/[pcre]/code/trunk/doc/pcretest.txt
ViewVC logotype

Diff of /code/trunk/doc/pcretest.txt

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 71 by nigel, Sat Feb 24 21:40:24 2007 UTC revision 878 by ph10, Sun Jan 15 15:44:47 2012 UTC
# Line 1  Line 1 
1    PCRETEST(1)                                                        PCRETEST(1)
2    
3    
4  NAME  NAME
5       pcretest - a program  for  testing  Perl-compatible  regular         pcretest - a program for testing Perl-compatible regular expressions.
      expressions.  
6    
7    
8  SYNOPSIS  SYNOPSIS
      pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source]  [des-  
      tination]  
9    
10       pcretest was written as a test program for the PCRE  regular         pcretest [options] [input file [output file]]
11       expression  library  itself,  but  it  can  also be used for  
12       experimenting  with  regular  expressions.   This   document         pcretest  was written as a test program for the PCRE regular expression
13       describes  the  features of the test program; for details of         library itself, but it can also be used for experimenting with  regular
14       the regular  expressions  themselves,  see  the  pcrepattern         expressions.  This document describes the features of the test program;
15       documentation.  For details of PCRE and its options, see the         for details of the regular expressions themselves, see the  pcrepattern
16       pcreapi documentation.         documentation. For details of the PCRE library function calls and their
17           options, see the  pcreapi  and  pcre16  documentation.  The  input  for
18           pcretest is a sequence of regular expression patterns and strings to be
19  OPTIONS         matched, as described below. The output shows the result of each match.
20           Options  on  the command line and the patterns control PCRE options and
21           exactly what is output.
22       -C        Output the version number of the PCRE library, and  
23                 all   available  information  about  the  optional  
24                 features that are included, and then exit.  PCRE's 8-BIT and 16-BIT LIBRARIES
25    
26       -d        Behave as if each regex had the /D  modifier  (see         From release 8.30, two separate PCRE libraries can be built. The origi-
27                 below); the internal form is output after compila-         nal  one  supports  8-bit  character  strings, whereas the newer 16-bit
28                 tion.         library  supports  character  strings  encoded  in  16-bit  units.  The
29           pcretest  program  can  be  used to test both libraries. However, it is
30       -i        Behave as if  each  regex  had  the  /I  modifier;         itself still an 8-bit program, reading 8-bit input  and  writing  8-bit
31                 information  about  the  compiled pattern is given         output.  When testing the 16-bit library, the patterns and data strings
32                 after compilation.         are converted to 16-bit format before being passed to the PCRE  library
33           functions. Results are converted to 8-bit for output.
34       -m        Output the size of each compiled pattern after  it  
35                 has been compiled. This is equivalent to adding /M         References  to  functions  and structures of the form pcre[16]_xx below
36                 to each regular expression. For compatibility with         mean "pcre_xx when using the 8-bit library or pcre16_xx when using  the
37                 earlier  versions of pcretest, -s is a synonym for         16-bit library".
38                 -m.  
39    
40       -o osize  Set the number of elements in  the  output  vector  COMMAND LINE OPTIONS
41                 that  is  used  when calling PCRE to be osize. The  
42                 default value is 45, which is enough for  14  cap-         -16       If  both  the 8-bit and the 16-bit libraries have been built,
43                 turing  subexpressions.  The  vector  size  can be                   this option causes the 16-bit library to be used. If only the
44                 changed for individual matching calls by including                   16-bit library has been built, this is the default (so has no
45                 \O in the data line (see below).                   effect). If only the  8-bit  library  has  been  built,  this
46                     option causes an error.
47       -p        Behave as if each regex has /P modifier; the POSIX  
48                 wrapper  API  is  used  to  call PCRE. None of the         -b        Behave  as  if each pattern has the /B (show byte code) modi-
49                 other options has any effect when -p is set.                   fier; the internal form is output after compilation.
50    
51       -t        Run each compile, study, and match many times with         -C        Output the version number of the PCRE library, and all avail-
52                 a  timer, and output resulting time per compile or                   able   information  about  the  optional  features  that  are
53                 match (in milliseconds). Do not set  -t  with  -m,                   included, and then exit. All other options are ignored.
54                 because  you  will  then get the size output 20000  
55                 times and the timing will be distorted.         -C option Output information about a specific build-time  option,  then
56                     exit.  This functionality is intended for use in scripts such
57                     as RunTest. The following options output the value indicated:
58    
59                       linksize   the internal link size (2, 3, or 4)
60                       newline    the default newline setting:
61                                    CR, LF, CRLF, ANYCRLF, or ANY
62    
63                     The following options output 1 for true or zero for false:
64    
65                       jit        just-in-time support is available
66                       pcre16     the 16-bit library was built
67                       pcre8      the 8-bit library was built
68                       ucp        Unicode property support is available
69                       utf        UTF-8 and/or UTF-16 support is available
70    
71           -d        Behave as if each pattern has the /D  (debug)  modifier;  the
72                     internal  form  and information about the compiled pattern is
73                     output after compilation; -d is equivalent to -b -i.
74    
75           -dfa      Behave as if each data line contains the \D escape  sequence;
76                     this    causes    the    alternative    matching    function,
77                     pcre[16]_dfa_exec(), to  be  used  instead  of  the  standard
78                     pcre[16]_exec() function (more detail is given below).
79    
80           -help     Output a brief summary these options and then exit.
81    
82           -i        Behave  as  if  each pattern has the /I modifier; information
83                     about the compiled pattern is given after compilation.
84    
85           -M        Behave as if each data line contains the \M escape  sequence;
86                     this  causes  PCRE  to  discover  the minimum MATCH_LIMIT and
87                     MATCH_LIMIT_RECURSION  settings  by  calling  pcre[16]_exec()
88                     repeatedly with different limits.
89    
90           -m        Output  the  size  of each compiled pattern after it has been
91                     compiled. This is equivalent to adding  /M  to  each  regular
92                     expression. The size is given in bytes for both libraries.
93    
94           -o osize  Set  the number of elements in the output vector that is used
95                     when calling pcre[16]_exec()  or  pcre[16]_dfa_exec()  to  be
96                     osize.  The  default value is 45, which is enough for 14 cap-
97                     turing subexpressions for  pcre[16]_exec()  or  22  different
98                     matches  for  pcre[16]_dfa_exec().   The  vector  size can be
99                     changed for individual matching calls by including \O in  the
100                     data line (see below).
101    
102           -p        Behave  as  if  each  pattern  has the /P modifier; the POSIX
103                     wrapper API is used to call PCRE. None of the  other  options
104                     has  any  effect when -p is set. This option can be used only
105                     with the 8-bit library.
106    
107           -q        Do not output the version number of pcretest at the start  of
108                     execution.
109    
110           -S size   On  Unix-like  systems, set the size of the run-time stack to
111                     size megabytes.
112    
113           -s or -s+ Behave as if each pattern  has  the  /S  modifier;  in  other
114                     words,  force each pattern to be studied. If -s+ is used, the
115                     PCRE_STUDY_JIT_COMPILE flag is  passed  to  pcre[16]_study(),
116                     causing  just-in-time  optimization  to  be  set  up if it is
117                     available. If the /I or /D option is  present  on  a  pattern
118                     (requesting  output  about the compiled pattern), information
119                     about the result of studying is not included when studying is
120                     caused  only  by  -s  and neither -i nor -d is present on the
121                     command line. This behaviour means that the output from tests
122                     that  are run with and without -s should be identical, except
123                     when options that output information about the actual running
124                     of a match are set.
125    
126                     The  -M,  -t,  and  -tm options, which give information about
