/[pcre]/code/trunk/doc/pcretest.txt
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revision 96 by nigel, Fri Mar 2 13:10:43 2007 UTC revision 512 by ph10, Tue Mar 30 11:11:52 2010 UTC
# Line 40  OPTIONS Line 40  OPTIONS
40         -i        Behave as if each regex  has  the  /I  modifier;  information         -i        Behave as if each regex  has  the  /I  modifier;  information
41                   about the compiled pattern is given after compilation.                   about the compiled pattern is given after compilation.
42    
43         -m        Output  the  size  of each compiled pattern after it has been         -M        Behave  as if each data line contains the \M escape sequence;
44                   compiled. This is equivalent to adding  /M  to  each  regular                   this causes PCRE to  discover  the  minimum  MATCH_LIMIT  and
45                   expression.   For  compatibility  with  earlier  versions  of                   MATCH_LIMIT_RECURSION settings by calling pcre_exec() repeat-
46                     edly with different limits.
47    
48           -m        Output the size of each compiled pattern after  it  has  been
49                     compiled.  This  is  equivalent  to adding /M to each regular
50                     expression.  For  compatibility  with  earlier  versions   of
51                   pcretest, -s is a synonym for -m.                   pcretest, -s is a synonym for -m.
52    
53         -o osize  Set the number of elements in the output vector that is  used         -o osize  Set  the number of elements in the output vector that is used
54                   when  calling pcre_exec() or pcre_dfa_exec() to be osize. The                   when calling pcre_exec() or pcre_dfa_exec() to be osize.  The
55                   default value is 45, which is enough for 14 capturing  subex-                   default  value is 45, which is enough for 14 capturing subex-
56                   pressions   for  pcre_exec()  or  22  different  matches  for                   pressions  for  pcre_exec()  or  22  different  matches   for
57                   pcre_dfa_exec(). The vector size can be changed for  individ-                   pcre_dfa_exec().  The vector size can be changed for individ-
58                   ual  matching  calls  by  including  \O in the data line (see                   ual matching calls by including \O  in  the  data  line  (see
59                   below).                   below).
60    
61         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-         -p        Behave  as if each regex has the /P modifier; the POSIX wrap-
62                   per  API  is used to call PCRE. None of the other options has                   per API is used to call PCRE. None of the other  options  has
63                   any effect when -p is set.                   any effect when -p is set.
64    
65         -q        Do not output the version number of pcretest at the start  of         -q        Do  not output the version number of pcretest at the start of
66                   execution.                   execution.
67    
68         -S size   On  Unix-like  systems,  set the size of the runtime stack to         -S size   On Unix-like systems, set the size of the  runtime  stack  to
69                   size megabytes.                   size megabytes.
70    
71         -t        Run each compile, study, and match many times with  a  timer,         -t        Run  each  compile, study, and match many times with a timer,
72                   and  output resulting time per compile or match (in millisec-                   and output resulting time per compile or match (in  millisec-
73                   onds). Do not set -m with -t, because you will then  get  the                   onds).  Do  not set -m with -t, because you will then get the
74                   size  output  a  zillion  times,  and the timing will be dis-                   size output a zillion times, and  the  timing  will  be  dis-
75                   torted. You can control the number  of  iterations  that  are                   torted.  You  can  control  the number of iterations that are
76                   used  for timing by following -t with a number (as a separate                   used for timing by following -t with a number (as a  separate
77                   item on the command line). For example, "-t 1000" would iter-                   item on the command line). For example, "-t 1000" would iter-
78                   ate 1000 times. The default is to iterate 500000 times.                   ate 1000 times. The default is to iterate 500000 times.
