/[pcre]/code/trunk/README
ViewVC logotype

Contents of /code/trunk/README

Parent Directory Parent Directory | Revision Log Revision Log


Revision 452 - (show annotations)
Wed Sep 16 19:18:51 2009 UTC (5 years, 10 months ago) by ph10
File size: 35484 byte(s)
Error occurred while calculating annotation data.
Add note about MySQL to README.
1 README file for PCRE (Perl-compatible regular expression library)
2 -----------------------------------------------------------------
3
4 The latest release of PCRE is always available in three alternative formats
5 from:
6
7 ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.gz
8 ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.bz2
9 ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.zip
10
11 There is a mailing list for discussion about the development of PCRE at
12
13 pcre-dev@exim.org
14
15 Please read the NEWS file if you are upgrading from a previous release.
16 The contents of this README file are:
17
18 The PCRE APIs
19 Documentation for PCRE
20 Contributions by users of PCRE
21 Building PCRE on non-Unix systems
22 Building PCRE on Unix-like systems
23 Retrieving configuration information on Unix-like systems
24 Shared libraries on Unix-like systems
25 Cross-compiling on Unix-like systems
26 Using HP's ANSI C++ compiler (aCC)
27 Using PCRE from MySQL
28 Making new tarballs
29 Testing PCRE
30 Character tables
31 File manifest
32
33
34 The PCRE APIs
35 -------------
36
37 PCRE is written in C, and it has its own API. The distribution also includes a
38 set of C++ wrapper functions (see the pcrecpp man page for details), courtesy
39 of Google Inc.
40
41 In addition, there is a set of C wrapper functions that are based on the POSIX
42 regular expression API (see the pcreposix man page). These end up in the
43 library called libpcreposix. Note that this just provides a POSIX calling
44 interface to PCRE; the regular expressions themselves still follow Perl syntax
45 and semantics. The POSIX API is restricted, and does not give full access to
46 all of PCRE's facilities.
47
48 The header file for the POSIX-style functions is called pcreposix.h. The
49 official POSIX name is regex.h, but I did not want to risk possible problems
50 with existing files of that name by distributing it that way. To use PCRE with
51 an existing program that uses the POSIX API, pcreposix.h will have to be
52 renamed or pointed at by a link.
53
54 If you are using the POSIX interface to PCRE and there is already a POSIX regex
55 library installed on your system, as well as worrying about the regex.h header
56 file (as mentioned above), you must also take care when linking programs to
57 ensure that they link with PCRE's libpcreposix library. Otherwise they may pick
58 up the POSIX functions of the same name from the other library.
59
60 One way of avoiding this confusion is to compile PCRE with the addition of
61 -Dregcomp=PCREregcomp (and similarly for the other POSIX functions) to the
62 compiler flags (CFLAGS if you are using "configure" -- see below). This has the
63 effect of renaming the functions so that the names no longer clash. Of course,
64 you have to do the same thing for your applications, or write them using the
65 new names.
66
67
68 Documentation for PCRE
69 ----------------------
70
71 If you install PCRE in the normal way on a Unix-like system, you will end up
72 with a set of man pages whose names all start with "pcre". The one that is just
73 called "pcre" lists all the others. In addition to these man pages, the PCRE
74 documentation is supplied in two other forms:
75
76 1. There are files called doc/pcre.txt, doc/pcregrep.txt, and
77 doc/pcretest.txt in the source distribution. The first of these is a
78 concatenation of the text forms of all the section 3 man pages except
79 those that summarize individual functions. The other two are the text
80 forms of the section 1 man pages for the pcregrep and pcretest commands.
81 These text forms are provided for ease of scanning with text editors or
82 similar tools. They are installed in <prefix>/share/doc/pcre, where
83 <prefix> is the installation prefix (defaulting to /usr/local).
84
85 2. A set of files containing all the documentation in HTML form, hyperlinked
86 in various ways, and rooted in a file called index.html, is distributed in
87 doc/html and installed in <prefix>/share/doc/pcre/html.
88
89 Users of PCRE have contributed files containing the documentation for various
90 releases in CHM format. These can be found in the Contrib directory of the FTP
91 site (see next section).