127                     resources used, are likely to produce different  output  with
128                     and  without  -s.  Output may also differ if the /C option is
129                     present on an individual pattern. This uses callouts to trace
130                     the  the  matching process, and this may be different between
131                     studied and non-studied patterns.  If  the  pattern  contains
132                     (*MARK)  items  there  may  also be differences, for the same
133                     reason. The -s command line option can be overridden for spe-
134                     cific  patterns that should never be studied (see the /S pat-
135                     tern modifier below).
136    
137           -t        Run each compile, study, and match many times with  a  timer,
138                     and  output resulting time per compile or match (in millisec-
139                     onds). Do not set -m with -t, because you will then  get  the
140                     size  output  a  zillion  times,  and the timing will be dis-
141                     torted. You can control the number  of  iterations  that  are
142                     used  for timing by following -t with a number (as a separate
143                     item on the command line). For example, "-t 1000" would iter-
144                     ate 1000 times. The default is to iterate 500000 times.
145    
146           -tm       This is like -t except that it times only the matching phase,
147                     not the compile or study phases.
148    
149    
150  DESCRIPTION  DESCRIPTION
151    
152       If pcretest is given two filename arguments, it  reads  from         If pcretest is given two filename arguments, it reads  from  the  first
153       the  first and writes to the second. If it is given only one         and writes to the second. If it is given only one filename argument, it
154       filename argument, it reads from that  file  and  writes  to         reads from that file and writes to stdout.  Otherwise,  it  reads  from
155       stdout. Otherwise, it reads from stdin and writes to stdout,         stdin  and  writes to stdout, and prompts for each line of input, using
156       and prompts for each line of input, using  "re>"  to  prompt         "re>" to prompt for regular expressions, and "data>" to prompt for data
157       for  regular  expressions,  and  "data>"  to prompt for data         lines.
158       lines.  
159           When  pcretest  is  built,  a  configuration option can specify that it
160       The program handles any number of sets of input on a  single         should be linked with the libreadline library. When this  is  done,  if
161       input  file.  Each set starts with a regular expression, and         the input is from a terminal, it is read using the readline() function.
162       continues with any  number  of  data  lines  to  be  matched         This provides line-editing and history facilities. The output from  the
163       against the pattern.         -help option states whether or not readline() will be used.
164    
165       Each line is matched separately and  independently.  If  you         The program handles any number of sets of input on a single input file.
166       want  to  do  multiple-line  matches, you have to use the \n         Each set starts with a regular expression, and continues with any  num-
167       escape sequence in a single line of input to encode the new-         ber of data lines to be matched against the pattern.
168       line  characters.  The maximum length of data line is 30,000  
169       characters.         Each  data line is matched separately and independently. If you want to
170           do multi-line matches, you have to use the \n escape sequence (or \r or
171       An empty line signals the end of the data  lines,  at  which         \r\n, etc., depending on the newline setting) in a single line of input
172       point  a new regular expression is read. The regular expres-         to encode the newline sequences. There is no limit  on  the  length  of
173       sions are given enclosed in  any  non-alphameric  delimiters         data  lines;  the  input  buffer is automatically extended if it is too
174       other than backslash, for example         small.
175    
176         /(a|bc)x+yz/         An empty line signals the end of the data lines, at which point  a  new
177           regular  expression is read. The regular expressions are given enclosed
178       White space before the initial delimiter is ignored. A regu-         in any non-alphanumeric delimiters other than backslash, for example:
179       lar expression may be continued over several input lines, in  
180       which case the newline characters are included within it. It           /(a|bc)x+yz/
181       is  possible  to include the delimiter within the pattern by  
182       escaping it, for example         White space before the initial delimiter is ignored. A regular  expres-
183           sion  may be continued over several input lines, in which case the new-
184         /abc\/def/         line characters are included within it. It is possible to  include  the
185           delimiter within the pattern by escaping it, for example
186       If you do so, the escape and the delimiter form part of  the  
187       pattern,  but  since  delimiters  are always non-alphameric,           /abc\/def/
188       this does not affect its interpretation.  If the terminating  
189       delimiter  is immediately followed by a backslash, for exam-         If  you  do  so, the escape and the delimiter form part of the pattern,
190       ple,         but since delimiters are always non-alphanumeric, this does not  affect
191           its  interpretation.   If the terminating delimiter is immediately fol-
192         /abc/\         lowed by a backslash, for example,
193    
194       then a backslash is added to the end of the pattern. This is           /abc/\
195       done  to  provide  a way of testing the error condition that  
196       arises if a pattern finishes with a backslash, because         then a backslash is added to the end of the pattern. This  is  done  to
197           provide  a  way of testing the error condition that arises if a pattern
198         /abc\/         finishes with a backslash, because
199    
200       is interpreted as the first line of a  pattern  that  starts           /abc\/
201       with  "abc/",  causing  pcretest  to read the next line as a  
202       continuation of the regular expression.         is interpreted as the first line of a pattern that starts with  "abc/",
203           causing pcretest to read the next line as a continuation of the regular
204           expression.
205    
206    
207  PATTERN MODIFIERS  PATTERN MODIFIERS
208    
209       The pattern may be followed by i, m, s,  or  x  to  set  the         A pattern may be followed by any number of modifiers, which are  mostly
210       PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED         single  characters.  Following  Perl usage, these are referred to below
211       options, respectively. For example:         as, for example, "the /i modifier", even though the  delimiter  of  the
212           pattern  need  not always be a slash, and no slash is used when writing
213         /caseless/i         modifiers. White space may appear between the final  pattern  delimiter
214           and the first modifier, and between the modifiers themselves.
215       These modifier letters have the same effect as  they  do  in  
216       Perl.  There  are  others  that set PCRE options that do not         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
217       correspond to anything in Perl:  /A, /E, /N, /U, and /X  set         PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre[16]_com-
218       PCRE_ANCHORED,   PCRE_DOLLAR_ENDONLY,  PCRE_NO_AUTO_CAPTURE,         pile()  is  called. These four modifier letters have the same effect as
219       PCRE_UNGREEDY, and PCRE_EXTRA respectively.         they do in Perl. For example:
220    
221       Searching for  all  possible  matches  within  each  subject           /caseless/i
222       string  can  be  requested  by  the /g or /G modifier. After  
223       finding  a  match,  PCRE  is  called  again  to  search  the         The following table shows additional modifiers for  setting  PCRE  com-
224       remainder  of  the subject string. The difference between /g         pile-time options that do not correspond to anything in Perl:
225       and /G is that the former uses the startoffset  argument  to  
226       pcre_exec()  to  start  searching  at a new point within the           /8              PCRE_UTF8           ) when using the 8-bit
227       entire string (which is in effect what Perl  does),  whereas           /?              PCRE_NO_UTF8_CHECK  )   library
228       the  latter  passes over a shortened substring. This makes a  
229       difference to the matching process  if  the  pattern  begins           /8              PCRE_UTF16          ) when using the 16-bit
230       with a lookbehind assertion (including \b or \B).           /?              PCRE_NO_UTF16_CHECK )   library
231    
232       If any call to pcre_exec() in a /g or /G sequence matches an           /A              PCRE_ANCHORED
233       empty  string,  the next call is done with the PCRE_NOTEMPTY           /C              PCRE_AUTO_CALLOUT
234       and PCRE_ANCHORED flags set in order to search for  another,           /E              PCRE_DOLLAR_ENDONLY
235       non-empty,  match  at  the same point.  If this second match           /f              PCRE_FIRSTLINE
236       fails, the start offset is advanced by one, and  the  normal           /J              PCRE_DUPNAMES
237       match  is  retried.  This imitates the way Perl handles such           /N              PCRE_NO_AUTO_CAPTURE
