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1  README file for PCRE (Perl-compatible regular expressions)  README file for PCRE (Perl-compatible regular expression library)
2  ----------------------------------------------------------  -----------------------------------------------------------------
3    
4  The distribution should contain the following files:  The latest release of PCRE is always available from
5    
6      ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.gz
7    
8    Please read the NEWS file if you are upgrading from a previous release.
9    
10    
11    Building PCRE on a Unix system
12    ------------------------------
13    
14    To build PCRE on a Unix system, run the "configure" command in the PCRE
15    distribution directory. This is a standard GNU "autoconf" configuration script,
16    for which generic instructions are supplied in INSTALL. On many systems just
17    running "./configure" is sufficient, but the usual methods of changing standard
18    defaults are available. For example
19    
20    CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
21    
22    specifies that the C compiler should be run with the flags '-O2 -Wall' instead
23    of the default, and that "make install" should install PCRE under /opt/local
24    instead of the default /usr/local. The "configure" script builds thre files:
25    
26    . Makefile is built by copying Makefile.in and making substitutions.
27    . config.h is built by copying config.in and making substitutions.
28    . pcre-config is built by copying pcre-config.in and making substitutions.
29    
30    Once "configure" has run, you can run "make". It builds two libraries called
31    libpcre and libpcreposix, a test program called pcretest, and the pgrep
32    command. You can use "make install" to copy these, and the public header file
33    pcre.h, to appropriate live directories on your system, in the normal way.
34    
35    Running "make install" also installs the command pcre-config, which can be used
36    to recall information about the PCRE configuration and installation. For
37    example,
38    
39      pcre-config --version
40    
41    prints the version number, and
42    
43     pcre-config --libs
44    
45    outputs information about where the library is installed. This command can be
46    included in makefiles for programs that use PCRE, saving the programmer from
47    having to remember too many details.
48    
49    
50    Shared libraries on Unix systems
51    --------------------------------
52    
53    The default distribution builds PCRE as two shared libraries. This support is
54    new and experimental and may not work on all systems. It relies on the
55    "libtool" scripts - these are distributed with PCRE. It should build a
56    "libtool" script and use this to compile and link shared libraries, which are
57    placed in a subdirectory called .libs. The programs pcretest and pgrep are
58    built to use these uninstalled libraries by means of wrapper scripts. When you
59    use "make install" to install shared libraries, pgrep and pcretest are
60    automatically re-built to use the newly installed libraries. However, only
61    pgrep is installed, as pcretest is really just a test program.
62    
63    To build PCRE using static libraries you must use --disable-shared when
64    configuring it. For example
65    
66    ChangeLog         log of changes to the code  ./configure --prefix=/usr/gnu --disable-shared
67    Makefile          for building PCRE  
68    Performance       notes on performance  Then run "make" in the usual way.
69    README            this file  
70    Tech.Notes        notes on the encoding  
71    pcre.3            man page for the functions  Building on non-Unix systems
72    pcreposix.3       man page for the POSIX wrapper API  ----------------------------
73    maketables.c      auxiliary program for building chartables.c  
74    study.c           ) source of  For a non-Unix system, read the comments in the file NON-UNIX-USE. PCRE has
75    pcre.c            )   the functions  been compiled on Windows systems and on Macintoshes, but I don't know the
76    pcreposix.c       )  details because I don't use those systems. It should be straightforward to
77    pcre.h            header for the external API  build PCRE on any system that has a Standard C compiler, because it uses only
78    pcreposix.h       header for the external POSIX wrapper API  Standard C functions.
79    internal.h        header for internal use  
80    pcretest.c        test program  
81    pgrep.1           man page for pgrep  Testing PCRE
82    pgrep.c           source of a grep utility that uses PCRE  ------------
83    perltest          Perl test program  
84    testinput         test data, compatible with Perl  To test PCRE on a Unix system, run the RunTest script in the pcre directory.
85    testinput2        test data for error messages and non-Perl things  (This can also be run by "make runtest" or "make check".) For other systems,
86    testoutput        test results corresponding to testinput  see the instruction in NON-UNIX-USE.
87    testoutput2       test results corresponding to testinput2  
88    The script runs the pcretest test program (which is documented in
89  To build PCRE, edit Makefile for your system (it is a fairly simple make file)  doc/pcretest.txt) on each of the testinput files (in the testdata directory) in
