/[pcre]/code/trunk/README

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-revision 41 by nigel,
Sat Feb 24 21:39:17 2007 UTC
+revision 65 by nigel,
Sat Feb 24 21:40:08 2007 UTC
 Line 1
  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.
+ 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. 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.
- Building PCRE on a Unix system
+ Contributions by users of PCRE
  ------------------------------
- To build PCRE on a Unix system, run the "configure" command in the PCRE
+ You can find contributions from PCRE users in the directory
- distribution directory. This is a standard GNU "autoconf" configuration script,
- for which generic instructions are supplied in INSTALL. On many systems just
+   ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib
- running "./configure" is sufficient, but the usual methods of changing standard
- defaults are available. For example
+ where there is also a README file giving brief descriptions of what they are.
+ Several of them provide support for compiling PCRE on various flavours of
+ Windows systems (I myself do not use Windows). Some are complete in themselves;
+ others are pointers to URLs containing relevant files.
+ Building PCRE on a Unix-like system
+ -----------------------------------
+ To build PCRE on a Unix-like system, first run the "configure" command from the
+ PCRE distribution directory, with your current directory set to the directory
+ where you want the files to be created. This command is a standard GNU
+ "autoconf" configuration script, for which generic instructions are supplied in
+ INSTALL.
+ Most commonly, people build PCRE within its own distribution directory, and in
+ this case, 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:
+ instead of the default /usr/local.
- . Makefile is built by copying Makefile.in and making certain substitutions.
+ If you want to build in a different directory, just run "configure" with that
- . config.h is built by copying config.in and making certain substitutions.
+ directory as current. For example, suppose you have unpacked the PCRE source
+ into /source/pcre/pcre-xxx, but you want to build it in /build/pcre/pcre-xxx:
+ cd /build/pcre/pcre-xxx
+ /source/pcre/pcre-xxx/configure
+ There are some optional features that can be included or omitted from the PCRE
+ library. You can read more about them in the pcrebuild man page.
+ . If you want to make use of the support for UTF-8 character strings in PCRE,
+   you must add --enable-utf8 to the "configure" command. Without it, the code
+   for handling UTF-8 is not included in the library. (Even when included, it
+   still has to be enabled by an option at run time.)
+ . You can build PCRE to recognized CR or NL as the newline character, instead
+   of whatever your compiler uses for "\n", by adding --newline-is-cr or
+   --newline-is-nl to the "configure" command, respectively. Only do this if you
+   really understand what you are doing. On traditional Unix-like systems, the
+   newline character is NL.
+ . When called via the POSIX interface, PCRE uses malloc() to get additional
+   storage for processing capturing parentheses if there are more than 10 of
+   them. You can increase this threshold by setting, for example,
+   --with-posix-malloc-threshold=20
+   on the "configure" command.
+ . PCRE has a counter which can be set to limit the amount of resources it uses.
+   If the limit is exceeded during a match, the match fails. The default is ten
+   million. You can change the default by setting, for example,
+   --with-match-limit=500000
+   on the "configure" command. This is just the default; individual calls to
+   pcre_exec() can supply their own value. There is discussion on the pcreapi
+   man page.
+ . The default maximum compiled pattern size is around 64K. You can increase
+   this by adding --with-link-size=3 to the "configure" command. You can
+   increase it even more by setting --with-link-size=4, but this is unlikely
+   ever to be necessary. If you build PCRE with an increased link size, test 2
+   (and 5 if you are using UTF-8) will fail. Part of the output of these tests
+   is a representation of the compiled pattern, and this changes with the link
+   size.
+ The "configure" script builds five files:
+ . libtool is a script that builds shared and/or static libraries
+ . 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.
+ . RunTest is a script for running tests
  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
+ libpcre and libpcreposix, a test program called pcretest, and the pcregrep
- command. You can use "make install" to copy these, and the public header file
+ command. You can use "make install" to copy these, the public header files
- pcre.h, to appropriate live directories on your system, in the normal way.
+ pcre.h and pcreposix.h, and the man pages to appropriate live directories on
+ your system, in the normal way.