238       cases when using the /g modifier or the split() function.           /U              PCRE_UNGREEDY
239             /W              PCRE_UCP
240       There are a number of other modifiers  for  controlling  the           /X              PCRE_EXTRA
241       way pcretest operates.           /Y              PCRE_NO_START_OPTIMIZE
242             /<JS>           PCRE_JAVASCRIPT_COMPAT
243       The /+ modifier requests that as well as outputting the sub-           /<cr>           PCRE_NEWLINE_CR
244       string  that  matched the entire pattern, pcretest should in           /<lf>           PCRE_NEWLINE_LF
245       addition output the remainder of the subject string. This is           /<crlf>         PCRE_NEWLINE_CRLF
246       useful  for tests where the subject contains multiple copies           /<anycrlf>      PCRE_NEWLINE_ANYCRLF
247       of the same substring.           /<any>          PCRE_NEWLINE_ANY
248             /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
249       The /L modifier must be followed directly by the name  of  a           /<bsr_unicode>  PCRE_BSR_UNICODE
250       locale, for example,  
251           The  modifiers  that are enclosed in angle brackets are literal strings
252         /pattern/Lfr         as shown, including the angle brackets, but the letters within  can  be
253           in  either case.  This example sets multiline matching with CRLF as the
254       For this reason, it must be the last  modifier  letter.  The         line ending sequence:
255       given  locale is set, pcre_maketables() is called to build a  
256       set of character tables for the locale,  and  this  is  then           /^abc/m<CRLF>
257       passed  to pcre_compile() when compiling the regular expres-  
258       sion. Without an /L modifier, NULL is passed as  the  tables         As well as turning on the PCRE_UTF8/16 option, the /8  modifier  causes
259       pointer; that is, /L applies only to the expression on which         all  non-printing  characters in output strings to be printed using the
260       it appears.         \x{hh...} notation. Otherwise, those less than 0x100 are output in  hex
261           without the curly brackets.
262       The /I modifier requests that  pcretest  output  information  
263       about the compiled expression (whether it is anchored, has a         Full  details  of  the PCRE options are given in the pcreapi documenta-
264       fixed first character, and so on). It does this  by  calling         tion.
265       pcre_fullinfo()  after  compiling an expression, and output-  
266       ting the information it gets back. If the  pattern  is  stu-     Finding all matches in a string
267       died, the results of that are also output.  
268           Searching for all possible matches within each subject  string  can  be
269       The /D modifier is a  PCRE  debugging  feature,  which  also         requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
270       assumes /I.  It causes the internal form of compiled regular         called again to search the remainder of the subject string. The differ-
271       expressions to be output after compilation. If  the  pattern         ence between /g and /G is that the former uses the startoffset argument
272       was studied, the information returned is also output.         to pcre[16]_exec() to start searching at a new point within the  entire
273           string  (which  is in effect what Perl does), whereas the latter passes
274       The /S modifier causes pcre_study() to be called  after  the         over a shortened substring. This makes a  difference  to  the  matching
275       expression  has been compiled, and the results used when the         process if the pattern begins with a lookbehind assertion (including \b
276       expression is matched.         or \B).
277    
278       The /M modifier causes the size of memory block used to hold         If any call to pcre[16]_exec() in a /g or /G sequence matches an  empty
279       the compiled pattern to be output.         string,  the  next  call  is  done  with  the PCRE_NOTEMPTY_ATSTART and
280           PCRE_ANCHORED flags set in order  to  search  for  another,  non-empty,
281       The /P modifier causes pcretest to call PCRE via  the  POSIX         match  at  the same point. If this second match fails, the start offset
282       wrapper  API  rather than its native API. When this is done,         is advanced, and the normal match is retried.  This  imitates  the  way
283       all other modifiers except  /i,  /m,  and  /+  are  ignored.         Perl handles such cases when using the /g modifier or the split() func-
284       REG_ICASE is set if /i is present, and REG_NEWLINE is set if         tion. Normally, the start offset is advanced by one character,  but  if
285       /m    is    present.    The    wrapper    functions    force         the  newline  convention  recognizes CRLF as a newline, and the current
286       PCRE_DOLLAR_ENDONLY    always,    and   PCRE_DOTALL   unless         character is CR followed by LF, an advance of two is used.
287       REG_NEWLINE is set.  
288       Other modifiers
289       The /8 modifier  causes  pcretest  to  call  PCRE  with  the  
290       PCRE_UTF8  option set. This turns on support for UTF-8 char-         There are yet more modifiers for controlling the way pcretest operates.
291       acter handling in PCRE, provided that it was  compiled  with  
292       this  support  enabled.  This  modifier also causes any non-         The /+ modifier requests that as well as outputting the substring  that
293       printing characters in output strings to  be  printed  using         matched  the  entire  pattern,  pcretest  should in addition output the
294       the \x{hh...} notation if they are valid UTF-8 sequences.         remainder of the subject string. This is useful  for  tests  where  the
295           subject  contains multiple copies of the same substring. If the + modi-
296       If the /? modifier is used with /8, it  causes  pcretest  to         fier appears twice, the same action is taken for  captured  substrings.
297       call  pcre_compile()  with the PCRE_NO_UTF8_CHECK option, to         In  each case the remainder is output on the following line with a plus
298       suppress the checking of the string for UTF-8 validity.         character following the capture number. Note that  this  modifier  must
299           not immediately follow the /S modifier because /S+ has another meaning.
300    
301           The  /=  modifier  requests  that  the values of all potential captured
302           parentheses be output after a match. By default, only those up  to  the
303           highest one actually used in the match are output (corresponding to the
304           return code from pcre[16]_exec()). Values in the offsets vector  corre-
305           sponding to higher numbers should be set to -1, and these are output as
306           "<unset>". This modifier gives a way of checking that this  is  happen-
307           ing.
308    
309           The  /B modifier is a debugging feature. It requests that pcretest out-
310           put a representation of the compiled code after  compilation.  Normally
311           this  information  contains length and offset values; however, if /Z is
312           also present, this data is replaced by spaces. This is a  special  fea-
313           ture  for  use  in the automatic test scripts; it ensures that the same
314           output is generated for different internal link sizes.
315    
316           The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
317           that is, both the /B and the /I modifiers.
318    
319           The  /F  modifier  causes pcretest to flip the byte order of the 2-byte
320           and 4-byte fields in the compiled pattern. This facility is for testing
321           the  feature  in PCRE that allows it to execute patterns that were com-
322           piled on a host with a different endianness. This feature is not avail-
323           able  when the POSIX interface to PCRE is being used, that is, when the
324           /P pattern modifier is specified. See also the section about saving and
325           reloading compiled patterns below.
326    
327           The  /I  modifier  requests  that pcretest output information about the
328           compiled pattern (whether it is anchored, has a fixed first  character,
329           and so on). It does this by calling pcre[16]_fullinfo() after compiling
330           a pattern. If the pattern is studied, the results of that are also out-
331           put.
332    
333           The  /K modifier requests pcretest to show names from backtracking con-
334           trol verbs that are returned from calls to pcre[16]_exec().  It  causes
335           pcretest  to  create a pcre[16]_extra block if one has not already been
336           created by a call to pcre[16]_study(), and to set  the  PCRE_EXTRA_MARK
337           flag  and  the mark field within it, every time that pcre[16]_exec() is
338           called. If the variable that the mark field points to is non-NULL for a
339           match, non-match, or partial match, pcretest prints the string to which
340           it points. For a match, this is shown on a line by itself, tagged  with
341           "MK:". For a non-match it is added to the message.
342    
343           The  /L modifier must be followed directly by the name of a locale, for
344           example,
345    
346             /pattern/Lfr_FR
347    
348           For this reason, it must be the last modifier. The given locale is set,
349           pcre[16]_maketables()  is called to build a set of character tables for
350           the locale, and this is then passed to pcre[16]_compile() when  compil-
351           ing  the  regular  expression.  Without an /L (or /T) modifier, NULL is
