NCBI C++ Toolkit Cross Reference

   README file for PCRE (Perl-compatible regular expression library)
   -----------------------------------------------------------------
   
   The latest release of PCRE is always available in three alternative formats
   from:
   
     ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.gz
     ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.bz2
     ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.zip
  
  There is a mailing list for discussion about the development of PCRE at
  
    pcre-dev@exim.org
  
  Please read the NEWS file if you are upgrading from a previous release.
  The contents of this README file are:
  
    The PCRE APIs
    Documentation for PCRE
    Contributions by users of PCRE
    Building PCRE on non-Unix systems
    Building PCRE on Unix-like systems
    Retrieving configuration information on Unix-like systems
    Shared libraries on Unix-like systems
    Cross-compiling on Unix-like systems
    Using HP's ANSI C++ compiler (aCC)
    Making new tarballs
    Testing PCRE
    Character tables
    File manifest
  
  
  The PCRE APIs
  -------------
  
  PCRE is written in C, and it has its own API. The distribution also includes a
  set of C++ wrapper functions (see the pcrecpp man page for details), courtesy
  of Google Inc.
  
  In addition, there is a set of C wrapper functions that are based on the POSIX
  regular expression API (see the pcreposix man page). 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 POSIX API is restricted, and does not give full access to
  all of PCRE's facilities.
  
  The header file for the POSIX-style functions is called pcreposix.h. The
  official POSIX name is regex.h, but I did not want to risk possible problems
  with existing files of that name by distributing it that way. To use PCRE with
  an existing program that uses the POSIX API, pcreposix.h 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, as well as worrying about the regex.h header
  file (as mentioned above), you must also take care when linking programs to
  ensure that they link with PCRE's libpcreposix library. Otherwise they may pick
  up the POSIX functions of the same name from the other library.
  
  One way of avoiding this confusion is to compile PCRE with the addition of
  -Dregcomp=PCREregcomp (and similarly for the other POSIX functions) to the
  compiler flags (CFLAGS if you are using "configure" -- see below). This has the
  effect of renaming the functions so that the names no longer clash. Of course,
  you have to do the same thing for your applications, or write them using the
  new names.
  
  
  Documentation for PCRE
  ----------------------
  
  If you install PCRE in the normal way on a Unix-like system, you will end up
  with a set of man pages whose names all start with "pcre". The one that is just
  called "pcre" lists all the others. In addition to these man pages, the PCRE
  documentation is supplied in two other forms:
  
    1. There are files called doc/pcre.txt, doc/pcregrep.txt, and
       doc/pcretest.txt in the source distribution. 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.
       These text forms are provided for ease of scanning with text editors or
       similar tools. They are installed in <prefix>/share/doc/pcre, where
       <prefix> is the installation prefix (defaulting to /usr/local).
  
    2. A set of files containing all the documentation in HTML form, hyperlinked
       in various ways, and rooted in a file called index.html, is distributed in
       doc/html and installed in <prefix>/share/doc/pcre/html.
  
  Users of PCRE have contributed files containing the documentation for various
  releases in CHM format. These can be found in the Contrib directory of the FTP
  site (see next section).
  
  
  Contributions by users of PCRE
  ------------------------------
  
  You can find contributions from PCRE users in the directory
  
    ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib
  
 There is a README file giving brief descriptions of what they are. Some are
 complete in themselves; others are pointers to URLs containing relevant files.
 Some of this material is likely to be well out-of-date. Several of the earlier
 contributions provided support for compiling PCRE on various flavours of
 Windows (I myself do not use Windows). Nowadays there is more Windows support
 in the standard distribution, so these contibutions have been archived.
 
 
 Building PCRE on non-Unix systems
 ---------------------------------
 
 For a non-Unix system, please read the comments in the file NON-UNIX-USE,
 though if your system supports the use of "configure" and "make" you may be
 able to build PCRE in the same way as for Unix-like systems. PCRE can also be
 configured in many platform environments using the GUI facility of CMake's
 CMakeSetup. It creates Makefiles, solution files, etc.
 
 PCRE has been compiled on many different operating systems. It should be
 straightforward to build PCRE on any system that has a Standard C compiler and
 library, because it uses only Standard C functions.
 
 
 Building PCRE on Unix-like systems
 ----------------------------------
 
 If you are using HP's ANSI C++ compiler (aCC), please see the special note
 in the section entitled "Using HP's ANSI C++ compiler (aCC)" below.
 
