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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  *******************************************************************************  Please read the NEWS file if you are upgrading from a previous release.
 *           IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00           *  
 *                                                                             *  
 * Please note that there has been a change in the API such that a larger      *  
 * ovector is required at matching time, to provide some additional workspace. *  
 * The new man page has details. This change was necessary in order to support *  
 * some of the new functionality in Perl 5.005.                                *  
 *                                                                             *  
 *           IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00                   *  
 *                                                                             *  
 * Another (I hope this is the last!) change has been made to the API for the  *  
 * pcre_compile() function. An additional argument has been added to make it   *  
 * possible to pass over a pointer to character tables built in the current    *  
 * locale by pcre_maketables(). To use the default tables, this new arguement  *  
 * should be passed as NULL.                                                   *  
 *******************************************************************************  
5    
 The distribution should contain the following files:  
6    
7    ChangeLog         log of changes to the code  Building PCRE on a Unix system
8    Makefile          for building PCRE  ------------------------------
9    README            this file  
10    RunTest           a shell script for running tests  To build PCRE on a Unix system, run the "configure" command in the PCRE
11    Tech.Notes        notes on the encoding  distribution directory. This is a standard GNU "autoconf" configuration script,
12    pcre.3            man page for the functions  for which generic instructions are supplied in INSTALL. On many systems just
13    pcreposix.3       man page for the POSIX wrapper API  running "./configure" is sufficient, but the usual methods of changing standard
14    dftables.c        auxiliary program for building chartables.c  defaults are available. For example
15    maketables.c      )  
16    study.c           ) source of  CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local
17    pcre.c            )   the functions  
18    pcreposix.c       )  specifies that the C compiler should be run with the flags '-O2 -Wall' instead
19    pcre.h            header for the external API  of the default, and that "make install" should install PCRE under /opt/local
20    pcreposix.h       header for the external POSIX wrapper API  instead of the default /usr/local. The "configure" script builds two files:
21    internal.h        header for internal use  
22    pcretest.c        test program  . Makefile is built by copying Makefile.in and making certain substitutions.
23    pgrep.1           man page for pgrep  . config.h is built by copying config.in and making certain substitutions.
24    pgrep.c           source of a grep utility that uses PCRE  
25    perltest          Perl test program  Once "configure" has run, you can run "make". It builds two libraries called
26    testinput         test data, compatible with Perl 5.004 and 5.005  libpcre.a and libpcreposix.a, a test program called pcretest, and the pgrep
27    testinput2        test data for error messages and non-Perl things  command. You can use "make install" to copy these, and the public header file
28    testinput3        test data, compatible with Perl 5.005  pcre.h, to appropriate live directories on your system, in the normal way.
29    testinput4        test data for locale-specific tests  
30    testoutput        test results corresponding to testinput  
31    testoutput2       test results corresponding to testinput2  Shared libraries on Unix systems
32    testoutput3       test results corresponding to testinput3  --------------------------------
33    testoutput4       test results corresponding to testinput4  
34    The default distribution builds static libraries. It is also possible to build
35  To build PCRE, edit Makefile for your system (it is a fairly simple make file,  PCRE as two shared libraries. This support is new and experimental and may not
