pcrebuild


       PCRE  is  distributed with a configure script that can be used to build
       the library in Unix-like environments using the applications  known  as
       Autotools.   Also  in  the  distribution  are files to support building
       using CMake instead of configure. The text file README contains general
       information  about  building  with Autotools (some of which is repeated
       below), and also has some comments about building on various  operating
       systems.  There  is  a lot more information about building PCRE without
       using Autotools (including information about using CMake  and  building
       "by  hand")  in  the  text file called NON-AUTOTOOLS-BUILD.  You should
       consult this file as well as the README file if you are building  in  a
       non-Unix-like environment.

PCRE BUILD-TIME OPTIONS

       The  rest of this document describes the optional features of PCRE that
       can be selected when the library is compiled. It  assumes  use  of  the
       configure  script,  where  the  optional features are selected or dese-
       lected by providing options to configure before running the  make  com-
       mand.  However,  the same options can be selected in both Unix-like and
       non-Unix-like environments using the GUI facility of cmake-gui  if  you
       are using CMake instead of configure to build PCRE.

       If  you  are not using Autotools or CMake, option selection can be done
       by editing the config.h file, or by passing parameter settings  to  the
       compiler, as described in NON-AUTOTOOLS-BUILD.

       The complete list of options for configure (which includes the standard
       ones such as the  selection  of  the  installation  directory)  can  be
       obtained by running

         ./configure --help

       The  following  sections  include  descriptions  of options whose names
       begin with --enable or --disable. These settings specify changes to the
       defaults  for  the configure command. Because of the way that configure
       works, --enable and --disable always come in pairs, so  the  complemen-
       tary  option always exists as well, but as it specifies the default, it
       is not described.

BUILDING 8-BIT, 16-BIT AND 32-BIT LIBRARIES

       By default, a library called libpcre  is  built,  containing  functions
       that  take  string  arguments  contained in vectors of bytes, either as
       single-byte characters, or interpreted as UTF-8 strings. You  can  also
       build  a  separate library, called libpcre16, in which strings are con-
       tained in vectors of 16-bit data units and interpreted either  as  sin-
       gle-unit characters or UTF-16 strings, by adding

         --enable-pcre16

       to  the  configure  command.  You  can  also build yet another separate
       library, called libpcre32, in which strings are contained in vectors of
       32-bit  data  units and interpreted either as single-unit characters or

BUILDING SHARED AND STATIC LIBRARIES

       The  Autotools  PCRE building process uses libtool to build both shared
       and static libraries by default. You  can  suppress  one  of  these  by
       adding one of

         --disable-shared
         --disable-static

       to the configure command, as required.

C++ SUPPORT

       By  default,  if the 8-bit library is being built, the configure script
       will search for a C++ compiler and C++ header files. If it finds  them,
       it  automatically  builds  the C++ wrapper library (which supports only
       8-bit strings). You can disable this by adding

         --disable-cpp

       to the configure command.

UTF-8, UTF-16 AND UTF-32 SUPPORT

       To build PCRE with support for UTF Unicode character strings, add

         --enable-utf

       to the configure command. This setting applies to all three  libraries,
       adding  support  for  UTF-8 to the 8-bit library, support for UTF-16 to
       the 16-bit library, and  support  for  UTF-32  to  the  to  the  32-bit
       library.  There  are no separate options for enabling UTF-8, UTF-16 and
       UTF-32 independently because that would allow ridiculous settings  such
       as  requesting UTF-16 support while building only the 8-bit library. It
       is not possible to build one library with UTF support and another with-
       out  in the same configuration. (For backwards compatibility, --enable-
       utf8 is a synonym of --enable-utf.)

       Of itself, this setting does not make  PCRE  treat  strings  as  UTF-8,
       UTF-16  or UTF-32. As well as compiling PCRE with this option, you also
       have have to set the PCRE_UTF8, PCRE_UTF16  or  PCRE_UTF32  option  (as
       appropriate) when you call one of the pattern compiling functions.

       If  you  set --enable-utf when compiling in an EBCDIC environment, PCRE
       expects its input to be either ASCII or UTF-8 (depending  on  the  run-
       time option). It is not possible to support both EBCDIC and UTF-8 codes
       in the same version of  the  library.  Consequently,  --enable-utf  and
       --enable-ebcdic are mutually exclusive.

UNICODE CHARACTER PROPERTY SUPPORT

       UTF  support allows the libraries to process character codepoints up to
       0x10ffff in the strings that they handle. On its own, however, it  does

JUST-IN-TIME COMPILER SUPPORT

       Just-in-time compiler support is included in the build by specifying

         --enable-jit

       This support is available only for certain hardware  architectures.  If
       this  option  is  set  for  an unsupported architecture, a compile time
       error occurs.  See the pcrejit documentation for a  discussion  of  JIT
       usage. When JIT support is enabled, pcregrep automatically makes use of
       it, unless you add

         --disable-pcregrep-jit

       to the "configure" command.

