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<H1>pcretest specification</H1>
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<UL>
<LI><A NAME="TOC1" HREF="#SEC1">NAME</A>
<LI><A NAME="TOC2" HREF="#SEC2">SYNOPSIS</A>
<LI><A NAME="TOC3" HREF="#SEC3">OPTIONS</A>
<LI><A NAME="TOC4" HREF="#SEC4">DESCRIPTION</A>
<LI><A NAME="TOC5" HREF="#SEC5">PATTERN MODIFIERS</A>
<LI><A NAME="TOC6" HREF="#SEC6">DATA LINES</A>
<LI><A NAME="TOC7" HREF="#SEC7">OUTPUT FROM PCRETEST</A>
<LI><A NAME="TOC8" HREF="#SEC8">AUTHOR</A>
</UL>
<LI><A NAME="SEC1" HREF="#TOC1">NAME</A>
<P>
pcretest - a program for testing Perl-compatible regular expressions.
</P>
<LI><A NAME="SEC2" HREF="#TOC1">SYNOPSIS</A>
<P>
<B>pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]</B>
</P>
<P>
<B>pcretest</B> was written as a test program for the PCRE regular expression
library itself, but it can also be used for experimenting with regular
expressions. This man page describes the features of the test program; for
details of the regular expressions themselves, see the <B>pcre</B> man page.
</P>
<LI><A NAME="SEC3" HREF="#TOC1">OPTIONS</A>
<P>
<B>-d</B>
Behave as if each regex had the <B>/D</B> modifier (see below); the internal
form is output after compilation.
</P>
<P>
<B>-i</B>
Behave as if each regex had the <B>/I</B> modifier; information about the
compiled pattern is given after compilation.
</P>
<P>
<B>-m</B>
Output the size of each compiled pattern after it has been compiled. This is
equivalent to adding /M to each regular expression. For compatibility with
earlier versions of pcretest, <B>-s</B> is a synonym for <B>-m</B>.
</P>
<P>
<B>-o</B> <I>osize</I>
Set the number of elements in the output vector that is used when calling PCRE
to be <I>osize</I>. The default value is 45, which is enough for 14 capturing
subexpressions. The vector size can be changed for individual matching calls by
including \O in the data line (see below).
</P>
<P>
<B>-p</B>
Behave as if each regex has <B>/P</B> modifier; the POSIX wrapper API is used
to call PCRE. None of the other options has any effect when <B>-p</B> is set.
</P>
<P>
<B>-t</B>
Run each compile, study, and match 20000 times with a timer, and output
resulting time per compile or match (in milliseconds). Do not set <B>-t</B> with
<B>-m</B>, because you will then get the size output 20000 times and the timing
will be distorted.
</P>
<LI><A NAME="SEC4" HREF="#TOC1">DESCRIPTION</A>
<P>
If <B>pcretest</B> 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, using "re&#62;" to prompt for regular
expressions, and "data&#62;" to prompt for data lines.
</P>
<P>
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
data lines, at which point a new regular expression is read. The regular
expressions are given enclosed in any non-alphameric delimiters other than
backslash, for example
</P>
<P>
<PRE>
  /(a|bc)x+yz/
</PRE>
</P>
<P>
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. It is possible to include the delimiter within the pattern
by escaping it, for example
</P>
<P>
<PRE>
  /abc\/def/
</PRE>
</P>
<P>
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,
</P>
<P>
<PRE>
  /abc/\
</PRE>
</P>
<P>
then a backslash is added to the end of the pattern. This is done to provide a
way of testing the error condition that arises if a pattern finishes with a
backslash, because
</P>
<P>
<PRE>
  /abc\/
</PRE>
</P>
<P>
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.
</P>
<LI><A NAME="SEC5" HREF="#TOC1">PATTERN MODIFIERS</A>
<P>
The pattern may be followed by <B>i</B>, <B>m</B>, <B>s</B>, or <B>x</B> to set the
PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options,
respectively. For example:
</P>
<P>
<PRE>
  /caseless/i
</PRE>
</P>
<P>
These modifier letters have the same effect as they do in Perl. There are
others which set PCRE options that do not correspond to anything in Perl:
<B>/A</B>, <B>/E</B>, and <B>/X</B> set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and
PCRE_EXTRA respectively.