36  and there are some comments at the top) and then run it. It builds two  work on all systems. It relies on the "libtool" scripts - these are distributed
37  libraries called libpcre.a and libpcreposix.a, a test program called pcretest,  with PCRE. To build PCRE using shared libraries you must use --enable-shared
38  and the pgrep command.  when configuring it. For example
39    
40  To test PCRE, run the RunTest script in the pcre directory. This runs pcretest  ./configure --prefix=/usr/gnu --enable-shared
41  on each of the testinput files in turn, and compares the output with the  
42  contents of the corresponding testoutput file. A file called testtry is used to  Then run "make" in the usual way. It should build a "libtool" script and use
43  hold the output from pcretest (which is documented below).  this to compile and link shared libraries, which are placed in a subdirectory
44    called .libs. The programs pcretest and pgrep are built to use these
45    uninstalled libraries by means of wrapper scripts. When you use "make install"
46    to install shared libraries, pgrep is automatically re-built to use the newly
47    installed library before it itself is installed.
48    
49  To run pcretest on just one of the test files, give its number as an argument  
50  to RunTest, for example:  Building on non-Unix systems
51    ----------------------------
52    
53    For a non-Unix system, read the comments in the file NON-UNIX-USE. PCRE has
54    been compiled on Windows systems and on Macintoshes, but I don't know the
55    details because I don't use those systems. It should be straightforward to
56    build PCRE on any system that has a Standard C compiler, because it uses only
57    Standard C functions.
58    
59    
60    Testing PCRE
61    ------------
62    
63    To test PCRE on a Unix system, run the RunTest script in the pcre directory.
64    (This can also be run by "make runtest" or "make check".) For other systems,
65    see the instruction in NON-UNIX-USE.
66    
67    The script runs the pcretest test program (which is documented in
68    doc/pcretest.txt) on each of the testinput files (in the testdata directory) in
69    turn, and compares the output with the contents of the corresponding testoutput
70    file. A file called testtry is used to hold the output from pcretest. To run
71    pcretest on just one of the test files, give its number as an argument to
72    RunTest, for example:
73    
74    RunTest 3    RunTest 3
75    
76  The first and third test files can also be fed directly into the perltest  The first and third test files can also be fed directly into the perltest
77  program to check that Perl gives the same results. The third file requires the  script to check that Perl gives the same results. The third file requires the
78  additional features of release 5.005, which is why it is kept separate from the  additional features of release 5.005, which is why it is kept separate from the
79  main test input, which needs only Perl 5.004. In the long run, when 5.005 is  main test input, which needs only Perl 5.004. In the long run, when 5.005 is
80  widespread, these two test files may get amalgamated.  widespread, these two test files may get amalgamated.
81    
82  The second set of tests check pcre_info(), pcre_study(), error detection and  The second set of tests check pcre_info(), pcre_study(), pcre_copy_substring(),
83  run-time flags that are specific to PCRE, as well as the POSIX wrapper API.  pcre_get_substring(), pcre_get_substring_list(), error detection and run-time
84    flags that are specific to PCRE, as well as the POSIX wrapper API.
85    
86  The fourth set of tests checks pcre_maketables(), the facility for building a  The fourth set of tests checks pcre_maketables(), the facility for building a
87  set of character tables for a specific locale and using them instead of the  set of character tables for a specific locale and using them instead of the
# Line 85  output to say why. If running this test Line 96  output to say why. If running this test
96  in the comparison output, it means that locale is not available on your system,  in the comparison output, it means that locale is not available on your system,
97  despite being listed by "locale". This does not mean that PCRE is broken.  despite being listed by "locale". This does not mean that PCRE is broken.
98    
 To install PCRE, copy libpcre.a to any suitable library directory (e.g.  
 /usr/local/lib), pcre.h to any suitable include directory (e.g.  
 /usr/local/include), and pcre.3 to any suitable man directory (e.g.  
 /usr/local/man/man3).  
   
