Contents of /code/trunk/README

README file for PCRE (Perl-compatible regular expressions)
----------------------------------------------------------

*******************************************************************************
*           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.                                                   *
*******************************************************************************

The distribution should contain the following files:

  ChangeLog         log of changes to the code
  LICENCE           conditions for the use of PCRE
  Makefile          for building PCRE
  README            this file
  RunTest           a shell script for running tests
  Tech.Notes        notes on the encoding
  pcre.3            man page for the functions
  pcreposix.3       man page for the POSIX wrapper API
  dftables.c        auxiliary program for building chartables.c
  get.c             )
  maketables.c      )
  study.c           ) source of
  pcre.c            )   the functions
  pcreposix.c       )
  pcre.h            header for the external API
  pcreposix.h       header for the external POSIX wrapper API
  internal.h        header for internal use
  pcretest.c        test program
  pgrep.1           man page for pgrep
  pgrep.c           source of a grep utility that uses PCRE
  perltest          Perl test program
  testinput         test data, compatible with Perl 5.004 and 5.005
  testinput2        test data for error messages and non-Perl things
  testinput3        test data, compatible with Perl 5.005
  testinput4        test data for locale-specific tests
  testoutput        test results corresponding to testinput
  testoutput2       test results corresponding to testinput2
  testoutput3       test results corresponding to testinput3
  testoutput4       test results corresponding to testinput4

To build PCRE, edit Makefile for your system (it is a fairly simple make file,
and there are some comments at the top) and then run it. It builds two
libraries called libpcre.a and libpcreposix.a, a test program called pcretest,
and the pgrep command.

To test PCRE, run the RunTest script in the pcre directory. This runs pcretest
on each of the testinput files in turn, and compares the output with the
contents of the corresponding testoutput file. A file called testtry is used to
hold the output from pcretest (which is documented below).

To run pcretest on just one of the test files, give its number as an argument
to RunTest, for example:

  RunTest 3

The first and third test files can also be fed directly into the perltest
program to check that Perl gives the same results. The third file requires the
additional features of release 5.005, which is why it is kept separate from the
main test input, which needs only Perl 5.004. In the long run, when 5.005 is
widespread, these two test files may get amalgamated.

The second set of tests check 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.

The fourth 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" (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" in the
list of available locales, the fourth 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"

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.

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).

PCRE has its own native API, but a set of "wrapper" functions that are based on
the POSIX API are also supplied in the library libpcreposix.a. Note that this
just provides a POSIX calling interface to PCRE: the regular expressions
themselves still follow Perl syntax and semantics. The header file
for the POSIX-style functions is called pcreposix.h. The official POSIX name is
regex.h, but I didn't want to risk possible problems with existing files of
that name by distributing it that way. To use it with an existing program that
uses the POSIX API, it will have to be renamed or pointed at by a link.


Character tables
----------------

PCRE uses four tables for manipulating and identifying characters. 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() is used to
generate a set of tables in the current locale. However, if the final argument
is passed as NULL, a set of default tables that is built into the binary is
used.

The source file called chartables.c contains the default set of tables. This is
not supplied in the distribution, but 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 set your system will control the
contents of the tables. You can change the default tables by editing
chartables.c and then re-building PCRE. If you do this, you should probably
also edit Makefile to ensure that the file doesn't ever get re-generated.

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.

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.


The pcretest program
--------------------

This program is intended for testing PCRE, but it can also be used for
experimenting with regular expressions.

If it is given two filename arguments, it reads from the first and writes to
the second. If it is given only one filename argument, it reads from that file
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 other than backslash, for example

  /(a|bc)x+yz/

White space before the initial delimiter is ignored. A regular expression may
be continued over several input lines, in which case the newline characters are
included within it. See the testinput files for many examples. It is possible
to include the delimiter within the pattern by escaping it, for example

  /abc\/def/

If you do so, the escape and the delimiter form part of the pattern, but since
delimiters are always non-alphameric, this does not affect its interpretation.
If the terminating delimiter is immediately followed by a backslash, for
example,

  /abc/\

then a backslash is added to the end of the pattern. This provides a way of
testing the error condition that arises if a pattern finishes with a backslash,
because

  /abc\/

is interpreted as the first line of a pattern that starts with "abc/", causing
pcretest to read the next line as a continuation of the regular expression.