CODE VALUE OF NEWLINE

       By default, PCRE interprets the linefeed (LF) character  as  indicating
       the  end  of  a line. This is the normal newline character on Unix-like
       systems. You can compile PCRE to use carriage return (CR)  instead,  by
       adding

         --enable-newline-is-cr

       to  the  configure  command.  There  is  also  a --enable-newline-is-lf
       option, which explicitly specifies linefeed as the newline character.

       Alternatively, you can specify that line endings are to be indicated by
       the two character sequence CRLF. If you want this, add

         --enable-newline-is-crlf

       to the configure command. There is a fourth option, specified by

         --enable-newline-is-anycrlf

       which  causes  PCRE  to recognize any of the three sequences CR, LF, or
       CRLF as indicating a line ending. Finally, a fifth option, specified by

         --enable-newline-is-any

       causes PCRE to recognize any Unicode newline sequence.

       Whatever line ending convention is selected when PCRE is built  can  be
       overridden  when  the library functions are called. At build time it is
       conventional to use the standard for your operating system.

WHAT \R MATCHES

       By default, the sequence \R in a pattern matches  any  Unicode  newline
       sequence,  whatever  has  been selected as the line ending sequence. If
       you specify
       three integers per substring, whereas the POSIX interface provides only
       two. If the number of expected substrings is small, the  wrapper  func-
       tion  uses  space  on the stack, because this is faster than using mal-
       loc() for each call. The default threshold above which the stack is  no
       longer used is 10; it can be changed by adding a setting such as

         --with-posix-malloc-threshold=20

       to the configure command.

HANDLING VERY LARGE PATTERNS

       Within  a  compiled  pattern,  offset values are used to point from one
       part to another (for example, from an opening parenthesis to an  alter-
       nation  metacharacter).  By default, in the 8-bit and 16-bit libraries,
       two-byte values are used for these offsets, leading to a  maximum  size
       for  a compiled pattern of around 64K. This is sufficient to handle all
       but the most gigantic patterns.  Nevertheless, some people do  want  to
       process  truly  enormous patterns, so it is possible to compile PCRE to
       use three-byte or four-byte offsets by adding a setting such as

         --with-link-size=3

       to the configure command. The value given must be 2, 3, or 4.  For  the
       16-bit  library,  a  value of 3 is rounded up to 4. In these libraries,
       using longer offsets slows down the operation of PCRE because it has to
       load  additional  data  when  handling them. For the 32-bit library the
       value is always 4 and cannot be overridden; the value  of  --with-link-
       size is ignored.

AVOIDING EXCESSIVE STACK USAGE

       When matching with the pcre_exec() function, PCRE implements backtrack-
       ing by making recursive calls to an internal function  called  match().
       In  environments  where  the size of the stack is limited, this can se-
       verely limit PCRE's operation. (The Unix environment does  not  usually
       suffer from this problem, but it may sometimes be necessary to increase
       the maximum stack size.  There is a discussion in the  pcrestack  docu-
       mentation.)  An alternative approach to recursion that uses memory from
       the heap to remember data, instead of using recursive  function  calls,
       has  been  implemented to work round the problem of limited stack size.
       If you want to build a version of PCRE that works this way, add

         --disable-stack-for-recursion

       to the configure command. With this configuration, PCRE  will  use  the
       pcre_stack_malloc  and pcre_stack_free variables to call memory manage-
       ment functions. By default these point to malloc() and free(), but  you
       can replace the pointers so that your own functions are used instead.

       Separate  functions  are  provided  rather  than  using pcre_malloc and
       pcre_free because the  usage  is  very  predictable:  the  block  sizes
       requested  are  always  the  same,  and  the blocks are always freed in
       reverse order. A calling program might be able to  implement  optimized
       tation.  The default is 10 million, but this can be changed by adding a
       setting such as

         --with-match-limit=500000

       to  the  configure  command.  This  setting  has  no  effect   on   the
       pcre_dfa_exec() matching function.

       In  some  environments  it is desirable to limit the depth of recursive
       calls of match() more strictly than the total number of calls, in order
       to  restrict  the maximum amount of stack (or heap, if --disable-stack-
       for-recursion is specified) that is used. A second limit controls this;
       it  defaults  to  the  value  that is set for --with-match-limit, which
       imposes no additional constraints. However, you can set a  lower  limit
       by adding, for example,

         --with-match-limit-recursion=10000

       to  the  configure  command.  This  value can also be overridden at run
       time.