79    
# Line 78  OPTIONS Line 83  OPTIONS
83    
84  DESCRIPTION  DESCRIPTION
85    
86         If pcretest is given two filename arguments, it reads  from  the  first         If  pcretest  is  given two filename arguments, it reads from the first
87         and writes to the second. If it is given only one filename argument, it         and writes to the second. If it is given only one filename argument, it
88         reads from that file and writes to stdout.  Otherwise,  it  reads  from         reads  from  that  file  and writes to stdout. Otherwise, it reads from
89         stdin  and  writes to stdout, and prompts for each line of input, using         stdin and writes to stdout, and prompts for each line of  input,  using
90         "re>" to prompt for regular expressions, and "data>" to prompt for data         "re>" to prompt for regular expressions, and "data>" to prompt for data
91         lines.         lines.
92    
93           When pcretest is built, a configuration  option  can  specify  that  it
94           should  be  linked  with the libreadline library. When this is done, if
95           the input is from a terminal, it is read using the readline() function.
96           This  provides line-editing and history facilities. The output from the
97           -help option states whether or not readline() will be used.
98    
99         The program handles any number of sets of input on a single input file.         The program handles any number of sets of input on a single input file.
100         Each set starts with a regular expression, and continues with any  num-         Each  set starts with a regular expression, and continues with any num-
101         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
102    
103         Each  data line is matched separately and independently. If you want to         Each data line is matched separately and independently. If you want  to
104         do multi-line matches, you have to use the \n escape sequence (or \r or         do multi-line matches, you have to use the \n escape sequence (or \r or
105         \r\n, etc., depending on the newline setting) in a single line of input         \r\n, etc., depending on the newline setting) in a single line of input
106         to encode the newline sequences. There is no limit  on  the  length  of         to  encode  the  newline  sequences. There is no limit on the length of
107         data  lines;  the  input  buffer is automatically extended if it is too         data lines; the input buffer is automatically extended  if  it  is  too
108         small.         small.
109    
110         An empty line signals the end of the data lines, at which point  a  new         An  empty  line signals the end of the data lines, at which point a new
111         regular  expression is read. The regular expressions are given enclosed         regular expression is read. The regular expressions are given  enclosed
112         in any non-alphanumeric delimiters other than backslash, for example:         in any non-alphanumeric delimiters other than backslash, for example:
113    
114           /(a|bc)x+yz/           /(a|bc)x+yz/
115    
116         White space before the initial delimiter is ignored. A regular  expres-         White  space before the initial delimiter is ignored. A regular expres-
117         sion  may be continued over several input lines, in which case the new-         sion may be continued over several input lines, in which case the  new-
118         line characters are included within it. It is possible to  include  the         line  characters  are included within it. It is possible to include the
119         delimiter within the pattern by escaping it, for example         delimiter within the pattern by escaping it, for example
120    
121           /abc\/def/           /abc\/def/
122    
123         If  you  do  so, the escape and the delimiter form part of the pattern,         If you do so, the escape and the delimiter form part  of  the  pattern,
124         but since delimiters are always non-alphanumeric, this does not  affect         but  since delimiters are always non-alphanumeric, this does not affect
125         its  interpretation.   If the terminating delimiter is immediately fol-         its interpretation.  If the terminating delimiter is  immediately  fol-
126         lowed by a backslash, for example,         lowed by a backslash, for example,
127    
128           /abc/\           /abc/\
129    
130         then a backslash is added to the end of the pattern. This  is  done  to         then  a  backslash  is added to the end of the pattern. This is done to
131         provide  a  way of testing the error condition that arises if a pattern         provide a way of testing the error condition that arises if  a  pattern
132         finishes with a backslash, because         finishes with a backslash, because
133    
134           /abc\/           /abc\/
135    
136         is interpreted as the first line of a pattern that starts with  "abc/",         is  interpreted as the first line of a pattern that starts with "abc/",
137         causing pcretest to read the next line as a continuation of the regular         causing pcretest to read the next line as a continuation of the regular
138         expression.         expression.
