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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 1113 by chpe, Tue Oct 16 15:57:12 2012 UTC
# Line 1  Line 1 
1  .TH PCRE 3  .TH PCREAPI 3 "07 September 2012" "PCRE 8.32"
2  .SH NAME  .SH NAME
3  PCRE - Perl-compatible regular expressions  PCRE - Perl-compatible regular expressions
 .SH "PCRE NATIVE API"  
 .rs  
4  .sp  .sp
5  .B #include <pcre.h>  .B #include <pcre.h>
6  .PP  .
7    .
8    .SH "PCRE NATIVE API BASIC FUNCTIONS"
9    .rs
10    .sp
11  .SM  .SM
 .br  
12  .B pcre *pcre_compile(const char *\fIpattern\fP, int \fIoptions\fP,  .B pcre *pcre_compile(const char *\fIpattern\fP, int \fIoptions\fP,
13  .ti +5n  .ti +5n
14  .B const char **\fIerrptr\fP, int *\fIerroffset\fP,  .B const char **\fIerrptr\fP, int *\fIerroffset\fP,
15  .ti +5n  .ti +5n
16  .B const unsigned char *\fItableptr\fP);  .B const unsigned char *\fItableptr\fP);
17  .PP  .PP
 .br  
18  .B pcre *pcre_compile2(const char *\fIpattern\fP, int \fIoptions\fP,  .B pcre *pcre_compile2(const char *\fIpattern\fP, int \fIoptions\fP,
19  .ti +5n  .ti +5n
20  .B int *\fIerrorcodeptr\fP,  .B int *\fIerrorcodeptr\fP,
# Line 23  PCRE - Perl-compatible regular expressio Line 23  PCRE - Perl-compatible regular expressio
23  .ti +5n  .ti +5n
24  .B const unsigned char *\fItableptr\fP);  .B const unsigned char *\fItableptr\fP);
25  .PP  .PP
 .br  
26  .B pcre_extra *pcre_study(const pcre *\fIcode\fP, int \fIoptions\fP,  .B pcre_extra *pcre_study(const pcre *\fIcode\fP, int \fIoptions\fP,
27  .ti +5n  .ti +5n
28  .B const char **\fIerrptr\fP);  .B const char **\fIerrptr\fP);
29  .PP  .PP
30  .br  .B void pcre_free_study(pcre_extra *\fIextra\fP);
31    .PP
32  .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"  .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
33  .ti +5n  .ti +5n
34  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
35  .ti +5n  .ti +5n
36  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);
37  .PP  .PP
 .br  
38  .B int pcre_dfa_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"  .B int pcre_dfa_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
39  .ti +5n  .ti +5n
40  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
# Line 43  PCRE - Perl-compatible regular expressio Line 42  PCRE - Perl-compatible regular expressio
42  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP,  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP,
43  .ti +5n  .ti +5n
44  .B int *\fIworkspace\fP, int \fIwscount\fP);  .B int *\fIworkspace\fP, int \fIwscount\fP);
45  .PP  .
46  .br  .
47    .SH "PCRE NATIVE API STRING EXTRACTION FUNCTIONS"
48    .rs
49    .sp
50  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,
51  .ti +5n  .ti +5n
52  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 53  PCRE - Perl-compatible regular expressio Line 55  PCRE - Perl-compatible regular expressio
55  .ti +5n  .ti +5n
56  .B char *\fIbuffer\fP, int \fIbuffersize\fP);  .B char *\fIbuffer\fP, int \fIbuffersize\fP);
57  .PP  .PP
 .br  
58  .B int pcre_copy_substring(const char *\fIsubject\fP, int *\fIovector\fP,  .B int pcre_copy_substring(const char *\fIsubject\fP, int *\fIovector\fP,
59  .ti +5n  .ti +5n
60  .B int \fIstringcount\fP, int \fIstringnumber\fP, char *\fIbuffer\fP,  .B int \fIstringcount\fP, int \fIstringnumber\fP, char *\fIbuffer\fP,
61  .ti +5n  .ti +5n
62  .B int \fIbuffersize\fP);  .B int \fIbuffersize\fP);
63  .PP  .PP
 .br  
64  .B int pcre_get_named_substring(const pcre *\fIcode\fP,  .B int pcre_get_named_substring(const pcre *\fIcode\fP,
65  .ti +5n  .ti +5n
66  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 69  PCRE - Perl-compatible regular expressio Line 69  PCRE - Perl-compatible regular expressio
69  .ti +5n  .ti +5n
70  .B const char **\fIstringptr\fP);  .B const char **\fIstringptr\fP);
71  .PP  .PP
 .br  
72  .B int pcre_get_stringnumber(const pcre *\fIcode\fP,  .B int pcre_get_stringnumber(const pcre *\fIcode\fP,
73  .ti +5n  .ti +5n
74  .B const char *\fIname\fP);  .B const char *\fIname\fP);
75  .PP  .PP
76  .br  .B int pcre_get_stringtable_entries(const pcre *\fIcode\fP,
77    .ti +5n
78    .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
79    .PP
80  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,
81  .ti +5n  .ti +5n
82  .B int \fIstringcount\fP, int \fIstringnumber\fP,  .B int \fIstringcount\fP, int \fIstringnumber\fP,
83  .ti +5n  .ti +5n
84  .B const char **\fIstringptr\fP);  .B const char **\fIstringptr\fP);
85  .PP  .PP
 .br  
86  .B int pcre_get_substring_list(const char *\fIsubject\fP,  .B int pcre_get_substring_list(const char *\fIsubject\fP,
87  .ti +5n  .ti +5n
88  .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"  .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"
89  .PP  .PP
 .br  
90  .B void pcre_free_substring(const char *\fIstringptr\fP);  .B void pcre_free_substring(const char *\fIstringptr\fP);
91  .PP  .PP
 .br  
92  .B void pcre_free_substring_list(const char **\fIstringptr\fP);  .B void pcre_free_substring_list(const char **\fIstringptr\fP);
93    .
94    .
95    .SH "PCRE NATIVE API AUXILIARY FUNCTIONS"
96    .rs
97    .sp
98    .B pcre_jit_stack *pcre_jit_stack_alloc(int \fIstartsize\fP, int \fImaxsize\fP);
99    .PP
100    .B void pcre_jit_stack_free(pcre_jit_stack *\fIstack\fP);
101    .PP
102    .B void pcre_assign_jit_stack(pcre_extra *\fIextra\fP,
103    .ti +5n
104    .B pcre_jit_callback \fIcallback\fP, void *\fIdata\fP);
105  .PP  .PP
 .br  
106  .B const unsigned char *pcre_maketables(void);  .B const unsigned char *pcre_maketables(void);
107  .PP  .PP
 .br  
108  .B int pcre_fullinfo(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"  .B int pcre_fullinfo(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
109  .ti +5n  .ti +5n
110  .B int \fIwhat\fP, void *\fIwhere\fP);  .B int \fIwhat\fP, void *\fIwhere\fP);
111  .PP  .PP
 .br  
 .B int pcre_info(const pcre *\fIcode\fP, int *\fIoptptr\fP, int  
 .B *\fIfirstcharptr\fP);  
 .PP  
 .br  
112  .B int pcre_refcount(pcre *\fIcode\fP, int \fIadjust\fP);  .B int pcre_refcount(pcre *\fIcode\fP, int \fIadjust\fP);
113  .PP  .PP
 .br  
114  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);
115  .PP  .PP
116  .br  .B const char *pcre_version(void);
 .B char *pcre_version(void);  
117  .PP  .PP
118  .br  .B int pcre_pattern_to_host_byte_order(pcre *\fIcode\fP,
119    .ti +5n
120    .B pcre_extra *\fIextra\fP, const unsigned char *\fItables\fP);
121    .
122    .
123    .SH "PCRE NATIVE API INDIRECTED FUNCTIONS"
124    .rs
125    .sp
126  .B void *(*pcre_malloc)(size_t);  .B void *(*pcre_malloc)(size_t);
127  .PP  .PP
 .br  
128  .B void (*pcre_free)(void *);  .B void (*pcre_free)(void *);
129  .PP  .PP
 .br  
130  .B void *(*pcre_stack_malloc)(size_t);  .B void *(*pcre_stack_malloc)(size_t);
131  .PP  .PP
 .br  
132  .B void (*pcre_stack_free)(void *);  .B void (*pcre_stack_free)(void *);
133  .PP  .PP
 .br  
134  .B int (*pcre_callout)(pcre_callout_block *);  .B int (*pcre_callout)(pcre_callout_block *);
135  .  .
136  .  .
137    .SH "PCRE 8-BIT, 16-BIT AND 32-BIT LIBRARIES"
138    .rs
139    .sp
140    From release 8.30, PCRE can be compiled as a library for handling 16-bit
141    character strings as well as, or instead of, the original library that handles
142    8-bit character strings. From release 8.32, PCRE can also be compiled as a
143    library for handling 32-bit character strings. To avoid too much complication,
144    this document describes the 8-bit versions of the functions, with only
145    occasional references to the 16-bit and 32-bit libraries.
146    .P
147    The 16-bit functions operate in the same way as their 8-bit counterparts; they
148    just use different data types for their arguments and results, and their names
149    start with \fBpcre16_\fP instead of \fBpcre_\fP. For every option that has UTF8
150    in its name (for example, PCRE_UTF8), there is a corresponding 16-bit name with
151    UTF8 replaced by UTF16. This facility is in fact just cosmetic; the 16-bit
152    option names define the same bit values.
153    .P
154    The 32-bit functions operate in the same way as their 8-bit counterparts; they
155    just use different data types for their arguments and results, and their names
156    start with \fBpcre32_\fP instead of \fBpcre_\fP. For every option that has UTF8
157    in its name (for example, PCRE_UTF8), there is a corresponding 32-bit name with
158    UTF8 replaced by UTF32. This facility is in fact just cosmetic; the 32-bit
159    option names define the same bit values.
160    .P
161    References to bytes and UTF-8 in this document should be read as references to
162    16-bit data quantities and UTF-16 when using the 16-bit library, unless
163    specified otherwise. More details of the specific differences for the 16-bit
164    library are given in the
165    .\" HREF
166    \fBpcre16\fP
167    .\"
168    page.
169    .
170    .P
171    References to bytes and UTF-8 in this document should be read as references to
172    32-bit data quantities and UTF-32 when using the 32-bit library, unless
173    specified otherwise. More details of the specific differences for the 32-bit
174    library are given in the
175    .\" HREF
176    \fBpcre32\fP
177    .\"
178    page.
179    .
180    .
181  .SH "PCRE API OVERVIEW"  .SH "PCRE API OVERVIEW"
182  .rs  .rs
183  .sp  .sp
184  PCRE has its own native API, which is described in this document. There is  PCRE has its own native API, which is described in this document. There are
185  also a set of wrapper functions that correspond to the POSIX regular expression  also some wrapper functions (for the 8-bit library only) that correspond to the
186  API. These are described in the  POSIX regular expression API, but they do not give access to all the
187    functionality. They are described in the
188  .\" HREF  .\" HREF
189  \fBpcreposix\fP  \fBpcreposix\fP
190  .\"  .\"
191  documentation. Both of these APIs define a set of C function calls. A C++  documentation. Both of these APIs define a set of C function calls. A C++
192  wrapper is distributed with PCRE. It is documented in the  wrapper (again for the 8-bit library only) is also distributed with PCRE. It is
193    documented in the
194  .\" HREF  .\" HREF
195  \fBpcrecpp\fP  \fBpcrecpp\fP
196  .\"  .\"
197  page.  page.
198  .P  .P
199  The native API C function prototypes are defined in the header file  The native API C function prototypes are defined in the header file
200  \fBpcre.h\fP, and on Unix systems the library itself is called \fBlibpcre\fP.  \fBpcre.h\fP, and on Unix-like systems the (8-bit) library itself is called
201  It can normally be accessed by adding \fB-lpcre\fP to the command for linking  \fBlibpcre\fP. It can normally be accessed by adding \fB-lpcre\fP to the
202  an application that uses PCRE. The header file defines the macros PCRE_MAJOR  command for linking an application that uses PCRE. The header file defines the
203  and PCRE_MINOR to contain the major and minor release numbers for the library.  macros PCRE_MAJOR and PCRE_MINOR to contain the major and minor release numbers
204  Applications can use these to include support for different releases of PCRE.  for the library. Applications can use these to include support for different
205    releases of PCRE.
206    .P
207    In a Windows environment, if you want to statically link an application program
208    against a non-dll \fBpcre.a\fP file, you must define PCRE_STATIC before
209    including \fBpcre.h\fP or \fBpcrecpp.h\fP, because otherwise the
210    \fBpcre_malloc()\fP and \fBpcre_free()\fP exported functions will be declared
211    \fB__declspec(dllimport)\fP, with unwanted results.
