcreposix.def
520    
521    (D) Auxiliary file for VPASCAL
522    
523      makevp.bat
524    
525    Philip Hazel
526    Email local part: ph10
527    Email domain: cam.ac.uk
528    June 2006

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