/[pcre]/code/trunk/README

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-revision 53 by nigel,
Sat Feb 24 21:39:42 2007 UTC
+revision 77 by nigel,
Sat Feb 24 21:40:45 2007 UTC
 Line 7 
 The latest release of PCRE is always ava
  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
+ The PCRE APIs
- 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
+ PCRE is written in C, and it has its own API. The distribution now includes a
- regex.h, but I didn't want to risk possible problems with existing files of
+ set of C++ wrapper functions, courtesy of Google Inc. (see the pcrecpp man page
- that name by distributing it that way. To use it with an existing program that
+ for details).
- uses the POSIX API, it will have to be renamed or pointed at by a link.
+ Also included are a set of C wrapper functions that are based on the POSIX
+ API. These end up in the library called 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.
+ If you are using the POSIX interface to PCRE and there is already a POSIX regex
+ library installed on your system, you must take care when linking programs to
+ ensure that they link with PCRE's libpcreposix library. Otherwise they may pick
+ up the "real" POSIX functions of the same name.
+ Documentation for PCRE
+ ----------------------
+ If you install PCRE in the normal way, you will end up with an installed set of
+ man pages whose names all start with "pcre". The one that is called "pcre"
+ lists all the others. In addition to these man pages, the PCRE documentation is
+ supplied in two other forms; however, as there is no standard place to install
+ them, they are left in the doc directory of the unpacked source distribution.
+ These forms are:
+. Files called doc/pcre.txt, doc/pcregrep.txt, and doc/pcretest.txt. The
+      first of these is a concatenation of the text forms of all the section 3
+      man pages except those that summarize individual functions. The other two
+      are the text forms of the section 1 man pages for the pcregrep and
+      pcretest commands. Text forms are provided for ease of scanning with text
+      editors or similar tools.
+. A subdirectory called doc/html contains all the documentation in HTML
+      form, hyperlinked in various ways, and rooted in a file called
+      doc/index.html.
  Contributions by users of PCRE
-Line 30 
 Windows systems (I myself do not use Win
+Line 65 
 Windows systems (I myself do not use Win
  others are pointers to URLs containing relevant files.
- Building PCRE on a Unix system
+ Building PCRE on a Unix-like system
- ------------------------------
+ -----------------------------------
- To build PCRE on a Unix system, first run the "configure" command from the PCRE
+ To build PCRE on a Unix-like system, first run the "configure" command from the
- distribution directory, with your current directory set to the directory where
+ PCRE distribution directory, with your current directory set to the directory
- you want the files to be created. This command is a standard GNU "autoconf"
+ where you want the files to be created. This command is a standard GNU
- configuration script, for which generic instructions are supplied in INSTALL.
+ "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,
+ usual methods of changing standard defaults are available. For example:
  CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
-Line 55 
 into /source/pcre/pcre-xxx, but you want
+Line 91 
 into /source/pcre/pcre-xxx, but you want
  cd /build/pcre/pcre-xxx
  /source/pcre/pcre-xxx/configure
- If you want to make use of the experimential, incomplete support for UTF-8
+ There are some optional features that can be included or omitted from the PCRE
- character strings in PCRE, you must add --enable-utf8 to the "configure"
+ library. You can read more about them in the pcrebuild man page.
- 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.)
- The "configure" script builds five files:
+ . 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.)
+ . If, in addition to support for UTF-8 character strings, you want to include
+   support for the \P, \p, and \X sequences that recognize Unicode character
+   properties, you must add --enable-unicode-properties to the "configure"
+   command. This adds about 90K to the size of the library (in the form of a
+   property table); only the basic two-letter properties such as Lu are
+   supported.
+ . 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 that 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.
+ . You can build PCRE so that its internal match() function that is called from
+   pcre_exec() does not call itself recursively. Instead, it uses blocks of data
+   from the heap via special functions pcre_stack_malloc() and pcre_stack_free()
+   to save data that would otherwise be saved on the stack. To build PCRE like
+   this, use
+   --disable-stack-for-recursion
+   on the "configure" command. PCRE runs more slowly in this mode, but it may be
+   necessary in environments with limited stack sizes. This applies only to the
+   pcre_exec() function; it does not apply to pcre_dfa_exec(), which does not
+   use deeply nested recursion.