212  .P  .P
213  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,
214  and \fBpcre_exec()\fP are used for compiling and matching regular expressions  and \fBpcre_exec()\fP are used for compiling and matching regular expressions
215  in a Perl-compatible manner. A sample program that demonstrates the simplest  in a Perl-compatible manner. A sample program that demonstrates the simplest
216  way of using them is provided in the file called \fIpcredemo.c\fP in the source  way of using them is provided in the file called \fIpcredemo.c\fP in the PCRE
217  distribution. The  source distribution. A listing of this program is given in the
218    .\" HREF
219    \fBpcredemo\fP
220    .\"
221    documentation, and the
222  .\" HREF  .\" HREF
223  \fBpcresample\fP  \fBpcresample\fP
224  .\"  .\"
225  documentation describes how to run it.  documentation describes how to compile and run it.
226    .P
227    Just-in-time compiler support is an optional feature of PCRE that can be built
228    in appropriate hardware environments. It greatly speeds up the matching
229    performance of many patterns. Simple programs can easily request that it be
230    used if available, by setting an option that is ignored when it is not
231    relevant. More complicated programs might need to make use of the functions
232    \fBpcre_jit_stack_alloc()\fP, \fBpcre_jit_stack_free()\fP, and
233    \fBpcre_assign_jit_stack()\fP in order to control the JIT code's memory usage.
234    These functions are discussed in the
235    .\" HREF
236    \fBpcrejit\fP
237    .\"
238    documentation.
239  .P  .P
240  A second matching function, \fBpcre_dfa_exec()\fP, which is not  A second matching function, \fBpcre_dfa_exec()\fP, which is not
241  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
242  matching. This allows it to find all possible matches (at a given point in the  matching. The alternative algorithm finds all possible matches (at a given
243  subject), not just one. However, this algorithm does not return captured  point in the subject), and scans the subject just once (unless there are
244    lookbehind assertions). However, this algorithm does not return captured
245  substrings. A description of the two matching algorithms and their advantages  substrings. A description of the two matching algorithms and their advantages
246  and disadvantages is given in the  and disadvantages is given in the
247  .\" HREF  .\" HREF
# Line 183  matched by \fBpcre_exec()\fP. They are: Line 259  matched by \fBpcre_exec()\fP. They are:
259    \fBpcre_get_named_substring()\fP    \fBpcre_get_named_substring()\fP
260    \fBpcre_get_substring_list()\fP    \fBpcre_get_substring_list()\fP
261    \fBpcre_get_stringnumber()\fP    \fBpcre_get_stringnumber()\fP
262      \fBpcre_get_stringtable_entries()\fP
263  .sp  .sp
264  \fBpcre_free_substring()\fP and \fBpcre_free_substring_list()\fP are also  \fBpcre_free_substring()\fP and \fBpcre_free_substring_list()\fP are also
265  provided, to free the memory used for extracted strings.  provided, to free the memory used for extracted strings.
# Line 194  specialist use. Most commonly, no specia Line 271  specialist use. Most commonly, no specia
271  internal tables that are generated when PCRE is built are used.  internal tables that are generated when PCRE is built are used.
272  .P  .P
273  The function \fBpcre_fullinfo()\fP is used to find out information about a  The function \fBpcre_fullinfo()\fP is used to find out information about a
274  compiled pattern; \fBpcre_info()\fP is an obsolete version that returns only  compiled pattern. The function \fBpcre_version()\fP returns a pointer to a
275  some of the available information, but is retained for backwards compatibility.  string containing the version of PCRE and its date of release.
 The function \fBpcre_version()\fP returns a pointer to a string containing the  
 version of PCRE and its date of release.  
276  .P  .P
277  The function \fBpcre_refcount()\fP maintains a reference count in a data block  The function \fBpcre_refcount()\fP maintains a reference count in a data block
278  containing a compiled pattern. This is provided for the benefit of  containing a compiled pattern. This is provided for the benefit of
# Line 212  should be done before calling any PCRE f Line 287  should be done before calling any PCRE f
287  The global variables \fBpcre_stack_malloc\fP and \fBpcre_stack_free\fP are also  The global variables \fBpcre_stack_malloc\fP and \fBpcre_stack_free\fP are also
288  indirections to memory management functions. These special functions are used  indirections to memory management functions. These special functions are used
289  only when PCRE is compiled to use the heap for remembering data, instead of  only when PCRE is compiled to use the heap for remembering data, instead of
290  recursive function calls, when running the \fBpcre_exec()\fP function. This is  recursive function calls, when running the \fBpcre_exec()\fP function. See the
291  a non-standard way of building PCRE, for use in environments that have limited  .\" HREF
292  stacks. Because of the greater use of memory management, it runs more slowly.  \fBpcrebuild\fP
293  Separate functions are provided so that special-purpose external code can be  .\"
294  used for this case. When used, these functions are always called in a  documentation for details of how to do this. It is a non-standard way of
295  stack-like manner (last obtained, first freed), and always for memory blocks of  building PCRE, for use in environments that have limited stacks. Because of the
296  the same size.  greater use of memory management, it runs more slowly. Separate functions are
297    provided so that special-purpose external code can be used for this case. When
298    used, these functions are always called in a stack-like manner (last obtained,
299    first freed), and always for memory blocks of the same size. There is a
300    discussion about PCRE's stack usage in the
301    .\" HREF
302    \fBpcrestack\fP
303    .\"
304    documentation.
305  .P  .P
306  The global variable \fBpcre_callout\fP initially contains NULL. It can be set  The global variable \fBpcre_callout\fP initially contains NULL. It can be set
307  by the caller to a "callout" function, which PCRE will then call at specified  by the caller to a "callout" function, which PCRE will then call at specified
# Line 229  points during a matching operation. Deta Line 312  points during a matching operation. Deta
312  documentation.  documentation.
313  .  .
314  .  .
315    .\" HTML <a name="newlines"></a>
316    .SH NEWLINES
317    .rs
318    .sp
319    PCRE supports five different conventions for indicating line breaks in
320    strings: a single CR (carriage return) character, a single LF (linefeed)
321    character, the two-character sequence CRLF, any of the three preceding, or any
322    Unicode newline sequence. The Unicode newline sequences are the three just
323    mentioned, plus the single characters VT (vertical tab, U+000B), FF (form feed,
324    U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
325    (paragraph separator, U+2029).
326    .P
327    Each of the first three conventions is used by at least one operating system as
328    its standard newline sequence. When PCRE is built, a default can be specified.
329    The default default is LF, which is the Unix standard. When PCRE is run, the
330    default can be overridden, either when a pattern is compiled, or when it is
331    matched.
332    .P
333    At compile time, the newline convention can be specified by the \fIoptions\fP
334    argument of \fBpcre_compile()\fP, or it can be specified by special text at the
335    start of the pattern itself; this overrides any other settings. See the
336    .\" HREF
337    \fBpcrepattern\fP
338    .\"
339    page for details of the special character sequences.
340    .P
341    In the PCRE documentation the word "newline" is used to mean "the character or
342    pair of characters that indicate a line break". The choice of newline
343    convention affects the handling of the dot, circumflex, and dollar
344    metacharacters, the handling of #-comments in /x mode, and, when CRLF is a
345    recognized line ending sequence, the match position advancement for a
346    non-anchored pattern. There is more detail about this in the
347    .\" HTML <a href="#execoptions">
348    .\" </a>
349    section on \fBpcre_exec()\fP options
350    .\"
351    below.
352    .P
353    The choice of newline convention does not affect the interpretation of
354    the \en or \er escape sequences, nor does it affect what \eR matches, which is
355    controlled in a similar way, but by separate options.
356    .
357    .
358  .SH MULTITHREADING  .SH MULTITHREADING
359  .rs  .rs
360  .sp  .sp
# Line 239  callout function pointed to by \fBpcre_c Line 365  callout function pointed to by \fBpcre_c
365  .P  .P
366  The compiled form of a regular expression is not altered during matching, so  The compiled form of a regular expression is not altered during matching, so
367  the same compiled pattern can safely be used by several threads at once.  the same compiled pattern can safely be used by several threads at once.
368    .P
369    If the just-in-time optimization feature is being used, it needs separate
370    memory stack areas for each thread. See the
371    .\" HREF
372    \fBpcrejit\fP
373    .\"
374    documentation for more details.
375  .  .
376  .  .
377  .SH "SAVING PRECOMPILED PATTERNS FOR LATER USE"  .SH "SAVING PRECOMPILED PATTERNS FOR LATER USE"
# Line 250  which it was compiled. Details are given Line 383  which it was compiled. Details are given
383  .\" HREF  .\" HREF
384  \fBpcreprecompile\fP  \fBpcreprecompile\fP
385  .\"  .\"
386  documentation.  documentation, which includes a description of the
387    \fBpcre_pattern_to_host_byte_order()\fP function. However, compiling a regular
388    expression with one version of PCRE for use with a different version is not
389    guaranteed to work and may cause crashes.
390  .  .
391  .  .
392  .SH "CHECKING BUILD-TIME OPTIONS"  .SH "CHECKING BUILD-TIME OPTIONS"
# Line 267  documentation has more details about the Line 403  documentation has more details about the
403  .P  .P
404  The first argument for \fBpcre_config()\fP is an integer, specifying which  The first argument for \fBpcre_config()\fP is an integer, specifying which
405  information is required; the second argument is a pointer to a variable into  information is required; the second argument is a pointer to a variable into
406  which the information is placed. The following information is available:  which the information is placed. The returned value is zero on success, or the
407    negative error code PCRE_ERROR_BADOPTION if the value in the first argument is
408    not recognized. The following information is available:
409  .sp  .sp
410    PCRE_CONFIG_UTF8    PCRE_CONFIG_UTF8
411  .sp  .sp
412  The output is an integer that is set to one if UTF-8 support is available;  The output is an integer that is set to one if UTF-8 support is available;
413  otherwise it is set to zero.  otherwise it is set to zero. This value should normally be given to the 8-bit
414    version of this function, \fBpcre_config()\fP. If it is given to the 16-bit
415    or 32-bit version of this function, the result is PCRE_ERROR_BADOPTION.
416    .sp
417      PCRE_CONFIG_UTF16
418    .sp
419    The output is an integer that is set to one if UTF-16 support is available;
420    otherwise it is set to zero. This value should normally be given to the 16-bit
421    version of this function, \fBpcre16_config()\fP. If it is given to the 8-bit
422    or 32-bit version of this function, the result is PCRE_ERROR_BADOPTION.
423    .sp
424      PCRE_CONFIG_UTF32
425    .sp
426    The output is an integer that is set to one if UTF-32 support is available;
427    otherwise it is set to zero. This value should normally be given to the 32-bit
428    version of this function, \fBpcre32_config()\fP. If it is given to the 8-bit
429    or 16-bit version of this function, the result is PCRE_ERROR_BADOPTION.
430  .sp  .sp
431    PCRE_CONFIG_UNICODE_PROPERTIES    PCRE_CONFIG_UNICODE_PROPERTIES
432  .sp  .sp
433  The output is an integer that is set to one if support for Unicode character  The output is an integer that is set to one if support for Unicode character
434  properties is available; otherwise it is set to zero.  properties is available; otherwise it is set to zero.
435  .sp  .sp
436      PCRE_CONFIG_JIT
437    .sp
438    The output is an integer that is set to one if support for just-in-time
439    compiling is available; otherwise it is set to zero.
440    .sp
441      PCRE_CONFIG_JITTARGET
442    .sp
443    The output is a pointer to a zero-terminated "const char *" string. If JIT
444    support is available, the string contains the name of the architecture for
445    which the JIT compiler is configured, for example "x86 32bit (little endian +
446    unaligned)". If JIT support is not available, the result is NULL.
447    .sp
448    PCRE_CONFIG_NEWLINE    PCRE_CONFIG_NEWLINE
449  .sp  .sp
450  The output is an integer that is set to the value of the code that is used for  The output is an integer whose value specifies the default character sequence
451  the newline character. It is either linefeed (10) or carriage return (13), and  that is recognized as meaning "newline". The values that are supported in
452  should normally be the standard character for your operating system.  ASCII/Unicode environments are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for
453    ANYCRLF, and -1 for ANY. In EBCDIC environments, CR, ANYCRLF, and ANY yield the
454    same values. However, the value for LF is normally 21, though some EBCDIC
455    environments use 37. The corresponding values for CRLF are 3349 and 3365. The
456    default should normally correspond to the standard sequence for your operating
457    system.
458    .sp
459      PCRE_CONFIG_BSR
460    .sp
461    The output is an integer whose value indicates what character sequences the \eR
462    escape sequence matches by default. A value of 0 means that \eR matches any
463    Unicode line ending sequence; a value of 1 means that \eR matches only CR, LF,
464    or CRLF. The default can be overridden when a pattern is compiled or matched.