92
93
94 Contributions by users of PCRE
95 ------------------------------
96
97 You can find contributions from PCRE users in the directory
98
99 ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib
100
101 There is a README file giving brief descriptions of what they are. Some are
102 complete in themselves; others are pointers to URLs containing relevant files.
103 Some of this material is likely to be well out-of-date. Several of the earlier
104 contributions provided support for compiling PCRE on various flavours of
105 Windows (I myself do not use Windows). Nowadays there is more Windows support
106 in the standard distribution, so these contibutions have been archived.
107
108
109 Building PCRE on non-Unix systems
110 ---------------------------------
111
112 For a non-Unix system, please read the comments in the file NON-UNIX-USE,
113 though if your system supports the use of "configure" and "make" you may be
114 able to build PCRE in the same way as for Unix-like systems. PCRE can also be
115 configured in many platform environments using the GUI facility provided by
116 CMake's cmake-gui command. This creates Makefiles, solution files, etc.
117
118 PCRE has been compiled on many different operating systems. It should be
119 straightforward to build PCRE on any system that has a Standard C compiler and
120 library, because it uses only Standard C functions.
121
122
123 Building PCRE on Unix-like systems
124 ----------------------------------
125
126 If you are using HP's ANSI C++ compiler (aCC), please see the special note
127 in the section entitled "Using HP's ANSI C++ compiler (aCC)" below.
128
129 The following instructions assume the use of the widely used "configure, make,
130 make install" process. There is also support for CMake in the PCRE
131 distribution; there are some comments about using CMake in the NON-UNIX-USE
132 file, though it can also be used in Unix-like systems.
133
134 To build PCRE on a Unix-like system, first run the "configure" command from the
135 PCRE distribution directory, with your current directory set to the directory
136 where you want the files to be created. This command is a standard GNU
137 "autoconf" configuration script, for which generic instructions are supplied in
138 the file INSTALL.
139
140 Most commonly, people build PCRE within its own distribution directory, and in
141 this case, on many systems, just running "./configure" is sufficient. However,
142 the usual methods of changing standard defaults are available. For example:
143
144 CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
145
146 specifies that the C compiler should be run with the flags '-O2 -Wall' instead
147 of the default, and that "make install" should install PCRE under /opt/local
148 instead of the default /usr/local.
149
150 If you want to build in a different directory, just run "configure" with that
151 directory as current. For example, suppose you have unpacked the PCRE source
152 into /source/pcre/pcre-xxx, but you want to build it in /build/pcre/pcre-xxx:
153
154 cd /build/pcre/pcre-xxx
155 /source/pcre/pcre-xxx/configure
156
157 PCRE is written in C and is normally compiled as a C library. However, it is
158 possible to build it as a C++ library, though the provided building apparatus
159 does not have any features to support this.
160
161 There are some optional features that can be included or omitted from the PCRE
162 library. You can read more about them in the pcrebuild man page.
163
164 . If you want to suppress the building of the C++ wrapper library, you can add
165 --disable-cpp to the "configure" command. Otherwise, when "configure" is run,
166 it will try to find a C++ compiler and C++ header files, and if it succeeds,
167 it will try to build the C++ wrapper.
168
169 . If you want to make use of the support for UTF-8 Unicode character strings in
170 PCRE, you must add --enable-utf8 to the "configure" command. Without it, the
171 code for handling UTF-8 is not included in the library. Even when included,
172 it still has to be enabled by an option at run time. When PCRE is compiled
173 with this option, its input can only either be ASCII or UTF-8, even when
174 running on EBCDIC platforms. It is not possible to use both --enable-utf8 and
175 --enable-ebcdic at the same time.
176
177 . If, in addition to support for UTF-8 character strings, you want to include
178 support for the \P, \p, and \X sequences that recognize Unicode character
179 properties, you must add --enable-unicode-properties to the "configure"
180 command. This adds about 30K to the size of the library (in the form of a
181 property table); only the basic two-letter properties such as Lu are
182 supported.