+ The "configure" script builds eight files for the basic C library:
+ . pcre.h is the header file for C programs that call PCRE
+ . Makefile is the makefile that builds the library
+ . config.h contains build-time configuration options for the library
+ . pcre-config is a script that shows the settings of "configure" options
+ . libpcre.pc is data for the pkg-config command
  . libtool is a script that builds shared and/or static libraries
- . Makefile is built by copying Makefile.in and making substitutions.
+ . RunTest is a script for running tests on the library
- . config.h is built by copying config.in and making substitutions.
+ . RunGrepTest is a script for running tests on the pcregrep command
- . 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
+ In addition, if a C++ compiler is found, the following are also built:
+ . pcrecpp.h is the header file for programs that call PCRE via the C++ wrapper
+ . pcre_stringpiece.h is the header for the C++ "stringpiece" functions
+ The "configure" script also creates config.status, which is an executable
+ script that can be run to recreate the configuration, and config.log, which
+ contains compiler output from tests that "configure" runs.
+ Once "configure" has run, you can run "make". It builds two libraries, called
  libpcre and libpcreposix, a test program called pcretest, and the pcregrep
- command. You can use "make install" to copy these, the public header files
+ command. If a C++ compiler was found on your system, it also builds the C++
- pcre.h and pcreposix.h, and the man pages to appropriate live directories on
+ wrapper library, which is called libpcrecpp, and some test programs called
- your system, in the normal way.
+ pcrecpp_unittest, pcre_scanner_unittest, and pcre_stringpiece_unittest.
+ The command "make test" runs all the appropriate tests. Details of the PCRE
+ tests are given in a separate section of this document, below.
+ You can use "make install" to copy the libraries, the public header files
+ pcre.h, pcreposix.h, pcrecpp.h, and pcre_stringpiece.h (the last two only if
+ the C++ wrapper was built), and the man pages to appropriate live directories
+ on your system, in the normal way.
+ If you want to remove PCRE from your system, you can run "make uninstall".
+ This removes all the files that "make install" installed. However, it does not
+ remove any directories, because these are often shared with other programs.
+ Retrieving configuration information on Unix-like 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,
+ example:
    pcre-config --version
  prints the version number, and
-  pcre-config --libs
+   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.
- There is one esoteric feature that is controlled by "configure". It concerns
+ The pkg-config command is another system for saving and retrieving information
- the character value used for "newline", and is something that you probably do
+ about installed libraries. Instead of separate commands for each library, a
- not want to change on a Unix system. The default is to use whatever value your
+ single command is used. For example:
- compiler gives to '\n'. By using --enable-newline-is-cr or
- --enable-newline-is-lf you can force the value to be CR (13) or LF (10) if you
+   pkg-config --cflags pcre
- really want to.
+ The data is held in *.pc files that are installed in a directory called
+ pkgconfig.
- Shared libraries on Unix systems
+ Shared libraries on Unix-like systems
- --------------------------------
+ -------------------------------------
- The default distribution builds PCRE as two shared libraries and two static
+ The default distribution builds PCRE as shared libraries and static libraries,
- libraries, as long as the operating system supports shared libraries. Shared
+ as long as the operating system supports shared libraries. Shared library
- library support relies on the "libtool" script which is built as part of the
+ 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
-Line 115 
 installed themselves. However, the versi
+Line 235 
 installed themselves. However, the versi
  use the uninstalled libraries.
  To build PCRE using static libraries only you must use --disable-shared when
- configuring it. For example
+ configuring it. For example:
  ./configure --prefix=/usr/gnu --disable-shared
-Line 123 
 Then run "make" in the usual way. Simila
+Line 243 
 Then run "make" in the usual way. Simila
  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 CC_FOR_BUILD (and if necessary CFLAGS_FOR_BUILD;
+ there are also CXX_FOR_BUILD and CXXFLAGS_FOR_BUILD for the C++ wrapper)
+ when calling the "configure" command. If they are not specified, they default
+ to the values of CC and CFLAGS.
  Building on non-Unix systems
  ----------------------------
- For a non-Unix system, read the comments in the file NON-UNIX-USE. PCRE has
+ For a non-Unix system, read the comments in the file NON-UNIX-USE, though if
- been compiled on Windows systems and on Macintoshes, but I don't know the
+ the system supports the use of "configure" and "make" you may be able to build
- details because I don't use those systems. It should be straightforward to
+ PCRE in the same way as for Unix systems.