352           passed as the tables pointer; that is, /L applies only to  the  expres-
353           sion on which it appears.
354    
355           The  /M  modifier  causes the size in bytes of the memory block used to
356           hold the compiled pattern to be output. This does not include the  size
357           of the pcre[16] block; it is just the actual compiled data. If the pat-
358           tern is successfully studied with  the  PCRE_STUDY_JIT_COMPILE  option,
359           the size of the JIT compiled code is also output.
360    
361           If  the  /S  modifier  appears  once,  it causes pcre[16]_study() to be
362           called after the expression has been compiled,  and  the  results  used
363           when  the  expression  is  matched.  If /S appears twice, it suppresses
364           studying, even if it was requested externally by the  -s  command  line
365           option.  This  makes  it  possible to specify that certain patterns are
366           always studied, and others are never studied, independently of -s. This
367           feature  is  used  in the test files in a few cases where the output is
368           different when the pattern is studied.
369    
370           If the /S modifier is immediately followed by a + character,  the  call
371           to  pcre[16]_study()  is  made  with the PCRE_STUDY_JIT_COMPILE option,
372           requesting just-in-time optimization support if it is  available.  Note
373           that  there  is  also  a  /+ modifier; it must not be given immediately
374           after /S because this will be misinterpreted. If JIT studying  is  suc-
375           cessful,  it  will  automatically  be used when pcre[16]_exec() is run,
376           except when incompatible run-time options are specified. These  include
377           the  partial  matching options; a complete list is given in the pcrejit
378           documentation. See also the \J escape sequence below for a way of  set-
379           ting the size of the JIT stack.
380    
381           The  /T  modifier  must be followed by a single digit. It causes a spe-
382           cific set of built-in character tables to be  passed  to  pcre[16]_com-
383           pile().  It  is used in the standard PCRE tests to check behaviour with
384           different character tables. The digit specifies the tables as follows:
385    
386             0   the default ASCII tables, as distributed in
387                   pcre_chartables.c.dist
388             1   a set of tables defining ISO 8859 characters
389    
390           In table 1, some characters whose codes are greater than 128 are  iden-
391           tified as letters, digits, spaces, etc.
392    
393       Using the POSIX wrapper API
394    
395           The  /P modifier causes pcretest to call PCRE via the POSIX wrapper API
396           rather than its native API. This supports only the 8-bit library.  When
397           /P  is set, the following modifiers set options for the regcomp() func-
398           tion:
399    
400             /i    REG_ICASE
401             /m    REG_NEWLINE
402             /N    REG_NOSUB
403             /s    REG_DOTALL     )
404             /U    REG_UNGREEDY   ) These options are not part of
405             /W    REG_UCP        )   the POSIX standard
406             /8    REG_UTF8       )
407    
408           The /+ modifier works as  described  above.  All  other  modifiers  are
409           ignored.
410    
411    
412    DATA LINES
413    
414           Before  each data line is passed to pcre[16]_exec(), leading and trail-
415           ing white space is removed, and it is then scanned for \ escapes.  Some
416           of  these  are pretty esoteric features, intended for checking out some
417           of the more complicated features of  PCRE.  If  you  are  just  testing
418           "ordinary"  regular  expressions, you probably don't need any of these.
419           The following escapes are recognized:
420    
421             \a         alarm (BEL, \x07)
422             \b         backspace (\x08)
423             \e         escape (\x27)
424             \f         form feed (\x0c)
425             \n         newline (\x0a)
426             \qdd       set the PCRE_MATCH_LIMIT limit to dd
427                          (any number of digits)
428             \r         carriage return (\x0d)
429             \t         tab (\x09)
430             \v         vertical tab (\x0b)
431             \nnn       octal character (up to 3 octal digits); always
432                          a byte unless > 255 in UTF-8 or 16-bit mode
433             \xhh       hexadecimal byte (up to 2 hex digits)
434             \x{hh...}  hexadecimal character (any number of hex digits)
435             \A         pass the PCRE_ANCHORED option to pcre[16]_exec()
436                          or pcre[16]_dfa_exec()
437             \B         pass the PCRE_NOTBOL option to pcre[16]_exec()
438                          or pcre[16]_dfa_exec()
439             \Cdd       call pcre[16]_copy_substring() for substring dd
440                          after a successful match (number less than 32)
441             \Cname     call pcre[16]_copy_named_substring() for substring
442                          "name" after a successful match (name termin-
443                          ated by next non alphanumeric character)
444             \C+        show the current captured substrings at callout
445                          time
446             \C-        do not supply a callout function
447             \C!n       return 1 instead of 0 when callout number n is
448                          reached
449             \C!n!m     return 1 instead of 0 when callout number n is
450                          reached for the nth time
451             \C*n       pass the number n (may be negative) as callout
452                          data; this is used as the callout return value
453             \D         use the pcre[16]_dfa_exec() match function
454             \F         only shortest match for pcre[16]_dfa_exec()
455             \Gdd       call pcre[16]_get_substring() for substring dd
456                          after a successful match (number less than 32)
457             \Gname     call pcre[16]_get_named_substring() for substring
458                          "name" after a successful match (name termin-
459                          ated by next non-alphanumeric character)
460             \Jdd       set up a JIT stack of dd kilobytes maximum (any
461                          number of digits)
462             \L         call pcre[16]_get_substringlist() after a
463                          successful match
464             \M         discover the minimum MATCH_LIMIT and
465                          MATCH_LIMIT_RECURSION settings
466             \N         pass the PCRE_NOTEMPTY option to pcre[16]_exec()
467                          or pcre[16]_dfa_exec(); if used twice, pass the
468                          PCRE_NOTEMPTY_ATSTART option
469             \Odd       set the size of the output vector passed to
470                          pcre[16]_exec() to dd (any number of digits)
471             \P         pass the PCRE_PARTIAL_SOFT option to pcre[16]_exec()
472                          or pcre[16]_dfa_exec(); if used twice, pass the
473                          PCRE_PARTIAL_HARD option
474             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
475                          (any number of digits)
476             \R         pass the PCRE_DFA_RESTART option to pcre[16]_dfa_exec()
477             \S         output details of memory get/free calls during matching
478             \Y         pass the PCRE_NO_START_OPTIMIZE option to pcre[16]_exec()
479                          or pcre[16]_dfa_exec()
480             \Z         pass the PCRE_NOTEOL option to pcre[16]_exec()
481                          or pcre[16]_dfa_exec()
482             \?         pass the PCRE_NO_UTF[8|16]_CHECK option to
483                          pcre[16]_exec() or pcre[16]_dfa_exec()
484             \>dd       start the match at offset dd (optional "-"; then
485                          any number of digits); this sets the startoffset
486                          argument for pcre[16]_exec() or pcre[16]_dfa_exec()
487             \<cr>      pass the PCRE_NEWLINE_CR option to pcre[16]_exec()
488                          or pcre[16]_dfa_exec()
489             \<lf>      pass the PCRE_NEWLINE_LF option to pcre[16]_exec()
490                          or pcre[16]_dfa_exec()
491             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre[16]_exec()
492                          or pcre[16]_dfa_exec()
493             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16]_exec()
494                          or pcre[16]_dfa_exec()
495             \<any>     pass the PCRE_NEWLINE_ANY option to pcre[16]_exec()
496                          or pcre[16]_dfa_exec()
497    
498           The use of \x{hh...} is not dependent on the use of the /8 modifier  on
499           the  pattern. It is recognized always. There may be any number of hexa-
500           decimal digits inside the braces; invalid  values  provoke  error  mes-
501           sages.
502    
503           Note  that  \xhh  specifies one byte rather than one character in UTF-8
504           mode; this makes it possible to construct invalid UTF-8  sequences  for
505           testing  purposes.  On the other hand, \x{hh} is interpreted as a UTF-8
506           character in UTF-8 mode, generating more than one byte if the value  is
507           greater  than  127.   When testing the 8-bit library not in UTF-8 mode,
508           \x{hh} generates one byte for values less than 256, and causes an error
509           for greater values.
510    
511           In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
512           possible to construct invalid UTF-16 sequences for testing purposes.
513    