 The following instructions assume the use of the widely used "configure, make,
 make install" process. There is also support for CMake in the PCRE
 distribution; there are some comments about using CMake in the NON-UNIX-USE
 file, though it can also be used in Unix-like systems.
 
 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
 the file INSTALL.
 
 Most commonly, people build PCRE within its own distribution directory, and in
 this case, on many systems, just running "./configure" is sufficient. However,
 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.
 
 If you want to build in a different directory, just run "configure" with that
 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
 
 PCRE is written in C and is normally compiled as a C library. However, it is
 possible to build it as a C++ library, though the provided building apparatus
 does not have any features to support this.
 
 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 suppress the building of the C++ wrapper library, you can add
   --disable-cpp to the "configure" command. Otherwise, when "configure" is run,
   it will try to find a C++ compiler and C++ header files, and if it succeeds,
   it will try to build the C++ wrapper.
 
 . If you want to make use of the support for UTF-8 Unicode 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. When PCRE is compiled
   with this option, its input can only either be ASCII or UTF-8, even when
   running on EBCDIC platforms. It is not possible to use both --enable-utf8 and
   --enable-ebcdic at the same 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 30K 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 recognize either CR or LF or the sequence CRLF or any
   of the preceding, or any of the Unicode newline sequences as indicating the
   end of a line. Whatever you specify at build time is the default; the caller
   of PCRE can change the selection at run time. The default newline indicator
   is a single LF character (the Unix standard). You can specify the default
   newline indicator by adding --enable-newline-is-cr or --enable-newline-is-lf
   or --enable-newline-is-crlf or --enable-newline-is-anycrlf or
   --enable-newline-is-any to the "configure" command, respectively.
 
   If you specify --enable-newline-is-cr or --enable-newline-is-crlf, some of
   the standard tests will fail, because the lines in the test files end with
   LF. Even if the files are edited to change the line endings, there are likely
   to be some failures. With --enable-newline-is-anycrlf or
   --enable-newline-is-any, many tests should succeed, but there may be some
   failures.
 
 . By default, the sequence \R in a pattern matches any Unicode line ending
   sequence. This is independent of the option specifying what PCRE considers to
   be the end of a line (see above). However, the caller of PCRE can restrict \R
   to match only CR, LF, or CRLF. You can make this the default by adding
   --enable-bsr-anycrlf to the "configure" command (bsr = "backslash R").
 
 . 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 in a pattern. 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 more discussion on the
   pcreapi man page.
 
 . There is a separate counter that limits the depth of recursive function calls
   during a matching process. This also has a default of ten million, which is
   essentially "unlimited". You can change the default by setting, for example,
 
   --with-match-limit-recursion=500000
 
   Recursive function calls use up the runtime stack; running out of stack can
   cause programs to crash in strange ways. There is a discussion about stack
   sizes in the pcrestack 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. Increasing the internal link size will reduce
   performance.
 
 . You can build PCRE so that its internal match() function that is called from
   pcre_exec() does not call itself recursively. Instead, it uses memory blocks
   obtained from the heap via the 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. There is a discussion about stack sizes in the
   pcrestack man page.
 
 . For speed, PCRE uses four tables for manipulating and identifying characters
   whose code point values are less than 256. By default, it uses a set of
   tables for ASCII encoding that is part of the distribution. If you specify
 
   --enable-rebuild-chartables
 
   a program called dftables is compiled and run in the default C locale when
   you obey "make". It builds a source file called pcre_chartables.c. If you do
   not specify this option, pcre_chartables.c is created as a copy of
   pcre_chartables.c.dist. See "Character tables" below for further information.
 
 . It is possible to compile PCRE for use on systems that use EBCDIC as their
   character code (as opposed to ASCII) by specifying
 
   --enable-ebcdic
 
   This automatically implies --enable-rebuild-chartables (see above). However,
   when PCRE is built this way, it always operates in EBCDIC. It cannot support
   both EBCDIC and UTF-8.
 
 . It is possible to compile pcregrep to use libz and/or libbz2, in order to
   read .gz and .bz2 files (respectively), by specifying one or both of
 
   --enable-pcregrep-libz
   --enable-pcregrep-libbz2
 
   Of course, the relevant libraries must be installed on your system.
 
 . It is possible to compile pcretest so that it links with the libreadline
   library, by specifying
 
   --enable-pcretest-libreadline
 
   If this is done, when pcretest's input is from a terminal, it reads it using
   the readline() function. This provides line-editing and history facilities.
   Note that libreadline is GPL-licenced, so if you distribute a binary of
   pcretest linked in this way, there may be licensing issues.
 