465  .sp  .sp
466    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
467  .sp  .sp
468  The output is an integer that contains the number of bytes used for internal  The output is an integer that contains the number of bytes used for internal
469  linkage in compiled regular expressions. The value is 2, 3, or 4. Larger values  linkage in compiled regular expressions. For the 8-bit library, the value can
470  allow larger regular expressions to be compiled, at the expense of slower  be 2, 3, or 4. For the 16-bit library, the value is either 2 or 4 and is still
471  matching. The default value of 2 is sufficient for all but the most massive  a number of bytes. For the 32-bit library, the value is either 2 or 4 and is
472  patterns, since it allows the compiled pattern to be up to 64K in size.  still a number of bytes. The default value of 2 is sufficient for all but the
473    most massive patterns, since it allows the compiled pattern to be up to 64K in
474    size. Larger values allow larger regular expressions to be compiled, at the
475    expense of slower matching.
476  .sp  .sp
477    PCRE_CONFIG_POSIX_MALLOC_THRESHOLD    PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
478  .sp  .sp
# Line 305  documentation. Line 486  documentation.
486  .sp  .sp
487    PCRE_CONFIG_MATCH_LIMIT    PCRE_CONFIG_MATCH_LIMIT
488  .sp  .sp
489  The output is an integer that gives the default limit for the number of  The output is a long integer that gives the default limit for the number of
490  internal matching function calls in a \fBpcre_exec()\fP execution. Further  internal matching function calls in a \fBpcre_exec()\fP execution. Further
491  details are given with \fBpcre_exec()\fP below.  details are given with \fBpcre_exec()\fP below.
492  .sp  .sp
493      PCRE_CONFIG_MATCH_LIMIT_RECURSION
494    .sp
495    The output is a long integer that gives the default limit for the depth of
496    recursion when calling the internal matching function in a \fBpcre_exec()\fP
497    execution. Further details are given with \fBpcre_exec()\fP below.
498    .sp
499    PCRE_CONFIG_STACKRECURSE    PCRE_CONFIG_STACKRECURSE
500  .sp  .sp
501  The output is an integer that is set to one if internal recursion when running  The output is an integer that is set to one if internal recursion when running
# Line 340  avoiding the use of the stack. Line 527  avoiding the use of the stack.
527  Either of the functions \fBpcre_compile()\fP or \fBpcre_compile2()\fP can be  Either of the functions \fBpcre_compile()\fP or \fBpcre_compile2()\fP can be
528  called to compile a pattern into an internal form. The only difference between  called to compile a pattern into an internal form. The only difference between
529  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,
530  \fIerrorcodeptr\fP, via which a numerical error code can be returned.  \fIerrorcodeptr\fP, via which a numerical error code can be returned. To avoid
531    too much repetition, we refer just to \fBpcre_compile()\fP below, but the
532    information applies equally to \fBpcre_compile2()\fP.
533  .P  .P
534  The pattern is a C string terminated by a binary zero, and is passed in the  The pattern is a C string terminated by a binary zero, and is passed in the
535  \fIpattern\fP argument. A pointer to a single block of memory that is obtained  \fIpattern\fP argument. A pointer to a single block of memory that is obtained
536  via \fBpcre_malloc\fP is returned. This contains the compiled code and related  via \fBpcre_malloc\fP is returned. This contains the compiled code and related
537  data. The \fBpcre\fP type is defined for the returned block; this is a typedef  data. The \fBpcre\fP type is defined for the returned block; this is a typedef
538  for a structure whose contents are not externally defined. It is up to the  for a structure whose contents are not externally defined. It is up to the
539  caller to free the memory when it is no longer required.  caller to free the memory (via \fBpcre_free\fP) when it is no longer required.
540  .P  .P
541  Although the compiled code of a PCRE regex is relocatable, that is, it does not  Although the compiled code of a PCRE regex is relocatable, that is, it does not
542  depend on memory location, the complete \fBpcre\fP data block is not  depend on memory location, the complete \fBpcre\fP data block is not
543  fully relocatable, because it may contain a copy of the \fItableptr\fP  fully relocatable, because it may contain a copy of the \fItableptr\fP
544  argument, which is an address (see below).  argument, which is an address (see below).
545  .P  .P
546  The \fIoptions\fP argument contains independent bits that affect the  The \fIoptions\fP argument contains various bit settings that affect the
547  compilation. It should be zero if no options are required. The available  compilation. It should be zero if no options are required. The available
548  options are described below. Some of them, in particular, those that are  options are described below. Some of them (in particular, those that are
549  compatible with Perl, can also be set and unset from within the pattern (see  compatible with Perl, but some others as well) can also be set and unset from
550  the detailed description in the  within the pattern (see the detailed description in the
551  .\" HREF  .\" HREF
552  \fBpcrepattern\fP  \fBpcrepattern\fP
553  .\"  .\"
554  documentation). For these options, the contents of the \fIoptions\fP argument  documentation). For those options that can be different in different parts of
555  specifies their initial settings at the start of compilation and execution. The  the pattern, the contents of the \fIoptions\fP argument specifies their
556  PCRE_ANCHORED option can be set at the time of matching as well as at compile  settings at the start of compilation and execution. The PCRE_ANCHORED,
557  time.  PCRE_BSR_\fIxxx\fP, PCRE_NEWLINE_\fIxxx\fP, PCRE_NO_UTF8_CHECK, and
558    PCRE_NO_START_OPTIMIZE options can be set at the time of matching as well as at
559    compile time.
560  .P  .P
561  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
562  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
563  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual
564  error message. The offset from the start of the pattern to the character where  error message. This is a static string that is part of the library. You must
565  the error was discovered is placed in the variable pointed to by  not try to free it. Normally, the offset from the start of the pattern to the
566  \fIerroffset\fP, which must not be NULL. If it is, an immediate error is given.  byte that was being processed when the error was discovered is placed in the
567    variable pointed to by \fIerroffset\fP, which must not be NULL (if it is, an
568    immediate error is given). However, for an invalid UTF-8 string, the offset is
569    that of the first byte of the failing character.
570    .P
571    Some errors are not detected until the whole pattern has been scanned; in these
572    cases, the offset passed back is the length of the pattern. Note that the
573    offset is in bytes, not characters, even in UTF-8 mode. It may sometimes point
574    into the middle of a UTF-8 character.
575  .P  .P
576  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the
577  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is
# Line 419  facility, see the Line 618  facility, see the
618  .\"  .\"
619  documentation.  documentation.
620  .sp  .sp
621      PCRE_BSR_ANYCRLF
622      PCRE_BSR_UNICODE
623    .sp
624    These options (which are mutually exclusive) control what the \eR escape
625    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
626    match any Unicode newline sequence. The default is specified when PCRE is
627    built. It can be overridden from within the pattern, or by setting an option
628    when a compiled pattern is matched.
629    .sp
630    PCRE_CASELESS    PCRE_CASELESS
631  .sp  .sp
632  If this bit is set, letters in the pattern match both upper and lower case  If this bit is set, letters in the pattern match both upper and lower case
# Line 435  with UTF-8 support. Line 643  with UTF-8 support.
643  .sp  .sp
644  If this bit is set, a dollar metacharacter in the pattern matches only at the  If this bit is set, a dollar metacharacter in the pattern matches only at the
645  end of the subject string. Without this option, a dollar also matches  end of the subject string. Without this option, a dollar also matches
646  immediately before the final character if it is a newline (but not before any  immediately before a newline at the end of the string (but not before any other
647  other newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is  newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is set.
648  set. There is no equivalent to this option in Perl, and no way to set it within  There is no equivalent to this option in Perl, and no way to set it within a
649  a pattern.  pattern.
650  .sp  .sp
651    PCRE_DOTALL    PCRE_DOTALL
652  .sp  .sp
653  If this bit is set, a dot metacharater in the pattern matches all characters,  If this bit is set, a dot metacharacter in the pattern matches a character of
654  including newlines. Without it, newlines are excluded. This option is  any value, including one that indicates a newline. However, it only ever
655    matches one character, even if newlines are coded as CRLF. Without this option,
656    a dot does not match when the current position is at a newline. This option is
657  equivalent to Perl's /s option, and it can be changed within a pattern by a  equivalent to Perl's /s option, and it can be changed within a pattern by a
658  (?s) option setting. A negative class such as [^a] always matches a newline  (?s) option setting. A negative class such as [^a] always matches newline
659  character, independent of the setting of this option.  characters, independent of the setting of this option.
660    .sp
661      PCRE_DUPNAMES
662    .sp
663    If this bit is set, names used to identify capturing subpatterns need not be
664    unique. This can be helpful for certain types of pattern when it is known that
665    only one instance of the named subpattern can ever be matched. There are more
666    details of named subpatterns below; see also the
667    .\" HREF
668    \fBpcrepattern\fP
669    .\"
670    documentation.
671  .sp  .sp
672    PCRE_EXTENDED    PCRE_EXTENDED
673  .sp  .sp
674  If this bit is set, whitespace data characters in the pattern are totally  If this bit is set, white space data characters in the pattern are totally
675  ignored except when escaped or inside a character class. Whitespace does not  ignored except when escaped or inside a character class. White space does not
676  include the VT character (code 11). In addition, characters between an  include the VT character (code 11). In addition, characters between an
677  unescaped # outside a character class and the next newline character,  unescaped # outside a character class and the next newline, inclusive, are also
678  inclusive, are also ignored. This is equivalent to Perl's /x option, and it can  ignored. This is equivalent to Perl's /x option, and it can be changed within a
679  be changed within a pattern by a (?x) option setting.  pattern by a (?x) option setting.
680    .P
681    Which characters are interpreted as newlines is controlled by the options
682    passed to \fBpcre_compile()\fP or by a special sequence at the start of the
683    pattern, as described in the section entitled
684    .\" HTML <a href="pcrepattern.html#newlines">
685    .\" </a>
686    "Newline conventions"
687    .\"
688    in the \fBpcrepattern\fP documentation. Note that the end of this type of
689    comment is a literal newline sequence in the pattern; escape sequences that
690    happen to represent a newline do not count.
691  .P  .P
692  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
693  Note, however, that this applies only to data characters. Whitespace characters  Note, however, that this applies only to data characters. White space characters
694  may never appear within special character sequences in a pattern, for example  may never appear within special character sequences in a pattern, for example
695  within the sequence (?( which introduces a conditional subpattern.  within the sequence (?( that introduces a conditional subpattern.
696  .sp  .sp
697    PCRE_EXTRA    PCRE_EXTRA
698  .sp  .sp
# Line 469  that is incompatible with Perl, but it i Line 701  that is incompatible with Perl, but it i
701  set, any backslash in a pattern that is followed by a letter that has no  set, any backslash in a pattern that is followed by a letter that has no
702  special meaning causes an error, thus reserving these combinations for future  special meaning causes an error, thus reserving these combinations for future
703  expansion. By default, as in Perl, a backslash followed by a letter with no  expansion. By default, as in Perl, a backslash followed by a letter with no
704  special meaning is treated as a literal. There are at present no other features  special meaning is treated as a literal. (Perl can, however, be persuaded to
705  controlled by this option. It can also be set by a (?X) option setting within a  give an error for this, by running it with the -w option.) There are at present
706  pattern.  no other features controlled by this option. It can also be set by a (?X)
707    option setting within a pattern.
708  .sp  .sp
709    PCRE_FIRSTLINE    PCRE_FIRSTLINE
710  .sp  .sp
711  If this option is set, an unanchored pattern is required to match before or at  If this option is set, an unanchored pattern is required to match before or at
712  the first newline character in the subject string, though the matched text may  the first newline in the subject string, though the matched text may continue
713  continue over the newline.  over the newline.
714    .sp
715      PCRE_JAVASCRIPT_COMPAT
716    .sp
717    If this option is set, PCRE's behaviour is changed in some ways so that it is
718    compatible with JavaScript rather than Perl. The changes are as follows:
719    .P
720    (1) A lone closing square bracket in a pattern causes a compile-time error,
721    because this is illegal in JavaScript (by default it is treated as a data
722    character). Thus, the pattern AB]CD becomes illegal when this option is set.
723    .P
724    (2) At run time, a back reference to an unset subpattern group matches an empty
725    string (by default this causes the current matching alternative to fail). A
726    pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
727    an "a" in the subject), whereas it fails by default, for Perl compatibility.
728    .P
729    (3) \eU matches an upper case "U" character; by default \eU causes a compile
730    time error (Perl uses \eU to upper case subsequent characters).
731    .P
732    (4) \eu matches a lower case "u" character unless it is followed by four
733    hexadecimal digits, in which case the hexadecimal number defines the code point
734    to match. By default, \eu causes a compile time error (Perl uses it to upper
735    case the following character).
736    .P
737    (5) \ex matches a lower case "x" character unless it is followed by two
738    hexadecimal digits, in which case the hexadecimal number defines the code point
739    to match. By default, as in Perl, a hexadecimal number is always expected after
740    \ex, but it may have zero, one, or two digits (so, for example, \exz matches a
741    binary zero character followed by z).