+ 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.
-Line 137 
 Testing PCRE
+Line 274 
 Testing PCRE
  ------------
  To test PCRE on a Unix system, run the RunTest script that is created by the
- configuring process. (This can also be run by "make runtest", "make check", or
+ configuring process. There is also a script called RunGrepTest that tests the
- "make test".) For other systems, see the instruction in NON-UNIX-USE.
+ options of the pcregrep command. If the C++ wrapper library is build, three
+ test programs called pcrecpp_unittest, pcre_scanner_unittest, and
- The script runs the pcretest test program (which is documented in the doc
+ pcre_stringpiece_unittest are provided.
- directory) on each of the testinput files (in the testdata directory) in turn,
- and compares the output with the contents of the corresponding testoutput file.
+ Both the scripts and all the program tests are run if you obey "make runtest",
- A file called testtry is used to hold the output from pcretest. To run pcretest
+ "make check", or "make test". For other systems, see the instructions in
- on just one of the test files, give its number as an argument to RunTest, for
+ NON-UNIX-USE.
- example:
+ The RunTest script runs the pcretest test program (which is documented in its
-   RunTest 3
+ own man page) on each of the testinput files (in the testdata directory) in
+ turn, and compares the output with the contents of the corresponding testoutput
- The first and third test files can also be fed directly into the perltest
+ file. A file called testtry is used to hold the main output from pcretest
- script to check that Perl gives the same results. The third file requires the
+ (testsavedregex is also used as a working file). To run pcretest on just one of
- additional features of release 5.005, which is why it is kept separate from the
+ the test files, give its number as an argument to RunTest, for example:
- main test input, which needs only Perl 5.004. In the long run, when 5.005 (or
- higher) is widespread, these two test files may get amalgamated.
+   RunTest 2
+ The first file can also be fed directly into the perltest script to check that
+ Perl gives the same results. The only difference you should see is in the first
+ few lines, where the Perl version is given instead of the PCRE version.
  The second set of tests check pcre_fullinfo(), pcre_info(), pcre_study(),
  pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error
-Line 171 
 listed for checking. Where the compariso
+Line 312 
 listed for checking. Where the compariso
  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
+ default tables. The tests make use of the "fr_FR" (French) locale. Before
- the test, the script checks for the presence of this locale by running the
+ running the test, the script checks for the presence of this locale by running
- "locale" command. If that command fails, or if it doesn't include "fr" in the
+ the "locale" command. If that command fails, or if it doesn't include "fr_FR"
- list of available locales, the fourth test cannot be run, and a comment is
+ in the list of available locales, the third test cannot be run, and a comment
- output to say why. If running this test produces instances of the error
+ is output to say why. If running this test produces instances of the error
-   ** Failed to set locale "fr"
+   ** Failed to set locale "fr_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.
- The fifth test checks the experimental, incomplete UTF-8 support. It is not run
+ The fourth test checks the UTF-8 support. It is not run automatically unless
- automatically unless PCRE is built with UTF-8 support. This file can be fed
+ PCRE is built with UTF-8 support. To do this you must set --enable-utf8 when
- directly to the perltest8 script, which requires Perl 5.6 or higher. The sixth
+ running "configure". This file can be also fed directly to the perltest script,
- file tests internal UTF-8 features of PCRE that are not relevant to Perl.
+ provided you are running Perl 5.8 or higher. (For Perl 5.6, a small patch,
+ commented in the script, can be be used.)
+ The fifth test checks error handling with UTF-8 encoding, and internal UTF-8
+ features of PCRE that are not relevant to Perl.
+ The sixth and test checks the support for Unicode character properties. It it
+ not run automatically unless PCRE is built with Unicode property support. To to
+ this you must set --enable-unicode-properties when running "configure".
+ The seventh, eighth, and ninth tests check the pcre_dfa_exec() alternative
+ matching function, in non-UTF-8 mode, UTF-8 mode, and UTF-8 mode with Unicode
+ property support, respectively. The eighth and ninth tests are not run
+ automatically unless PCRE is build with the relevant support.