139    
140    
141  PATTERN MODIFIERS  PATTERN MODIFIERS
142    
143         A pattern may be followed by any number of modifiers, which are  mostly         A  pattern may be followed by any number of modifiers, which are mostly
144         single  characters.  Following  Perl usage, these are referred to below         single characters. Following Perl usage, these are  referred  to  below
145         as, for example, "the /i modifier", even though the  delimiter  of  the         as,  for  example,  "the /i modifier", even though the delimiter of the
146         pattern  need  not always be a slash, and no slash is used when writing         pattern need not always be a slash, and no slash is used  when  writing
147         modifiers. Whitespace may appear between the  final  pattern  delimiter         modifiers.  Whitespace  may  appear between the final pattern delimiter
148         and the first modifier, and between the modifiers themselves.         and the first modifier, and between the modifiers themselves.
149    
150         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
151         PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-         PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-
152         pile()  is  called. These four modifier letters have the same effect as         pile() is called. These four modifier letters have the same  effect  as
153         they do in Perl. For example:         they do in Perl. For example:
154    
155           /caseless/i           /caseless/i
# Line 146  PATTERN MODIFIERS Line 157  PATTERN MODIFIERS
157         The following table shows additional modifiers for setting PCRE options         The following table shows additional modifiers for setting PCRE options
158         that do not correspond to anything in Perl:         that do not correspond to anything in Perl:
159    
160           /A       PCRE_ANCHORED           /A              PCRE_ANCHORED
161           /C       PCRE_AUTO_CALLOUT           /C              PCRE_AUTO_CALLOUT
162           /E       PCRE_DOLLAR_ENDONLY           /E              PCRE_DOLLAR_ENDONLY
163           /f       PCRE_FIRSTLINE           /f              PCRE_FIRSTLINE
164           /J       PCRE_DUPNAMES           /J              PCRE_DUPNAMES
165           /N       PCRE_NO_AUTO_CAPTURE           /N              PCRE_NO_AUTO_CAPTURE
166           /U       PCRE_UNGREEDY           /U              PCRE_UNGREEDY
167           /X       PCRE_EXTRA           /X              PCRE_EXTRA
168           /<cr>    PCRE_NEWLINE_CR           /<JS>           PCRE_JAVASCRIPT_COMPAT
169           /<lf>    PCRE_NEWLINE_LF           /<cr>           PCRE_NEWLINE_CR
170           /<crlf>  PCRE_NEWLINE_CRLF           /<lf>           PCRE_NEWLINE_LF
171           /<any>   PCRE_NEWLINE_ANY           /<crlf>         PCRE_NEWLINE_CRLF
172             /<anycrlf>      PCRE_NEWLINE_ANYCRLF
173         Those  specifying  line ending sequencess are literal strings as shown.           /<any>          PCRE_NEWLINE_ANY
174         This example sets multiline matching  with  CRLF  as  the  line  ending           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
175         sequence:           /<bsr_unicode>  PCRE_BSR_UNICODE
176    
177           Those specifying line ending sequences are literal  strings  as  shown,
178           but  the  letters  can  be  in either case. This example sets multiline
179           matching with CRLF as the line ending sequence:
180    
181           /^abc/m<crlf>           /^abc/m<crlf>
182    
183         Details  of the meanings of these PCRE options are given in the pcreapi         Details of the meanings of these PCRE options are given in the  pcreapi
184         documentation.         documentation.
185    
186     Finding all matches in a string     Finding all matches in a string
187    
188         Searching for all possible matches within each subject  string  can  be         Searching  for  all  possible matches within each subject string can be
189         requested  by  the  /g  or  /G modifier. After finding a match, PCRE is         requested by the /g or /G modifier. After  finding  a  match,  PCRE  is
190         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
191         ence between /g and /G is that the former uses the startoffset argument         ence between /g and /G is that the former uses the startoffset argument
192         to pcre_exec() to start searching at a  new  point  within  the  entire         to  pcre_exec()  to  start  searching  at a new point within the entire
193         string  (which  is in effect what Perl does), whereas the latter passes         string (which is in effect what Perl does), whereas the  latter  passes
194         over a shortened substring. This makes a  difference  to  the  matching         over  a  shortened  substring.  This makes a difference to the matching
195         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
196         or \B).         or \B).