183
184 . You can build PCRE to recognize either CR or LF or the sequence CRLF or any
185 of the preceding, or any of the Unicode newline sequences as indicating the
186 end of a line. Whatever you specify at build time is the default; the caller
187 of PCRE can change the selection at run time. The default newline indicator
188 is a single LF character (the Unix standard). You can specify the default
189 newline indicator by adding --enable-newline-is-cr or --enable-newline-is-lf
190 or --enable-newline-is-crlf or --enable-newline-is-anycrlf or
191 --enable-newline-is-any to the "configure" command, respectively.
192
193 If you specify --enable-newline-is-cr or --enable-newline-is-crlf, some of
194 the standard tests will fail, because the lines in the test files end with
195 LF. Even if the files are edited to change the line endings, there are likely
196 to be some failures. With --enable-newline-is-anycrlf or
197 --enable-newline-is-any, many tests should succeed, but there may be some
198 failures.
199
200 . By default, the sequence \R in a pattern matches any Unicode line ending
201 sequence. This is independent of the option specifying what PCRE considers to
202 be the end of a line (see above). However, the caller of PCRE can restrict \R
203 to match only CR, LF, or CRLF. You can make this the default by adding
204 --enable-bsr-anycrlf to the "configure" command (bsr = "backslash R").
205
206 . When called via the POSIX interface, PCRE uses malloc() to get additional
207 storage for processing capturing parentheses if there are more than 10 of
208 them in a pattern. You can increase this threshold by setting, for example,
209
210 --with-posix-malloc-threshold=20
211
212 on the "configure" command.
213
214 . PCRE has a counter that can be set to limit the amount of resources it uses.
215 If the limit is exceeded during a match, the match fails. The default is ten
216 million. You can change the default by setting, for example,
217
218 --with-match-limit=500000
219
220 on the "configure" command. This is just the default; individual calls to
221 pcre_exec() can supply their own value. There is more discussion on the
222 pcreapi man page.
223
224 . There is a separate counter that limits the depth of recursive function calls
225 during a matching process. This also has a default of ten million, which is
226 essentially "unlimited". You can change the default by setting, for example,
227
228 --with-match-limit-recursion=500000
229
230 Recursive function calls use up the runtime stack; running out of stack can
231 cause programs to crash in strange ways. There is a discussion about stack
232 sizes in the pcrestack man page.
233
234 . The default maximum compiled pattern size is around 64K. You can increase
235 this by adding --with-link-size=3 to the "configure" command. You can
236 increase it even more by setting --with-link-size=4, but this is unlikely
237 ever to be necessary. Increasing the internal link size will reduce
238 performance.
239
240 . You can build PCRE so that its internal match() function that is called from
241 pcre_exec() does not call itself recursively. Instead, it uses memory blocks
242 obtained from the heap via the special functions pcre_stack_malloc() and
243 pcre_stack_free() to save data that would otherwise be saved on the stack. To
244 build PCRE like this, use
245
246 --disable-stack-for-recursion
247
248 on the "configure" command. PCRE runs more slowly in this mode, but it may be
249 necessary in environments with limited stack sizes. This applies only to the
250 pcre_exec() function; it does not apply to pcre_dfa_exec(), which does not
251 use deeply nested recursion. There is a discussion about stack sizes in the
252 pcrestack man page.
253
254 . For speed, PCRE uses four tables for manipulating and identifying characters
255 whose code point values are less than 256. By default, it uses a set of
256 tables for ASCII encoding that is part of the distribution. If you specify
257
258 --enable-rebuild-chartables
259
260 a program called dftables is compiled and run in the default C locale when
261 you obey "make". It builds a source file called pcre_chartables.c. If you do
262 not specify this option, pcre_chartables.c is created as a copy of
263 pcre_chartables.c.dist. See "Character tables" below for further information.
264
265 . It is possible to compile PCRE for use on systems that use EBCDIC as their
266 character code (as opposed to ASCII) by specifying
267
268 --enable-ebcdic
269
270 This automatically implies --enable-rebuild-chartables (see above). However,
271 when PCRE is built this way, it always operates in EBCDIC. It cannot support
272 both EBCDIC and UTF-8.