</P>
<P>
Searching for all possible matches within each subject string can be requested
by the <B>/g</B> or <B>/G</B> modifier. After finding a match, PCRE is called
again to search the remainder of the subject string. The difference between
<B>/g</B> and <B>/G</B> is that the former uses the <I>startoffset</I> argument to
<B>pcre_exec()</B> to start searching at a new point within the entire string
(which is in effect what Perl does), whereas the latter passes over a shortened
substring. This makes a difference to the matching process if the pattern
begins with a lookbehind assertion (including \b or \B).
</P>
<P>
If any call to <B>pcre_exec()</B> in a <B>/g</B> or <B>/G</B> sequence matches an
empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
flags set in order to search for another, non-empty, match at the same point.
If this second match fails, the start offset is advanced by one, and the normal
match is retried. This imitates the way Perl handles such cases when using the
<B>/g</B> modifier or the <B>split()</B> function.
</P>
<P>
There are a number of other modifiers for controlling the way <B>pcretest</B>
operates.
</P>
<P>
The <B>/+</B> modifier requests that as well as outputting the substring that
matched the entire pattern, pcretest should in addition output the remainder of
the subject string. This is useful for tests where the subject contains
multiple copies of the same substring.
</P>
<P>
The <B>/L</B> modifier must be followed directly by the name of a locale, for
example,
</P>
<P>
<PRE>
  /pattern/Lfr
</PRE>
</P>
<P>
For this reason, it must be the last modifier letter. The given locale is set,
<B>pcre_maketables()</B> is called to build a set of character tables for the
locale, and this is then passed to <B>pcre_compile()</B> when compiling the
regular expression. Without an <B>/L</B> modifier, NULL is passed as the tables
pointer; that is, <B>/L</B> applies only to the expression on which it appears.
</P>
<P>
The <B>/I</B> modifier requests that <B>pcretest</B> output information about the
compiled expression (whether it is anchored, has a fixed first character, and
so on). It does this by calling <B>pcre_fullinfo()</B> after compiling an
expression, and outputting the information it gets back. If the pattern is
studied, the results of that are also output.
</P>
<P>
The <B>/D</B> modifier is a PCRE debugging feature, which also assumes <B>/I</B>.
It causes the internal form of compiled regular expressions to be output after
compilation.
</P>
<P>
The <B>/S</B> modifier causes <B>pcre_study()</B> to be called after the
expression has been compiled, and the results used when the expression is
matched.
</P>
<P>
The <B>/M</B> modifier causes the size of memory block used to hold the compiled
pattern to be output.
</P>
<P>
The <B>/P</B> modifier causes <B>pcretest</B> to call PCRE via the POSIX wrapper
API rather than its native API. When this is done, all other modifiers except
<B>/i</B>, <B>/m</B>, and <B>/+</B> are ignored. REG_ICASE is set if <B>/i</B> is
present, and REG_NEWLINE is set if <B>/m</B> is present. The wrapper functions
force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
</P>
<P>
The <B>/8</B> modifier causes <B>pcretest</B> to call PCRE with the PCRE_UTF8
option set. This turns on the (currently incomplete) support for UTF-8
character handling in PCRE, provided that it was compiled with this support
enabled. This modifier also causes any non-printing characters in output
strings to be printed using the \x{hh...} notation if they are valid UTF-8
sequences.
</P>
<LI><A NAME="SEC6" HREF="#TOC1">DATA LINES</A>
<P>
Before each data line is passed to <B>pcre_exec()</B>, leading and trailing
whitespace is removed, and it is then scanned for \ escapes. The following are
recognized:
</P>
<P>
<PRE>
  \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)
  \x{hh...}  hexadecimal UTF-8 character
</PRE>
</P>
<P>
<PRE>
  \A         pass the PCRE_ANCHORED option to <B>pcre_exec()</B>
  \B         pass the PCRE_NOTBOL option to <B>pcre_exec()</B>
  \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
  \N         pass the PCRE_NOTEMPTY option to <B>pcre_exec()</B>
  \Odd       set the size of the output vector passed to
                <B>pcre_exec()</B> to dd (any number of decimal
                digits)
  \Z         pass the PCRE_NOTEOL option to <B>pcre_exec()</B>
</PRE>
</P>
<P>
When \O is used, it may be higher or lower than the size set by the <B>-O</B>
option (or defaulted to 45); \O applies only to the call of <B>pcre_exec()</B>
for the line in which it appears.
</P>
<P>
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.
</P>
<P>
If <B>/P</B> was present on the regex, causing the POSIX wrapper API to be used,
only <B>\B</B>, and <B>\Z</B> have any effect, causing REG_NOTBOL and REG_NOTEOL
to be passed to <B>regexec()</B> respectively.