197    
198         If any call to pcre_exec() in a /g or  /G  sequence  matches  an  empty         If  any  call  to  pcre_exec()  in a /g or /G sequence matches an empty
199         string,  the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED         string, the next  call  is  done  with  the  PCRE_NOTEMPTY_ATSTART  and
200         flags set in order to search for another, non-empty, match at the  same         PCRE_ANCHORED  flags  set  in  order  to search for another, non-empty,
201         point.   If  this  second  match fails, the start offset is advanced by         match at the same point. If this second match fails, the  start  offset
202         one, and the normal match is retried. This imitates the way  Perl  han-         is  advanced  by  one  character, and the normal match is retried. This
203         dles such cases when using the /g modifier or the split() function.         imitates the way Perl handles such cases when using the /g modifier  or
204           the split() function.
205    
206     Other modifiers     Other modifiers
207    
208         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
209    
210         The /+ modifier requests that as well as outputting the substring  that         The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
211         matched  the  entire  pattern,  pcretest  should in addition output the         set. This turns on support for UTF-8 character handling in  PCRE,  pro-
212         remainder of the subject string. This is useful  for  tests  where  the         vided  that  it  was  compiled with this support enabled. This modifier
213           also causes any non-printing characters in output strings to be printed
214           using the \x{hh...} notation if they are valid UTF-8 sequences.
215    
216           If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call
217           pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the
218           checking of the string for UTF-8 validity.
219    
220           The  /+ modifier requests that as well as outputting the substring that
221           matched the entire pattern, pcretest  should  in  addition  output  the
222           remainder  of  the  subject  string. This is useful for tests where the
223         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
224    
225         The  /B modifier is a debugging feature. It requests that pcretest out-         The /B modifier is a debugging feature. It requests that pcretest  out-
226         put a representation of the compiled byte code after compilation.         put  a representation of the compiled byte code after compilation. Nor-
227           mally this information contains length and offset values;  however,  if
228           /Z  is also present, this data is replaced by spaces. This is a special
229           feature for use in the automatic test scripts; it ensures that the same
230           output is generated for different internal link sizes.
231    
232           The  /D modifier is a PCRE debugging feature, and is equivalent to /BI,
233           that is, both the /B and the /I modifiers.
234    
235           The /F modifier causes pcretest to flip the byte order of the fields in
236           the  compiled  pattern  that  contain  2-byte  and 4-byte numbers. This
237           facility is for testing the feature in PCRE that allows it  to  execute
238           patterns that were compiled on a host with a different endianness. This
239           feature is not available when the POSIX  interface  to  PCRE  is  being
240           used,  that is, when the /P pattern modifier is specified. See also the
241           section about saving and reloading compiled patterns below.
242    
243           The /I modifier requests that pcretest  output  information  about  the
244           compiled  pattern (whether it is anchored, has a fixed first character,
245           and so on). It does this by calling pcre_fullinfo() after  compiling  a
246           pattern.  If  the pattern is studied, the results of that are also out-
247           put.
248    
249           The /K modifier requests pcretest to show names from backtracking  con-
250           trol  verbs  that  are  returned  from  calls to pcre_exec(). It causes
251           pcretest to create a pcre_extra block if one has not already been  cre-
252           ated by a call to pcre_study(), and to set the PCRE_EXTRA_MARK flag and
253           the mark field within it, every time that pcre_exec() is called. If the
254           variable  that  the  mark field points to is non-NULL for a match, non-
255           match, or partial match, pcretest prints the string to which it points.
256           For a match, this is shown on a line by itself, tagged with "MK:".  For
257           a non-match it is added to the message.