273
274 . It is possible to compile pcregrep to use libz and/or libbz2, in order to
275 read .gz and .bz2 files (respectively), by specifying one or both of
276
277 --enable-pcregrep-libz
278 --enable-pcregrep-libbz2
279
280 Of course, the relevant libraries must be installed on your system.
281
282 . It is possible to compile pcretest so that it links with the libreadline
283 library, by specifying
284
285 --enable-pcretest-libreadline
286
287 If this is done, when pcretest's input is from a terminal, it reads it using
288 the readline() function. This provides line-editing and history facilities.
289 Note that libreadline is GPL-licenced, so if you distribute a binary of
290 pcretest linked in this way, there may be licensing issues.
291
292 Setting this option causes the -lreadline option to be added to the pcretest
293 build. In many operating environments with a sytem-installed readline
294 library this is sufficient. However, in some environments (e.g. if an
295 unmodified distribution version of readline is in use), it may be necessary
296 to specify something like LIBS="-lncurses" as well. This is because, to quote
297 the readline INSTALL, "Readline uses the termcap functions, but does not link
298 with the termcap or curses library itself, allowing applications which link
299 with readline the to choose an appropriate library." If you get error
300 messages about missing functions tgetstr, tgetent, tputs, tgetflag, or tgoto,
301 this is the problem, and linking with the ncurses library should fix it.
302
303 The "configure" script builds the following files for the basic C library:
304
305 . Makefile is the makefile that builds the library
306 . config.h contains build-time configuration options for the library
307 . pcre.h is the public PCRE header file
308 . pcre-config is a script that shows the settings of "configure" options
309 . libpcre.pc is data for the pkg-config command
310 . libtool is a script that builds shared and/or static libraries
311 . RunTest is a script for running tests on the basic C library
312 . RunGrepTest is a script for running tests on the pcregrep command
313
314 Versions of config.h and pcre.h are distributed in the PCRE tarballs under
315 the names config.h.generic and pcre.h.generic. These are provided for the
316 benefit of those who have to built PCRE without the benefit of "configure". If
317 you use "configure", the .generic versions are not used.
318
319 If a C++ compiler is found, the following files are also built:
320
321 . libpcrecpp.pc is data for the pkg-config command
322 . pcrecpparg.h is a header file for programs that call PCRE via the C++ wrapper
323 . pcre_stringpiece.h is the header for the C++ "stringpiece" functions
324
325 The "configure" script also creates config.status, which is an executable
326 script that can be run to recreate the configuration, and config.log, which
327 contains compiler output from tests that "configure" runs.
328
329 Once "configure" has run, you can run "make". It builds two libraries, called
330 libpcre and libpcreposix, a test program called pcretest, and the pcregrep
331 command. If a C++ compiler was found on your system, "make" also builds the C++
332 wrapper library, which is called libpcrecpp, and some test programs called
333 pcrecpp_unittest, pcre_scanner_unittest, and pcre_stringpiece_unittest.
334 Building the C++ wrapper can be disabled by adding --disable-cpp to the
335 "configure" command.
336
337 The command "make check" runs all the appropriate tests. Details of the PCRE
338 tests are given below in a separate section of this document.
339
340 You can use "make install" to install PCRE into live directories on your
341 system. The following are installed (file names are all relative to the
342 <prefix> that is set when "configure" is run):
343
344 Commands (bin):
345 pcretest
346 pcregrep
347 pcre-config
348
349 Libraries (lib):
350 libpcre
351 libpcreposix
352 libpcrecpp (if C++ support is enabled)
353
354 Configuration information (lib/pkgconfig):
355 libpcre.pc
356 libpcrecpp.pc (if C++ support is enabled)
357
358 Header files (include):
359 pcre.h
360 pcreposix.h
361 pcre_scanner.h )
362 pcre_stringpiece.h ) if C++ support is enabled
363 pcrecpp.h )
364 pcrecpparg.h )
365
366 Man pages (share/man/man{1,3}):
367 pcregrep.1
368 pcretest.1
369 pcre.3
370 pcre*.3 (lots more pages, all starting "pcre")
371
372 HTML documentation (share/doc/pcre/html):
373 index.html
374 *.html (lots more pages, hyperlinked from index.html)
375
376 Text file documentation (share/doc/pcre):
377 AUTHORS
378 COPYING
379 ChangeLog
380 LICENCE
381 NEWS
382 README
383 pcre.txt (a concatenation of the man(3) pages)
384 pcretest.txt the pcretest man page
385 pcregrep.txt the pcregrep man page
386
387 If you want to remove PCRE from your system, you can run "make uninstall".
388 This removes all the files that "make install" installed. However, it does not
389 remove any directories, because these are often shared with other programs.