742  .sp  .sp
743    PCRE_MULTILINE    PCRE_MULTILINE
744  .sp  .sp
# Line 489  terminating newline (unless PCRE_DOLLAR_ Line 750  terminating newline (unless PCRE_DOLLAR_
750  Perl.  Perl.
751  .P  .P
752  When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs  When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs
753  match immediately following or immediately before any newline in the subject  match immediately following or immediately before internal newlines in the
754  string, respectively, as well as at the very start and end. This is equivalent  subject string, respectively, as well as at the very start and end. This is
755  to Perl's /m option, and it can be changed within a pattern by a (?m) option  equivalent to Perl's /m option, and it can be changed within a pattern by a
756  setting. If there are no "\en" characters in a subject string, or no  (?m) option setting. If there are no newlines in a subject string, or no
757  occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect.  occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect.
758  .sp  .sp
759      PCRE_NEWLINE_CR
760      PCRE_NEWLINE_LF
761      PCRE_NEWLINE_CRLF
762      PCRE_NEWLINE_ANYCRLF
763      PCRE_NEWLINE_ANY
764    .sp
765    These options override the default newline definition that was chosen when PCRE
766    was built. Setting the first or the second specifies that a newline is
767    indicated by a single character (CR or LF, respectively). Setting
768    PCRE_NEWLINE_CRLF specifies that a newline is indicated by the two-character
769    CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three
770    preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
771    that any Unicode newline sequence should be recognized.
772    .P
773    In an ASCII/Unicode environment, the Unicode newline sequences are the three
774    just mentioned, plus the single characters VT (vertical tab, U+000B), FF (form
775    feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
776    (paragraph separator, U+2029). For the 8-bit library, the last two are
777    recognized only in UTF-8 mode.
778    .P
779    When PCRE is compiled to run in an EBCDIC (mainframe) environment, the code for
780    CR is 0x0d, the same as ASCII. However, the character code for LF is normally
781    0x15, though in some EBCDIC environments 0x25 is used. Whichever of these is
782    not LF is made to correspond to Unicode's NEL character. EBCDIC codes are all
783    less than 256. For more details, see the
784    .\" HREF
785    \fBpcrebuild\fP
786    .\"
787    documentation.
788    .P
789    The newline setting in the options word uses three bits that are treated
790    as a number, giving eight possibilities. Currently only six are used (default
791    plus the five values above). This means that if you set more than one newline
792    option, the combination may or may not be sensible. For example,
793    PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
794    other combinations may yield unused numbers and cause an error.
795    .P
796    The only time that a line break in a pattern is specially recognized when
797    compiling is when PCRE_EXTENDED is set. CR and LF are white space characters,
798    and so are ignored in this mode. Also, an unescaped # outside a character class
799    indicates a comment that lasts until after the next line break sequence. In
800    other circumstances, line break sequences in patterns are treated as literal
801    data.
802    .P
803    The newline option that is set at compile time becomes the default that is used
804    for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.
805    .sp
806    PCRE_NO_AUTO_CAPTURE    PCRE_NO_AUTO_CAPTURE
807  .sp  .sp
808  If this option is set, it disables the use of numbered capturing parentheses in  If this option is set, it disables the use of numbered capturing parentheses in
# Line 503  were followed by ?: but named parenthese Line 811  were followed by ?: but named parenthese
811  they acquire numbers in the usual way). There is no equivalent of this option  they acquire numbers in the usual way). There is no equivalent of this option
812  in Perl.  in Perl.
813  .sp  .sp
814      NO_START_OPTIMIZE
815    .sp
816    This is an option that acts at matching time; that is, it is really an option
817    for \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. If it is set at compile time,
818    it is remembered with the compiled pattern and assumed at matching time. For
819    details see the discussion of PCRE_NO_START_OPTIMIZE
820    .\" HTML <a href="#execoptions">
821    .\" </a>
822    below.
823    .\"
824    .sp
825      PCRE_UCP
826    .sp
827    This option changes the way PCRE processes \eB, \eb, \eD, \ed, \eS, \es, \eW,
828    \ew, and some of the POSIX character classes. By default, only ASCII characters
829    are recognized, but if PCRE_UCP is set, Unicode properties are used instead to
830    classify characters. More details are given in the section on
831    .\" HTML <a href="pcre.html#genericchartypes">
832    .\" </a>
833    generic character types
834    .\"
835    in the
836    .\" HREF
837    \fBpcrepattern\fP
838    .\"
839    page. If you set PCRE_UCP, matching one of the items it affects takes much
840    longer. The option is available only if PCRE has been compiled with Unicode
841    property support.
842    .sp
843    PCRE_UNGREEDY    PCRE_UNGREEDY
844  .sp  .sp
845  This option inverts the "greediness" of the quantifiers so that they are not  This option inverts the "greediness" of the quantifiers so that they are not
# Line 512  with Perl. It can also be set by a (?U) Line 849  with Perl. It can also be set by a (?U)
849    PCRE_UTF8    PCRE_UTF8
850  .sp  .sp
851  This option causes PCRE to regard both the pattern and the subject as strings  This option causes PCRE to regard both the pattern and the subject as strings
852  of UTF-8 characters instead of single-byte character strings. However, it is  of UTF-8 characters instead of single-byte strings. However, it is available
853  available only when PCRE is built to include UTF-8 support. If not, the use  only when PCRE is built to include UTF support. If not, the use of this option
854  of this option provokes an error. Details of how this option changes the  provokes an error. Details of how this option changes the behaviour of PCRE are
855  behaviour of PCRE are given in the  given in the
 .\" HTML <a href="pcre.html#utf8support">  
 .\" </a>  
 section on UTF-8 support  
 .\"  
 in the main  
856  .\" HREF  .\" HREF
857  \fBpcre\fP  \fBpcreunicode\fP
858  .\"  .\"
859  page.  page.
860  .sp  .sp
861    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
862  .sp  .sp
863  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8
864  automatically checked. If an invalid UTF-8 sequence of bytes is found,  string is automatically checked. There is a discussion about the
865  \fBpcre_compile()\fP returns an error. If you already know that your pattern is  .\" HTML <a href="pcreunicode.html#utf8strings">
866  valid, and you want to skip this check for performance reasons, you can set the  .\" </a>
867  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  validity of UTF-8 strings
868  UTF-8 string as a pattern is undefined. It may cause your program to crash.  .\"
869  Note that this option can also be passed to \fBpcre_exec()\fP and  in the
870  \fBpcre_dfa_exec()\fP, to suppress the UTF-8 validity checking of subject  .\" HREF
871  strings.  \fBpcreunicode\fP
872    .\"
873    page. If an invalid UTF-8 sequence is found, \fBpcre_compile()\fP returns an
874    error. If you already know that your pattern is valid, and you want to skip
875    this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK option.
876    When it is set, the effect of passing an invalid UTF-8 string as a pattern is
877    undefined. It may cause your program to crash. Note that this option can also
878    be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress the
879    validity checking of subject strings.
880  .  .
881  .  .
882  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 544  strings. Line 884  strings.
884  .sp  .sp
885  The following table lists the error codes than may be returned by  The following table lists the error codes than may be returned by
886  \fBpcre_compile2()\fP, along with the error messages that may be returned by  \fBpcre_compile2()\fP, along with the error messages that may be returned by
887  both compiling functions.  both compiling functions. Note that error messages are always 8-bit ASCII
888    strings, even in 16-bit or 32-bit mode. As PCRE has developed, some error codes
889    have fallen out of use. To avoid confusion, they have not been re-used.
890  .sp  .sp
891     0  no error     0  no error
892     1  \e at end of pattern     1  \e at end of pattern
# Line 556  both compiling functions. Line 898  both compiling functions.
898     7  invalid escape sequence in character class     7  invalid escape sequence in character class
899     8  range out of order in character class     8  range out of order in character class
900     9  nothing to repeat     9  nothing to repeat
901    10  operand of unlimited repeat could match the empty string    10  [this code is not in use]
902    11  internal error: unexpected repeat    11  internal error: unexpected repeat
903    12  unrecognized character after (?    12  unrecognized character after (? or (?-
904    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
905    14  missing )    14  missing )
906    15  reference to non-existent subpattern    15  reference to non-existent subpattern
907    16  erroffset passed as NULL    16  erroffset passed as NULL
908    17  unknown option bit(s) set    17  unknown option bit(s) set
909    18  missing ) after comment    18  missing ) after comment
910    19  parentheses nested too deeply    19  [this code is not in use]
911    20  regular expression too large    20  regular expression is too large
912    21  failed to get memory    21  failed to get memory
913    22  unmatched parentheses    22  unmatched parentheses
914    23  internal error: code overflow    23  internal error: code overflow
915    24  unrecognized character after (?<    24  unrecognized character after (?<
916    25  lookbehind assertion is not fixed length    25  lookbehind assertion is not fixed length
917    26  malformed number after (?(    26  malformed number or name after (?(
918    27  conditional group contains more than two branches    27  conditional group contains more than two branches
919    28  assertion expected after (?(    28  assertion expected after (?(
920    29  (?R or (?digits must be followed by )    29  (?R or (?[+-]digits must be followed by )
921    30  unknown POSIX class name    30  unknown POSIX class name
922    31  POSIX collating elements are not supported    31  POSIX collating elements are not supported
923    32  this version of PCRE is not compiled with PCRE_UTF8 support    32  this version of PCRE is compiled without UTF support
924    33  spare error    33  [this code is not in use]
925    34  character value in \ex{...} sequence is too large    34  character value in \ex{...} sequence is too large
926    35  invalid condition (?(0)    35  invalid condition (?(0)
927    36  \eC not allowed in lookbehind assertion    36  \eC not allowed in lookbehind assertion
928    37  PCRE does not support \eL, \el, \eN, \eU, or \eu    37  PCRE does not support \eL, \el, \eN{name}, \eU, or \eu
929    38  number after (?C is > 255    38  number after (?C is > 255
930    39  closing ) for (?C expected    39  closing ) for (?C expected
931    40  recursive call could loop indefinitely    40  recursive call could loop indefinitely
932    41  unrecognized character after (?P    41  unrecognized character after (?P
933    42  syntax error after (?P    42  syntax error in subpattern name (missing terminator)
934    43  two named groups have the same name    43  two named subpatterns have the same name
935    44  invalid UTF-8 string    44  invalid UTF-8 string (specifically UTF-8)
936    45  support for \eP, \ep, and \eX has not been compiled    45  support for \eP, \ep, and \eX has not been compiled
937    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
938    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
939      48  subpattern name is too long (maximum 32 characters)
940      49  too many named subpatterns (maximum 10000)
941      50  [this code is not in use]
942      51  octal value is greater than \e377 in 8-bit non-UTF-8 mode
943      52  internal error: overran compiling workspace
944      53  internal error: previously-checked referenced subpattern
945            not found
946      54  DEFINE group contains more than one branch
947      55  repeating a DEFINE group is not allowed
948      56  inconsistent NEWLINE options
949      57  \eg is not followed by a braced, angle-bracketed, or quoted
950            name/number or by a plain number
951      58  a numbered reference must not be zero
952      59  an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
953      60  (*VERB) not recognized
954      61  number is too big
955      62  subpattern name expected
956      63  digit expected after (?+
957      64  ] is an invalid data character in JavaScript compatibility mode
958      65  different names for subpatterns of the same number are
959            not allowed
960      66  (*MARK) must have an argument
961      67  this version of PCRE is not compiled with Unicode property
962            support
963      68  \ec must be followed by an ASCII character
964      69  \ek is not followed by a braced, angle-bracketed, or quoted name
965      70  internal error: unknown opcode in find_fixedlength()
966      71  \eN is not supported in a class
967      72  too many forward references
968      73  disallowed Unicode code point (>= 0xd800 && <= 0xdfff)
969      74  invalid UTF-16 string (specifically UTF-16)
970      75  name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN)
971      76  character value in \eu.... sequence is too large
972      77  invalid UTF-32 string (specifically UTF-32)
973    .sp
974    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
975    be used if the limits were changed when PCRE was built.
976  .  .
977  .  .
978    .\" HTML <a name="studyingapattern"></a>
979  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
980  .rs  .rs
981  .sp  .sp
# Line 612  help speed up matching, \fBpcre_study()\ Line 992  help speed up matching, \fBpcre_study()\
992  results of the study.  results of the study.
993  .P  .P
994  The returned value from \fBpcre_study()\fP can be passed directly to  The returned value from \fBpcre_study()\fP can be passed directly to
995  \fBpcre_exec()\fP. However, a \fBpcre_extra\fP block also contains other  \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. However, a \fBpcre_extra\fP block
996  fields that can be set by the caller before the block is passed; these are  also contains other fields that can be set by the caller before the block is
997  described  passed; these are described
998  .\" HTML <a href="#extradata">  .\" HTML <a href="#extradata">
999  .\" </a>  .\" </a>
1000  below  below
1001  .\"  .\"
1002  in the section on matching a pattern.  in the section on matching a pattern.