   Setting this option causes the -lreadline option to be added to the pcretest
   build. In many operating environments with a sytem-installed readline
   library this is sufficient. However, in some environments (e.g. if an
   unmodified distribution version of readline is in use), it may be necessary
   to specify something like LIBS="-lncurses" as well. This is because, to quote
   the readline INSTALL, "Readline uses the termcap functions, but does not link
   with the termcap or curses library itself, allowing applications which link
   with readline the to choose an appropriate library." If you get error
   messages about missing functions tgetstr, tgetent, tputs, tgetflag, or tgoto,
   this is the problem, and linking with the ncurses library should fix it.
 
 The "configure" script builds the following files for the basic C library:
 
 . Makefile is the makefile that builds the library
 . config.h contains build-time configuration options for the library
 . pcre.h is the public PCRE header file
 . 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
 . RunTest is a script for running tests on the basic C library
 . RunGrepTest is a script for running tests on the pcregrep command
 
 Versions of config.h and pcre.h are distributed in the PCRE tarballs under
 the names config.h.generic and pcre.h.generic. These are provided for the
 benefit of those who have to built PCRE without the benefit of "configure". If
 you use "configure", the .generic versions are not used.
 
 If a C++ compiler is found, the following files are also built:
 
 . libpcrecpp.pc is data for the pkg-config command
 . pcrecpparg.h is a 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. If a C++ compiler was found on your system, "make" also builds the C++
 wrapper library, which is called libpcrecpp, and some test programs called
 pcrecpp_unittest, pcre_scanner_unittest, and pcre_stringpiece_unittest.
 Building the C++ wrapper can be disabled by adding --disable-cpp to the
 "configure" command.
 
 The command "make check" runs all the appropriate tests. Details of the PCRE
 tests are given below in a separate section of this document.
 
 You can use "make install" to install PCRE into live directories on your
 system. The following are installed (file names are all relative to the
 <prefix> that is set when "configure" is run):
 
   Commands (bin):
     pcretest
     pcregrep
     pcre-config
 
   Libraries (lib):
     libpcre
     libpcreposix
     libpcrecpp (if C++ support is enabled)
 
   Configuration information (lib/pkgconfig):
     libpcre.pc
     libpcrecpp.pc (if C++ support is enabled)
 
   Header files (include):
     pcre.h
     pcreposix.h
     pcre_scanner.h      )
     pcre_stringpiece.h  ) if C++ support is enabled
     pcrecpp.h           )
     pcrecpparg.h        )
 
   Man pages (share/man/man{1,3}):
     pcregrep.1
     pcretest.1
     pcre.3
     pcre*.3 (lots more pages, all starting "pcre")
 
   HTML documentation (share/doc/pcre/html):
     index.html
     *.html (lots more pages, hyperlinked from index.html)
 
   Text file documentation (share/doc/pcre):
     AUTHORS
     COPYING
     ChangeLog
     LICENCE
     NEWS
     README
     pcre.txt       (a concatenation of the man(3) pages)
     pcretest.txt   the pcretest man page
     pcregrep.txt   the pcregrep man page
 
 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" 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.
 
 The pkg-config command is another system for saving and retrieving information
 about installed libraries. Instead of separate commands for each library, a
 single command is used. For example:
 
   pkg-config --cflags pcre
 
 The data is held in *.pc files that are installed in a directory called
 <prefix>/lib/pkgconfig.
 
 
 Shared libraries on Unix-like systems
 -------------------------------------
 
 The default distribution builds PCRE as shared libraries and 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 build 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 Unix-like systems
 ------------------------------------
 
 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, you should NOT
 specify --enable-rebuild-chartables, because if you do, the dftables.c source
 file is compiled and run on the local host, in order to generate the inbuilt
 character tables (the pcre_chartables.c file). This will probably not work,
 because dftables.c needs to be compiled with the local compiler, not the cross
 compiler.
 
 When --enable-rebuild-chartables is not specified, pcre_chartables.c is created
 by making a copy of pcre_chartables.c.dist, which is a default set of tables
 that assumes ASCII code. Cross-compiling with the default tables should not be
 a problem.
 
 If you need to modify the character tables when cross-compiling, you should
 move pcre_chartables.c.dist out of the way, then compile dftables.c by hand and
 run it on the local host to make a new version of pcre_chartables.c.dist.
 Then when you cross-compile PCRE this new version of the tables will be used.
 