390
391
392 Retrieving configuration information on Unix-like systems
393 ---------------------------------------------------------
394
395 Running "make install" installs the command pcre-config, which can be used to
396 recall information about the PCRE configuration and installation. For example:
397
398 pcre-config --version
399
400 prints the version number, and
401
402 pcre-config --libs
403
404 outputs information about where the library is installed. This command can be
405 included in makefiles for programs that use PCRE, saving the programmer from
406 having to remember too many details.
407
408 The pkg-config command is another system for saving and retrieving information
409 about installed libraries. Instead of separate commands for each library, a
410 single command is used. For example:
411
412 pkg-config --cflags pcre
413
414 The data is held in *.pc files that are installed in a directory called
415 <prefix>/lib/pkgconfig.
416
417
418 Shared libraries on Unix-like systems
419 -------------------------------------
420
421 The default distribution builds PCRE as shared libraries and static libraries,
422 as long as the operating system supports shared libraries. Shared library
423 support relies on the "libtool" script which is built as part of the
424 "configure" process.
425
426 The libtool script is used to compile and link both shared and static
427 libraries. They are placed in a subdirectory called .libs when they are newly
428 built. The programs pcretest and pcregrep are built to use these uninstalled
429 libraries (by means of wrapper scripts in the case of shared libraries). When
430 you use "make install" to install shared libraries, pcregrep and pcretest are
431 automatically re-built to use the newly installed shared libraries before being
432 installed themselves. However, the versions left in the build directory still
433 use the uninstalled libraries.
434
435 To build PCRE using static libraries only you must use --disable-shared when
436 configuring it. For example:
437
438 ./configure --prefix=/usr/gnu --disable-shared
439
440 Then run "make" in the usual way. Similarly, you can use --disable-static to
441 build only shared libraries.
442
443
444 Cross-compiling on Unix-like systems
445 ------------------------------------
446
447 You can specify CC and CFLAGS in the normal way to the "configure" command, in
448 order to cross-compile PCRE for some other host. However, you should NOT
449 specify --enable-rebuild-chartables, because if you do, the dftables.c source
450 file is compiled and run on the local host, in order to generate the inbuilt
451 character tables (the pcre_chartables.c file). This will probably not work,
452 because dftables.c needs to be compiled with the local compiler, not the cross
453 compiler.
454
455 When --enable-rebuild-chartables is not specified, pcre_chartables.c is created
456 by making a copy of pcre_chartables.c.dist, which is a default set of tables
457 that assumes ASCII code. Cross-compiling with the default tables should not be
458 a problem.
459
460 If you need to modify the character tables when cross-compiling, you should
461 move pcre_chartables.c.dist out of the way, then compile dftables.c by hand and
462 run it on the local host to make a new version of pcre_chartables.c.dist.
463 Then when you cross-compile PCRE this new version of the tables will be used.
464
465
466 Using HP's ANSI C++ compiler (aCC)
467 ----------------------------------
468
469 Unless C++ support is disabled by specifying the "--disable-cpp" option of the
470 "configure" script, you must include the "-AA" option in the CXXFLAGS
471 environment variable in order for the C++ components to compile correctly.
472
473 Also, note that the aCC compiler on PA-RISC platforms may have a defect whereby
474 needed libraries fail to get included when specifying the "-AA" compiler
475 option. If you experience unresolved symbols when linking the C++ programs,
476 use the workaround of specifying the following environment variable prior to
477 running the "configure" script:
478
479 CXXLDFLAGS="-lstd_v2 -lCsup_v2"
480
481
482 Using PCRE from MySQL
483 ---------------------
484
485 On systems where both PCRE and MySQL are installed, it is possible to make use
486 of PCRE from within MySQL, as an alternative to the built-in pattern matching.