258    
259         The /L modifier must be followed directly by the name of a locale,  for         The /L modifier must be followed directly by the name of a locale,  for
260         example,         example,
# Line 211  PATTERN MODIFIERS Line 268  PATTERN MODIFIERS
268         tables  pointer; that is, /L applies only to the expression on which it         tables  pointer; that is, /L applies only to the expression on which it
269         appears.         appears.
270    
271         The /I modifier requests that pcretest  output  information  about  the         The /M modifier causes the size of memory block used to hold  the  com-
272         compiled  pattern (whether it is anchored, has a fixed first character,         piled pattern to be output.
        and so on). It does this by calling pcre_fullinfo() after  compiling  a  
        pattern.  If  the pattern is studied, the results of that are also out-  
        put.  
   
        The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,  
        that is, both the /B and the /I modifiers.  
273    
274         The /F modifier causes pcretest to flip the byte order of the fields in         The  /P modifier causes pcretest to call PCRE via the POSIX wrapper API
275         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This         rather than its native API. When this  is  done,  all  other  modifiers
276         facility  is  for testing the feature in PCRE that allows it to execute         except  /i,  /m, and /+ are ignored. REG_ICASE is set if /i is present,
277         patterns that were compiled on a host with a different endianness. This         and REG_NEWLINE is set if /m is present. The  wrapper  functions  force
278         feature  is  not  available  when  the POSIX interface to PCRE is being         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
        used, that is, when the /P pattern modifier is specified. See also  the  
        section about saving and reloading compiled patterns below.  
279    
280         The  /S  modifier causes pcre_study() to be called after the expression         The  /S  modifier causes pcre_study() to be called after the expression
281         has been compiled, and the results used when the expression is matched.         has been compiled, and the results used when the expression is matched.
282    
        The  /M  modifier causes the size of memory block used to hold the com-  
        piled pattern to be output.  
   
        The /P modifier causes pcretest to call PCRE via the POSIX wrapper  API  
        rather  than  its  native  API.  When this is done, all other modifiers  
        except /i, /m, and /+ are ignored. REG_ICASE is set if /i  is  present,  
        and  REG_NEWLINE  is  set if /m is present. The wrapper functions force  
        PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.  
   
        The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option  
        set. This turns on support for UTF-8 character handling in  PCRE,  pro-  
        vided  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.  
   
        If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call  
        pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the  
        checking of the string for UTF-8 validity.  
   
283    
284  DATA LINES  DATA LINES
285    
286         Before  each  data  line is passed to pcre_exec(), leading and trailing         Before each data line is passed to pcre_exec(),  leading  and  trailing
287         whitespace is removed, and it is then scanned for \  escapes.  Some  of         whitespace  is  removed,  and it is then scanned for \ escapes. Some of
288         these  are  pretty esoteric features, intended for checking out some of         these are pretty esoteric features, intended for checking out  some  of
289         the more complicated features of PCRE. If you are just  testing  "ordi-         the  more  complicated features of PCRE. If you are just testing "ordi-
290         nary"  regular  expressions,  you probably don't need any of these. The         nary" regular expressions, you probably don't need any  of  these.  The
291         following escapes are recognized:         following escapes are recognized:
292    
293           \a         alarm (BEL, \x07)           \a         alarm (BEL, \x07)
# Line 304  DATA LINES Line 334  DATA LINES
334           \M         discover the minimum MATCH_LIMIT and           \M         discover the minimum MATCH_LIMIT and
335                        MATCH_LIMIT_RECURSION settings                        MATCH_LIMIT_RECURSION settings
336           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
337                        or pcre_dfa_exec()                        or pcre_dfa_exec(); if used twice, pass the
338                          PCRE_NOTEMPTY_ATSTART option
339           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
340                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
341           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
342                        or pcre_dfa_exec()                        or pcre_dfa_exec(); if used twice, pass the
343                          PCRE_PARTIAL_HARD option
344           \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd           \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
345                        (any number of digits)                        (any number of digits)
346           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
347           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
348             \Y         pass the PCRE_NO_START_OPTIMIZE option to pcre_exec()
349                          or pcre_dfa_exec()
350           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
351                        or pcre_dfa_exec()                        or pcre_dfa_exec()
352           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
# Line 326  DATA LINES Line 360  DATA LINES
360                        or pcre_dfa_exec()                        or pcre_dfa_exec()
361           \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()           \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
362                        or pcre_dfa_exec()                        or pcre_dfa_exec()
363             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
364                          or pcre_dfa_exec()
365           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
366                        or pcre_dfa_exec()                        or pcre_dfa_exec()
367    
368         The escapes that specify line ending  sequences  are  literal  strings,         The  escapes  that  specify  line ending sequences are literal strings,
369         exactly as shown. No more than one newline setting should be present in         exactly as shown. No more than one newline setting should be present in
370         any data line.         any data line.