1003  .P  .P
1004  If studying the pattern does not produce any additional information  If studying the pattern does not produce any useful information,
1005  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL by default. In that circumstance, if the
1006  wants to pass any of the other fields to \fBpcre_exec()\fP, it must set up its  calling program wants to pass any of the other fields to \fBpcre_exec()\fP or
1007  own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block. However,
1008  .P  if \fBpcre_study()\fP is called with the PCRE_STUDY_EXTRA_NEEDED option, it
1009  The second argument of \fBpcre_study()\fP contains option bits. At present, no  returns a \fBpcre_extra\fP block even if studying did not find any additional
1010  options are defined, and this argument should always be zero.  information. It may still return NULL, however, if an error occurs in
1011    \fBpcre_study()\fP.
1012    .P
1013    The second argument of \fBpcre_study()\fP contains option bits. There are three
1014    further options in addition to PCRE_STUDY_EXTRA_NEEDED:
1015    .sp
1016      PCRE_STUDY_JIT_COMPILE
1017      PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE
1018      PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE
1019    .sp
1020    If any of these are set, and the just-in-time compiler is available, the
1021    pattern is further compiled into machine code that executes much faster than
1022    the \fBpcre_exec()\fP interpretive matching function. If the just-in-time
1023    compiler is not available, these options are ignored. All undefined bits in the
1024    \fIoptions\fP argument must be zero.
1025    .P
1026    JIT compilation is a heavyweight optimization. It can take some time for
1027    patterns to be analyzed, and for one-off matches and simple patterns the
1028    benefit of faster execution might be offset by a much slower study time.
1029    Not all patterns can be optimized by the JIT compiler. For those that cannot be
1030    handled, matching automatically falls back to the \fBpcre_exec()\fP
1031    interpreter. For more details, see the
1032    .\" HREF
1033    \fBpcrejit\fP
1034    .\"
1035    documentation.
1036  .P  .P
1037  The third argument for \fBpcre_study()\fP is a pointer for an error message. If  The third argument for \fBpcre_study()\fP is a pointer for an error message. If
1038  studying succeeds (even if no data is returned), the variable it points to is  studying succeeds (even if no data is returned), the variable it points to is
1039  set to NULL. Otherwise it points to a textual error message. You should  set to NULL. Otherwise it is set to point to a textual error message. This is a
1040  therefore test the error pointer for NULL after calling \fBpcre_study()\fP, to  static string that is part of the library. You must not try to free it. You
1041  be sure that it has run successfully.  should test the error pointer for NULL after calling \fBpcre_study()\fP, to be
1042    sure that it has run successfully.
1043    .P
1044    When you are finished with a pattern, you can free the memory used for the
1045    study data by calling \fBpcre_free_study()\fP. This function was added to the
1046    API for release 8.20. For earlier versions, the memory could be freed with
1047    \fBpcre_free()\fP, just like the pattern itself. This will still work in cases
1048    where JIT optimization is not used, but it is advisable to change to the new
1049    function when convenient.
1050  .P  .P
1051  This is a typical call to \fBpcre_study\fP():  This is a typical way in which \fBpcre_study\fP() is used (except that in a
1052    real application there should be tests for errors):
1053  .sp  .sp
1054    pcre_extra *pe;    int rc;
1055    pe = pcre_study(    pcre *re;
1056      pcre_extra *sd;
1057      re = pcre_compile("pattern", 0, &error, &erroroffset, NULL);
1058      sd = pcre_study(
1059      re,             /* result of pcre_compile() */      re,             /* result of pcre_compile() */
1060      0,              /* no options exist */      0,              /* no options */
1061      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
1062  .sp    rc = pcre_exec(   /* see below for details of pcre_exec() options */
1063  At present, studying a pattern is useful only for non-anchored patterns that do      re, sd, "subject", 7, 0, 0, ovector, 30);
1064  not have a single fixed starting character. A bitmap of possible starting    ...
1065  bytes is created.    pcre_free_study(sd);
1066      pcre_free(re);
1067    .sp
1068    Studying a pattern does two things: first, a lower bound for the length of
1069    subject string that is needed to match the pattern is computed. This does not
1070    mean that there are any strings of that length that match, but it does
1071    guarantee that no shorter strings match. The value is used to avoid wasting
1072    time by trying to match strings that are shorter than the lower bound. You can
1073    find out the value in a calling program via the \fBpcre_fullinfo()\fP function.
1074    .P
1075    Studying a pattern is also useful for non-anchored patterns that do not have a
1076    single fixed starting character. A bitmap of possible starting bytes is
1077    created. This speeds up finding a position in the subject at which to start
1078    matching. (In 16-bit mode, the bitmap is used for 16-bit values less than 256.
1079    In 32-bit mode, the bitmap is used for 32-bit values less than 256.)
1080    .P
1081    These two optimizations apply to both \fBpcre_exec()\fP and
1082    \fBpcre_dfa_exec()\fP, and the information is also used by the JIT compiler.
1083    The optimizations can be disabled by setting the PCRE_NO_START_OPTIMIZE option
1084    when calling \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP, but if this is done,
1085    JIT execution is also disabled. You might want to do this if your pattern
1086    contains callouts or (*MARK) and you want to make use of these facilities in
1087    cases where matching fails. See the discussion of PCRE_NO_START_OPTIMIZE
1088    .\" HTML <a href="#execoptions">
1089    .\" </a>
1090    below.
1091    .\"
1092  .  .
1093  .  .
1094  .\" HTML <a name="localesupport"></a>  .\" HTML <a name="localesupport"></a>
1095  .SH "LOCALE SUPPORT"  .SH "LOCALE SUPPORT"
1096  .rs  .rs
1097  .sp  .sp
1098  PCRE handles caseless matching, and determines whether characters are letters  PCRE handles caseless matching, and determines whether characters are letters,
1099  digits, or whatever, by reference to a set of tables, indexed by character  digits, or whatever, by reference to a set of tables, indexed by character
1100  value. When running in UTF-8 mode, this applies only to characters with codes  value. When running in UTF-8 mode, this applies only to characters
1101  less than 128. Higher-valued codes never match escapes such as \ew or \ed, but  with codes less than 128. By default, higher-valued codes never match escapes
1102  can be tested with \ep if PCRE is built with Unicode character property  such as \ew or \ed, but they can be tested with \ep if PCRE is built with
1103  support.  Unicode character property support. Alternatively, the PCRE_UCP option can be
1104  .P  set at compile time; this causes \ew and friends to use Unicode property
1105  An internal set of tables is created in the default C locale when PCRE is  support instead of built-in tables. The use of locales with Unicode is
1106  built. This is used when the final argument of \fBpcre_compile()\fP is NULL,  discouraged. If you are handling characters with codes greater than 128, you
1107  and is sufficient for many applications. An alternative set of tables can,  should either use UTF-8 and Unicode, or use locales, but not try to mix the
1108  however, be supplied. These may be created in a different locale from the  two.
1109  default. As more and more applications change to using Unicode, the need for  .P
1110  this locale support is expected to die away.  PCRE contains an internal set of tables that are used when the final argument
1111    of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.
1112    Normally, the internal tables recognize only ASCII characters. However, when
1113    PCRE is built, it is possible to cause the internal tables to be rebuilt in the
1114    default "C" locale of the local system, which may cause them to be different.
1115    .P
1116    The internal tables can always be overridden by tables supplied by the
1117    application that calls PCRE. These may be created in a different locale from
1118    the default. As more and more applications change to using Unicode, the need
1119    for this locale support is expected to die away.
1120  .P  .P
1121  External tables are built by calling the \fBpcre_maketables()\fP function,  External tables are built by calling the \fBpcre_maketables()\fP function,
1122  which has no arguments, in the relevant locale. The result can then be passed  which has no arguments, in the relevant locale. The result can then be passed
# Line 677  the following code could be used: Line 1129  the following code could be used:
1129    tables = pcre_maketables();    tables = pcre_maketables();
1130    re = pcre_compile(..., tables);    re = pcre_compile(..., tables);
1131  .sp  .sp
1132    The locale name "fr_FR" is used on Linux and other Unix-like systems; if you
1133    are using Windows, the name for the French locale is "french".
1134    .P
1135  When \fBpcre_maketables()\fP runs, the tables are built in memory that is  When \fBpcre_maketables()\fP runs, the tables are built in memory that is
1136  obtained via \fBpcre_malloc\fP. It is the caller's responsibility to ensure  obtained via \fBpcre_malloc\fP. It is the caller's responsibility to ensure
1137  that the memory containing the tables remains available for as long as it is  that the memory containing the tables remains available for as long as it is
# Line 695  one in which it was compiled. Passing ta Line 1150  one in which it was compiled. Passing ta
1150  below in the section on matching a pattern.  below in the section on matching a pattern.
1151  .  .
1152  .  .
1153    .\" HTML <a name="infoaboutpattern"></a>
1154  .SH "INFORMATION ABOUT A PATTERN"  .SH "INFORMATION ABOUT A PATTERN"
1155  .rs  .rs
1156  .sp  .sp
# Line 703  below in the section on matching a patte Line 1159  below in the section on matching a patte
1159  .B int \fIwhat\fP, void *\fIwhere\fP);  .B int \fIwhat\fP, void *\fIwhere\fP);
1160  .PP  .PP
1161  The \fBpcre_fullinfo()\fP function returns information about a compiled  The \fBpcre_fullinfo()\fP function returns information about a compiled
1162  pattern. It replaces the obsolete \fBpcre_info()\fP function, which is  pattern. It replaces the \fBpcre_info()\fP function, which was removed from the
1163  nevertheless retained for backwards compability (and is documented below).  library at version 8.30, after more than 10 years of obsolescence.
1164  .P  .P
1165  The first argument for \fBpcre_fullinfo()\fP is a pointer to the compiled  The first argument for \fBpcre_fullinfo()\fP is a pointer to the compiled
1166  pattern. The second argument is the result of \fBpcre_study()\fP, or NULL if  pattern. The second argument is the result of \fBpcre_study()\fP, or NULL if
# Line 713  information is required, and the fourth Line 1169  information is required, and the fourth
1169  to receive the data. The yield of the function is zero for success, or one of  to receive the data. The yield of the function is zero for success, or one of
1170  the following negative numbers:  the following negative numbers:
1171  .sp  .sp
1172    PCRE_ERROR_NULL       the argument \fIcode\fP was NULL    PCRE_ERROR_NULL           the argument \fIcode\fP was NULL
1173                          the argument \fIwhere\fP was NULL                              the argument \fIwhere\fP was NULL
1174    PCRE_ERROR_BADMAGIC   the "magic number" was not found    PCRE_ERROR_BADMAGIC       the "magic number" was not found
1175    PCRE_ERROR_BADOPTION  the value of \fIwhat\fP was invalid    PCRE_ERROR_BADENDIANNESS  the pattern was compiled with different
1176                                endianness
1177      PCRE_ERROR_BADOPTION      the value of \fIwhat\fP was invalid
1178  .sp  .sp
1179  The "magic number" is placed at the start of each compiled pattern as an simple  The "magic number" is placed at the start of each compiled pattern as an simple
1180  check against passing an arbitrary memory pointer. Here is a typical call of  check against passing an arbitrary memory pointer. The endianness error can
1181  \fBpcre_fullinfo()\fP, to obtain the length of the compiled pattern:  occur if a compiled pattern is saved and reloaded on a different host. Here is
1182    a typical call of \fBpcre_fullinfo()\fP, to obtain the length of the compiled
1183    pattern:
1184  .sp  .sp
1185    int rc;    int rc;
1186    unsigned long int length;    size_t length;
1187    rc = pcre_fullinfo(    rc = pcre_fullinfo(
1188      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
1189      pe,               /* result of pcre_study(), or NULL */      sd,               /* result of pcre_study(), or NULL */
1190      PCRE_INFO_SIZE,   /* what is required */      PCRE_INFO_SIZE,   /* what is required */
1191      &length);         /* where to put the data */      &length);         /* where to put the data */
1192  .sp  .sp
# Line 754  a NULL table pointer. Line 1214  a NULL table pointer.
1214  .sp  .sp
1215    PCRE_INFO_FIRSTBYTE    PCRE_INFO_FIRSTBYTE
1216  .sp  .sp
1217  Return information about the first byte of any matched string, for a  Return information about the first data unit of any matched string, for a
1218  non-anchored pattern. (This option used to be called PCRE_INFO_FIRSTCHAR; the  non-anchored pattern. (The name of this option refers to the 8-bit library,
1219  old name is still recognized for backwards compatibility.)  where data units are bytes.) The fourth argument should point to an \fBint\fP
1220  .P  variable.
1221  If there is a fixed first byte, for example, from a pattern such as  .P
1222  (cat|cow|coyote), it is returned in the integer pointed to by \fIwhere\fP.  If there is a fixed first value, for example, the letter "c" from a pattern
1223  Otherwise, if either  such as (cat|cow|coyote), its value is returned. In the 8-bit library, the
1224    value is always less than 256. In the 16-bit library the value can be up to
1225    0xffff. In the 32-bit library the value can be up to 0x10ffff.