90  and then run it. It builds a two libraries called libpcre.a and libpcreposix.a,  turn, and compares the output with the contents of the corresponding testoutput
91  a test program called pcretest, and the pgrep command.  file. A file called testtry is used to hold the output from pcretest. To run
92    pcretest on just one of the test files, give its number as an argument to
93  To test PCRE, run pcretest on the file testinput, and compare the output with  RunTest, for example:
94  the contents of testoutput. There should be no differences. For example:  
95      RunTest 3
96    pcretest testinput /tmp/anything  
97    diff /tmp/anything testoutput  The first and third test files can also be fed directly into the perltest
98    script to check that Perl gives the same results. The third file requires the
99  Do the same with testinput2, comparing the output with testoutput2, but this  additional features of release 5.005, which is why it is kept separate from the
100  time using the -i flag for pcretest, i.e.  main test input, which needs only Perl 5.004. In the long run, when 5.005 is
101    widespread, these two test files may get amalgamated.
102    pcretest -i testinput2 /tmp/anything  
103    diff /tmp/anything testoutput2  The second set of tests check pcre_info(), pcre_study(), pcre_copy_substring(),
104    pcre_get_substring(), pcre_get_substring_list(), error detection and run-time
105  There are two sets of tests because the first set can also be fed directly into  flags that are specific to PCRE, as well as the POSIX wrapper API.
106  the perltest program to check that Perl gives the same results. The second set  
107  of tests check pcre_info(), pcre_study(), error detection and run-time flags  The fourth set of tests checks pcre_maketables(), the facility for building a
108  that are specific to PCRE, as well as the POSIX wrapper API.  set of character tables for a specific locale and using them instead of the
109    default tables. The tests make use of the "fr" (French) locale. Before running
110  To install PCRE, copy libpcre.a to any suitable library directory (e.g.  the test, the script checks for the presence of this locale by running the
111  /usr/local/lib), pcre.h to any suitable include directory (e.g.  "locale" command. If that command fails, or if it doesn't include "fr" in the
112  /usr/local/include), and pcre.3 to any suitable man directory (e.g.  list of available locales, the fourth test cannot be run, and a comment is
113  /usr/local/man/man3).  output to say why. If running this test produces instances of the error
114    
115  To install the pgrep command, copy it to any suitable binary directory, (e.g.    ** Failed to set locale "fr"
116  /usr/local/bin) and pgrep.1 to any suitable man directory (e.g.  
117  /usr/local/man/man1).  in the comparison output, it means that locale is not available on your system,
118    despite being listed by "locale". This does not mean that PCRE is broken.
119    
120  PCRE has its own native API, but a set of "wrapper" functions that are based on  PCRE has its own native API, but a set of "wrapper" functions that are based on
121  the POSIX API are also supplied in the library libpcreposix.a. Note that this  the POSIX API are also supplied in the library libpcreposix.a. Note that this
# Line 63  themselves still follow Perl syntax and Line 124  themselves still follow Perl syntax and
124  for the POSIX-style functions is called pcreposix.h. The official POSIX name is  for the POSIX-style functions is called pcreposix.h. The official POSIX name is
125  regex.h, but I didn't want to risk possible problems with existing files of  regex.h, but I didn't want to risk possible problems with existing files of
126  that name by distributing it that way. To use it with an existing program that  that name by distributing it that way. To use it with an existing program that
127  uses the POSIX API it will have to be renamed or pointed at by a link.  uses the POSIX API, it will have to be renamed or pointed at by a link.
128    
129    
130  Character tables  Character tables
131  ----------------  ----------------
132    
133  PCRE uses four tables for manipulating and identifying characters. These are  PCRE uses four tables for manipulating and identifying characters. The final
134  compiled from a source file called chartables.c. This is not supplied in  argument of the pcre_compile() function is a pointer to a block of memory
135  the distribution, but is built by the program maketables (compiled from  containing the concatenated tables. A call to pcre_maketables() can be used to
136  maketables.c), which uses the ANSI C character handling functions such as  generate a set of tables in the current locale. If the final argument for
137  isalnum(), isalpha(), isupper(), islower(), etc. to build the table sources.  pcre_compile() is passed as NULL, a set of default tables that is built into
138  This means that the default C locale set in your system may affect the contents  the binary is used.
139  of the tables. You can change the tables by editing chartables.c and then  
140  re-building PCRE. If you do this, you should probably also edit Makefile to  The source file called chartables.c contains the default set of tables. This is
141  ensure that the file doesn't ever get re-generated.  not supplied in the distribution, but is built by the program dftables
142    (compiled from dftables.c), which uses the ANSI C character handling functions