- Shared libraries on Unix systems
+ Running "make install" also installs the command pcre-config, which can be used
- --------------------------------
+ to recall information about the PCRE configuration and installation. For
+ example,
- 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
+   pcre-config --version
- 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
+ prints the version number, and
- when configuring it. For example
+  pcre-config --libs
- ./configure --prefix=/usr/gnu --enable-shared
+ outputs information about where the library is installed. This command can be
- Then run "make" in the usual way. It should build a "libtool" script and use
+ included in makefiles for programs that use PCRE, saving the programmer from
- this to compile and link shared libraries, which are placed in a subdirectory
+ having to remember too many details.
- 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
+ Cross-compiling PCRE on a Unix-like system
- installed library before it itself is installed.
+ ------------------------------------------
+ PCRE needs to compile and run an auxiliary program as part of the building
+ process. Obviously, if the real compilation is for some other system, it can't
+ use the same CC and CFLAGS values when it is doing this. For cross compilation,
+ therefore, you must set CC_FOR_BUILD to the local host's compiler, and you can
+ set flags in CFLAGS_FOR_BUILD if you need to.
+ Shared libraries on Unix-like systems
+ -------------------------------------
+ The default distribution builds PCRE as two shared libraries and two static
+ libraries, as long as the operating system supports shared libraries. Shared
+ library support relies on the "libtool" script which is built as part of the
+ "configure" process.
+ The libtool script is used to compile and link both shared and static
+ libraries. They are placed in a subdirectory called .libs when they are newly
+ built. The programs pcretest and pcregrep are built to use these uninstalled
+ libraries (by means of wrapper scripts in the case of shared libraries). When
+ you use "make install" to install shared libraries, pcregrep and pcretest are
+ automatically re-built to use the newly installed shared libraries before being
+ installed themselves. However, the versions left in the source directory still
+ use the uninstalled libraries.
+ To build PCRE using static libraries only you must use --disable-shared when
+ configuring it. For example
+ ./configure --prefix=/usr/gnu --disable-shared
+ Then run "make" in the usual way. Similarly, you can use --disable-static to
+ build only shared libraries.
+ Cross-compiling on a Unix-like system
+ -------------------------------------
+ You can specify CC and CFLAGS in the normal way to the "configure" command, in
+ order to cross-compile PCRE for some other host. However, during the building
+ process, the dftables.c source file is compiled *and run* on the local host, in
+ order to generate the default character tables (the chartables.c file). It
+ therefore needs to be compiled with the local compiler, not the cross compiler.
+ You can do this by specifying HOST_CC (and if necessary HOST_CFLAGS) when
+ calling the "configure" command. If they are not specified, they default to the
+ values of CC and CFLAGS.
  Building on non-Unix systems
-Line 60 
 Standard C functions.
+Line 187 
 Standard C functions.
  Testing PCRE
  ------------
- To test PCRE on a Unix system, run the RunTest script in the pcre directory.
+ To test PCRE on a Unix system, run the RunTest script that is created by the
- (This can also be run by "make runtest" or "make check".) For other systems,
+ configuring process. (This can also be run by "make runtest", "make check", or
- see the instruction in NON-UNIX-USE.
+ "make test".) For other systems, see the instruction in NON-UNIX-USE.
- The script runs the pcretest test program (which is documented in
+ The script runs the pcretest test program (which is documented in its own man
- doc/pcretest.txt) on each of the testinput files (in the testdata directory) in
+ page) on each of the testinput files (in the testdata directory) in turn,
- turn, and compares the output with the contents of the corresponding testoutput
+ and compares the output with the contents of the corresponding testoutput file.
- file. A file called testtry is used to hold the output from pcretest. To run
+ A file called testtry is used to hold the output from pcretest. To run pcretest
- pcretest on just one of the test files, give its number as an argument to
+ on just one of the test files, give its number as an argument to RunTest, for
- RunTest, for example:
+ example:
-   RunTest 3
+   RunTest 2
- The first and third test files can also be fed directly into the perltest
+ The first file can also be fed directly into the perltest script to check that
- script to check that Perl gives the same results. The third file requires the
+ Perl gives the same results. The only difference you should see is in the first
- additional features of release 5.005, which is why it is kept separate from the
+ few lines, where the Perl version is given instead of the PCRE version.
