Contents of /code/trunk/README

README file for PCRE (Perl-compatible regular expression library)
-----------------------------------------------------------------

The latest release of PCRE is always available from

  ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.gz

Please read the NEWS file if you are upgrading from a previous release.


Building PCRE on a Unix system
------------------------------

To build PCRE on a Unix system, run the "configure" command in the PCRE
distribution directory. This is a standard GNU "autoconf" configuration script,
for which generic instructions are supplied in INSTALL. On many systems just
running "./configure" is sufficient, but the usual methods of changing standard
defaults are available. For example

CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local

specifies that the C compiler should be run with the flags '-O2 -Wall' instead
of the default, and that "make install" should install PCRE under /opt/local
instead of the default /usr/local. The "configure" script builds thre files:

. Makefile is built by copying Makefile.in and making substitutions.
. config.h is built by copying config.in and making substitutions.
. pcre-config is built by copying pcre-config.in and making substitutions.

Once "configure" has run, you can run "make". It builds two libraries called
libpcre and libpcreposix, a test program called pcretest, and the pgrep
command. You can use "make install" to copy these, and the public header file
pcre.h, to appropriate live directories on your system, in the normal way.

Running "make install" also installs the command pcre-config, which can be used
to recall information about the PCRE configuration and installation. For
example,

  pcre-config --version

prints the version number, and

 pcre-config --libs

outputs information about where the library is installed. This command can be
included in makefiles for programs that use PCRE, saving the programmer from
having to remember too many details.


Shared libraries on Unix systems
--------------------------------

The default distribution builds PCRE as two shared libraries. This support is
new and experimental and may not work on all systems. It relies on the
"libtool" scripts - these are distributed with PCRE. It should build a
"libtool" script and use this to compile and link shared libraries, which are
placed in a subdirectory called .libs. The programs pcretest and pgrep are
built to use these uninstalled libraries by means of wrapper scripts. When you
use "make install" to install shared libraries, pgrep and pcretest are
automatically re-built to use the newly installed libraries. However, only
pgrep is installed, as pcretest is really just a test program.

To build PCRE using static libraries you must use --disable-shared when
configuring it. For example

./configure --prefix=/usr/gnu --disable-shared

Then run "make" in the usual way.


Building on non-Unix systems
----------------------------

For a non-Unix system, read the comments in the file NON-UNIX-USE. PCRE has
been compiled on Windows systems and on Macintoshes, but I don't know the
details because I don't use those systems. It should be straightforward to
build PCRE on any system that has a Standard C compiler, because it uses only
Standard C functions.


Testing PCRE
------------

To test PCRE on a Unix system, run the RunTest script in the pcre directory.
(This can also be run by "make runtest" or "make check".) For other systems,
see the instruction in NON-UNIX-USE.

The script runs the pcretest test program (which is documented in
doc/pcretest.txt) on each of the testinput files (in the testdata directory) 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. 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
script 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.

The fourth set of tests checks pcre_maketables(), the facility for building a
set of character tables for a specific locale and using them instead of the
default tables. The tests make use of the "fr" (French) locale. Before running
the test, the script checks for the presence of this locale by running the
"locale" command. If that command fails, or if it doesn't include "fr" in the
list of available locales, the fourth test cannot be run, and a comment is
output to say why. If running this test produces instances of the error

  ** Failed to set locale "fr"

in the comparison output, it means that locale is not available on your system,
despite being listed by "locale". This does not mean that PCRE is broken.

PCRE has its own native API, but a set of "wrapper" functions that are based on
the POSIX API are also supplied in the library libpcreposix.a. Note that this
just provides a POSIX calling interface to PCRE: the regular expressions
themselves still follow Perl syntax and semantics. The header file
for the POSIX-style functions is called pcreposix.h. The official POSIX name is
regex.h, but I didn't want to risk possible problems with existing files of
that name by distributing it that way. To use it with an existing program that
uses the POSIX API, it will have to be renamed or pointed at by a link.


Character tables
----------------

PCRE uses four tables for manipulating and identifying characters. The final
argument of the pcre_compile() function is a pointer to a block of memory
containing the concatenated tables. A call to pcre_maketables() can be used to
generate a set of tables in the current locale. If the final argument for
pcre_compile() is passed as NULL, a set of default tables that is built into
the binary is used.

The source file called chartables.c contains the default set of tables. This is
not supplied in the distribution, but is built by the program dftables
(compiled from dftables.c), which uses the ANSI C character handling functions
such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table
sources. This means that the default C locale which is set for your system will
control the contents of these default tables. You can change the default tables
by editing chartables.c and then re-building PCRE. If you do this, you should
probably also edit Makefile to ensure that the file doesn't ever get
re-generated.