371    
372         A backslash followed by anything else just escapes the  anything  else.         A  backslash  followed by anything else just escapes the anything else.
373         If  the very last character is a backslash, it is ignored. This gives a         If the very last character is a backslash, it is ignored. This gives  a
374         way of passing an empty line as data, since a real  empty  line  termi-         way  of  passing  an empty line as data, since a real empty line termi-
375         nates the data input.         nates the data input.
376    
377         If  \M  is present, pcretest calls pcre_exec() several times, with dif-         If \M is present, pcretest calls pcre_exec() several times,  with  dif-
378         ferent values in the match_limit and  match_limit_recursion  fields  of         ferent  values  in  the match_limit and match_limit_recursion fields of
379         the  pcre_extra  data structure, until it finds the minimum numbers for         the pcre_extra data structure, until it finds the minimum  numbers  for
380         each parameter that allow pcre_exec() to complete. The match_limit num-         each parameter that allow pcre_exec() to complete. The match_limit num-
381         ber  is  a  measure of the amount of backtracking that takes place, and         ber is a measure of the amount of backtracking that  takes  place,  and
382         checking it out can be instructive. For most simple matches, the number         checking it out can be instructive. For most simple matches, the number
383         is  quite  small,  but for patterns with very large numbers of matching         is quite small, but for patterns with very large  numbers  of  matching
384         possibilities, it can become large very quickly with increasing  length         possibilities,  it can become large very quickly with increasing length
385         of subject string. The match_limit_recursion number is a measure of how         of subject string. The match_limit_recursion number is a measure of how
386         much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)         much  stack  (or,  if  PCRE is compiled with NO_RECURSE, how much heap)
387         memory is needed to complete the match attempt.         memory is needed to complete the match attempt.
388    
389         When  \O  is  used, the value specified may be higher or lower than the         When \O is used, the value specified may be higher or  lower  than  the
390         size set by the -O command line option (or defaulted to 45); \O applies         size set by the -O command line option (or defaulted to 45); \O applies
391         only to the call of pcre_exec() for the line in which it appears.         only to the call of pcre_exec() for the line in which it appears.
392    
393         If  the /P modifier was present on the pattern, causing the POSIX wrap-         If the /P modifier was present on the pattern, causing the POSIX  wrap-
394         per API to be used, the only option-setting  sequences  that  have  any         per  API  to  be  used, the only option-setting sequences that have any
395         effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,         effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL,  respectively,
396         to be passed to regexec().         to be passed to regexec().
397    
398         The use of \x{hh...} to represent UTF-8 characters is not dependent  on         The  use of \x{hh...} to represent UTF-8 characters is not dependent on
399         the  use  of  the  /8 modifier on the pattern. It is recognized always.         the use of the /8 modifier on the pattern.  It  is  recognized  always.
