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1 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
10 PCRE has its own native API, but a set of "wrapper" functions that are based on
11 the POSIX API are also supplied in the library libpcreposix. Note that this
12 just provides a POSIX calling interface to PCRE: the regular expressions
13 themselves still follow Perl syntax and semantics. The header file
14 for the POSIX-style functions is called pcreposix.h. The official POSIX name is
15 regex.h, but I didn't want to risk possible problems with existing files of
16 that name by distributing it that way. To use it with an existing program that
17 uses the POSIX API, it will have to be renamed or pointed at by a link.
18
19
20 Contributions by users of PCRE
21 ------------------------------
22
23 You can find contributions from PCRE users in the directory
24
25 ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib
26
27 where there is also a README file giving brief descriptions of what they are.
28 Several of them provide support for compiling PCRE on various flavours of
29 Windows systems (I myself do not use Windows). Some are complete in themselves;
30 others are pointers to URLs containing relevant files.
31
32
33 Building PCRE on a Unix system
34 ------------------------------
35
36 To build PCRE on a Unix system, first run the "configure" command from the PCRE
37 distribution directory, with your current directory set to the directory where
38 you want the files to be created. This command is a standard GNU "autoconf"
39 configuration script, for which generic instructions are supplied in INSTALL.
40
41 Most commonly, people build PCRE within its own distribution directory, and in
42 this case, on many systems, just running "./configure" is sufficient, but the
43 usual methods of changing standard defaults are available. For example,
44
45 CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
46
47 specifies that the C compiler should be run with the flags '-O2 -Wall' instead
48 of the default, and that "make install" should install PCRE under /opt/local
49 instead of the default /usr/local.
50
51 If you want to build in a different directory, just run "configure" with that
52 directory as current. For example, suppose you have unpacked the PCRE source
53 into /source/pcre/pcre-xxx, but you want to build it in /build/pcre/pcre-xxx:
54
55 cd /build/pcre/pcre-xxx
56 /source/pcre/pcre-xxx/configure
57
58 If you want to make use of the experimential, incomplete support for UTF-8
59 character strings in PCRE, you must add --enable-utf8 to the "configure"
60 command. Without it, the code for handling UTF-8 is not included in the
61 library. (Even when included, it still has to be enabled by an option at run
62 time.)
63
64 The "configure" script builds five files:
65
66 . libtool is a script that builds shared and/or static libraries
67 . Makefile is built by copying Makefile.in and making substitutions.
68 . config.h is built by copying config.in and making substitutions.
69 . pcre-config is built by copying pcre-config.in and making substitutions.
70 . RunTest is a script for running tests
71
72 Once "configure" has run, you can run "make". It builds two libraries called
73 libpcre and libpcreposix, a test program called pcretest, and the pcregrep
74 command. You can use "make install" to copy these, the public header files
75 pcre.h and pcreposix.h, and the man pages to appropriate live directories on
76 your system, in the normal way.
77
78 Running "make install" also installs the command pcre-config, which can be used
79 to recall information about the PCRE configuration and installation. For
80 example,
81
82 pcre-config --version
83
84 prints the version number, and
85
86 pcre-config --libs
87
88 outputs information about where the library is installed. This command can be
89 included in makefiles for programs that use PCRE, saving the programmer from
90 having to remember too many details.
91
92 There is one esoteric feature that is controlled by "configure". It concerns
93 the character value used for "newline", and is something that you probably do
94 not want to change on a Unix system. The default is to use whatever value your
95 compiler gives to '\n'. By using --enable-newline-is-cr or
96 --enable-newline-is-lf you can force the value to be CR (13) or LF (10) if you
97 really want to.
98
99
100 Shared libraries on Unix systems
101 --------------------------------
102
103 The default distribution builds PCRE as two shared libraries and two static
104 libraries, as long as the operating system supports shared libraries. Shared
105 library support relies on the "libtool" script which is built as part of the
106 "configure" process.