 
 Using HP's ANSI C++ compiler (aCC)
 ----------------------------------
 
 Unless C++ support is disabled by specifying the "--disable-cpp" option of the
 "configure" script, you must include the "-AA" option in the CXXFLAGS
 environment variable in order for the C++ components to compile correctly.
 
 Also, note that the aCC compiler on PA-RISC platforms may have a defect whereby
 needed libraries fail to get included when specifying the "-AA" compiler
 option. If you experience unresolved symbols when linking the C++ programs,
 use the workaround of specifying the following environment variable prior to
 running the "configure" script:
 
   CXXLDFLAGS="-lstd_v2 -lCsup_v2"
 
 
 Making new tarballs
 -------------------
 
 The command "make dist" creates three PCRE tarballs, in tar.gz, tar.bz2, and
 zip formats. The command "make distcheck" does the same, but then does a trial
 build of the new distribution to ensure that it works.
 
 If you have modified any of the man page sources in the doc directory, you
 should first run the PrepareRelease script before making a distribution. This
 script creates the .txt and HTML forms of the documentation from the man pages.
 
 
 Testing PCRE
 ------------
 
 To test the basic PCRE library on a Unix system, run the RunTest script that is
 created by the configuring process. There is also a script called RunGrepTest
 that tests the options of the pcregrep command. If the C++ wrapper library is
 built, three test programs called pcrecpp_unittest, pcre_scanner_unittest, and
 pcre_stringpiece_unittest are also built.
 
 Both the scripts and all the program tests are run if you obey "make check" or
 "make test". For other systems, see the instructions in NON-UNIX-USE.
 
 The RunTest script runs the pcretest test program (which is documented in its
 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
 files. A file called testtry is used to hold the main output from pcretest
 (testsavedregex is also used as a working file). To run pcretest on just one of
 the test files, give its number as an argument to RunTest, for example:
 
   RunTest 2
 
 The first test file can also be fed directly into the perltest.pl 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
 detection, and run-time flags that are specific to PCRE, as well as the POSIX
 wrapper API. It also uses the debugging flags to check some of the internals of
 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 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_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_FR"
 in the 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_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.
 
 [If you are trying to run this test on Windows, you may be able to get it to
 work by changing "fr_FR" to "french" everywhere it occurs. Alternatively, use
 RunTest.bat. The version of RunTest.bat included with PCRE 7.4 and above uses
 Windows versions of test 2. More info on using RunTest.bat is included in the
 document entitled NON-UNIX-USE.]
 
 The fourth test checks the UTF-8 support. It is not run automatically unless
 PCRE is built with UTF-8 support. To do this you must set --enable-utf8 when
 running "configure". This file can be also fed directly to the perltest script,
 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 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
 ----------------
 
 For speed, PCRE uses four tables for manipulating and identifying characters
 whose code point values are less than 256. 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 pcre_chartables.c contains the default set of tables. By
 default, this is created as a copy of pcre_chartables.c.dist, which contains
 tables for ASCII coding. However, if --enable-rebuild-chartables is specified
 for ./configure, a different version of pcre_chartables.c 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 pcre_chartables.c and then re-building PCRE. If
 you do this, you should take care to ensure that the file does not get
 automatically re-generated. The best way to do this is to move
 pcre_chartables.c.dist out of the way and replace it with your customized
 tables.
 
 When the dftables program is run as a result of --enable-rebuild-chartables,
 it uses the default C locale that is set on your system. It does not pay
 attention to the LC_xxx environment variables. In other words, it uses the
 system's default locale rather than whatever the compiling user happens to have
 set. If you really do want to build a source set of character tables in a
 locale that is specified by the LC_xxx variables, you can run the dftables
 program by hand with the -L option. For example:
 
   ./dftables -L pcre_chartables.c.special
 
 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 for code points less
 than 256.
 
 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.
 