400         There may be any number of hexadecimal digits inside  the  braces.  The         There  may  be  any number of hexadecimal digits inside the braces. The
401         result  is from one to six bytes, encoded according to the UTF-8 rules.         result is from one to six bytes,  encoded  according  to  the  original
402           UTF-8  rules  of  RFC  2279.  This  allows for values in the range 0 to
403           0x7FFFFFFF. Note that not all of those are valid Unicode  code  points,
404           or  indeed  valid  UTF-8 characters according to the later rules in RFC
405           3629.
406    
407    
408  THE ALTERNATIVE MATCHING FUNCTION  THE ALTERNATIVE MATCHING FUNCTION
# Line 387  DEFAULT OUTPUT FROM PCRETEST Line 427  DEFAULT OUTPUT FROM PCRETEST
427    
428         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
429         that pcre_exec() returns, starting with number 0 for  the  string  that         that pcre_exec() returns, starting with number 0 for  the  string  that
430         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched  the  whole  pattern. Otherwise, it outputs "No match" when the
431         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-         return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-
432         TIAL,  respectively, and otherwise the PCRE negative error number. Here         tially  matching substring when pcre_exec() returns PCRE_ERROR_PARTIAL.
433           For any other returns, it outputs the PCRE negative error number.  Here
434         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
435    
436           $ pcretest           $ pcretest
# Line 402  DEFAULT OUTPUT FROM PCRETEST Line 443  DEFAULT OUTPUT FROM PCRETEST
443           data> xyz           data> xyz
444           No match           No match
445    
446           Note  that unset capturing substrings that are not followed by one that
447           is set are not returned by pcre_exec(), and are not shown by  pcretest.
448           In  the following example, there are two capturing substrings, but when
449           the first data line is matched, the  second,  unset  substring  is  not
450           shown.  An "internal" unset substring is shown as "<unset>", as for the
451           second data line.
452    
453               re> /(a)|(b)/
454             data> a
455              0: a
456              1: a
457             data> b
458              0: b
459              1: <unset>
460              2: b
461    
462         If the strings contain any non-printing characters, they are output  as         If the strings contain any non-printing characters, they are output  as
463         \0x  escapes,  or  as \x{...} escapes if the /8 modifier was present on         \0x  escapes,  or  as \x{...} escapes if the /8 modifier was present on
464         the pattern. See below for the definition of  non-printing  characters.         the pattern. See below for the definition of  non-printing  characters.
# Line 456  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 513  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
513    
514         (Using  the  normal  matching function on this data finds only "tang".)         (Using  the  normal  matching function on this data finds only "tang".)
515         The longest matching string is always given first (and numbered  zero).         The longest matching string is always given first (and numbered  zero).
516           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
517           lowed by the partially matching substring.
518    
519         If /g is present on the pattern, the search for further matches resumes         If /g is present on the pattern, the search for further matches resumes
520         at the end of the longest match. For example:         at the end of the longest match. For example:
# Line 469  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 528  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
528            1: tan            1: tan
529            0: tan            0: tan
530    
531         Since the matching function does not  support  substring  capture,  the         Since  the  matching  function  does not support substring capture, the
532         escape  sequences  that  are concerned with captured substrings are not         escape sequences that are concerned with captured  substrings  are  not
533         relevant.         relevant.
534    
535    
536  RESTARTING AFTER A PARTIAL MATCH  RESTARTING AFTER A PARTIAL MATCH
537    
538         When the alternative matching function has given the PCRE_ERROR_PARTIAL         When the alternative matching function has given the PCRE_ERROR_PARTIAL
539         return,  indicating that the subject partially matched the pattern, you         return, indicating that the subject partially matched the pattern,  you
540         can restart the match with additional subject data by means of  the  \R         can  restart  the match with additional subject data by means of the \R
541         escape sequence. For example:         escape sequence. For example:
542    
543             re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
544           data> 23ja\P\D           data> 23ja\P\D
545           Partial match: 23ja           Partial match: 23ja
546           data> n05\R\D           data> n05\R\D
547            0: n05            0: n05
548    
549         For  further  information  about  partial matching, see the pcrepartial         For further information about partial  matching,  see  the  pcrepartial
550         documentation.         documentation.