The pattern 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.

The /M option causes information about the size of memory block used to hold
the compile pattern to be output.

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.

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()
  \Cdd   call pcre_copy_substring() for substring dd after a successful match
           (any decimal number less than 32)
  \Gdd   call pcre_get_substring() for substring dd after a successful match
           (any decimal number less than 32)
  \L     call pcre_get_substringlist() after a successful match
  \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 captured 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

If any of \C, \G, or \L are present in a data line that is successfully
matched, the substrings extracted by the convenience functions are output with
C, G, or L after the string number instead of a colon. This is in addition to
the normal full list. The string length (that is, the return from the
extraction function) is given in parentheses after each string for \C and \G.

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 -m is given to pcretest, it outputs the size of each compiled
pattern after it has been compiled. It is equivalent to adding /M to each
regular expression. For compatibility with earlier versions of pcretest, -s is
a synonym for -m.

If the -t option is given, each compile, study, and match is run 20000 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
20000 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.

Philip Hazel <ph10@cam.ac.uk>
February 1999
1	nigel	3	README file for PCRE (Perl-compatible regular expressions)
2			----------------------------------------------------------
3
4	nigel	23	*******************************************************************************
5			* IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00 *
6			* *
7			* Please note that there has been a change in the API such that a larger *
8			* ovector is required at matching time, to provide some additional workspace. *
9			* The new man page has details. This change was necessary in order to support *
10			* some of the new functionality in Perl 5.005. *
11	nigel	25	* *
12			* IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00 *
13			* *
14			* Another (I hope this is the last!) change has been made to the API for the *
15			* pcre_compile() function. An additional argument has been added to make it *
16			* possible to pass over a pointer to character tables built in the current *
17			* locale by pcre_maketables(). To use the default tables, this new arguement *
18			* should be passed as NULL. *
19	nigel	23	*******************************************************************************
20
21	nigel	3	The distribution should contain the following files:
22
23			ChangeLog log of changes to the code
24	nigel	29	LICENCE conditions for the use of PCRE
25	nigel	3	Makefile for building PCRE
26			README this file
27	nigel	23	RunTest a shell script for running tests
28	nigel	3	Tech.Notes notes on the encoding
29			pcre.3 man page for the functions
30			pcreposix.3 man page for the POSIX wrapper API
31	nigel	27	dftables.c auxiliary program for building chartables.c
32	nigel	29	get.c )
33	nigel	25	maketables.c )
34	nigel	3	study.c ) source of
35			pcre.c ) the functions
36			pcreposix.c )
37			pcre.h header for the external API
38			pcreposix.h header for the external POSIX wrapper API
39			internal.h header for internal use
40			pcretest.c test program
41			pgrep.1 man page for pgrep
42			pgrep.c source of a grep utility that uses PCRE
43			perltest Perl test program
44	nigel	23	testinput test data, compatible with Perl 5.004 and 5.005
45	nigel	3	testinput2 test data for error messages and non-Perl things
46	nigel	23	testinput3 test data, compatible with Perl 5.005
47	nigel	25	testinput4 test data for locale-specific tests
48	nigel	3	testoutput test results corresponding to testinput
49			testoutput2 test results corresponding to testinput2
50	nigel	25	testoutput3 test results corresponding to testinput3
51			testoutput4 test results corresponding to testinput4
52	nigel	3
53	nigel	23	To build PCRE, edit Makefile for your system (it is a fairly simple make file,
54			and there are some comments at the top) and then run it. It builds two
55			libraries called libpcre.a and libpcreposix.a, a test program called pcretest,
56			and the pgrep command.
57	nigel	3
58	nigel	23	To test PCRE, run the RunTest script in the pcre directory. This runs pcretest
59			on each of the testinput files in turn, and compares the output with the