</P>
<P>
The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
of the <B>/8</B> modifier on the pattern. It is recognized always. There may be
any number of hexadecimal digits inside the braces. The result is from one to
six bytes, encoded according to the UTF-8 rules.
</P>
<LI><A NAME="SEC7" HREF="#TOC1">OUTPUT FROM PCRETEST</A>
<P>
When a match succeeds, pcretest outputs the list of captured substrings that
<B>pcre_exec()</B> returns, starting with number 0 for the string that matched
the whole pattern. Here is an example of an interactive pcretest run.
</P>
<P>
<PRE>
  $ pcretest
  PCRE version 2.06 08-Jun-1999
</PRE>
</P>
<P>
<PRE>
    re&#62; /^abc(\d+)/
  data&#62; abc123
   0: abc123
   1: 123
  data&#62; xyz
  No match
</PRE>
</P>
<P>
If the strings contain any non-printing characters, they are output as \0x
escapes, or as \x{...} escapes if the <B>/8</B> modifier was present on the
pattern. If the pattern has the <B>/+</B> modifier, then the output for
substring 0 is followed by the the rest of the subject string, identified by
"0+" like this:
</P>
<P>
<PRE>
    re&#62; /cat/+
  data&#62; cataract
   0: cat
   0+ aract
</PRE>
</P>
<P>
If the pattern has the <B>/g</B> or <B>/G</B> modifier, the results of successive
matching attempts are output in sequence, like this:
</P>
<P>
<PRE>
    re&#62; /\Bi(\w\w)/g
  data&#62; Mississippi
   0: iss
   1: ss
   0: iss
   1: ss
   0: ipp
   1: pp
</PRE>
</P>
<P>
"No match" is output only if the first match attempt fails.
</P>
<P>
If any of the sequences <B>\C</B>, <B>\G</B>, or <B>\L</B> 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 <B>\C</B> and <B>\G</B>.
</P>
<P>
Note that while patterns can be continued over several lines (a plain "&#62;"
prompt is used for continuations), data lines may not. However newlines can be
included in data by means of the \n escape.
</P>
<LI><A NAME="SEC8" HREF="#TOC1">AUTHOR</A>
<P>
Philip Hazel &#60;ph10@cam.ac.uk&#62;
<BR>
University Computing Service,
<BR>
New Museums Site,
<BR>
Cambridge CB2 3QG, England.
<BR>
Phone: +44 1223 334714
</P>
<P>
Last updated: 15 August 2001
<BR>
Copyright (c) 1997-2001 University of Cambridge.
1	nigel	53	<HTML>
2			<HEAD>
3			<TITLE>pcretest specification</TITLE>
4			</HEAD>
5			<body bgcolor="#FFFFFF" text="#00005A">
6			<H1>pcretest specification</H1>
7			This HTML document has been generated automatically from the original man page.
8			If there is any nonsense in it, please consult the man page in case the
9			conversion went wrong.
10			<UL>
11			<LI><A NAME="TOC1" HREF="#SEC1">NAME</A>
12			<LI><A NAME="TOC2" HREF="#SEC2">SYNOPSIS</A>
13			<LI><A NAME="TOC3" HREF="#SEC3">OPTIONS</A>
14			<LI><A NAME="TOC4" HREF="#SEC4">DESCRIPTION</A>
15			<LI><A NAME="TOC5" HREF="#SEC5">PATTERN MODIFIERS</A>
16			<LI><A NAME="TOC6" HREF="#SEC6">DATA LINES</A>
17			<LI><A NAME="TOC7" HREF="#SEC7">OUTPUT FROM PCRETEST</A>
18			<LI><A NAME="TOC8" HREF="#SEC8">AUTHOR</A>
19			</UL>
20			<LI><A NAME="SEC1" HREF="#TOC1">NAME</A>
21			<P>
22			pcretest - a program for testing Perl-compatible regular expressions.
23			</P>
24			<LI><A NAME="SEC2" HREF="#TOC1">SYNOPSIS</A>
25			<P>
26			<B>pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]</B>
27			</P>
28			<P>
29			<B>pcretest</B> was written as a test program for the PCRE regular expression
30			library itself, but it can also be used for experimenting with regular
31			expressions. This man page describes the features of the test program; for
32			details of the regular expressions themselves, see the <B>pcre</B> man page.