107
108 The libtool script is used to compile and link both shared and static
109 libraries. They are placed in a subdirectory called .libs when they are newly
110 built. The programs pcretest and pcregrep are built to use these uninstalled
111 libraries (by means of wrapper scripts in the case of shared libraries). When
112 you use "make install" to install shared libraries, pcregrep and pcretest are
113 automatically re-built to use the newly installed shared libraries before being
114 installed themselves. However, the versions left in the source directory still
115 use the uninstalled libraries.
116
117 To build PCRE using static libraries only you must use --disable-shared when
118 configuring it. For example
119
120 ./configure --prefix=/usr/gnu --disable-shared
121
122 Then run "make" in the usual way. Similarly, you can use --disable-static to
123 build only shared libraries.
124
125
126 Building on non-Unix systems
127 ----------------------------
128
129 For a non-Unix system, read the comments in the file NON-UNIX-USE. PCRE has
130 been compiled on Windows systems and on Macintoshes, but I don't know the
131 details because I don't use those systems. It should be straightforward to
132 build PCRE on any system that has a Standard C compiler, because it uses only
133 Standard C functions.
134
135
136 Testing PCRE
137 ------------
138
139 To test PCRE on a Unix system, run the RunTest script that is created by the
140 configuring process. (This can also be run by "make runtest", "make check", or
141 "make test".) For other systems, see the instruction in NON-UNIX-USE.
142
143 The script runs the pcretest test program (which is documented in the doc
144 directory) on each of the testinput files (in the testdata directory) in turn,
145 and compares the output with the contents of the corresponding testoutput file.
146 A file called testtry is used to hold the output from pcretest. To run pcretest
147 on just one of the test files, give its number as an argument to RunTest, for
148 example:
149
150 RunTest 3
151
152 The first and third test files can also be fed directly into the perltest
153 script to check that Perl gives the same results. The third file requires the
154 additional features of release 5.005, which is why it is kept separate from the
155 main test input, which needs only Perl 5.004. In the long run, when 5.005 (or
156 higher) is widespread, these two test files may get amalgamated.
157
158 The second set of tests check pcre_fullinfo(), pcre_info(), pcre_study(),
159 pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error
160 detection, and run-time flags that are specific to PCRE, as well as the POSIX
161 wrapper API. It also uses the debugging flag to check some of the internals of
162 pcre_compile().
163
164 If you build PCRE with a locale setting that is not the standard C locale, the
165 character tables may be different (see next paragraph). In some cases, this may
166 cause failures in the second set of tests. For example, in a locale where the
167 isprint() function yields TRUE for characters in the range 128-255, the use of
168 [:isascii:] inside a character class defines a different set of characters, and
169 this shows up in this test as a difference in the compiled code, which is being
170 listed for checking. Where the comparison test output contains [\x00-\x7f] the
171 test will contain [\x00-\xff], and similarly in some other cases. This is not a
172 bug in PCRE.
173
174 The fourth set of tests checks pcre_maketables(), the facility for building a
175 set of character tables for a specific locale and using them instead of the
176 default tables. The tests make use of the "fr" (French) locale. Before running
177 the test, the script checks for the presence of this locale by running the
178 "locale" command. If that command fails, or if it doesn't include "fr" in the
179 list of available locales, the fourth test cannot be run, and a comment is
180 output to say why. If running this test produces instances of the error
181
182 ** Failed to set locale "fr"
183
184 in the comparison output, it means that locale is not available on your system,
185 despite being listed by "locale". This does not mean that PCRE is broken.
186
187 The fifth test checks the experimental, incomplete UTF-8 support. It is not run
188 automatically unless PCRE is built with UTF-8 support. This file can be fed
189 directly to the perltest8 script, which requires Perl 5.6 or higher. The sixth
190 file tests internal UTF-8 features of PCRE that are not relevant to Perl.
191
192
193 Character tables
194 ----------------
195
196 PCRE uses four tables for manipulating and identifying characters. The final
197 argument of the pcre_compile() function is a pointer to a block of memory
198 containing the concatenated tables. A call to pcre_maketables() can be used to
199 generate a set of tables in the current locale. If the final argument for
200 pcre_compile() is passed as NULL, a set of default tables that is built into
201 the binary is used.