143  The first two tables pcre_lcc[] and pcre_fcc[] provide lower casing and a  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table
144  case flipping functions, respectively. The pcre_cbits[] table consists of four  sources. This means that the default C locale which is set for your system will
145  32-byte bit maps which identify digits, letters, "word" characters, and white  control the contents of these default tables. You can change the default tables
146  space, respectively. These are used when building 32-byte bit maps that  by editing chartables.c and then re-building PCRE. If you do this, you should
147  represent character classes.  probably also edit Makefile to ensure that the file doesn't ever get
148    re-generated.
149    
150    The first two 256-byte tables provide lower casing and case flipping functions,
151    respectively. The next table consists of three 32-byte bit maps which identify
152    digits, "word" characters, and white space, respectively. These are used when
153    building 32-byte bit maps that represent character classes.
154    
155  The pcre_ctypes[] table has bits indicating various character types, as  The final 256-byte table has bits indicating various character types, as
156  follows:  follows:
157    
158      1   white space character      1   white space character
# Line 99  You should not alter the set of characte Line 166  You should not alter the set of characte
166  will cause PCRE to malfunction.  will cause PCRE to malfunction.
167    
168    
169  The pcretest program  Manifest
170  --------------------  --------
171    
172    The distribution should contain the following files:
173    
174    (A) The actual source files of the PCRE library functions and their
175        headers:
176    
177      dftables.c            auxiliary program for building chartables.c
178      get.c                 )
179      maketables.c          )
180      study.c               ) source of
181      pcre.c                )   the functions
182      pcreposix.c           )
183      pcre.in               "source" for the header for the external API; pcre.h
184                              is built from this by "configure"
185      pcreposix.h           header for the external POSIX wrapper API
186      internal.h            header for internal use
187      config.in             template for config.h, which is built by configure
188    
189    (B) Auxiliary files:
190    
191      AUTHORS               information about the author of PCRE
192      ChangeLog             log of changes to the code
193      INSTALL               generic installation instructions
194      LICENCE               conditions for the use of PCRE
195      COPYING               the same, using GNU's standard name
196      Makefile.in           template for Unix Makefile, which is built by configure
197      NEWS                  important changes in this release
198      NON-UNIX-USE          notes on building PCRE on non-Unix systems
199      README                this file
200      RunTest               a Unix shell script for running tests
201      config.guess          ) files used by libtool,
202      config.sub            )   used only when building a shared library
203      configure             a configuring shell script (built by autoconf)
204      configure.in          the autoconf input used to build configure
205      doc/Tech.Notes        notes on the encoding
206      doc/pcre.3            man page source for the PCRE functions
207      doc/pcre.html         HTML version
208      doc/pcre.txt          plain text version
209      doc/pcreposix.3       man page source for the POSIX wrapper API
210      doc/pcreposix.html    HTML version
211      doc/pcreposix.txt     plain text version
212      doc/pcretest.txt      documentation of test program
213      doc/perltest.txt      documentation of Perl test program
214      doc/pgrep.1           man page source for the pgrep utility
215      doc/pgrep.html        HTML version
216      doc/pgrep.txt         plain text version
217      install-sh            a shell script for installing files
218      ltconfig              ) files used to build "libtool",
219      ltmain.sh             )   used only when building a shared library
220      pcretest.c            test program
221      perltest              Perl test program
222      pgrep.c               source of a grep utility that uses PCRE
223      pcre-config.in        source of script which retains PCRE information
224      testdata/testinput1   test data, compatible with Perl 5.004 and 5.005
225      testdata/testinput2   test data for error messages and non-Perl things
226      testdata/testinput3   test data, compatible with Perl 5.005
227      testdata/testinput4   test data for locale-specific tests
228      testdata/testoutput1  test results corresponding to testinput1
229      testdata/testoutput2  test results corresponding to testinput2
230      testdata/testoutput3  test results corresponding to testinput3
231      testdata/testoutput4  test results corresponding to testinput4
232    
233  This program is intended for testing PCRE, but it can also be used for  (C) Auxiliary files for Win32 DLL
 experimenting with regular expressions.  
234    
235  If it is given two filename arguments, it reads from the first and writes to    dll.mk
236  the second. If it is given only one filename argument, it reads from that file    pcre.def
 and writes to stdout. Otherwise, it reads from stdin and writes to stdout, and  
 prompts for each line of input.  
   