487 There is a web page that tells you how to do this:
488
489 http://www.mysqludf.org/lib_mysqludf_preg/index.php
490
491
492 Making new tarballs
493 -------------------
494
495 The command "make dist" creates three PCRE tarballs, in tar.gz, tar.bz2, and
496 zip formats. The command "make distcheck" does the same, but then does a trial
497 build of the new distribution to ensure that it works.
498
499 If you have modified any of the man page sources in the doc directory, you
500 should first run the PrepareRelease script before making a distribution. This
501 script creates the .txt and HTML forms of the documentation from the man pages.
502
503
504 Testing PCRE
505 ------------
506
507 To test the basic PCRE library on a Unix system, run the RunTest script that is
508 created by the configuring process. There is also a script called RunGrepTest
509 that tests the options of the pcregrep command. If the C++ wrapper library is
510 built, three test programs called pcrecpp_unittest, pcre_scanner_unittest, and
511 pcre_stringpiece_unittest are also built.
512
513 Both the scripts and all the program tests are run if you obey "make check" or
514 "make test". For other systems, see the instructions in NON-UNIX-USE.
515
516 The RunTest script runs the pcretest test program (which is documented in its
517 own man page) on each of the testinput files in the testdata directory in
518 turn, and compares the output with the contents of the corresponding testoutput
519 files. A file called testtry is used to hold the main output from pcretest
520 (testsavedregex is also used as a working file). To run pcretest on just one of
521 the test files, give its number as an argument to RunTest, for example:
522
523 RunTest 2
524
525 The first test file can also be fed directly into the perltest.pl script to
526 check that Perl gives the same results. The only difference you should see is
527 in the first few lines, where the Perl version is given instead of the PCRE
528 version.
529
530 The second set of tests check pcre_fullinfo(), pcre_info(), pcre_study(),
531 pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error
532 detection, and run-time flags that are specific to PCRE, as well as the POSIX
533 wrapper API. It also uses the debugging flags to check some of the internals of
534 pcre_compile().
535
536 If you build PCRE with a locale setting that is not the standard C locale, the
537 character tables may be different (see next paragraph). In some cases, this may
538 cause failures in the second set of tests. For example, in a locale where the
539 isprint() function yields TRUE for characters in the range 128-255, the use of
540 [:isascii:] inside a character class defines a different set of characters, and
541 this shows up in this test as a difference in the compiled code, which is being
542 listed for checking. Where the comparison test output contains [\x00-\x7f] the
543 test will contain [\x00-\xff], and similarly in some other cases. This is not a
544 bug in PCRE.
545
546 The third set of tests checks pcre_maketables(), the facility for building a
547 set of character tables for a specific locale and using them instead of the
548 default tables. The tests make use of the "fr_FR" (French) locale. Before
549 running the test, the script checks for the presence of this locale by running
550 the "locale" command. If that command fails, or if it doesn't include "fr_FR"
551 in the list of available locales, the third test cannot be run, and a comment
552 is output to say why. If running this test produces instances of the error
553
554 ** Failed to set locale "fr_FR"
555
556 in the comparison output, it means that locale is not available on your system,
557 despite being listed by "locale". This does not mean that PCRE is broken.
558
559 [If you are trying to run this test on Windows, you may be able to get it to
560 work by changing "fr_FR" to "french" everywhere it occurs. Alternatively, use
561 RunTest.bat. The version of RunTest.bat included with PCRE 7.4 and above uses
562 Windows versions of test 2. More info on using RunTest.bat is included in the
563 document entitled NON-UNIX-USE.]
564
565 The fourth test checks the UTF-8 support. It is not run automatically unless
566 PCRE is built with UTF-8 support. To do this you must set --enable-utf8 when
567 running "configure". This file can be also fed directly to the perltest script,
568 provided you are running Perl 5.8 or higher. (For Perl 5.6, a small patch,
569 commented in the script, can be be used.)
570
571 The fifth test checks error handling with UTF-8 encoding, and internal UTF-8
572 features of PCRE that are not relevant to Perl.
573
574 The sixth test checks the support for Unicode character properties. It it not
575 run automatically unless PCRE is built with Unicode property support. To to
576 this you must set --enable-unicode-properties when running "configure".