514           The escapes that specify line ending  sequences  are  literal  strings,
515           exactly as shown. No more than one newline setting should be present in
516           any data line.
517    
518           A backslash followed by anything else just escapes the  anything  else.
519           If  the very last character is a backslash, it is ignored. This gives a
520           way of passing an empty line as data, since a real  empty  line  termi-
521           nates the data input.
522    
523           The  \J escape provides a way of setting the maximum stack size that is
524           used by the just-in-time optimization code. It is ignored if JIT  opti-
525           mization  is  not being used. Providing a stack that is larger than the
526           default 32K is necessary only for very complicated patterns.
527    
528           If \M is present, pcretest calls pcre[16]_exec()  several  times,  with
529           different values in the match_limit and match_limit_recursion fields of
530           the pcre[16]_extra data structure, until it finds the  minimum  numbers
531           for  each  parameter  that  allow  pcre[16]_exec()  to complete without
532           error. Because this is testing a specific feature of the normal  inter-
533           pretive pcre[16]_exec() execution, the use of any JIT optimization that
534           might have been set up by the /S+ qualifier of -s+ option is disabled.
535    
536           The match_limit number is a measure of the amount of backtracking  that
537           takes  place,  and  checking it out can be instructive. For most simple
538           matches, the number is quite small, but for patterns  with  very  large
539           numbers  of  matching  possibilities,  it can become large very quickly
540           with increasing length of  subject  string.  The  match_limit_recursion
541           number  is  a  measure  of how much stack (or, if PCRE is compiled with
542           NO_RECURSE, how much heap) memory  is  needed  to  complete  the  match
543           attempt.
544    
545           When  \O  is  used, the value specified may be higher or lower than the
546           size set by the -O command line option (or defaulted to 45); \O applies
547           only to the call of pcre[16]_exec() for the line in which it appears.
548    
549           If  the /P modifier was present on the pattern, causing the POSIX wrap-
550           per API to be used, the only option-setting  sequences  that  have  any
551           effect  are  \B,  \N,  and  \Z,  causing  REG_NOTBOL, REG_NOTEMPTY, and
552           REG_NOTEOL, respectively, to be passed to regexec().
553    
554    
555    THE ALTERNATIVE MATCHING FUNCTION
556    
557           By  default,  pcretest  uses  the  standard  PCRE  matching   function,
558           pcre[16]_exec() to match each data line. PCRE also supports an alterna-
559           tive matching function, pcre[16]_dfa_test(), which operates in  a  dif-
560           ferent  way, and has some restrictions. The differences between the two
561           functions are described in the pcrematching documentation.
562    
563           If a data line contains the \D escape sequence, or if the command  line
564           contains  the  -dfa  option, the alternative matching function is used.
565           This function finds all possible matches at a given point. If, however,
566           the  \F escape sequence is present in the data line, it stops after the
567           first match is found. This is always the shortest possible match.
568    
569    
570    DEFAULT OUTPUT FROM PCRETEST
571    
572           This section describes the output when the  normal  matching  function,
573           pcre[16]_exec(), is being used.
574    
575           When a match succeeds, pcretest outputs the list of captured substrings
576           that pcre[16]_exec() returns, starting with number  0  for  the  string
577           that  matched  the whole pattern. Otherwise, it outputs "No match" when
578           the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by  the
579           partially    matching    substring    when    pcre[16]_exec()   returns
580           PCRE_ERROR_PARTIAL. (Note that this is the entire  substring  that  was
581           inspected  during  the  partial match; it may include characters before
582           the actual match start if a lookbehind assertion, \K,  \b,  or  \B  was
583           involved.)  For  any  other  return, pcretest outputs the PCRE negative
584           error number and a short descriptive phrase. If the error is  a  failed
585           UTF  string check, the offset of the start of the failing character and
586           the reason code are also output, provided that the size of  the  output
587           vector  is  at least two. Here is an example of an interactive pcretest
588           run.
589    
590             $ pcretest
591             PCRE version 8.13 2011-04-30
592    
593               re> /^abc(\d+)/
594             data> abc123
595              0: abc123
596              1: 123
597             data> xyz
598             No match
599    
600           Unset capturing substrings that are not followed by one that is set are
601           not  returned by pcre[16]_exec(), and are not shown by pcretest. In the
602           following example, there are two capturing  substrings,  but  when  the
603           first  data  line is matched, the second, unset substring is not shown.
604           An "internal" unset substring is shown as "<unset>", as for the  second
605           data line.
606    
607               re> /(a)|(b)/
608             data> a
609              0: a
610              1: a
611             data> b
612              0: b
613              1: <unset>
614              2: b
615    
616           If  the strings contain any non-printing characters, they are output as
617           \xhh escapes if the value is less than 256 and UTF  mode  is  not  set.
618           Otherwise they are output as \x{hh...} escapes. See below for the defi-
619           nition of non-printing characters. If the pattern has the /+  modifier,
620           the  output  for substring 0 is followed by the the rest of the subject
621           string, identified by "0+" like this:
622    
623               re> /cat/+
624             data> cataract
625              0: cat
626              0+ aract
627    
628           If the pattern has the /g or /G modifier,  the  results  of  successive
629           matching attempts are output in sequence, like this:
630    
631               re> /\Bi(\w\w)/g
632             data> Mississippi
633              0: iss
634              1: ss
635              0: iss
636              1: ss
637              0: ipp
638              1: pp
639    
640           "No  match" is output only if the first match attempt fails. Here is an
641           example of a failure message (the offset 4 that is specified by \>4  is
642           past the end of the subject string):
643    
644               re> /xyz/
645             data> xyz\>4
646             Error -24 (bad offset value)
647    
648           If  any  of the sequences \C, \G, or \L are present in a data line that
649           is successfully matched, the substrings extracted  by  the  convenience
650           functions are output with C, G, or L after the string number instead of
651           a colon. This is in addition to the normal full list. The string length
652           (that  is,  the return from the extraction function) is given in paren-
653           theses after each string for \C and \G.
654    
655           Note that whereas patterns can be continued over several lines (a plain
656           ">" prompt is used for continuations), data lines may not. However new-
657           lines can be included in data by means of the \n escape (or  \r,  \r\n,
658           etc., depending on the newline sequence setting).
659    
660    
661    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
662    
663           When  the  alternative  matching function, pcre[16]_dfa_exec(), is used
664           (by means of the \D escape sequence or the -dfa command  line  option),
665           the  output  consists  of  a  list of all the matches that start at the
666           first point in the subject where there is at least one match. For exam-
667           ple:
668    
669               re> /(tang|tangerine|tan)/
670             data> yellow tangerine\D
671              0: tangerine
672              1: tang
673              2: tan
674    
675           (Using  the  normal  matching function on this data finds only "tang".)
676           The longest matching string is always given first (and numbered  zero).
677           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
678           lowed by the partially matching  substring.  (Note  that  this  is  the
679           entire  substring  that  was inspected during the partial match; it may
680           include characters before the actual match start if a lookbehind asser-
681           tion, \K, \b, or \B was involved.)
682    
683           If /g is present on the pattern, the search for further matches resumes
684           at the end of the longest match. For example:
685    
686               re> /(tang|tangerine|tan)/g
687             data> yellow tangerine and tangy sultana\D
688              0: tangerine
689              1: tang
690              2: tan
691              0: tang
692              1: tan
693              0: tan
694    
695           Since the matching function does not  support  substring  capture,  the
696           escape  sequences  that  are concerned with captured substrings are not
697           relevant.
698    
699    
700    RESTARTING AFTER A PARTIAL MATCH
701    
702           When the alternative matching function has given the PCRE_ERROR_PARTIAL
703           return,  indicating that the subject partially matched the pattern, you