- 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_fullinfo(), pcre_info(), pcre_study(),
+ pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error
- The second set of tests check pcre_info(), pcre_study(), pcre_copy_substring(),
+ detection, and run-time flags that are specific to PCRE, as well as the POSIX
- pcre_get_substring(), pcre_get_substring_list(), error detection and run-time
+ wrapper API. It also uses the debugging flag to check some of the internals of
- flags that are specific to PCRE, as well as the POSIX wrapper API.
+ pcre_compile().
+ If you build PCRE with a locale setting that is not the standard C locale, the
+ character tables may be different (see next paragraph). In some cases, this may
+ cause failures in the second set of tests. For example, in a locale where the
+ isprint() function yields TRUE for characters in the range 128-255, the use of
+ [:isascii:] inside a character class defines a different set of characters, and
+ this shows up in this test as a difference in the compiled code, which is being
+ listed for checking. Where the comparison test output contains [\x00-\x7f] the
+ test will contain [\x00-\xff], and similarly in some other cases. This is not a
+ bug in PCRE.
- The fourth set of tests checks pcre_maketables(), the facility for building a
+ The third 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
+ list of available locales, the third 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"
-Line 96 
 output to say why. If running this test
+Line 233 
 output to say why. If running this test
  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 fourth test checks the UTF-8 support. It is not run automatically unless
- the POSIX API are also supplied in the library libpcreposix.a. Note that this
+ PCRE is built with UTF-8 support. To do this you must set --enable-utf8 when
- just provides a POSIX calling interface to PCRE: the regular expressions
+ running "configure". This file can be also fed directly to the perltest script,
- themselves still follow Perl syntax and semantics. The header file
+ provided you are running Perl 5.8 or higher. (For Perl 5.6, a small patch,
- for the POSIX-style functions is called pcreposix.h. The official POSIX name is
+ commented in the script, can be be used.)
- 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
+ The fifth and final file tests error handling with UTF-8 encoding, and internal
- uses the POSIX API, it will have to be renamed or pointed at by a link.
+ UTF-8 features of PCRE that are not relevant to Perl.
  Character tables
-Line 159 
 The distribution should contain the foll
+Line 296 
 The distribution should contain the foll
    study.c               ) source of
    pcre.c                )   the functions
    pcreposix.c           )
-   pcre.h                header for the external API
+   printint.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
-Line 170 
 The distribution should contain the foll
+Line 309 
 The distribution should contain the foll
    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
+   RunTest.in            template for 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/*.3               man page sources for the PCRE functions
-   doc/pcre.html         HTML version
+   doc/*.1               man page sources for pcregrep and pcretest
-   doc/pcre.txt          plain text version
+   doc/html/*            HTML documentation
-   doc/pcreposix.3       man page source for the POSIX wrapper API
+   doc/pcre.txt          plain text version of the man pages
-   doc/pcreposix.html    HTML version
+   doc/pcretest.txt      plain text documentation of test program
-   doc/pcreposix.txt     plain text version
+   doc/perltest.txt      plain text documentation of Perl test program
-   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             file used to build a libtool script
-   ltmain.sh             )   used only when building a shared library
+   pcretest.c            comprehensive test program
-   pcretest.c            test program
+   pcredemo.c            simple demonstration of coding calls to PCRE
    perltest              Perl test program
-   pgrep.c               source of a grep utility that uses PCRE
+   pcregrep.c            source of a grep utility that uses PCRE
-   testdata/testinput1   test data, compatible with Perl 5.004 and 5.005
+   pcre-config.in        source of script which retains PCRE information
+   testdata/testinput1   test data, compatible with Perl
    testdata/testinput2   test data for error messages and non-Perl things
-   testdata/testinput3   test data, compatible with Perl 5.005
+   testdata/testinput3   test data for locale-specific tests
-   testdata/testinput4   test data for locale-specific tests
+   testdata/testinput4   test data for UTF-8 tests compatible with Perl
+   testdata/testinput5   test data for other UTF-8 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
+   testdata/testoutput5  test results corresponding to testinput5
  (C) Auxiliary files for Win32 DLL
    dll.mk
    pcre.def
+ (D) Auxiliary file for VPASCAL
+   makevp.bat
  Philip Hazel <ph10@cam.ac.uk>
- January 2000
+ February 2003

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