577
578 The seventh, eighth, and ninth tests check the pcre_dfa_exec() alternative
579 matching function, in non-UTF-8 mode, UTF-8 mode, and UTF-8 mode with Unicode
580 property support, respectively. The eighth and ninth tests are not run
581 automatically unless PCRE is build with the relevant support.
582
583
584 Character tables
585 ----------------
586
587 For speed, PCRE uses four tables for manipulating and identifying characters
588 whose code point values are less than 256. The final argument of the
589 pcre_compile() function is a pointer to a block of memory containing the
590 concatenated tables. A call to pcre_maketables() can be used to generate a set
591 of tables in the current locale. If the final argument for pcre_compile() is
592 passed as NULL, a set of default tables that is built into the binary is used.
593
594 The source file called pcre_chartables.c contains the default set of tables. By
595 default, this is created as a copy of pcre_chartables.c.dist, which contains
596 tables for ASCII coding. However, if --enable-rebuild-chartables is specified
597 for ./configure, a different version of pcre_chartables.c is built by the
598 program dftables (compiled from dftables.c), which uses the ANSI C character
599 handling functions such as isalnum(), isalpha(), isupper(), islower(), etc. to
600 build the table sources. This means that the default C locale which is set for
601 your system will control the contents of these default tables. You can change
602 the default tables by editing pcre_chartables.c and then re-building PCRE. If
603 you do this, you should take care to ensure that the file does not get
604 automatically re-generated. The best way to do this is to move
605 pcre_chartables.c.dist out of the way and replace it with your customized
606 tables.
607
608 When the dftables program is run as a result of --enable-rebuild-chartables,
609 it uses the default C locale that is set on your system. It does not pay
610 attention to the LC_xxx environment variables. In other words, it uses the
611 system's default locale rather than whatever the compiling user happens to have
612 set. If you really do want to build a source set of character tables in a
613 locale that is specified by the LC_xxx variables, you can run the dftables
614 program by hand with the -L option. For example:
615
616 ./dftables -L pcre_chartables.c.special
617
618 The first two 256-byte tables provide lower casing and case flipping functions,
619 respectively. The next table consists of three 32-byte bit maps which identify
620 digits, "word" characters, and white space, respectively. These are used when
621 building 32-byte bit maps that represent character classes for code points less
622 than 256.
623
624 The final 256-byte table has bits indicating various character types, as
625 follows:
626
627 1 white space character
628 2 letter
629 4 decimal digit
630 8 hexadecimal digit
631 16 alphanumeric or '_'
632 128 regular expression metacharacter or binary zero
633
634 You should not alter the set of characters that contain the 128 bit, as that
635 will cause PCRE to malfunction.
636
637
638 File manifest
639 -------------
640
641 The distribution should contain the following files:
642
643 (A) Source files of the PCRE library functions and their headers:
644
645 dftables.c auxiliary program for building pcre_chartables.c
646 when --enable-rebuild-chartables is specified
647
648 pcre_chartables.c.dist a default set of character tables that assume ASCII
649 coding; used, unless --enable-rebuild-chartables is
650 specified, by copying to pcre_chartables.c
651
652 pcreposix.c )
653 pcre_compile.c )
654 pcre_config.c )
655 pcre_dfa_exec.c )
656 pcre_exec.c )
657 pcre_fullinfo.c )
658 pcre_get.c ) sources for the functions in the library,
659 pcre_globals.c ) and some internal functions that they use
660 pcre_info.c )
661 pcre_maketables.c )
662 pcre_newline.c )
663 pcre_ord2utf8.c )
664 pcre_refcount.c )
665 pcre_study.c )
666 pcre_tables.c )
667 pcre_try_flipped.c )
668 pcre_ucd.c )
669 pcre_valid_utf8.c )
670 pcre_version.c )
671 pcre_xclass.c )
672 pcre_printint.src ) debugging function that is #included in pcretest,
673 ) and can also be #included in pcre_compile()
674 pcre.h.in template for pcre.h when built by "configure"