704           can restart the match with additional subject data by means of  the  \R
705           escape sequence. For example:
706    
707               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
708             data> 23ja\P\D
709             Partial match: 23ja
710             data> n05\R\D
711              0: n05
712    
713           For  further  information  about  partial matching, see the pcrepartial
714           documentation.
715    
716    
717  CALLOUTS  CALLOUTS
718    
719       If the pattern contains  any  callout  requests,  pcretest's         If the pattern contains any callout requests, pcretest's callout  func-
720       callout function will be called. By default, it displays the         tion  is  called  during  matching. This works with both matching func-
721       callout number, and the start and current positions  in  the         tions. By default, the called function displays the callout number, the
722       text at the callout time. For example, the output         start  and  current  positions in the text at the callout time, and the
723           next pattern item to be tested. For example:
724         --->pqrabcdef  
725           0    ^  ^           --->pqrabcdef
726               0    ^  ^     \d
727       indicates that callout number 0 occurred for a match attempt  
728       starting at the fourth character of the subject string, when         This output indicates that  callout  number  0  occurred  for  a  match
729       the pointer was at the seventh character. The callout  func-         attempt  starting  at  the fourth character of the subject string, when
730       tion returns zero (carry on matching) by default.         the pointer was at the seventh character of the data, and when the next
731           pattern  item  was  \d.  Just one circumflex is output if the start and
732       Inserting callouts may be helpful  when  using  pcretest  to         current positions are the same.
733       check  complicated regular expressions. For further informa-  
734       tion about callouts, see the pcrecallout documentation.         Callouts numbered 255 are assumed to be automatic callouts, inserted as
735           a  result  of the /C pattern modifier. In this case, instead of showing
736       For testing the PCRE library, additional control of  callout         the callout number, the offset in the pattern, preceded by a  plus,  is
737       behaviour  is available via escape sequences in the data, as         output. For example:
738       described in the following section.  In  particular,  it  is  
739       possible to pass in a number as callout data (the default is             re> /\d?[A-E]\*/C
740       zero). If the callout function receives a  non-zero  number,           data> E*
741       it returns that value instead of zero.           --->E*
742              +0 ^      \d?
743              +3 ^      [A-E]
744              +8 ^^     \*
745             +10 ^ ^
746              0: E*
747    
748           If a pattern contains (*MARK) items, an additional line is output when-
749           ever a change of latest mark is passed to  the  callout  function.  For
750           example:
751    
752               re> /a(*MARK:X)bc/C
753             data> abc
754             --->abc
755              +0 ^       a
756              +1 ^^      (*MARK:X)
757             +10 ^^      b
758             Latest Mark: X
759             +11 ^ ^     c
760             +12 ^  ^
761              0: abc
762    
763           The  mark  changes between matching "a" and "b", but stays the same for
764           the rest of the match, so nothing more is output. If, as  a  result  of
765           backtracking,  the  mark  reverts to being unset, the text "<unset>" is
766           output.
767    
768           The callout function in pcretest returns zero (carry  on  matching)  by
769           default,  but you can use a \C item in a data line (as described above)
770           to change this and other parameters of the callout.
771    
772           Inserting callouts can be helpful when using pcretest to check  compli-
773           cated  regular expressions. For further information about callouts, see
774           the pcrecallout documentation.
775    
776    
777    NON-PRINTING CHARACTERS
778    
779           When pcretest is outputting text in the compiled version of a  pattern,
780           bytes  other  than 32-126 are always treated as non-printing characters
781           are are therefore shown as hex escapes.
782    
783           When pcretest is outputting text that is a matched part  of  a  subject
784           string,  it behaves in the same way, unless a different locale has been
785           set for the  pattern  (using  the  /L  modifier).  In  this  case,  the
786           isprint() function to distinguish printing and non-printing characters.
787    
788    
789    SAVING AND RELOADING COMPILED PATTERNS
790    
791           The  facilities  described  in  this section are not available when the
792           POSIX interface to PCRE is being used, that is,  when  the  /P  pattern
793           modifier is specified.
794    
795           When the POSIX interface is not in use, you can cause pcretest to write
796           a compiled pattern to a file, by following the modifiers with >  and  a
797           file name.  For example:
798    
799             /pattern/im >/some/file
800    
801           See  the pcreprecompile documentation for a discussion about saving and
802           re-using compiled patterns.  Note that if the pattern was  successfully
803           studied with JIT optimization, the JIT data cannot be saved.
804    
805           The  data  that  is  written  is  binary. The first eight bytes are the
806           length of the compiled pattern data  followed  by  the  length  of  the
807           optional  study  data,  each  written as four bytes in big-endian order
808           (most significant byte first). If there is no study  data  (either  the
809           pattern was not studied, or studying did not return any data), the sec-
810           ond length is zero. The lengths are followed by an exact  copy  of  the
811           compiled  pattern.  If  there is additional study data, this (excluding
812           any JIT data) follows immediately after  the  compiled  pattern.  After
813           writing the file, pcretest expects to read a new pattern.
814    
815           A  saved  pattern  can  be reloaded into pcretest by specifying < and a
816           file name instead of a pattern. The name of the file must not contain a
817           < character, as otherwise pcretest will interpret the line as a pattern
818           delimited by < characters.  For example:
819    
820              re> </some/file
821             Compiled pattern loaded from /some/file
822             No study data
823    
824           If the pattern was previously studied with the  JIT  optimization,  the
825           JIT  information cannot be saved and restored, and so is lost. When the
826           pattern has been loaded, pcretest proceeds to read data  lines  in  the
827           usual way.
828    
829           You  can copy a file written by pcretest to a different host and reload
830           it there, even if the new host has opposite endianness to  the  one  on
831           which  the pattern was compiled. For example, you can compile on an i86
832           machine and run on a SPARC machine. When a pattern  is  reloaded  on  a
833           host with different endianness, the confirmation message is changed to:
834    
835             Compiled pattern (byte-inverted) loaded from /some/file
836    
837           The test suite contains some saved pre-compiled patterns with different
838           endianness. These are reloaded using "<!" instead  of  just  "<".  This
839           suppresses the "(byte-inverted)" text so that the output is the same on
840           all hosts. It also forces debugging output once the  pattern  has  been
841           reloaded.
842    
843           File  names  for  saving and reloading can be absolute or relative, but
844           note that the shell facility of expanding a file name that starts  with
845           a tilde (~) is not available.
846    
847           The  ability to save and reload files in pcretest is intended for test-
848           ing and experimentation. It is not intended for production use  because
849           only  a  single pattern can be written to a file. Furthermore, there is
850           no facility for supplying  custom  character  tables  for  use  with  a
851           reloaded  pattern.  If  the  original  pattern was compiled with custom
852           tables, an attempt to match a subject string using a  reloaded  pattern
853           is  likely to cause pcretest to crash.  Finally, if you attempt to load
854           a file that is not in the correct format, the result is undefined.
855    
856    
857  DATA LINES  SEE ALSO
858    
859       Before each data line is passed to pcre_exec(), leading  and         pcre(3), pcre16(3),  pcreapi(3),  pcrecallout(3),  pcrejit,  pcrematch-
860       trailing whitespace is removed, and it is then scanned for \         ing(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
      escapes.  Some  of  these  are  pretty  esoteric   features,  
      intended  for  checking  out  some  of  the more complicated  
      features of PCRE. If you are just testing "ordinary" regular  
      expressions,  you probably don't need any of these. The fol-  
      lowing escapes 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)  
        \x{hh...}  hexadecimal character, any number of digits  
                     in UTF-8 mode  
        \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)  
        \Cname     call pcre_copy_named_substring() for substring  
   