60			contents of the corresponding testoutput file. A file called testtry is used to
61			hold the output from pcretest (which is documented below).
62	nigel	3
63	nigel	23	To run pcretest on just one of the test files, give its number as an argument
64			to RunTest, for example:
65	nigel	3
66	nigel	23	RunTest 3
67	nigel	3
68	nigel	23	The first and third test files can also be fed directly into the perltest
69			program to check that Perl gives the same results. The third file requires the
70			additional features of release 5.005, which is why it is kept separate from the
71			main test input, which needs only Perl 5.004. In the long run, when 5.005 is
72			widespread, these two test files may get amalgamated.
73	nigel	3
74	nigel	29	The second set of tests check pcre_info(), pcre_study(), pcre_copy_substring(),
75			pcre_get_substring(), pcre_get_substring_list(), error detection and run-time
76			flags that are specific to PCRE, as well as the POSIX wrapper API.
77	nigel	7
78	nigel	25	The fourth set of tests checks pcre_maketables(), the facility for building a
79			set of character tables for a specific locale and using them instead of the
80			default tables. The tests make use of the "fr" (French) locale. Before running
81			the test, the script checks for the presence of this locale by running the
82			"locale" command. If that command fails, or if it doesn't include "fr" in the
83			list of available locales, the fourth test cannot be run, and a comment is
84			output to say why. If running this test produces instances of the error
85
86			** Failed to set locale "fr"
87
88			in the comparison output, it means that locale is not available on your system,
89			despite being listed by "locale". This does not mean that PCRE is broken.
90
91	nigel	3	To install PCRE, copy libpcre.a to any suitable library directory (e.g.
92			/usr/local/lib), pcre.h to any suitable include directory (e.g.
93			/usr/local/include), and pcre.3 to any suitable man directory (e.g.
94			/usr/local/man/man3).
95
96			To install the pgrep command, copy it to any suitable binary directory, (e.g.
97			/usr/local/bin) and pgrep.1 to any suitable man directory (e.g.
98			/usr/local/man/man1).
99
100			PCRE has its own native API, but a set of "wrapper" functions that are based on
101			the POSIX API are also supplied in the library libpcreposix.a. Note that this
102			just provides a POSIX calling interface to PCRE: the regular expressions
103			themselves still follow Perl syntax and semantics. The header file
104			for the POSIX-style functions is called pcreposix.h. The official POSIX name is
105			regex.h, but I didn't want to risk possible problems with existing files of
106			that name by distributing it that way. To use it with an existing program that
107	nigel	23	uses the POSIX API, it will have to be renamed or pointed at by a link.
108	nigel	3
109
110			Character tables
111			----------------
112
113	nigel	25	PCRE uses four tables for manipulating and identifying characters. The final
114			argument of the pcre_compile() function is a pointer to a block of memory
115			containing the concatenated tables. A call to pcre_maketables() is used to
116			generate a set of tables in the current locale. However, if the final argument
117			is passed as NULL, a set of default tables that is built into the binary is
118			used.
119	nigel	3
120	nigel	25	The source file called chartables.c contains the default set of tables. This is
121	nigel	27	not supplied in the distribution, but is built by the program dftables
122			(compiled from dftables.c), which uses the ANSI C character handling functions
123	nigel	25	such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table
124			sources. This means that the default C locale set your system will control the
125			contents of the tables. You can change the default tables by editing
126			chartables.c and then re-building PCRE. If you do this, you should probably
127			also edit Makefile to ensure that the file doesn't ever get re-generated.
128	nigel	3
129	nigel	25	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
131			digits, "word" characters, and white space, respectively. These are used when
132			building 32-byte bit maps that represent character classes.
133
134			The final 256-byte table has bits indicating various character types, as
135	nigel	3	follows:
136
137			1 white space character
138			2 letter
139			4 decimal digit
140			8 hexadecimal digit
141			16 alphanumeric or '_'
142			128 regular expression metacharacter or binary zero
143
144			You should not alter the set of characters that contain the 128 bit, as that