 
 File manifest
 -------------
 
 The distribution should contain the following files:
 
 (A) Source files of the PCRE library functions and their headers:
 
   dftables.c              auxiliary program for building pcre_chartables.c
                             when --enable-rebuild-chartables is specified
 
   pcre_chartables.c.dist  a default set of character tables that assume ASCII
                             coding; used, unless --enable-rebuild-chartables is
                             specified, by copying to pcre_chartables.c
 
   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_newline.c          )
   pcre_ord2utf8.c         )
   pcre_refcount.c         )
   pcre_study.c            )
   pcre_tables.c           )
   pcre_try_flipped.c      )
   pcre_ucd.c              )
   pcre_valid_utf8.c       )
   pcre_version.c          )
   pcre_xclass.c           )
   pcre_printint.src       ) debugging function that is #included in pcretest,
                           )   and can also be #included in pcre_compile()
   pcre.h.in               template for pcre.h when built by "configure"
   pcreposix.h             header for the external POSIX wrapper API
   pcre_internal.h         header for internal use
   ucp.h                   header for Unicode property handling
 
   config.h.in             template for config.h, which is built by "configure"
 
   pcrecpp.h               public header file for the C++ wrapper
   pcrecpparg.h.in         template for another C++ header file
   pcre_scanner.h          public header file for C++ scanner functions
   pcrecpp.cc              )
   pcre_scanner.cc         ) source for the C++ wrapper library
 
   pcre_stringpiece.h.in   template for pcre_stringpiece.h, the header for the
                             C++ stringpiece functions
   pcre_stringpiece.cc     source for the C++ stringpiece functions
 
 (B) Source files for programs that use PCRE:
 
   pcredemo.c              simple demonstration of coding calls to PCRE
   pcregrep.c              source of a grep utility that uses PCRE
   pcretest.c              comprehensive test program
 
 (C) Auxiliary files:
 
   132html                 script to turn "man" pages into HTML
   AUTHORS                 information about the author of PCRE
   ChangeLog               log of changes to the code
   CleanTxt                script to clean nroff output for txt man pages
   Detrail                 script to remove trailing spaces
   HACKING                 some notes about the internals of PCRE
   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"
   Makefile.am             ) the automake input that was used to create
                           )   Makefile.in
   NEWS                    important changes in this release
   NON-UNIX-USE            notes on building PCRE on non-Unix systems
   PrepareRelease          script to make preparations for "make dist"
   README                  this file
   RunTest                 a Unix shell script for running tests
   RunGrepTest             a Unix shell script for pcregrep tests
   aclocal.m4              m4 macros (generated by "aclocal")
   config.guess            ) files used by libtool,
   config.sub              )   used only when building a shared library
   configure               a configuring shell script (built by autoconf)
   configure.ac            ) the autoconf input that was used to build
                           )   "configure" and config.h
   depcomp                 ) script to find program dependencies, generated by
                           )   automake
   doc/*.3                 man page sources for the PCRE functions
   doc/*.1                 man page sources for pcregrep and pcretest
   doc/index.html.src      the base HTML page
   doc/html/*              HTML documentation
   doc/pcre.txt            plain text version of the man pages
   doc/pcretest.txt        plain text documentation of test program
   doc/perltest.txt        plain text documentation of Perl test program
   install-sh              a shell script for installing files
   libpcre.pc.in           template for libpcre.pc for pkg-config
   libpcrecpp.pc.in        template for libpcrecpp.pc for pkg-config
   ltmain.sh               file used to build a libtool script
   missing                 ) common stub for a few missing GNU programs while
                           )   installing, generated by automake
   mkinstalldirs           script for making install directories
   perltest.pl             Perl test program
   pcre-config.in          source of script which retains PCRE information
   pcrecpp_unittest.cc          )
   pcre_scanner_unittest.cc     ) test programs for the C++ wrapper
   pcre_stringpiece_unittest.cc )
   testdata/testinput*     test data for main library tests
   testdata/testoutput*    expected test results
   testdata/grep*          input and output for pcregrep tests
 
 (D) Auxiliary files for cmake support
 
   cmake/COPYING-CMAKE-SCRIPTS
   cmake/FindPackageHandleStandardArgs.cmake
   cmake/FindReadline.cmake
   CMakeLists.txt
   config-cmake.h.in
 
 (E) Auxiliary files for VPASCAL
 
   makevp.bat
   makevp_c.txt
   makevp_l.txt
   pcregexp.pas
 
 (F) Auxiliary files for building PCRE "by hand"
 
   pcre.h.generic          ) a version of the public PCRE header file
                           )   for use in non-"configure" environments
   config.h.generic        ) a version of config.h for use in non-"configure"
                           )   environments
 
 (F) Miscellaneous
 
   RunTest.bat            a script for running tests under Windows
 
 Philip Hazel
 Email local part: ph10
 Email domain: cam.ac.uk
 Last updated: 21 March 2009