The first two 256-byte tables provide lower casing and case flipping functions,
respectively. The next table consists of three 32-byte bit maps which identify
digits, "word" characters, and white space, respectively. These are used when
building 32-byte bit maps that represent character classes.

The final 256-byte table has bits indicating various character types, as
follows:

    1   white space character
    2   letter
    4   decimal digit
    8   hexadecimal digit
   16   alphanumeric or '_'
  128   regular expression metacharacter or binary zero

You should not alter the set of characters that contain the 128 bit, as that
will cause PCRE to malfunction.


Manifest
--------

The distribution should contain the following files:

(A) The actual source files of the PCRE library functions and their
    headers:

  dftables.c            auxiliary program for building chartables.c
  get.c                 )
  maketables.c          )
  study.c               ) source of
  pcre.c                )   the functions
  pcreposix.c           )
  pcre.in               "source" for the header for the external API; pcre.h
                          is built from this by "configure"
  pcreposix.h           header for the external POSIX wrapper API
  internal.h            header for internal use
  config.in             template for config.h, which is built by configure

(B) Auxiliary files:

  AUTHORS               information about the author of PCRE
  ChangeLog             log of changes to the code
  INSTALL               generic installation instructions
  LICENCE               conditions for the use of PCRE
  COPYING               the same, using GNU's standard name
  Makefile.in           template for Unix Makefile, which is built by configure
  NEWS                  important changes in this release
  NON-UNIX-USE          notes on building PCRE on non-Unix systems
  README                this file
  RunTest               a Unix shell script for running tests
  config.guess          ) files used by libtool,
  config.sub            )   used only when building a shared library
  configure             a configuring shell script (built by autoconf)
  configure.in          the autoconf input used to build configure
  doc/Tech.Notes        notes on the encoding
  doc/pcre.3            man page source for the PCRE functions
  doc/pcre.html         HTML version
  doc/pcre.txt          plain text version
  doc/pcreposix.3       man page source for the POSIX wrapper API
  doc/pcreposix.html    HTML version
  doc/pcreposix.txt     plain text version
  doc/pcretest.txt      documentation of test program
  doc/perltest.txt      documentation of Perl test program
  doc/pgrep.1           man page source for the pgrep utility
  doc/pgrep.html        HTML version
  doc/pgrep.txt         plain text version
  install-sh            a shell script for installing files
  ltconfig              ) files used to build "libtool",
  ltmain.sh             )   used only when building a shared library
  pcretest.c            test program
  perltest              Perl test program
  pgrep.c               source of a grep utility that uses PCRE
  pcre-config.in        source of script which retains PCRE information
  testdata/testinput1   test data, compatible with Perl 5.004 and 5.005
  testdata/testinput2   test data for error messages and non-Perl things
  testdata/testinput3   test data, compatible with Perl 5.005
  testdata/testinput4   test data for locale-specific tests
  testdata/testoutput1  test results corresponding to testinput1
  testdata/testoutput2  test results corresponding to testinput2
  testdata/testoutput3  test results corresponding to testinput3
  testdata/testoutput4  test results corresponding to testinput4

