README file for PCRE (Perl-compatible regular expression library)
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NOTE: This set of files relates to PCRE releases that use the original API,
with library names libpcre, libpcre16, and libpcre32. January 2015 saw the
first release of a new API, known as PCRE2, with release numbers starting at
10.00 and library names libpcre2-8, libpcre2-16, and libpcre2-32. The old
libraries (now called PCRE1) are still being maintained for bug fixes, but
there will be no new development. New projects are advised to use the new PCRE2
libraries.
The latest release of PCRE1 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. You can access the archives and subscribe or manage your
subscription here:
https://lists.exim.org/mailman/listinfo/pcre-dev
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-like systems
Building PCRE without using autotools
Building PCRE using autotools
Retrieving configuration information
Shared libraries
Cross-compiling using autotools
Using HP's ANSI C++ compiler (aCC)
Compiling in Tru64 using native compilers
Using Sun's compilers for Solaris
Using PCRE from MySQL
Making new tarballs
Testing PCRE
Character tables
File manifest
The PCRE APIs
-------------
PCRE is written in C, and it has its own API. There are three sets of
functions, one for the 8-bit library, which processes strings of bytes, one for
the 16-bit library, which processes strings of 16-bit values, and one for the
32-bit library, which processes strings of 32-bit values. The distribution also
includes a set of C++ wrapper functions (see the pcrecpp man page for details),
courtesy of Google Inc., which can be used to call the 8-bit PCRE library from
C++. Other C++ wrappers have been created from time to time. See, for example:
https://github.com/YasserAsmi/regexp, which aims to be simple and similar in
style to the C API.
The distribution also contains a set of C wrapper functions (again, just for
the 8-bit library) 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
the listing of pcredemo.c and 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.
A PCRE user maintains downloadable Windows binaries of the pcregrep and
pcretest programs here:
http://www.rexegg.com/pcregrep-pcretest.html
Building PCRE on non-Unix-like systems
--------------------------------------
For a non-Unix-like system, please read the comments in the file
NON-AUTOTOOLS-BUILD, though if your system supports the use of "configure" and
"make" you may be able to build PCRE using autotools in the same way as for
many Unix-like systems.
PCRE can also be configured using the GUI facility provided by CMake's
cmake-gui command. This creates Makefiles, solution files, etc. The file
NON-AUTOTOOLS-BUILD has information about CMake.
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 without using autotools
-------------------------------------
The use of autotools (in particular, libtool) is problematic in some
environments, even some that are Unix or Unix-like. See the NON-AUTOTOOLS-BUILD
file for ways of building PCRE without using autotools.
Building PCRE using autotools
-----------------------------
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" (autotools) process.
To build PCRE on system that supports autotools, 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 availa