 The program handles any number of sets of input on a single input file. Each  
 set starts with a regular expression, and continues with any number of data  
 lines to be matched against the pattern. An empty line signals the end of the  
 set. The regular expressions are given enclosed in any non-alphameric  
 delimiters, for example  
   
   /(a|bc)x+yz/  
   
 and may be followed by i, m, s, or x to set the PCRE_CASELESS, PCRE_MULTILINE,  
 PCRE_DOTALL, or PCRE_EXTENDED options, respectively. These options have the  
 same effect as they do in Perl.  
   
 There are also some upper case options that do not match Perl options: /A, /E,  
 and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively.  
 The /D option is a PCRE debugging feature. It causes the internal form of  
 compiled regular expressions to be output after compilation. The /S option  
 causes pcre_study() to be called after the expression has been compiled, and  
 the results used when the expression is matched. If /I is present as well as  
 /S, then pcre_study() is called with the PCRE_CASELESS option.  
   
 Finally, the /P option causes pcretest to call PCRE via the POSIX wrapper API  
 rather than its native API. When this is done, all other options except /i and  
 /m are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is set if /m  
 is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always, and  
 PCRE_DOTALL unless REG_NEWLINE is set.  
   
 A regular expression can extend over several lines of input; the newlines are  
 included in it. See the testinput file for many examples.  
   
 Before each data line is passed to pcre_exec(), leading and trailing whitespace  
 is removed, and it is then scanned for \ escapes. The following are recognized:  
   
   \a     alarm (= BEL)  
   \b     backspace  
   \e     escape  
   \f     formfeed  
   \n     newline  
   \r     carriage return  
   \t     tab  
   \v     vertical tab  
   \nnn   octal character (up to 3 octal digits)  
   \xhh   hexadecimal character (up to 2 hex digits)  
   
   \A     pass the PCRE_ANCHORED option to pcre_exec()  
   \B     pass the PCRE_NOTBOL option to pcre_exec()  
   \E     pass the PCRE_DOLLAR_ENDONLY option to pcre_exec()  
   \I     pass the PCRE_CASELESS option to pcre_exec()  
   \M     pass the PCRE_MULTILINE option to pcre_exec()  
   \S     pass the PCRE_DOTALL option to pcre_exec()  
   \Odd   set the size of the output vector passed to pcre_exec() to dd  
            (any number of decimal digits)  
   \Z     pass the PCRE_NOTEOL option to pcre_exec()  
   
 A backslash followed by anything else just escapes the anything else. If the  
 very last character is a backslash, it is ignored. This gives a way of passing  
 an empty line as data, since a real empty line terminates the data input.  
   
 If /P was present on the regex, causing the POSIX wrapper API to be used, only  
 \B, and \Z have any effect, causing REG_NOTBOL and REG_NOTEOL to be passed to  
 regexec() respectively.  
   
 When a match succeeds, pcretest outputs the list of identified substrings that  
 pcre_exec() returns, starting with number 0 for the string that matched the  
 whole pattern. Here is an example of an interactive pcretest run.  
   
   $ pcretest  
   Testing Perl-Compatible Regular Expressions  
   PCRE version 0.90 08-Sep-1997  
   
       re> /^abc(\d+)/  
     data> abc123  
    0: abc123  
    1: 123  
     data> xyz  
   No match  
   
 Note that while patterns can be continued over several lines (a plain ">"  
 prompt is used for continuations), data lines may not. However newlines can be  
 included in data by means of the \n escape.  
   
 If the -p option is given to pcretest, it is equivalent to adding /P to each  
 regular expression: the POSIX wrapper API is used to call PCRE. None of the  
 following flags has any effect in this case.  
   
 If the option -d is given to pcretest, it is equivalent to adding /D to each  
 regular expression: the internal form is output after compilation.  
   
 If the option -i (for "information") is given to pcretest, it calls pcre_info()  
 after compiling an expression, and outputs the information it gets back. If the  
 pattern is studied, the results of that are also output.  
   
 If the option -s is given to pcretest, it outputs the size of each compiled  
 pattern after it has been compiled.  
   
 If the -t option is given, each compile, study, and match is run 2000 times  
 while being timed, and the resulting time per compile or match is output in  
 milliseconds. Do not set -t with -s, because you will then get the size output  
 2000 times and the timing will be distorted.  
   
   
   
 The perltest program  
 --------------------  
   
 The perltest program tests Perl's regular expressions; it has the same  
 specification as pcretest, and so can be given identical input, except that  
 input patterns can be followed only by Perl's lower case options.  
   
 The data lines are processed as Perl strings, so if they contain $ or @  
 characters, these have to be escaped. For this reason, all such characters in  
 the testinput file are escaped so that it can be used for perltest as well as  
 for pcretest, and the special upper case options such as /A that pcretest  
 recognizes are not used in this file. The output should be identical, apart  
 from the initial identifying banner.  
   
 The testinput2 file is not suitable for feeding to Perltest, since it does  
 make use of the special upper case options and escapes that pcretest uses to  
 test additional features of PCRE.  
237    
238  Philip Hazel <ph10@cam.ac.uk>  Philip Hazel <ph10@cam.ac.uk>
239  October 1997  February 2000

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