(C) Auxiliary files for Win32 DLL

  dll.mk
  pcre.def

Philip Hazel <ph10@cam.ac.uk>
February 2000
1	nigel	41	README file for PCRE (Perl-compatible regular expression library)
2			-----------------------------------------------------------------
3	nigel	3
4	nigel	43	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	nigel	41	Please read the NEWS file if you are upgrading from a previous release.
9	nigel	23
10	nigel	35
11	nigel	41	Building PCRE on a Unix system
12			------------------------------
13	nigel	3
14	nigel	41	To build PCRE on a Unix system, run the "configure" command in the PCRE
15			distribution directory. This is a standard GNU "autoconf" configuration script,
16			for which generic instructions are supplied in INSTALL. On many systems just
17			running "./configure" is sufficient, but the usual methods of changing standard
18			defaults are available. For example
19	nigel	3
20	nigel	41	CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
21
22			specifies that the C compiler should be run with the flags '-O2 -Wall' instead
23			of the default, and that "make install" should install PCRE under /opt/local
24	nigel	43	instead of the default /usr/local. The "configure" script builds thre files:
25	nigel	41
26	nigel	43	. Makefile is built by copying Makefile.in and making substitutions.
27			. config.h is built by copying config.in and making substitutions.
28			. pcre-config is built by copying pcre-config.in and making substitutions.
29	nigel	41
30			Once "configure" has run, you can run "make". It builds two libraries called
31	nigel	43	libpcre and libpcreposix, a test program called pcretest, and the pgrep
32	nigel	37	command. You can use "make install" to copy these, and the public header file
33	nigel	41	pcre.h, to appropriate live directories on your system, in the normal way.
34	nigel	3
35	nigel	43	Running "make install" also installs the command pcre-config, which can be used
36			to recall information about the PCRE configuration and installation. For
37			example,
38	nigel	37
39	nigel	43	pcre-config --version
40
41			prints the version number, and
42
43			pcre-config --libs
44
45			outputs information about where the library is installed. This command can be
46			included in makefiles for programs that use PCRE, saving the programmer from
47			having to remember too many details.
48
49
50	nigel	41	Shared libraries on Unix systems
51			--------------------------------
52	nigel	39
53	nigel	43	The default distribution builds PCRE as two shared libraries. This support is
54			new and experimental and may not work on all systems. It relies on the
55			"libtool" scripts - these are distributed with PCRE. It should build a
56			"libtool" script and use this to compile and link shared libraries, which are
57			placed in a subdirectory called .libs. The programs pcretest and pgrep are
58			built to use these uninstalled libraries by means of wrapper scripts. When you
59			use "make install" to install shared libraries, pgrep and pcretest are
60			automatically re-built to use the newly installed libraries. However, only
61			pgrep is installed, as pcretest is really just a test program.
62	nigel	39
63	nigel	43	To build PCRE using static libraries you must use --disable-shared when
64			configuring it. For example
65	nigel	3
66	nigel	43	./configure --prefix=/usr/gnu --disable-shared
67	nigel	41
68	nigel	43	Then run "make" in the usual way.
69	nigel	41
70	nigel	43
71	nigel	41	Building on non-Unix systems
72			----------------------------
73
74			For a non-Unix system, read the comments in the file NON-UNIX-USE. PCRE has
75			been compiled on Windows systems and on Macintoshes, but I don't know the
76			details because I don't use those systems. It should be straightforward to
77			build PCRE on any system that has a Standard C compiler, because it uses only
78			Standard C functions.
79
80
81			Testing PCRE
82			------------
83
84			To test PCRE on a Unix system, run the RunTest script in the pcre directory.
85			(This can also be run by "make runtest" or "make check".) For other systems,
86			see the instruction in NON-UNIX-USE.
87
88			The script runs the pcretest test program (which is documented in
89			doc/pcretest.txt) on each of the testinput files (in the testdata directory) in
90			turn, and compares the output with the contents of the corresponding testoutput
91			file. A file called testtry is used to hold the output from pcretest. To run
92			pcretest on just one of the test files, give its number as an argument to
93			RunTest, for example:
94
95	nigel	23	RunTest 3
96	nigel	3
97	nigel	23	The first and third test files can also be fed directly into the perltest
98	nigel	37	script to check that Perl gives the same results. The third file requires the
99	nigel	23	additional features of release 5.005, which is why it is kept separate from the
100			main test input, which needs only Perl 5.004. In the long run, when 5.005 is
101			widespread, these two test files may get amalgamated.
102	nigel	3
103	nigel	29	The second set of tests check pcre_info(), pcre_study(), pcre_copy_substring(),
104			pcre_get_substring(), pcre_get_substring_list(), error detection and run-time
105			flags that are specific to PCRE, as well as the POSIX wrapper API.
106	nigel	7
107	nigel	25	The fourth set of tests checks pcre_maketables(), the facility for building a
108			set of character tables for a specific locale and using them instead of the
109			default tables. The tests make use of the "fr" (French) locale. Before running
110			the test, the script checks for the presence of this locale by running the
111			"locale" command. If that command fails, or if it doesn't include "fr" in the
112			list of available locales, the fourth test cannot be run, and a comment is
113			output to say why. If running this test produces instances of the error
114
115			** Failed to set locale "fr"
116