33			</P>
34			<LI><A NAME="SEC3" HREF="#TOC1">OPTIONS</A>
35			<P>
36			<B>-d</B>
37			Behave as if each regex had the <B>/D</B> modifier (see below); the internal
38			form is output after compilation.
39			</P>
40			<P>
41			<B>-i</B>
42			Behave as if each regex had the <B>/I</B> modifier; information about the
43			compiled pattern is given after compilation.
44			</P>
45			<P>
46			<B>-m</B>
47			Output the size of each compiled pattern after it has been compiled. This is
48			equivalent to adding /M to each regular expression. For compatibility with
49			earlier versions of pcretest, <B>-s</B> is a synonym for <B>-m</B>.
50			</P>
51			<P>
52			<B>-o</B> <I>osize</I>
53			Set the number of elements in the output vector that is used when calling PCRE
54			to be <I>osize</I>. The default value is 45, which is enough for 14 capturing
55			subexpressions. The vector size can be changed for individual matching calls by
56			including \O in the data line (see below).
57			</P>
58			<P>
59			<B>-p</B>
60			Behave as if each regex has <B>/P</B> modifier; the POSIX wrapper API is used
61			to call PCRE. None of the other options has any effect when <B>-p</B> is set.
62			</P>
63			<P>
64			<B>-t</B>
65			Run each compile, study, and match 20000 times with a timer, and output
66			resulting time per compile or match (in milliseconds). Do not set <B>-t</B> with
67			<B>-m</B>, because you will then get the size output 20000 times and the timing
68			will be distorted.
69			</P>
70			<LI><A NAME="SEC4" HREF="#TOC1">DESCRIPTION</A>
71			<P>
72			If <B>pcretest</B> is given two filename arguments, it reads from the first and
73			writes to the second. If it is given only one filename argument, it reads from
74			that file and writes to stdout. Otherwise, it reads from stdin and writes to
75			stdout, and prompts for each line of input, using "re>" to prompt for regular
76			expressions, and "data>" to prompt for data lines.
77			</P>
78			<P>
79			The program handles any number of sets of input on a single input file. Each
80			set starts with a regular expression, and continues with any number of data
81			lines to be matched against the pattern. An empty line signals the end of the
82			data lines, at which point a new regular expression is read. The regular
83			expressions are given enclosed in any non-alphameric delimiters other than
84			backslash, for example
85			</P>
86			<P>
87			<PRE>
88			/(a\|bc)x+yz/
89			</PRE>
90			</P>
91			<P>
92			White space before the initial delimiter is ignored. A regular expression may
93			be continued over several input lines, in which case the newline characters are
94			included within it. It is possible to include the delimiter within the pattern
95			by escaping it, for example
96			</P>
97			<P>
98			<PRE>
99			/abc\/def/
100			</PRE>
101			</P>
102			<P>
103			If you do so, the escape and the delimiter form part of the pattern, but since
104			delimiters are always non-alphameric, this does not affect its interpretation.
105			If the terminating delimiter is immediately followed by a backslash, for
106			example,
107			</P>
108			<P>
109			<PRE>
110			/abc/\
111			</PRE>
112			</P>
113			<P>
114			then a backslash is added to the end of the pattern. This is done to provide a
115			way of testing the error condition that arises if a pattern finishes with a
116			backslash, because
117			</P>
118			<P>
119			<PRE>
120			/abc\/
121			</PRE>
122			</P>
123			<P>
124			is interpreted as the first line of a pattern that starts with "abc/", causing
125			pcretest to read the next line as a continuation of the regular expression.
126			</P>
127			<LI><A NAME="SEC5" HREF="#TOC1">PATTERN MODIFIERS</A>
128			<P>
129			The pattern may be followed by <B>i</B>, <B>m</B>, <B>s</B>, or <B>x</B> to set the
130			PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options,
131			respectively. For example:
132			</P>
133			<P>
134			<PRE>
135			/caseless/i
136			</PRE>
137			</P>
138			<P>
139			These modifier letters have the same effect as they do in Perl. There are
140			others which set PCRE options that do not correspond to anything in Perl:
141			<B>/A</B>, <B>/E</B>, and <B>/X</B> set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and
142			PCRE_EXTRA respectively.
143			</P>
144			<P>
145			Searching for all possible matches within each subject string can be requested
146			by the <B>/g</B> or <B>/G</B> modifier. After finding a match, PCRE is called
147			again to search the remainder of the subject string. The difference between
148			<B>/g</B> and <B>/G</B> is that the former uses the <I>startoffset</I> argument to
149			<B>pcre_exec()</B> to start searching at a new point within the entire string
150			(which is in effect what Perl does), whereas the latter passes over a shortened
151			substring. This makes a difference to the matching process if the pattern
152			begins with a lookbehind assertion (including \b or \B).