                     "name" after a successful match (name termin-  
                     ated by next non alphanumeric character)  
        \C+        show the current captured substrings at callout  
                     time  
        \C-        do not supply a callout function  
        \C!n       return 1 instead of 0 when callout number n is  
                     reached  
        \C!n!m     return 1 instead of 0 when callout number n is  
                     reached for the nth time  
        \C*n       pass the number n (may be negative) as callout  
                     data  
        \Gdd       call pcre_get_substring() for substring dd  
                     after a successful match (any decimal number  
                     less than 32)  
        \Gname     call pcre_get_named_substring() for substring  
                     "name" after a successful match (name termin-  
                     ated by next non-alphanumeric character)  
        \L         call pcre_get_substringlist() after a  
                     successful match  
        \M         discover the minimum MATCH_LIMIT setting  
        \N         pass the PCRE_NOTEMPTY 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()  
        \?         pass the PCRE_NO_UTF8_CHECK option to  
                     pcre_exec()  
   
      If \M is present, pcretest calls pcre_exec() several  times,  
      with  different  values  in  the  match_limit  field  of the  
      pcre_extra data structure, until it finds the minimum number  
      that is needed for pcre_exec() to complete. This number is a  
      measure of the amount of  recursion  and  backtracking  that  
      takes  place,  and  checking  it out can be instructive. For  
      most simple matches, the number is quite small, but for pat-  
      terns  with very large numbers of matching possibilities, it  
      can become large very quickly with increasing length of sub-  
      ject string.  
   