145			will cause PCRE to malfunction.
146
147
148			The pcretest program
149			--------------------
150
151			This program is intended for testing PCRE, but it can also be used for
152			experimenting with regular expressions.
153
154			If it is given two filename arguments, it reads from the first and writes to
155			the second. If it is given only one filename argument, it reads from that file
156			and writes to stdout. Otherwise, it reads from stdin and writes to stdout, and
157			prompts for each line of input.
158
159			The program handles any number of sets of input on a single input file. Each
160			set starts with a regular expression, and continues with any number of data
161			lines to be matched against the pattern. An empty line signals the end of the
162			set. The regular expressions are given enclosed in any non-alphameric
163	nigel	29	delimiters other than backslash, for example
164	nigel	3
165			/(a\|bc)x+yz/
166
167	nigel	29	White space before the initial delimiter is ignored. A regular expression may
168			be continued over several input lines, in which case the newline characters are
169			included within it. See the testinput files for many examples. It is possible
170			to include the delimiter within the pattern by escaping it, for example
171	nigel	3
172	nigel	29	/abc\/def/
173
174			If you do so, the escape and the delimiter form part of the pattern, but since
175			delimiters are always non-alphameric, this does not affect its interpretation.
176			If the terminating delimiter is immediately followed by a backslash, for
177			example,
178
179			/abc/\
180
181			then a backslash is added to the end of the pattern. This provides a way of
182			testing the error condition that arises if a pattern finishes with a backslash,
183			because
184
185			/abc\/
186
187			is interpreted as the first line of a pattern that starts with "abc/", causing
188			pcretest to read the next line as a continuation of the regular expression.
189
190			The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS,
191			PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. These
192			options have the same effect as they do in Perl.
193
194	nigel	3	There are also some upper case options that do not match Perl options: /A, /E,
195			and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively.
196
197	nigel	25	The /L option must be followed directly by the name of a locale, for example,
198
199			/pattern/Lfr
200
201			For this reason, it must be the last option letter. The given locale is set,
202			pcre_maketables() is called to build a set of character tables for the locale,
203			and this is then passed to pcre_compile() when compiling the regular
204			expression. Without an /L option, NULL is passed as the tables pointer; that
205			is, /L applies only to the expression on which it appears.
206
207			The /I option requests that pcretest output information about the compiled
208			expression (whether it is anchored, has a fixed first character, and so on). It
209			does this by calling pcre_info() after compiling an expression, and outputting
210			the information it gets back. If the pattern is studied, the results of that
211			are also output.
212
213			The /D option is a PCRE debugging feature, which also assumes /I. It causes the
214			internal form of compiled regular expressions to be output after compilation.
215
216			The /S option causes pcre_study() to be called after the expression has been
217			compiled, and the results used when the expression is matched.
218
219	nigel	31	The /M option causes information about the size of memory block used to hold
220			the compile pattern to be output.
221
222	nigel	3	Finally, the /P option causes pcretest to call PCRE via the POSIX wrapper API
223			rather than its native API. When this is done, all other options except /i and
224			/m are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is set if /m
225			is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always, and
226			PCRE_DOTALL unless REG_NEWLINE is set.
227
228			Before each data line is passed to pcre_exec(), leading and trailing whitespace
229			is removed, and it is then scanned for \ escapes. The following are recognized:
230
231			\a alarm (= BEL)
232			\b backspace
233			\e escape
234			\f formfeed
235			\n newline
236			\r carriage return
237			\t tab
238			\v vertical tab
239			\nnn octal character (up to 3 octal digits)
240			\xhh hexadecimal character (up to 2 hex digits)
241
242			\A pass the PCRE_ANCHORED option to pcre_exec()
243			\B pass the PCRE_NOTBOL option to pcre_exec()