  Character tables
  ----------------
- PCRE uses four tables for manipulating and identifying characters. The final
+ PCRE uses four tables for manipulating and identifying characters whose values
- argument of the pcre_compile() function is a pointer to a block of memory
+ are less than 256. The final argument of the pcre_compile() function is a
- containing the concatenated tables. A call to pcre_maketables() can be used to
+ pointer to a block of memory containing the concatenated tables. A call to
- generate a set of tables in the current locale. If the final argument for
+ pcre_maketables() can be used to generate a set of tables in the current
- pcre_compile() is passed as NULL, a set of default tables that is built into
+ locale. If the final argument for pcre_compile() is passed as NULL, a set of
- the binary is used.
+ 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
-Line 238 
 The distribution should contain the foll
+Line 392 
 The distribution should contain the foll
      headers:
    dftables.c            auxiliary program for building chartables.c
-   get.c                 )
-   maketables.c          )
-   study.c               ) source of
-   pcre.c                )   the functions
    pcreposix.c           )
+   pcre_compile.c        )
+   pcre_config.c         )
+   pcre_dfa_exec.c       )
+   pcre_exec.c           )
+   pcre_fullinfo.c       )
+   pcre_get.c            ) sources for the functions in the library,
+   pcre_globals.c        )   and some internal functions that they use
+   pcre_info.c           )
+   pcre_maketables.c     )
+   pcre_ord2utf8.c       )
+   pcre_printint.c       )
+   pcre_study.c          )
+   pcre_tables.c         )
+   pcre_try_flipped.c    )
+   pcre_ucp_findchar.c   )
+   pcre_valid_utf8.c     )
+   pcre_version.c        )
+   pcre_xclass.c         )
+   ucp_findchar.c        )
+   ucp.h                 ) source for the code that is used for
+   ucpinternal.h         )   Unicode property handling
+   ucptable.c            )
+   ucptypetable.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
+   pcre_internal.h       header for internal use
    config.in             template for config.h, which is built by configure
+   pcrecpp.h.in          "source" for the header file for the C++ wrapper
+   pcrecpp.cc            )
+   pcre_scanner.cc       ) source for the C++ wrapper library
+   pcre_stringpiece.h.in "source" for pcre_stringpiece.h, the header for the
+                           C++ stringpiece functions
+   pcre_stringpiece.cc   source for the C++ stringpiece functions
  (B) Auxiliary files:
    AUTHORS               information about the author of PCRE
-Line 261 
 The distribution should contain the foll
+Line 445 
 The distribution should contain the foll
    NON-UNIX-USE          notes on building PCRE on non-Unix systems
    README                this file
    RunTest.in            template for a Unix shell script for running tests
+   RunGrepTest.in        template for a Unix shell script for pcregrep 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/pcregrep.1        man page source for the pcregrep utility
-   doc/pcregrep.html     HTML version
-   doc/pcregrep.txt      plain text version
    install-sh            a shell script for installing files
+   libpcre.pc.in         "source" for libpcre.pc for pkg-config
    ltmain.sh             file used to build a libtool script
+   mkinstalldirs         script for making install directories
    pcretest.c            comprehensive test program
    pcredemo.c            simple demonstration of coding calls to PCRE
    perltest              Perl test program
-   perltest8             Perl test program for UTF-8 tests
    pcregrep.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
+   pcrecpp_unittest.c           )
-   testdata/testinput2   test data for error messages and non-Perl things
+   pcre_scanner_unittest.c      ) test programs for the C++ wrapper
-   testdata/testinput3   test data, compatible with Perl 5.005
+   pcre_stringpiece_unittest.c  )
-   testdata/testinput4   test data for locale-specific tests
+   testdata/testinput*   test data for main library tests
-   testdata/testinput5   test data for UTF-8 tests compatible with Perl 5.6
+   testdata/testoutput*  expected test results
-   testdata/testinput6   test data for other UTF-8 tests
+   testdata/grep*        input and output for pcregrep 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
-   testdata/testoutput6  test results corresponding to testinput6
  (C) Auxiliary files for Win32 DLL
-   dll.mk
+   libpcre.def
+   libpcreposix.def
    pcre.def
- Philip Hazel <ph10@cam.ac.uk>
+ (D) Auxiliary file for VPASCAL
- August 2001
+   makevp.bat
+ Philip Hazel
+ Email local part: ph10
+ Email domain: cam.ac.uk
+ June 2005

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-Removed from v.53
+Added in v.77

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