153			</P>
154			<P>
155			If any call to <B>pcre_exec()</B> in a <B>/g</B> or <B>/G</B> sequence matches an
156			empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
157			flags set in order to search for another, non-empty, match at the same point.
158			If this second match fails, the start offset is advanced by one, and the normal
159			match is retried. This imitates the way Perl handles such cases when using the
160			<B>/g</B> modifier or the <B>split()</B> function.
161			</P>
162			<P>
163			There are a number of other modifiers for controlling the way <B>pcretest</B>
164			operates.
165			</P>
166			<P>
167			The <B>/+</B> modifier requests that as well as outputting the substring that
168			matched the entire pattern, pcretest should in addition output the remainder of
169			the subject string. This is useful for tests where the subject contains
170			multiple copies of the same substring.
171			</P>
172			<P>
173			The <B>/L</B> modifier must be followed directly by the name of a locale, for
174			example,
175			</P>
176			<P>
177			<PRE>
178			/pattern/Lfr
179			</PRE>
180			</P>
181			<P>
182			For this reason, it must be the last modifier letter. The given locale is set,
183			<B>pcre_maketables()</B> is called to build a set of character tables for the
184			locale, and this is then passed to <B>pcre_compile()</B> when compiling the
185			regular expression. Without an <B>/L</B> modifier, NULL is passed as the tables
186			pointer; that is, <B>/L</B> applies only to the expression on which it appears.
187			</P>
188			<P>
189			The <B>/I</B> modifier requests that <B>pcretest</B> output information about the
190			compiled expression (whether it is anchored, has a fixed first character, and
191			so on). It does this by calling <B>pcre_fullinfo()</B> after compiling an
192			expression, and outputting the information it gets back. If the pattern is
193			studied, the results of that are also output.
194			</P>
195			<P>
196			The <B>/D</B> modifier is a PCRE debugging feature, which also assumes <B>/I</B>.
197			It causes the internal form of compiled regular expressions to be output after
198			compilation.
199			</P>
200			<P>
201			The <B>/S</B> modifier causes <B>pcre_study()</B> to be called after the
202			expression has been compiled, and the results used when the expression is
203			matched.
204			</P>
205			<P>
206			The <B>/M</B> modifier causes the size of memory block used to hold the compiled
207			pattern to be output.
208			</P>
209			<P>
210			The <B>/P</B> modifier causes <B>pcretest</B> to call PCRE via the POSIX wrapper
211			API rather than its native API. When this is done, all other modifiers except
212			<B>/i</B>, <B>/m</B>, and <B>/+</B> are ignored. REG_ICASE is set if <B>/i</B> is
213			present, and REG_NEWLINE is set if <B>/m</B> is present. The wrapper functions
214			force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
215			</P>
216			<P>
217			The <B>/8</B> modifier causes <B>pcretest</B> to call PCRE with the PCRE_UTF8
218			option set. This turns on the (currently incomplete) support for UTF-8
219			character handling in PCRE, provided that it was compiled with this support
220			enabled. This modifier also causes any non-printing characters in output
221			strings to be printed using the \x{hh...} notation if they are valid UTF-8
222			sequences.
223			</P>
224			<LI><A NAME="SEC6" HREF="#TOC1">DATA LINES</A>
225			<P>
226			Before each data line is passed to <B>pcre_exec()</B>, leading and trailing
227			whitespace is removed, and it is then scanned for \ escapes. The following are
228			recognized:
229			</P>
230			<P>
231			<PRE>
232			\a alarm (= BEL)
233			\b backspace
234			\e escape
235			\f formfeed
236			\n newline
237			\r carriage return
238			\t tab
239			\v vertical tab
240			\nnn octal character (up to 3 octal digits)
241			\xhh hexadecimal character (up to 2 hex digits)
242			\x{hh...} hexadecimal UTF-8 character
243			</PRE>
244			</P>
245			<P>
246			<PRE>
247			\A pass the PCRE_ANCHORED option to <B>pcre_exec()</B>
248			\B pass the PCRE_NOTBOL option to <B>pcre_exec()</B>
249			\Cdd call pcre_copy_substring() for substring dd
250			after a successful match (any decimal number
251			less than 32)
252			\Gdd call pcre_get_substring() for substring dd
253			after a successful match (any decimal number
254			less than 32)
255			\L call pcre_get_substringlist() after a
256			successful match
257			\N pass the PCRE_NOTEMPTY option to <B>pcre_exec()</B>
258			\Odd set the size of the output vector passed to
259			<B>pcre_exec()</B> to dd (any number of decimal
260			digits)
261			\Z pass the PCRE_NOTEOL option to <B>pcre_exec()</B>
262			</PRE>
263			</P>
264			<P>
265			When \O is used, it may be higher or lower than the size set by the <B>-O</B>
266			option (or defaulted to 45); \O applies only to the call of <B>pcre_exec()</B>
267			for the line in which it appears.