 To install the pgrep command, copy it to any suitable binary directory, (e.g.  
 /usr/local/bin) and pgrep.1 to any suitable man directory (e.g.  
 /usr/local/man/man1).  
   
99  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
100  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
101  just provides a POSIX calling interface to PCRE: the regular expressions  just provides a POSIX calling interface to PCRE: the regular expressions
# Line 109  Character tables Line 111  Character tables
111    
112  PCRE uses four tables for manipulating and identifying characters. The final  PCRE uses four tables for manipulating and identifying characters. The final
113  argument of the pcre_compile() function is a pointer to a block of memory  argument of the pcre_compile() function is a pointer to a block of memory
114  containing the concatenated tables. A call to pcre_maketables() is used to  containing the concatenated tables. A call to pcre_maketables() can be used to
115  generate a set of tables in the current locale. However, if the final argument  generate a set of tables in the current locale. If the final argument for
116  is passed as NULL, a set of default tables that is built into the binary is  pcre_compile() is passed as NULL, a set of default tables that is built into
117  used.  the binary is used.
118    
119  The source file called chartables.c contains the default set of tables. This is  The source file called chartables.c contains the default set of tables. This is
120  not supplied in the distribution, but is built by the program dftables  not supplied in the distribution, but is built by the program dftables
121  (compiled from dftables.c), which uses the ANSI C character handling functions  (compiled from dftables.c), which uses the ANSI C character handling functions
122  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table
123  sources. This means that the default C locale set your system will control the  sources. This means that the default C locale which is set for your system will
124  contents of the tables. You can change the default tables by editing  control the contents of these default tables. You can change the default tables
125  chartables.c and then re-building PCRE. If you do this, you should probably  by editing chartables.c and then re-building PCRE. If you do this, you should
126  also edit Makefile to ensure that the file doesn't ever get re-generated.  probably also edit Makefile to ensure that the file doesn't ever get
127    re-generated.
128    
129  The first two 256-byte tables provide lower casing and case flipping functions,  The first two 256-byte tables provide lower casing and case flipping functions,
130  respectively. The next table consists of three 32-byte bit maps which identify  respectively. The next table consists of three 32-byte bit maps which identify
# Line 142  You should not alter the set of characte Line 145  You should not alter the set of characte
145  will cause PCRE to malfunction.  will cause PCRE to malfunction.
146    
147    
148  The pcretest program  Manifest
149  --------------------  --------
150    
151    The distribution should contain the following files:
152    
153    (A) The actual source files of the PCRE library functions and their
154        headers:
155    
156      dftables.c            auxiliary program for building chartables.c
157      get.c                 )
158      maketables.c          )
159      study.c               ) source of
160      pcre.c                )   the functions
161      pcreposix.c           )
162      pcre.h                header for the external API
163      pcreposix.h           header for the external POSIX wrapper API
164      internal.h            header for internal use
165      config.in             template for config.h, which is built by configure
166    
167    (B) Auxiliary files:
168    
169      AUTHORS               information about the author of PCRE
170      ChangeLog             log of changes to the code
171      INSTALL               generic installation instructions
172      LICENCE               conditions for the use of PCRE
173      Makefile.in           template for Unix Makefile, which is built by configure
174      NEWS                  important changes in this release
175      NON-UNIX-USE          notes on building PCRE on non-Unix systems
176      README                this file
177      RunTest               a Unix shell script for running tests
178      config.guess          ) files used by libtool,
179      config.sub            )   used only when building a shared library
180      configure             a configuring shell script (built by autoconf)
181      configure.in          the autoconf input used to build configure
182      doc/Tech.Notes        notes on the encoding
183      doc/pcre.3            man page source for the PCRE functions
184      doc/pcre.html         HTML version
185      doc/pcre.txt          plain text version
186      doc/pcreposix.3       man page source for the POSIX wrapper API
187      doc/pcreposix.html    HTML version
188      doc/pcreposix.txt     plain text version
189      doc/pcretest.txt      documentation of test program
190      doc/perltest.txt      documentation of Perl test program
191      doc/pgrep.1           man page source for the pgrep utility
192      doc/pgrep.html        HTML version
193      doc/pgrep.txt         plain text version
194      install-sh            a shell script for installing files
195      ltconfig              ) files used to build "libtool",
196      ltmain.sh             )   used only when building a shared library
197      pcretest.c            test program
198      perltest              Perl test program
199      pgrep.c               source of a grep utility that uses PCRE
200      testdata/testinput1   test data, compatible with Perl 5.004 and 5.005
201      testdata/testinput2   test data for error messages and non-Perl things
202      testdata/testinput3   test data, compatible with Perl 5.005
203      testdata/testinput4   test data for locale-specific tests
204      testdata/testoutput1  test results corresponding to testinput1
205      testdata/testoutput2  test results corresponding to testinput2
206      testdata/testoutput3  test results corresponding to testinput3
207      testdata/testoutput4  test results corresponding to testinput4
208    
209  This program is intended for testing PCRE, but it can also be used for  (C) Auxiliary files for Win32 DLL
 experimenting with regular expressions.  
210    
211  If it is given two filename arguments, it reads from the first and writes to    dll.mk
212  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 /L option must be followed directly by the name of a locale, for example,  
   
   /pattern/Lfr  
   
 For this reason, it must be the last option letter. The given locale is set,  
 pcre_maketables() is called to build a set of character tables for the locale,  
 and this is then passed to pcre_compile() when compiling the regular  
 expression. Without an /L option, NULL is passed as the tables pointer; that  
 is, /L applies only to the expression on which it appears.  
   
 The /I option requests that pcretest output information about the compiled  
 expression (whether it is anchored, has a fixed first character, and so on). It  
 does this by calling pcre_info() after compiling an expression, and outputting  
 the information it gets back. If the pattern is studied, the results of that  
 are also output.  
   
 The /D option is a PCRE debugging feature, which also assumes /I. 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.  
   
 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 files 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()  
   \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 is given to pcretest, it is equivalent to adding /I to each  
 regular expression: information about the compiled pattern is given after  
 compilation.  
   
 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 10000 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  
 10000 times and the timing will be distorted. If you want to change the number  
 of repetitions used for timing, edit the definition of LOOPREPEAT at the top of  
 pcretest.c  
   
   
   
 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 contents  
 of testinput and testinput3 meet this condition.  
   
 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 and testinput4 files are not suitable for feeding to Perltest,  
 since they do make use of the special upper case options and escapes that  
 pcretest uses to test some features of PCRE. The first of these files also  
 contains malformed regular expressions, in order to check that PCRE diagnoses  
 them correctly.  
213    
214  Philip Hazel <ph10@cam.ac.uk>  Philip Hazel <ph10@cam.ac.uk>
215  January 1999  January 2000
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