Contents of /code/trunk/README

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

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 two files:

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

Once "configure" has run, you can run "make". It builds two libraries called
libpcre.a and libpcreposix.a, 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.


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

The default distribution builds static libraries. It is also possible to build
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. To build PCRE using shared libraries you must use --enable-shared
when configuring it. For example

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

Then run "make" in the usual way. 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 is automatically re-built to use the newly
installed library before it itself is installed.


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