551    
552    
553  CALLOUTS  CALLOUTS
554    
555         If the pattern contains any callout requests, pcretest's callout  func-         If  the pattern contains any callout requests, pcretest's callout func-
556         tion  is  called  during  matching. This works with both matching func-         tion is called during matching. This works  with  both  matching  func-
557         tions. By default, the called function displays the callout number, the         tions. By default, the called function displays the callout number, the
558         start  and  current  positions in the text at the callout time, and the         start and current positions in the text at the callout  time,  and  the
559         next pattern item to be tested. For example, the output         next pattern item to be tested. For example, the output
560    
561           --->pqrabcdef           --->pqrabcdef
562             0    ^  ^     \d             0    ^  ^     \d
563    
564         indicates that callout number 0 occurred for a match  attempt  starting         indicates  that  callout number 0 occurred for a match attempt starting
565         at  the fourth character of the subject string, when the pointer was at         at the fourth character of the subject string, when the pointer was  at
566         the seventh character of the data, and when the next pattern  item  was         the  seventh  character of the data, and when the next pattern item was
567         \d.  Just  one  circumflex is output if the start and current positions         \d. Just one circumflex is output if the start  and  current  positions
568         are the same.         are the same.
569    
570         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
571         a  result  of the /C pattern modifier. In this case, instead of showing         a result of the /C pattern modifier. In this case, instead  of  showing
572         the callout number, the offset in the pattern, preceded by a  plus,  is         the  callout  number, the offset in the pattern, preceded by a plus, is
573         output. For example:         output. For example:
574    
575             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 522  CALLOUTS Line 581  CALLOUTS
581           +10 ^ ^           +10 ^ ^
582            0: E*            0: E*
583    
584         The  callout  function  in pcretest returns zero (carry on matching) by         The callout function in pcretest returns zero (carry  on  matching)  by
585         default, but you can use a \C item in a data line (as described  above)         default,  but you can use a \C item in a data line (as described above)
586         to change this.         to change this.
587    
588         Inserting  callouts can be helpful when using pcretest to check compli-         Inserting callouts can be helpful when using pcretest to check  compli-
589         cated regular expressions. For further information about callouts,  see         cated  regular expressions. For further information about callouts, see
590         the pcrecallout documentation.         the pcrecallout documentation.
591    
592    
593  NON-PRINTING CHARACTERS  NON-PRINTING CHARACTERS
594    
595         When  pcretest is outputting text in the compiled version of a pattern,         When pcretest is outputting text in the compiled version of a  pattern,
596         bytes other than 32-126 are always treated as  non-printing  characters         bytes  other  than 32-126 are always treated as non-printing characters
597         are are therefore shown as hex escapes.         are are therefore shown as hex escapes.
598    
599         When  pcretest  is  outputting text that is a matched part of a subject         When pcretest is outputting text that is a matched part  of  a  subject
600         string, it behaves in the same way, unless a different locale has  been         string,  it behaves in the same way, unless a different locale has been
601         set  for  the  pattern  (using  the  /L  modifier).  In  this case, the         set for the  pattern  (using  the  /L  modifier).  In  this  case,  the
602         isprint() function to distinguish printing and non-printing characters.         isprint() function to distinguish printing and non-printing characters.
603    
604    
# Line 608  SEE ALSO Line 667  SEE ALSO
667  AUTHOR  AUTHOR
668    
669         Philip Hazel         Philip Hazel
670         University Computing Service,         University Computing Service
671         Cambridge CB2 3QH, England.         Cambridge CB2 3QH, England.
672    
673  Last updated: 30 November 2006  
674  Copyright (c) 1997-2006 University of Cambridge.  REVISION
675    
676           Last updated: 26 March 2010
677           Copyright (c) 1997-2010 University of Cambridge.

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