1226    .P
1227    If there is no fixed first value, and if either
1228  .sp  .sp
1229  (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch  (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
1230  starts with "^", or  starts with "^", or
# Line 771  starts with "^", or Line 1235  starts with "^", or
1235  -1 is returned, indicating that the pattern matches only at the start of a  -1 is returned, indicating that the pattern matches only at the start of a
1236  subject string or after any newline within the string. Otherwise -2 is  subject string or after any newline within the string. Otherwise -2 is
1237  returned. For anchored patterns, -2 is returned.  returned. For anchored patterns, -2 is returned.
1238    .P
1239    Since for the 32-bit library using the non-UTF-32 mode, this function is unable
1240    to return the full 32-bit range of the character, this value is deprecated;
1241    instead the PCRE_INFO_FIRSTCHARACTERFLAGS and PCRE_INFO_FIRSTCHARACTER values should
1242    be used.
1243  .sp  .sp
1244    PCRE_INFO_FIRSTTABLE    PCRE_INFO_FIRSTTABLE
1245  .sp  .sp
1246  If the pattern was studied, and this resulted in the construction of a 256-bit  If the pattern was studied, and this resulted in the construction of a 256-bit
1247  table indicating a fixed set of bytes for the first byte in any matching  table indicating a fixed set of values for the first data unit in any matching
1248  string, a pointer to the table is returned. Otherwise NULL is returned. The  string, a pointer to the table is returned. Otherwise NULL is returned. The
1249  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
1250  .sp  .sp
1251      PCRE_INFO_HASCRORLF
1252    .sp
1253    Return 1 if the pattern contains any explicit matches for CR or LF characters,
1254    otherwise 0. The fourth argument should point to an \fBint\fP variable. An
1255    explicit match is either a literal CR or LF character, or \er or \en.
1256    .sp
1257      PCRE_INFO_JCHANGED
1258    .sp
1259    Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise
1260    0. The fourth argument should point to an \fBint\fP variable. (?J) and
1261    (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
1262    .sp
1263      PCRE_INFO_JIT
1264    .sp
1265    Return 1 if the pattern was studied with one of the JIT options, and
1266    just-in-time compiling was successful. The fourth argument should point to an
1267    \fBint\fP variable. A return value of 0 means that JIT support is not available
1268    in this version of PCRE, or that the pattern was not studied with a JIT option,
1269    or that the JIT compiler could not handle this particular pattern. See the
1270    .\" HREF
1271    \fBpcrejit\fP
1272    .\"
1273    documentation for details of what can and cannot be handled.
1274    .sp
1275      PCRE_INFO_JITSIZE
1276    .sp
1277    If the pattern was successfully studied with a JIT option, return the size of
1278    the JIT compiled code, otherwise return zero. The fourth argument should point
1279    to a \fBsize_t\fP variable.
1280    .sp
1281    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1282  .sp  .sp
1283  Return the value of the rightmost literal byte that must exist in any matched  Return the value of the rightmost literal data unit that must exist in any
1284  string, other than at its start, if such a byte has been recorded. The fourth  matched string, other than at its start, if such a value has been recorded. The
1285  argument should point to an \fBint\fP variable. If there is no such byte, -1 is  fourth argument should point to an \fBint\fP variable. If there is no such
1286  returned. For anchored patterns, a last literal byte is recorded only if it  value, -1 is returned. For anchored patterns, a last literal value is recorded
1287  follows something of variable length. For example, for the pattern  only if it follows something of variable length. For example, for the pattern
1288  /^a\ed+z\ed+/ the returned value is "z", but for /^a\edz\ed/ the returned value  /^a\ed+z\ed+/ the returned value is "z", but for /^a\edz\ed/ the returned value
1289  is -1.  is -1.
1290    .P
1291    Since for the 32-bit library using the non-UTF-32 mode, this function is unable
1292    to return the full 32-bit range of the character, this value is deprecated;
1293    instead the PCRE_INFO_REQUIREDCHARFLAGS and PCRE_INFO_REQUIREDCHAR values should
1294    be used.
1295    .sp
1296      PCRE_INFO_MAXLOOKBEHIND
1297    .sp
1298    Return the number of characters (NB not bytes) in the longest lookbehind
1299    assertion in the pattern. Note that the simple assertions \eb and \eB require a
1300    one-character lookbehind. This information is useful when doing multi-segment
1301    matching using the partial matching facilities.
1302    .sp
1303      PCRE_INFO_MINLENGTH
1304    .sp
1305    If the pattern was studied and a minimum length for matching subject strings
1306    was computed, its value is returned. Otherwise the returned value is -1. The
1307    value is a number of characters, which in UTF-8 mode may be different from the
1308    number of bytes. The fourth argument should point to an \fBint\fP variable. A
1309    non-negative value is a lower bound to the length of any matching string. There
1310    may not be any strings of that length that do actually match, but every string
1311    that does match is at least that long.
1312  .sp  .sp
1313    PCRE_INFO_NAMECOUNT    PCRE_INFO_NAMECOUNT
1314    PCRE_INFO_NAMEENTRYSIZE    PCRE_INFO_NAMEENTRYSIZE
# Line 795  is -1. Line 1316  is -1.
1316  .sp  .sp
1317  PCRE supports the use of named as well as numbered capturing parentheses. The  PCRE supports the use of named as well as numbered capturing parentheses. The
1318  names are just an additional way of identifying the parentheses, which still  names are just an additional way of identifying the parentheses, which still
1319  acquire numbers. A convenience function called \fBpcre_get_named_substring()\fP  acquire numbers. Several convenience functions such as
1320  is provided for extracting an individual captured substring by name. It is also  \fBpcre_get_named_substring()\fP are provided for extracting captured
1321  possible to extract the data directly, by first converting the name to a number  substrings by name. It is also possible to extract the data directly, by first
1322  in order to access the correct pointers in the output vector (described with  converting the name to a number in order to access the correct pointers in the
1323  \fBpcre_exec()\fP below). To do the conversion, you need to use the  output vector (described with \fBpcre_exec()\fP below). To do the conversion,
1324  name-to-number map, which is described by these three values.  you need to use the name-to-number map, which is described by these three
1325    values.
1326  .P  .P
1327  The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT gives  The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT gives
1328  the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each  the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each
1329  entry; both of these return an \fBint\fP value. The entry size depends on the  entry; both of these return an \fBint\fP value. The entry size depends on the
1330  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first
1331  entry of the table (a pointer to \fBchar\fP). The first two bytes of each entry  entry of the table. This is a pointer to \fBchar\fP in the 8-bit library, where
1332  are the number of the capturing parenthesis, most significant byte first. The  the first two bytes of each entry are the number of the capturing parenthesis,
1333  rest of the entry is the corresponding name, zero terminated. The names are in  most significant byte first. In the 16-bit library, the pointer points to
1334  alphabetical order. For example, consider the following pattern (assume  16-bit data units, the first of which contains the parenthesis number.
1335  PCRE_EXTENDED is set, so white space - including newlines - is ignored):  In the 32-bit library, the pointer points to 32-bit data units, the first of
1336    which contains the parenthesis number. The rest
1337    of the entry is the corresponding name, zero terminated.
1338    .P
1339    The names are in alphabetical order. Duplicate names may appear if (?| is used
1340    to create multiple groups with the same number, as described in the
1341    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1342    .\" </a>
1343    section on duplicate subpattern numbers
1344    .\"
1345    in the
1346    .\" HREF
1347    \fBpcrepattern\fP
1348    .\"
1349    page. Duplicate names for subpatterns with different numbers are permitted only
1350    if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the
1351    table in the order in which they were found in the pattern. In the absence of
1352    (?| this is the order of increasing number; when (?| is used this is not
1353    necessarily the case because later subpatterns may have lower numbers.
1354    .P
1355    As a simple example of the name/number table, consider the following pattern
1356    after compilation by the 8-bit library (assume PCRE_EXTENDED is set, so white
1357    space - including newlines - is ignored):
1358  .sp  .sp
1359  .\" JOIN  .\" JOIN
1360    (?P<date> (?P<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
1361    (?P<month>\ed\ed) - (?P<day>\ed\ed) )    (?<month>\ed\ed) - (?<day>\ed\ed) )
1362  .sp  .sp
1363  There are four named subpatterns, so the table has four entries, and each entry  There are four named subpatterns, so the table has four entries, and each entry
1364  in the table is eight bytes long. The table is as follows, with non-printing  in the table is eight bytes long. The table is as follows, with non-printing
# Line 826  bytes shows in hexadecimal, and undefine Line 1370  bytes shows in hexadecimal, and undefine
1370    00 02 y  e  a  r  00 ??    00 02 y  e  a  r  00 ??
1371  .sp  .sp
1372  When writing code to extract data from named subpatterns using the  When writing code to extract data from named subpatterns using the
1373  name-to-number map, remember that the length of each entry is likely to be  name-to-number map, remember that the length of the entries is likely to be
1374  different for each compiled pattern.  different for each compiled pattern.
1375  .sp  .sp
1376      PCRE_INFO_OKPARTIAL
1377    .sp
1378    Return 1 if the pattern can be used for partial matching with
1379    \fBpcre_exec()\fP, otherwise 0. The fourth argument should point to an
1380    \fBint\fP variable. From release 8.00, this always returns 1, because the
1381    restrictions that previously applied to partial matching have been lifted. The
1382    .\" HREF
1383    \fBpcrepartial\fP
1384    .\"
1385    documentation gives details of partial matching.
1386    .sp
1387    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1388  .sp  .sp
1389  Return a copy of the options with which the pattern was compiled. The fourth  Return a copy of the options with which the pattern was compiled. The fourth
1390  argument should point to an \fBunsigned long int\fP variable. These option bits  argument should point to an \fBunsigned long int\fP variable. These option bits
1391  are those specified in the call to \fBpcre_compile()\fP, modified by any  are those specified in the call to \fBpcre_compile()\fP, modified by any
1392  top-level option settings within the pattern itself.  top-level option settings at the start of the pattern itself. In other words,
1393    they are the options that will be in force when matching starts. For example,
1394    if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
1395    result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
1396  .P  .P
1397  A pattern is automatically anchored by PCRE if all of its top-level  A pattern is automatically anchored by PCRE if all of its top-level
1398  alternatives begin with one of the following:  alternatives begin with one of the following:
# Line 851  For such patterns, the PCRE_ANCHORED bit Line 1409  For such patterns, the PCRE_ANCHORED bit
1409  .sp  .sp
1410    PCRE_INFO_SIZE    PCRE_INFO_SIZE
1411  .sp  .sp
1412  Return the size of the compiled pattern, that is, the value that was passed as  Return the size of the compiled pattern in bytes (for both libraries). The
1413  the argument to \fBpcre_malloc()\fP when PCRE was getting memory in which to  fourth argument should point to a \fBsize_t\fP variable. This value does not
1414  place the compiled data. The fourth argument should point to a \fBsize_t\fP  include the size of the \fBpcre\fP structure that is returned by
1415  variable.  \fBpcre_compile()\fP. The value that is passed as the argument to
1416    \fBpcre_malloc()\fP when \fBpcre_compile()\fP is getting memory in which to
1417    place the compiled data is the value returned by this option plus the size of
1418    the \fBpcre\fP structure. Studying a compiled pattern, with or without JIT,
1419    does not alter the value returned by this option.
1420  .sp  .sp
1421    PCRE_INFO_STUDYSIZE    PCRE_INFO_STUDYSIZE
1422  .sp  .sp
1423  Return the size of the data block pointed to by the \fIstudy_data\fP field in  Return the size in bytes of the data block pointed to by the \fIstudy_data\fP
1424  a \fBpcre_extra\fP block. That is, it is the value that was passed to  field in a \fBpcre_extra\fP block. If \fBpcre_extra\fP is NULL, or there is no
1425  \fBpcre_malloc()\fP when PCRE was getting memory into which to place the data  study data, zero is returned. The fourth argument should point to a
1426  created by \fBpcre_study()\fP. The fourth argument should point to a  \fBsize_t\fP variable. The \fIstudy_data\fP field is set by \fBpcre_study()\fP
1427  \fBsize_t\fP variable.  to record information that will speed up matching (see the section entitled
1428  .  .\" HTML <a href="#studyingapattern">
1429  .  .\" </a>
1430  .SH "OBSOLETE INFO FUNCTION"  "Studying a pattern"
1431  .rs  .\"
1432    above). The format of the \fIstudy_data\fP block is private, but its length
1433    is made available via this option so that it can be saved and restored (see the
1434    .\" HREF
1435    \fBpcreprecompile\fP
1436    .\"
1437    documentation for details).
1438  .sp  .sp
1439  .B int pcre_info(const pcre *\fIcode\fP, int *\fIoptptr\fP, int    PCRE_INFO_FIRSTCHARACTERFLAGS
1440  .B *\fIfirstcharptr\fP);  .sp
1441  .PP  Return information about the first data unit of any matched string, for a
1442  The \fBpcre_info()\fP function is now obsolete because its interface is too  non-anchored pattern. The fourth argument should point to an \fBint\fP
1443  restrictive to return all the available data about a compiled pattern. New  variable.