      When \O is used, it may be higher or lower than the size set  
      by  the  -O  option (or defaulted to 45); \O applies only to  
      the call of pcre_exec() for the line in which it appears.  
   
      A backslash followed by anything else just escapes the  any-  
      thing 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()  respec-  
      tively.  
      The use of \x{hh...} to represent UTF-8  characters  is  not  
      dependent  on  the use of the /8 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.  
   
   
 OUTPUT FROM PCRETEST  
   
      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  
        PCRE version 4.00 08-Jan-2003  
   
          re> /^abc(\d+)/  
        data> abc123  
         0: abc123  
         1: 123  
        data> xyz  
        No match  
   
      If the strings contain any non-printing characters, they are  
      output  as  \0x  escapes,  or  as  \x{...} escapes if the /8  
      modifier was present on the pattern. If the pattern has  the  
      /+  modifier, then the output for substring 0 is followed by  
      the the rest of the subject string, identified by "0+"  like  
      this:  
   
          re> /cat/+  
        data> cataract  
         0: cat  
         0+ aract  
   
      If the pattern has the /g or /G  modifier,  the  results  of  
      successive  matching  attempts  are output in sequence, like  
      this:  
   
          re> /\Bi(\w\w)/g  
        data> Mississippi  
         0: iss  
         1: ss  
         0: iss  
         1: ss  
         0: ipp  
         1: pp  
   
      "No match" is output only if the first match attempt fails.  
   
      If any of the sequences \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 addi-  
      tion 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.  
861    
862    
863  AUTHOR  AUTHOR
864    
865       Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
866       University Computing Service,         University Computing Service
867       Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
868    
869    
870    REVISION
871    
872  Last updated: 20 August 2003         Last updated: 14 January 2012
873  Copyright (c) 1997-2003 University of Cambridge.         Copyright (c) 1997-2012 University of Cambridge.

Legend:
Removed from v.71  
changed lines
  Added in v.878

  ViewVC Help
Powered by ViewVC 1.1.5