117			in the comparison output, it means that locale is not available on your system,
118			despite being listed by "locale". This does not mean that PCRE is broken.
119
120	nigel	3	PCRE has its own native API, but a set of "wrapper" functions that are based on
121			the POSIX API are also supplied in the library libpcreposix.a. Note that this
122			just provides a POSIX calling interface to PCRE: the regular expressions
123			themselves still follow Perl syntax and semantics. The header file
124			for the POSIX-style functions is called pcreposix.h. The official POSIX name is
125			regex.h, but I didn't want to risk possible problems with existing files of
126			that name by distributing it that way. To use it with an existing program that
127	nigel	23	uses the POSIX API, it will have to be renamed or pointed at by a link.
128	nigel	3
129
130			Character tables
131			----------------
132
133	nigel	25	PCRE uses four tables for manipulating and identifying characters. The final
134			argument of the pcre_compile() function is a pointer to a block of memory
135	nigel	35	containing the concatenated tables. A call to pcre_maketables() can be used to
136			generate a set of tables in the current locale. If the final argument for
137			pcre_compile() is passed as NULL, a set of default tables that is built into
138			the binary is used.
139	nigel	3
140	nigel	25	The source file called chartables.c contains the default set of tables. This is
141	nigel	27	not supplied in the distribution, but is built by the program dftables
142			(compiled from dftables.c), which uses the ANSI C character handling functions
143	nigel	25	such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table
144	nigel	35	sources. This means that the default C locale which is set for your system will
145			control the contents of these default tables. You can change the default tables
146			by editing chartables.c and then re-building PCRE. If you do this, you should
147			probably also edit Makefile to ensure that the file doesn't ever get
148			re-generated.
149	nigel	3
150	nigel	25	The first two 256-byte tables provide lower casing and case flipping functions,
151			respectively. The next table consists of three 32-byte bit maps which identify
152			digits, "word" characters, and white space, respectively. These are used when
153			building 32-byte bit maps that represent character classes.
154
155			The final 256-byte table has bits indicating various character types, as
156	nigel	3	follows:
157
158			1 white space character
159			2 letter
160			4 decimal digit
161			8 hexadecimal digit
162			16 alphanumeric or '_'
163			128 regular expression metacharacter or binary zero
164
165			You should not alter the set of characters that contain the 128 bit, as that
166			will cause PCRE to malfunction.
167
168
169	nigel	41	Manifest
170			--------
171	nigel	3
172	nigel	41	The distribution should contain the following files:
173	nigel	3
174	nigel	41	(A) The actual source files of the PCRE library functions and their
175			headers:
176	nigel	3
177	nigel	41	dftables.c auxiliary program for building chartables.c
178			get.c )
179			maketables.c )
180			study.c ) source of
181			pcre.c ) the functions
182			pcreposix.c )
183	nigel	43	pcre.in "source" for the header for the external API; pcre.h
184			is built from this by "configure"
185	nigel	41	pcreposix.h header for the external POSIX wrapper API
186			internal.h header for internal use
187			config.in template for config.h, which is built by configure
188	nigel	3
189	nigel	41	(B) Auxiliary files:
190	nigel	3
191	nigel	41	AUTHORS information about the author of PCRE
192			ChangeLog log of changes to the code
193			INSTALL generic installation instructions
194			LICENCE conditions for the use of PCRE
195	nigel	43	COPYING the same, using GNU's standard name
196	nigel	41	Makefile.in template for Unix Makefile, which is built by configure
197			NEWS important changes in this release
198			NON-UNIX-USE notes on building PCRE on non-Unix systems
199			README this file
200			RunTest a Unix shell script for running tests
201			config.guess ) files used by libtool,
202			config.sub ) used only when building a shared library
203			configure a configuring shell script (built by autoconf)
204			configure.in the autoconf input used to build configure
205			doc/Tech.Notes notes on the encoding
206			doc/pcre.3 man page source for the PCRE functions
207			doc/pcre.html HTML version
208			doc/pcre.txt plain text version
209			doc/pcreposix.3 man page source for the POSIX wrapper API
210			doc/pcreposix.html HTML version
211			doc/pcreposix.txt plain text version
212			doc/pcretest.txt documentation of test program
213			doc/perltest.txt documentation of Perl test program
214			doc/pgrep.1 man page source for the pgrep utility
215			doc/pgrep.html HTML version
216			doc/pgrep.txt plain text version
217			install-sh a shell script for installing files
218			ltconfig ) files used to build "libtool",
219			ltmain.sh ) used only when building a shared library
220			pcretest.c test program
221			perltest Perl test program
222			pgrep.c source of a grep utility that uses PCRE
223	nigel	43	pcre-config.in source of script which retains PCRE information
224	nigel	41	testdata/testinput1 test data, compatible with Perl 5.004 and 5.005
225			testdata/testinput2 test data for error messages and non-Perl things
226			testdata/testinput3 test data, compatible with Perl 5.005
227			testdata/testinput4 test data for locale-specific tests
228			testdata/testoutput1 test results corresponding to testinput1
229			testdata/testoutput2 test results corresponding to testinput2
230			testdata/testoutput3 test results corresponding to testinput3
231			testdata/testoutput4 test results corresponding to testinput4
232	nigel	3
233	nigel	41	(C) Auxiliary files for Win32 DLL
234	nigel	29
235	nigel	41	dll.mk
236			pcre.def
237	nigel	29
238	nigel	3	Philip Hazel <ph10@cam.ac.uk>
239	nigel	43	February 2000