675 pcreposix.h header for the external POSIX wrapper API
676 pcre_internal.h header for internal use
677 ucp.h header for Unicode property handling
678
679 config.h.in template for config.h, which is built by "configure"
680
681 pcrecpp.h public header file for the C++ wrapper
682 pcrecpparg.h.in template for another C++ header file
683 pcre_scanner.h public header file for C++ scanner functions
684 pcrecpp.cc )
685 pcre_scanner.cc ) source for the C++ wrapper library
686
687 pcre_stringpiece.h.in template for pcre_stringpiece.h, the header for the
688 C++ stringpiece functions
689 pcre_stringpiece.cc source for the C++ stringpiece functions
690
691 (B) Source files for programs that use PCRE:
692
693 pcredemo.c simple demonstration of coding calls to PCRE
694 pcregrep.c source of a grep utility that uses PCRE
695 pcretest.c comprehensive test program
696
697 (C) Auxiliary files:
698
699 132html script to turn "man" pages into HTML
700 AUTHORS information about the author of PCRE
701 ChangeLog log of changes to the code
702 CleanTxt script to clean nroff output for txt man pages
703 Detrail script to remove trailing spaces
704 HACKING some notes about the internals of PCRE
705 INSTALL generic installation instructions
706 LICENCE conditions for the use of PCRE
707 COPYING the same, using GNU's standard name
708 Makefile.in ) template for Unix Makefile, which is built by
709 ) "configure"
710 Makefile.am ) the automake input that was used to create
711 ) Makefile.in
712 NEWS important changes in this release
713 NON-UNIX-USE notes on building PCRE on non-Unix systems
714 PrepareRelease script to make preparations for "make dist"
715 README this file
716 RunTest a Unix shell script for running tests
717 RunGrepTest a Unix shell script for pcregrep tests
718 aclocal.m4 m4 macros (generated by "aclocal")
719 config.guess ) files used by libtool,
720 config.sub ) used only when building a shared library
721 configure a configuring shell script (built by autoconf)
722 configure.ac ) the autoconf input that was used to build
723 ) "configure" and config.h
724 depcomp ) script to find program dependencies, generated by
725 ) automake
726 doc/*.3 man page sources for PCRE
727 doc/*.1 man page sources for pcregrep and pcretest
728 doc/index.html.src the base HTML page
729 doc/html/* HTML documentation
730 doc/pcre.txt plain text version of the man pages
731 doc/pcretest.txt plain text documentation of test program
732 doc/perltest.txt plain text documentation of Perl test program
733 install-sh a shell script for installing files
734 libpcre.pc.in template for libpcre.pc for pkg-config
735 libpcreposix.pc.in template for libpcreposix.pc for pkg-config
736 libpcrecpp.pc.in template for libpcrecpp.pc for pkg-config
737 ltmain.sh file used to build a libtool script
738 missing ) common stub for a few missing GNU programs while
739 ) installing, generated by automake
740 mkinstalldirs script for making install directories
741 perltest.pl Perl test program
742 pcre-config.in source of script which retains PCRE information
743 pcrecpp_unittest.cc )
744 pcre_scanner_unittest.cc ) test programs for the C++ wrapper
745 pcre_stringpiece_unittest.cc )
746 testdata/testinput* test data for main library tests
747 testdata/testoutput* expected test results
748 testdata/grep* input and output for pcregrep tests
749
750 (D) Auxiliary files for cmake support
751
752 cmake/COPYING-CMAKE-SCRIPTS
753 cmake/FindPackageHandleStandardArgs.cmake
754 cmake/FindReadline.cmake
755 CMakeLists.txt
756 config-cmake.h.in
757
758 (E) Auxiliary files for VPASCAL
759
760 makevp.bat
761 makevp_c.txt
762 makevp_l.txt
763 pcregexp.pas
764
765 (F) Auxiliary files for building PCRE "by hand"
766
767 pcre.h.generic ) a version of the public PCRE header file
768 ) for use in non-"configure" environments
769 config.h.generic ) a version of config.h for use in non-"configure"
770 ) environments
771
772 (F) Miscellaneous
773
774 RunTest.bat a script for running tests under Windows
775
776 Philip Hazel
777 Email local part: ph10
778 Email domain: cam.ac.uk
779 Last updated: 16 September 2009

Properties

Name Value
svn:eol-style native
svn:keywords "Author Date Id Revision Url"

  ViewVC Help
Powered by ViewVC 1.1.5