1444  programs should use \fBpcre_fullinfo()\fP instead. The yield of  .P
1445  \fBpcre_info()\fP is the number of capturing subpatterns, or one of the  If there is a fixed first value, for example, the letter "c" from a pattern
1446  following negative numbers:  such as (cat|cow|coyote), 1 is returned, and the character value can be
1447    retrieved using PCRE_INFO_FIRSTCHARACTER.
1448    .P
1449    If there is no fixed first value, and if either
1450  .sp  .sp
1451    PCRE_ERROR_NULL       the argument \fIcode\fP was NULL  (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
1452    PCRE_ERROR_BADMAGIC   the "magic number" was not found  starts with "^", or
1453  .sp  .sp
1454  If the \fIoptptr\fP argument is not NULL, a copy of the options with which the  (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set
1455  pattern was compiled is placed in the integer it points to (see  (if it were set, the pattern would be anchored),
1456  PCRE_INFO_OPTIONS above).  .sp
1457    2 is returned, indicating that the pattern matches only at the start of a
1458    subject string or after any newline within the string. Otherwise 0 is
1459    returned. For anchored patterns, 0 is returned.
1460    .sp
1461      PCRE_INFO_FIRSTCHARACTER
1462    .sp
1463    Return the fixed first character value, if PCRE_INFO_FIRSTCHARACTERFLAGS returned 1;
1464    otherwise returns 0. The fourth argument should point to an \fBuint_t\fP
1465    variable.
1466    .P
1467    In the 8-bit library, the value is always less than 256. In the 16-bit library
1468    the value can be up to 0xffff. In the 32-bit library in UTF-32 mode the value
1469    can be up to 0x10ffff, and up to 0xffffffff when not using UTF-32 mode.
1470  .P  .P
1471  If the pattern is not anchored and the \fIfirstcharptr\fP argument is not NULL,  If there is no fixed first value, and if either
1472  it is used to pass back information about the first character of any matched  .sp
1473  string (see PCRE_INFO_FIRSTBYTE above).  (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
1474    starts with "^", or
1475    .sp
1476    (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set
1477    (if it were set, the pattern would be anchored),
1478    .sp
1479    -1 is returned, indicating that the pattern matches only at the start of a
1480    subject string or after any newline within the string. Otherwise -2 is
1481    returned. For anchored patterns, -2 is returned.
1482    .sp
1483      PCRE_INFO_REQUIREDCHARFLAGS
1484    .sp
1485    Returns 1 if there is a rightmost literal data unit that must exist in any matched
1486    string, other than at its start. The fourth argument should  point to an \fBint\fP
1487    variable. If there is no such value, 0 is returned. If returning 1, the character
1488    value itself can be retrieved using PCRE_INFO_REQUIREDCHAR.
1489    .P
1490    For anchored patterns, a last literal value is recorded only if it follows something
1491    of variable length. For example, for the pattern /^a\ed+z\ed+/ the returned value
1492    1 (with "z" returned from PCRE_INFO_REQUIREDCHAR), but for /^a\edz\ed/ the returned
1493    value is 0.
1494    .sp
1495      PCRE_INFO_REQUIREDCHAR
1496    .sp
1497    Return the value of the rightmost literal data unit that must exist in any
1498    matched string, other than at its start, if such a value has been recorded. The
1499    fourth argument should point to an \fBuint32_t\fP variable. If there is no such
1500    value, 0 is returned.
1501  .  .
1502  .  .
1503  .SH "REFERENCE COUNTS"  .SH "REFERENCE COUNTS"
# Line 923  is different. (This seems a highly unlik Line 1534  is different. (This seems a highly unlik
1534  .P  .P
1535  The function \fBpcre_exec()\fP is called to match a subject string against a  The function \fBpcre_exec()\fP is called to match a subject string against a
1536  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1537  pattern has been studied, the result of the study should be passed in the  pattern was studied, the result of the study should be passed in the
1538  \fIextra\fP argument. This function is the main matching facility of the  \fIextra\fP argument. You can call \fBpcre_exec()\fP with the same \fIcode\fP
1539  library, and it operates in a Perl-like manner. For specialist use there is  and \fIextra\fP arguments as many times as you like, in order to match
1540  also an alternative matching function, which is described  different subject strings with the same pattern.
1541    .P
1542    This function is the main matching facility of the library, and it operates in
1543    a Perl-like manner. For specialist use there is also an alternative matching
1544    function, which is described
1545  .\" HTML <a href="#dfamatch">  .\" HTML <a href="#dfamatch">
1546  .\" </a>  .\" </a>
1547  below  below
# Line 957  Here is an example of a simple call to \ Line 1572  Here is an example of a simple call to \
1572      ovector,        /* vector of integers for substring information */      ovector,        /* vector of integers for substring information */
1573      30);            /* number of elements (NOT size in bytes) */      30);            /* number of elements (NOT size in bytes) */
1574  .  .
1575    .
1576  .\" HTML <a name="extradata"></a>  .\" HTML <a name="extradata"></a>
1577  .SS "Extra data for \fBpcre_exec()\fR"  .SS "Extra data for \fBpcre_exec()\fR"
1578  .rs  .rs
# Line 964  Here is an example of a simple call to \ Line 1580  Here is an example of a simple call to \
1580  If the \fIextra\fP argument is not NULL, it must point to a \fBpcre_extra\fP  If the \fIextra\fP argument is not NULL, it must point to a \fBpcre_extra\fP
1581  data block. The \fBpcre_study()\fP function returns such a block (when it  data block. The \fBpcre_study()\fP function returns such a block (when it
1582  doesn't return NULL), but you can also create one for yourself, and pass  doesn't return NULL), but you can also create one for yourself, and pass
1583  additional information in it. The fields in a \fBpcre_extra\fP block are as  additional information in it. The \fBpcre_extra\fP block contains the following
1584  follows:  fields (not necessarily in this order):
1585  .sp  .sp
1586    unsigned long int \fIflags\fP;    unsigned long int \fIflags\fP;
1587    void *\fIstudy_data\fP;    void *\fIstudy_data\fP;
1588      void *\fIexecutable_jit\fP;
1589    unsigned long int \fImatch_limit\fP;    unsigned long int \fImatch_limit\fP;
1590      unsigned long int \fImatch_limit_recursion\fP;
1591    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1592    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1593      unsigned char **\fImark\fP;
1594  .sp  .sp
1595  The \fIflags\fP field is a bitmap that specifies which of the other fields  In the 16-bit version of this structure, the \fImark\fP field has type
1596  are set. The flag bits are:  "PCRE_UCHAR16 **".
1597    .sp
1598    In the 32-bit version of this structure, the \fImark\fP field has type
1599    "PCRE_UCHAR32 **".
1600    .P
1601    The \fIflags\fP field is used to specify which of the other fields are set. The
1602    flag bits are:
1603  .sp  .sp
   PCRE_EXTRA_STUDY_DATA  
   PCRE_EXTRA_MATCH_LIMIT  
1604    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1605      PCRE_EXTRA_EXECUTABLE_JIT
1606      PCRE_EXTRA_MARK
1607      PCRE_EXTRA_MATCH_LIMIT
1608      PCRE_EXTRA_MATCH_LIMIT_RECURSION
1609      PCRE_EXTRA_STUDY_DATA
1610    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1611  .sp  .sp
1612  Other flag bits should be set to zero. The \fIstudy_data\fP field is set in the  Other flag bits should be set to zero. The \fIstudy_data\fP field and sometimes
1613  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with  the \fIexecutable_jit\fP field are set in the \fBpcre_extra\fP block that is
1614  the appropriate flag bit. You should not set this yourself, but you may add to  returned by \fBpcre_study()\fP, together with the appropriate flag bits. You
1615  the block by setting the other fields and their corresponding flag bits.  should not set these yourself, but you may add to the block by setting other
1616    fields and their corresponding flag bits.
1617  .P  .P
1618  The \fImatch_limit\fP field provides a means of preventing PCRE from using up a  The \fImatch_limit\fP field provides a means of preventing PCRE from using up a
1619  vast amount of resources when running patterns that are not going to match,  vast amount of resources when running patterns that are not going to match,
1620  but which have a very large number of possibilities in their search trees. The  but which have a very large number of possibilities in their search trees. The
1621  classic example is the use of nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1622  .P  .P
1623  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly  Internally, \fBpcre_exec()\fP uses a function called \fBmatch()\fP, which it
1624  (sometimes recursively). The limit is imposed on the number of times this  calls repeatedly (sometimes recursively). The limit set by \fImatch_limit\fP is
1625  function is called during a match, which has the effect of limiting the amount  imposed on the number of times this function is called during a match, which
1626  of recursion and backtracking that can take place. For patterns that are not  has the effect of limiting the amount of backtracking that can take place. For
1627  anchored, the count starts from zero for each position in the subject string.  patterns that are not anchored, the count restarts from zero for each position
1628    in the subject string.
1629    .P
1630    When \fBpcre_exec()\fP is called with a pattern that was successfully studied
1631    with a JIT option, the way that the matching is executed is entirely different.
1632    However, there is still the possibility of runaway matching that goes on for a
1633    very long time, and so the \fImatch_limit\fP value is also used in this case
1634    (but in a different way) to limit how long the matching can continue.
1635  .P  .P
1636  The default limit for the library can be set when PCRE is built; the default  The default value for the limit can be set when PCRE is built; the default
1637  default is 10 million, which handles all but the most extreme cases. You can  default is 10 million, which handles all but the most extreme cases. You can
1638  reduce the default by suppling \fBpcre_exec()\fP with a \fBpcre_extra\fP block  override the default by suppling \fBpcre_exec()\fP with a \fBpcre_extra\fP
1639  in which \fImatch_limit\fP is set to a smaller value, and  block in which \fImatch_limit\fP is set, and PCRE_EXTRA_MATCH_LIMIT is set in
1640  PCRE_EXTRA_MATCH_LIMIT is set in the \fIflags\fP field. If the limit is  the \fIflags\fP field. If the limit is exceeded, \fBpcre_exec()\fP returns
1641  exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_MATCHLIMIT.  PCRE_ERROR_MATCHLIMIT.
1642    .P
1643    The \fImatch_limit_recursion\fP field is similar to \fImatch_limit\fP, but
1644    instead of limiting the total number of times that \fBmatch()\fP is called, it
1645    limits the depth of recursion. The recursion depth is a smaller number than the
1646    total number of calls, because not all calls to \fBmatch()\fP are recursive.
1647    This limit is of use only if it is set smaller than \fImatch_limit\fP.
1648    .P
1649    Limiting the recursion depth limits the amount of machine stack that can be
1650    used, or, when PCRE has been compiled to use memory on the heap instead of the
1651    stack, the amount of heap memory that can be used. This limit is not relevant,
1652    and is ignored, when matching is done using JIT compiled code.
1653    .P
1654    The default value for \fImatch_limit_recursion\fP can be set when PCRE is
1655    built; the default default is the same value as the default for
1656    \fImatch_limit\fP. You can override the default by suppling \fBpcre_exec()\fP
1657    with a \fBpcre_extra\fP block in which \fImatch_limit_recursion\fP is set, and
1658    PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the \fIflags\fP field. If the limit
1659    is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.
1660  .P  .P
1661  The \fIpcre_callout\fP field is used in conjunction with the "callout" feature,  The \fIcallout_data\fP field is used in conjunction with the "callout" feature,
1662  which is described in the  and is described in the
1663  .\" HREF  .\" HREF
1664  \fBpcrecallout\fP  \fBpcrecallout\fP
1665  .\"  .\"
# Line 1024  called. See the Line 1678  called. See the
1678  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1679  .\"  .\"
1680  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1681    .P
1682    If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1683    be set to point to a suitable variable. If the pattern contains any
1684    backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1685    a name to pass back, a pointer to the name string (zero terminated) is placed
1686    in the variable pointed to by the \fImark\fP field. The names are within the
1687    compiled pattern; if you wish to retain such a name you must copy it before
1688    freeing the memory of a compiled pattern. If there is no name to pass back, the
1689    variable pointed to by the \fImark\fP field is set to NULL. For details of the
1690    backtracking control verbs, see the section entitled
1691    .\" HTML <a href="pcrepattern#backtrackcontrol">
1692    .\" </a>
1693    "Backtracking control"
1694    .\"
1695    in the
1696    .\" HREF
1697    \fBpcrepattern\fP
1698    .\"
1699    documentation.
1700    .
1701  .  .
1702    .\" HTML <a name="execoptions"></a>
1703  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1704  .rs  .rs
1705  .sp  .sp
1706  The unused bits of the \fIoptions\fP argument for \fBpcre_exec()\fP must be  The unused bits of the \fIoptions\fP argument for \fBpcre_exec()\fP must be
1707  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NOTBOL,  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
1708  PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1709    PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, and
1710    PCRE_PARTIAL_SOFT.
1711    .P
1712    If the pattern was successfully studied with one of the just-in-time (JIT)
1713    compile options, the only supported options for JIT execution are
1714    PCRE_NO_UTF8_CHECK, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY,
1715    PCRE_NOTEMPTY_ATSTART, PCRE_PARTIAL_HARD, and PCRE_PARTIAL_SOFT. If an
1716    unsupported option is used, JIT execution is disabled and the normal
1717    interpretive code in \fBpcre_exec()\fP is run.