268			</P>
269			<P>
270			A backslash followed by anything else just escapes the anything else. If the
271			very last character is a backslash, it is ignored. This gives a way of passing
272			an empty line as data, since a real empty line terminates the data input.
273			</P>
274			<P>
275			If <B>/P</B> was present on the regex, causing the POSIX wrapper API to be used,
276			only <B>\B</B>, and <B>\Z</B> have any effect, causing REG_NOTBOL and REG_NOTEOL
277			to be passed to <B>regexec()</B> respectively.
278			</P>
279			<P>
280			The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
281			of the <B>/8</B> modifier on the pattern. It is recognized always. There may be
282			any number of hexadecimal digits inside the braces. The result is from one to
283			six bytes, encoded according to the UTF-8 rules.
284			</P>
285			<LI><A NAME="SEC7" HREF="#TOC1">OUTPUT FROM PCRETEST</A>
286			<P>
287			When a match succeeds, pcretest outputs the list of captured substrings that
288			<B>pcre_exec()</B> returns, starting with number 0 for the string that matched
289			the whole pattern. Here is an example of an interactive pcretest run.
290			</P>
291			<P>
292			<PRE>
293			$ pcretest
294			PCRE version 2.06 08-Jun-1999
295			</PRE>
296			</P>
297			<P>
298			<PRE>
299			re> /^abc(\d+)/
300			data> abc123
301			0: abc123
302			1: 123
303			data> xyz
304			No match
305			</PRE>
306			</P>
307			<P>
308			If the strings contain any non-printing characters, they are output as \0x
309			escapes, or as \x{...} escapes if the <B>/8</B> modifier was present on the
310			pattern. If the pattern has the <B>/+</B> modifier, then the output for
311			substring 0 is followed by the the rest of the subject string, identified by
312			"0+" like this:
313			</P>
314			<P>
315			<PRE>
316			re> /cat/+
317			data> cataract
318			0: cat
319			0+ aract
320			</PRE>
321			</P>
322			<P>
323			If the pattern has the <B>/g</B> or <B>/G</B> modifier, the results of successive
324			matching attempts are output in sequence, like this:
325			</P>
326			<P>
327			<PRE>
328			re> /\Bi(\w\w)/g
329			data> Mississippi
330			0: iss
331			1: ss
332			0: iss
333			1: ss
334			0: ipp
335			1: pp
336			</PRE>
337			</P>
338			<P>
339			"No match" is output only if the first match attempt fails.
340			</P>
341			<P>
342			If any of the sequences <B>\C</B>, <B>\G</B>, or <B>\L</B> are present in a
343			data line that is successfully matched, the substrings extracted by the
344			convenience functions are output with C, G, or L after the string number
345			instead of a colon. This is in addition to the normal full list. The string
346			length (that is, the return from the extraction function) is given in
347			parentheses after each string for <B>\C</B> and <B>\G</B>.
348			</P>
349			<P>
350			Note that while patterns can be continued over several lines (a plain ">"
351			prompt is used for continuations), data lines may not. However newlines can be
352			included in data by means of the \n escape.
353			</P>
354			<LI><A NAME="SEC8" HREF="#TOC1">AUTHOR</A>
355			<P>
356			Philip Hazel <ph10@cam.ac.uk>
357			<BR>
358			University Computing Service,
359			<BR>
360			New Museums Site,
361			<BR>
362			Cambridge CB2 3QG, England.
363			<BR>
364			Phone: +44 1223 334714
365			</P>
366			<P>
367			Last updated: 15 August 2001
368			<BR>
369			Copyright (c) 1997-2001 University of Cambridge.