202
203 The source file called chartables.c contains the default set of tables. This is
204 not supplied in the distribution, but is built by the program dftables
205 (compiled from dftables.c), which uses the ANSI C character handling functions
206 such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table
207 sources. This means that the default C locale which is set for your system will
208 control the contents of these default tables. You can change the default tables
209 by editing chartables.c and then re-building PCRE. If you do this, you should
210 probably also edit Makefile to ensure that the file doesn't ever get
211 re-generated.
212
213 The first two 256-byte tables provide lower casing and case flipping functions,
214 respectively. The next table consists of three 32-byte bit maps which identify
215 digits, "word" characters, and white space, respectively. These are used when
216 building 32-byte bit maps that represent character classes.
217
218 The final 256-byte table has bits indicating various character types, as
219 follows:
220
221 1 white space character
222 2 letter
223 4 decimal digit
224 8 hexadecimal digit
225 16 alphanumeric or '_'
226 128 regular expression metacharacter or binary zero
227
228 You should not alter the set of characters that contain the 128 bit, as that
229 will cause PCRE to malfunction.
230
231
232 Manifest
233 --------
234
235 The distribution should contain the following files:
236
237 (A) The actual source files of the PCRE library functions and their
238 headers:
239
240 dftables.c auxiliary program for building chartables.c
241 get.c )
242 maketables.c )
243 study.c ) source of
244 pcre.c ) the functions
245 pcreposix.c )
246 pcre.in "source" for the header for the external API; pcre.h
247 is built from this by "configure"
248 pcreposix.h header for the external POSIX wrapper API
249 internal.h header for internal use
250 config.in template for config.h, which is built by configure
251
252 (B) Auxiliary files:
253
254 AUTHORS information about the author of PCRE
255 ChangeLog log of changes to the code
256 INSTALL generic installation instructions
257 LICENCE conditions for the use of PCRE
258 COPYING the same, using GNU's standard name
259 Makefile.in template for Unix Makefile, which is built by configure
260 NEWS important changes in this release
261 NON-UNIX-USE notes on building PCRE on non-Unix systems
262 README this file
263 RunTest.in template for a Unix shell script for running tests
264 config.guess ) files used by libtool,
265 config.sub ) used only when building a shared library
266 configure a configuring shell script (built by autoconf)
267 configure.in the autoconf input used to build configure
268 doc/Tech.Notes notes on the encoding
269 doc/pcre.3 man page source for the PCRE functions
270 doc/pcre.html HTML version
271 doc/pcre.txt plain text version
272 doc/pcreposix.3 man page source for the POSIX wrapper API
273 doc/pcreposix.html HTML version
274 doc/pcreposix.txt plain text version
275 doc/pcretest.txt documentation of test program
276 doc/perltest.txt documentation of Perl test program
277 doc/pcregrep.1 man page source for the pcregrep utility
278 doc/pcregrep.html HTML version
279 doc/pcregrep.txt plain text version
280 install-sh a shell script for installing files
281 ltmain.sh file used to build a libtool script
282 pcretest.c comprehensive test program
283 pcredemo.c simple demonstration of coding calls to PCRE
284 perltest Perl test program
285 perltest8 Perl test program for UTF-8 tests
286 pcregrep.c source of a grep utility that uses PCRE
287 pcre-config.in source of script which retains PCRE information
288 testdata/testinput1 test data, compatible with Perl 5.004 and 5.005
289 testdata/testinput2 test data for error messages and non-Perl things
290 testdata/testinput3 test data, compatible with Perl 5.005
291 testdata/testinput4 test data for locale-specific tests
292 testdata/testinput5 test data for UTF-8 tests compatible with Perl 5.6
293 testdata/testinput6 test data for other UTF-8 tests
294 testdata/testoutput1 test results corresponding to testinput1
295 testdata/testoutput2 test results corresponding to testinput2
296 testdata/testoutput3 test results corresponding to testinput3
297 testdata/testoutput4 test results corresponding to testinput4
298 testdata/testoutput5 test results corresponding to testinput5
299 testdata/testoutput6 test results corresponding to testinput6
300
301 (C) Auxiliary files for Win32 DLL
302
303 dll.mk
304 pcre.def
305
306 Philip Hazel <ph10@cam.ac.uk>
307 August 2001

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