CREATING CHARACTER TABLES AT BUILD TIME

       PCRE uses fixed tables for processing characters whose code values  are
       less  than 256. By default, PCRE is built with a set of tables that are
       distributed in the file pcre_chartables.c.dist. These  tables  are  for
       ASCII codes only. If you add

         --enable-rebuild-chartables

       to  the  configure  command, the distributed tables are no longer used.
       Instead, a program called dftables is compiled and  run.  This  outputs
       the source for new set of tables, created in the default locale of your
       C run-time system. (This method of replacing the tables does  not  work
       if  you are cross compiling, because dftables is run on the local host.
       If you need to create alternative tables when cross compiling, you will
       have to do so "by hand".)

USING EBCDIC CODE

       PCRE  assumes  by  default that it will run in an environment where the
       character code is ASCII (or Unicode, which is  a  superset  of  ASCII).
       This  is  the  case for most computer operating systems. PCRE can, how-
       ever, be compiled to run in an EBCDIC environment by adding

         --enable-ebcdic

       to the configure command. This setting implies --enable-rebuild-charta-
       bles.  You  should  only  use  it if you know that you are in an EBCDIC
       environment (for example,  an  IBM  mainframe  operating  system).  The
       --enable-ebcdic option is incompatible with --enable-utf.

       The EBCDIC character that corresponds to an ASCII LF is assumed to have
       the value 0x15 by default. However, in some EBCDIC  environments,  0x25

PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT

       By default, pcregrep reads all files as plain text. You can build it so
       that it recognizes files whose names end in .gz or .bz2, and reads them
       with libz or libbz2, respectively, by adding one or both of

         --enable-pcregrep-libz
         --enable-pcregrep-libbz2

       to the configure command. These options naturally require that the rel-
       evant  libraries  are installed on your system. Configuration will fail
       if they are not.

PCREGREP BUFFER SIZE

       pcregrep uses an internal buffer to hold a "window" on the file  it  is
       scanning, in order to be able to output "before" and "after" lines when
       it finds a match. The size of the buffer is controlled by  a  parameter
       whose default value is 20K. The buffer itself is three times this size,
       but because of the way it is used for holding "before" lines, the long-
       est  line  that  is guaranteed to be processable is the parameter size.
       You can change the default parameter value by adding, for example,

         --with-pcregrep-bufsize=50K

       to the configure command. The caller of pcregrep can, however, override
       this value by specifying a run-time option.

PCRETEST OPTION FOR LIBREADLINE SUPPORT

       If you add

         --enable-pcretest-libreadline

       to  the  configure  command,  pcretest  is  linked with the libreadline
       library, and when its input is from a terminal, it reads it  using  the
       readline() function. This provides line-editing and history facilities.
       Note that libreadline is GPL-licensed, 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
       libreadline this is sufficient. However, in some environments (e.g.  if
       an unmodified distribution version of readline is in use),  some  extra
       configuration  may  be necessary. The INSTALL file for libreadline says
       this:

         "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 your environment has not been set up so that an appropriate  library
       is automatically included, you may need to add something like
       to mark certain memory regions as  unaddressable.  This  allows  it  to
       detect invalid memory accesses, and is mostly useful for debugging PCRE
       itself.

CODE COVERAGE REPORTING

       If your C compiler is gcc, you can build a version  of  PCRE  that  can
       generate a code coverage report for its test suite. To enable this, you
       must install lcov version 1.6 or above. Then specify

         --enable-coverage

       to the configure command and build PCRE in the usual way.

       Note that using ccache (a caching C compiler) is incompatible with code
       coverage  reporting. If you have configured ccache to run automatically
       on your system, you must set the environment variable

         CCACHE_DISABLE=1

       before running make to build PCRE, so that ccache is not used.

       When --enable-coverage is used,  the  following  addition  targets  are
       added to the Makefile:

         make coverage

       This  creates  a  fresh  coverage report for the PCRE test suite. It is
       equivalent to running "make coverage-reset", "make  coverage-baseline",
       "make check", and then "make coverage-report".

         make coverage-reset

       This zeroes the coverage counters, but does nothing else.

         make coverage-baseline

       This captures baseline coverage information.

         make coverage-report

       This creates the coverage report.

         make coverage-clean-report

       This  removes the generated coverage report without cleaning the cover-
       age data itself.

         make coverage-clean-data

       This removes the captured coverage data without removing  the  coverage
       files created at compile time (*.gcno).

         make coverage-clean

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       Cambridge CB2 3QH, England.

REVISION

       Last updated: 12 May 2013
       Copyright (c) 1997-2013 University of Cambridge.

PCRE 8.33                         12 May 2013                     PCREBUILD(3)
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