244	nigel	29	\Cdd call pcre_copy_substring() for substring dd after a successful match
245			(any decimal number less than 32)
246			\Gdd call pcre_get_substring() for substring dd after a successful match
247			(any decimal number less than 32)
248			\L call pcre_get_substringlist() after a successful match
249	nigel	3	\Odd set the size of the output vector passed to pcre_exec() to dd
250			(any number of decimal digits)
251			\Z pass the PCRE_NOTEOL option to pcre_exec()
252
253			A backslash followed by anything else just escapes the anything else. If the
254			very last character is a backslash, it is ignored. This gives a way of passing
255			an empty line as data, since a real empty line terminates the data input.
256
257			If /P was present on the regex, causing the POSIX wrapper API to be used, only
258			\B, and \Z have any effect, causing REG_NOTBOL and REG_NOTEOL to be passed to
259			regexec() respectively.
260
261	nigel	29	When a match succeeds, pcretest outputs the list of captured substrings that
262	nigel	3	pcre_exec() returns, starting with number 0 for the string that matched the
263			whole pattern. Here is an example of an interactive pcretest run.
264
265			$ pcretest
266			Testing Perl-Compatible Regular Expressions
267			PCRE version 0.90 08-Sep-1997
268
269	nigel	23	re> /^abc(\d+)/
270			data> abc123
271			0: abc123
272			1: 123
273			data> xyz
274	nigel	3	No match
275
276	nigel	29	If any of \C, \G, or \L are present in a data line that is successfully
277			matched, the substrings extracted by the convenience functions are output with
278			C, G, or L after the string number instead of a colon. This is in addition to
279			the normal full list. The string length (that is, the return from the
280			extraction function) is given in parentheses after each string for \C and \G.
281
282	nigel	3	Note that while patterns can be continued over several lines (a plain ">"
283			prompt is used for continuations), data lines may not. However newlines can be
284			included in data by means of the \n escape.
285
286			If the -p option is given to pcretest, it is equivalent to adding /P to each
287			regular expression: the POSIX wrapper API is used to call PCRE. None of the
288			following flags has any effect in this case.
289
290			If the option -d is given to pcretest, it is equivalent to adding /D to each
291			regular expression: the internal form is output after compilation.
292
293	nigel	25	If the option -i is given to pcretest, it is equivalent to adding /I to each
294			regular expression: information about the compiled pattern is given after
295			compilation.
296	nigel	3
297	nigel	31	If the option -m is given to pcretest, it outputs the size of each compiled
298			pattern after it has been compiled. It is equivalent to adding /M to each
299			regular expression. For compatibility with earlier versions of pcretest, -s is
300			a synonym for -m.
301	nigel	3
302	nigel	29	If the -t option is given, each compile, study, and match is run 20000 times
303	nigel	3	while being timed, and the resulting time per compile or match is output in
304			milliseconds. Do not set -t with -s, because you will then get the size output
305	nigel	29	20000 times and the timing will be distorted. If you want to change the number
306	nigel	23	of repetitions used for timing, edit the definition of LOOPREPEAT at the top of
307			pcretest.c
308	nigel	3
309
310
311			The perltest program
312			--------------------
313
314			The perltest program tests Perl's regular expressions; it has the same
315			specification as pcretest, and so can be given identical input, except that
316	nigel	23	input patterns can be followed only by Perl's lower case options. The contents
317			of testinput and testinput3 meet this condition.
318	nigel	3
319			The data lines are processed as Perl strings, so if they contain $ or @
320			characters, these have to be escaped. For this reason, all such characters in
321			the testinput file are escaped so that it can be used for perltest as well as
322			for pcretest, and the special upper case options such as /A that pcretest
323			recognizes are not used in this file. The output should be identical, apart
324			from the initial identifying banner.
325
326	nigel	25	The testinput2 and testinput4 files are not suitable for feeding to Perltest,
327			since they do make use of the special upper case options and escapes that
328			pcretest uses to test some features of PCRE. The first of these files also
329			contains malformed regular expressions, in order to check that PCRE diagnoses
330			them correctly.
331	nigel	3
332			Philip Hazel <ph10@cam.ac.uk>
333	nigel	29	February 1999