1718  .sp  .sp
1719    PCRE_ANCHORED    PCRE_ANCHORED
1720  .sp  .sp
# Line 1039  matching position. If a pattern was comp Line 1723  matching position. If a pattern was comp
1723  to be anchored by virtue of its contents, it cannot be made unachored at  to be anchored by virtue of its contents, it cannot be made unachored at
1724  matching time.  matching time.
1725  .sp  .sp
1726      PCRE_BSR_ANYCRLF
1727      PCRE_BSR_UNICODE
1728    .sp
1729    These options (which are mutually exclusive) control what the \eR escape
1730    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1731    match any Unicode newline sequence. These options override the choice that was
1732    made or defaulted when the pattern was compiled.
1733    .sp
1734      PCRE_NEWLINE_CR
1735      PCRE_NEWLINE_LF
1736      PCRE_NEWLINE_CRLF
1737      PCRE_NEWLINE_ANYCRLF
1738      PCRE_NEWLINE_ANY
1739    .sp
1740    These options override the newline definition that was chosen or defaulted when
1741    the pattern was compiled. For details, see the description of
1742    \fBpcre_compile()\fP above. During matching, the newline choice affects the
1743    behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1744    the way the match position is advanced after a match failure for an unanchored
1745    pattern.
1746    .P
1747    When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a
1748    match attempt for an unanchored pattern fails when the current position is at a
1749    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1750    characters, the match position is advanced by two characters instead of one, in
1751    other words, to after the CRLF.
1752    .P
1753    The above rule is a compromise that makes the most common cases work as
1754    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1755    set), it does not match the string "\er\enA" because, after failing at the
1756    start, it skips both the CR and the LF before retrying. However, the pattern
1757    [\er\en]A does match that string, because it contains an explicit CR or LF
1758    reference, and so advances only by one character after the first failure.
1759    .P
1760    An explicit match for CR of LF is either a literal appearance of one of those
1761    characters, or one of the \er or \en escape sequences. Implicit matches such as
1762    [^X] do not count, nor does \es (which includes CR and LF in the characters
1763    that it matches).
1764    .P
1765    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1766    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1767    .sp
1768    PCRE_NOTBOL    PCRE_NOTBOL
1769  .sp  .sp
1770  This option specifies that first character of the subject string is not the  This option specifies that first character of the subject string is not the
# Line 1063  match the empty string, the entire match Line 1789  match the empty string, the entire match
1789  .sp  .sp
1790    a?b?    a?b?
1791  .sp  .sp
1792  is applied to a string not beginning with "a" or "b", it matches the empty  is applied to a string not beginning with "a" or "b", it matches an empty
1793  string at the start of the subject. With PCRE_NOTEMPTY set, this match is not  string at the start of the subject. With PCRE_NOTEMPTY set, this match is not
1794  valid, so PCRE searches further into the string for occurrences of "a" or "b".  valid, so PCRE searches further into the string for occurrences of "a" or "b".
1795  .P  .sp
1796  Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case    PCRE_NOTEMPTY_ATSTART
1797  of a pattern match of the empty string within its \fBsplit()\fP function, and  .sp
1798  when using the /g modifier. It is possible to emulate Perl's behaviour after  This is like PCRE_NOTEMPTY, except that an empty string match that is not at
1799  matching a null string by first trying the match again at the same offset with  the start of the subject is permitted. If the pattern is anchored, such a match
1800  PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the  can occur only if the pattern contains \eK.
1801  starting offset (see below) and trying an ordinary match again. There is some  .P
1802  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.  Perl has no direct equivalent of PCRE_NOTEMPTY or PCRE_NOTEMPTY_ATSTART, but it
1803    does make a special case of a pattern match of the empty string within its
1804    \fBsplit()\fP function, and when using the /g modifier. It is possible to
1805    emulate Perl's behaviour after matching a null string by first trying the match
1806    again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then
1807    if that fails, by advancing the starting offset (see below) and trying an
1808    ordinary match again. There is some code that demonstrates how to do this in
1809    the
1810    .\" HREF
1811    \fBpcredemo\fP
1812    .\"
1813    sample program. In the most general case, you have to check to see if the
1814    newline convention recognizes CRLF as a newline, and if so, and the current
1815    character is CR followed by LF, advance the starting offset by two characters
1816    instead of one.
1817    .sp
1818      PCRE_NO_START_OPTIMIZE
1819    .sp
1820    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1821    a match, in order to speed up the process. For example, if it is known that an
1822    unanchored match must start with a specific character, it searches the subject
1823    for that character, and fails immediately if it cannot find it, without
1824    actually running the main matching function. This means that a special item
1825    such as (*COMMIT) at the start of a pattern is not considered until after a
1826    suitable starting point for the match has been found. When callouts or (*MARK)
1827    items are in use, these "start-up" optimizations can cause them to be skipped
1828    if the pattern is never actually used. The start-up optimizations are in effect
1829    a pre-scan of the subject that takes place before the pattern is run.
1830    .P
1831    The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1832    causing performance to suffer, but ensuring that in cases where the result is
1833    "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1834    are considered at every possible starting position in the subject string. If
1835    PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
1836    time. The use of PCRE_NO_START_OPTIMIZE disables JIT execution; when it is set,
1837    matching is always done using interpretively.
1838    .P
1839    Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1840    Consider the pattern
1841    .sp
1842      (*COMMIT)ABC
1843    .sp
1844    When this is compiled, PCRE records the fact that a match must start with the
1845    character "A". Suppose the subject string is "DEFABC". The start-up
1846    optimization scans along the subject, finds "A" and runs the first match
1847    attempt from there. The (*COMMIT) item means that the pattern must match the
1848    current starting position, which in this case, it does. However, if the same
1849    match is run with PCRE_NO_START_OPTIMIZE set, the initial scan along the
1850    subject string does not happen. The first match attempt is run starting from
1851    "D" and when this fails, (*COMMIT) prevents any further matches being tried, so
1852    the overall result is "no match". If the pattern is studied, more start-up
1853    optimizations may be used. For example, a minimum length for the subject may be
1854    recorded. Consider the pattern
1855    .sp
1856      (*MARK:A)(X|Y)
1857    .sp
1858    The minimum length for a match is one character. If the subject is "ABC", there
1859    will be attempts to match "ABC", "BC", "C", and then finally an empty string.
1860    If the pattern is studied, the final attempt does not take place, because PCRE
1861    knows that the subject is too short, and so the (*MARK) is never encountered.
1862    In this case, studying the pattern does not affect the overall match result,
1863    which is still "no match", but it does affect the auxiliary information that is
1864    returned.
1865  .sp  .sp
1866    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1867  .sp  .sp
1868  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8
1869  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1870  The value of \fIstartoffset\fP is also checked to ensure that it points to the  The entire string is checked before any other processing takes place. The value
1871  start of a UTF-8 character. If an invalid UTF-8 sequence of bytes is found,  of \fIstartoffset\fP is also checked to ensure that it points to the start of a
1872  \fBpcre_exec()\fP returns the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP  UTF-8 character. There is a discussion about the
1873  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  .\" HTML <a href="pcreunicode.html#utf8strings">
1874    .\" </a>
1875    validity of UTF-8 strings
1876    .\"
1877    in the
1878    .\" HREF
1879    \fBpcreunicode\fP
1880    .\"
1881    page. If an invalid sequence of bytes is found, \fBpcre_exec()\fP returns the
1882    error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is a
1883    truncated character at the end of the subject, PCRE_ERROR_SHORTUTF8. In both
1884    cases, information about the precise nature of the error may also be returned
1885    (see the descriptions of these errors in the section entitled \fIError return
1886    values from\fP \fBpcre_exec()\fP
1887    .\" HTML <a href="#errorlist">
1888    .\" </a>
1889    below).
1890    .\"
1891    If \fIstartoffset\fP contains a value that does not point to the start of a
1892    UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1893    returned.
1894  .P  .P
1895  If you already know that your subject is valid, and you want to skip these  If you already know that your subject is valid, and you want to skip these
1896  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when
1897  calling \fBpcre_exec()\fP. You might want to do this for the second and  calling \fBpcre_exec()\fP. You might want to do this for the second and
1898  subsequent calls to \fBpcre_exec()\fP if you are making repeated calls to find  subsequent calls to \fBpcre_exec()\fP if you are making repeated calls to find
1899  all the matches in a single subject string. However, you should be sure that  all the matches in a single subject string. However, you should be sure that
1900  the value of \fIstartoffset\fP points to the start of a UTF-8 character. When  the value of \fIstartoffset\fP points to the start of a character (or the end
1901  PCRE_NO_UTF8_CHECK is set, the effect of passing an invalid UTF-8 string as a  of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an
1902  subject, or a value of \fIstartoffset\fP that does not point to the start of a  invalid string as a subject or an invalid value of \fIstartoffset\fP is
1903  UTF-8 character, is undefined. Your program may crash.  undefined. Your program may crash.
1904  .sp  .sp
1905    PCRE_PARTIAL    PCRE_PARTIAL_HARD
1906  .sp    PCRE_PARTIAL_SOFT
1907  This option turns on the partial matching feature. If the subject string fails  .sp
1908  to match the pattern, but at some point during the matching process the end of  These options turn on the partial matching feature. For backwards
1909  the subject was reached (that is, the subject partially matches the pattern and  compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match
1910  the failure to match occurred only because there were not enough subject  occurs if the end of the subject string is reached successfully, but there are
1911  characters), \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL instead of  not enough subject characters to complete the match. If this happens when
1912  PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is used, there are restrictions on what  PCRE_PARTIAL_SOFT (but not PCRE_PARTIAL_HARD) is set, matching continues by
1913  may appear in the pattern. These are discussed in the  testing any remaining alternatives. Only if no complete match can be found is
1914    PCRE_ERROR_PARTIAL returned instead of PCRE_ERROR_NOMATCH. In other words,
1915    PCRE_PARTIAL_SOFT says that the caller is prepared to handle a partial match,
1916    but only if no complete match can be found.
1917    .P
1918    If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a
1919    partial match is found, \fBpcre_exec()\fP immediately returns
1920    PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1921    when PCRE_PARTIAL_HARD is set, a partial match is considered to be more
1922    important that an alternative complete match.
1923    .P
1924    In both cases, the portion of the string that was inspected when the partial
1925    match was found is set as the first matching string. There is a more detailed
1926    discussion of partial and multi-segment matching, with examples, in the
1927  .\" HREF  .\" HREF
1928  \fBpcrepartial\fP  \fBpcrepartial\fP
1929  .\"  .\"
1930  documentation.  documentation.
1931  .  .
1932    .
1933  .SS "The string to be matched by \fBpcre_exec()\fP"  .SS "The string to be matched by \fBpcre_exec()\fP"
1934  .rs  .rs
1935  .sp  .sp
1936  The subject string is passed to \fBpcre_exec()\fP as a pointer in  The subject string is passed to \fBpcre_exec()\fP as a pointer in
1937  \fIsubject\fP, a length in \fIlength\fP, and a starting byte offset in  \fIsubject\fP, a length in bytes in \fIlength\fP, and a starting byte offset
1938  \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of a  in \fIstartoffset\fP. If this is negative or greater than the length of the
1939  UTF-8 character. Unlike the pattern string, the subject may contain binary zero  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET. When the starting
1940  bytes. When the starting offset is zero, the search for a match starts at the  offset is zero, the search for a match starts at the beginning of the subject,
1941  beginning of the subject, and this is by far the most common case.  and this is by far the most common case. In UTF-8 mode, the byte offset must
1942    point to the start of a UTF-8 character (or the end of the subject). Unlike the
1943    pattern string, the subject may contain binary zero bytes.
1944  .P  .P
1945  A non-zero starting offset is useful when searching for another match in the  A non-zero starting offset is useful when searching for another match in the
1946  same subject by calling \fBpcre_exec()\fP again after a previous success.  same subject by calling \fBpcre_exec()\fP again after a previous success.
# Line 1136  start of the subject, which is deemed to Line 1960  start of the subject, which is deemed to
1960  set to 4, it finds the second occurrence of "iss" because it is able to look  set to 4, it finds the second occurrence of "iss" because it is able to look
1961  behind the starting point to discover that it is preceded by a letter.  behind the starting point to discover that it is preceded by a letter.
1962  .P  .P
1963    Finding all the matches in a subject is tricky when the pattern can match an
1964    empty string. It is possible to emulate Perl's /g behaviour by first trying the
1965    match again at the same offset, with the PCRE_NOTEMPTY_ATSTART and
1966    PCRE_ANCHORED options, and then if that fails, advancing the starting offset
1967    and trying an ordinary match again. There is some code that demonstrates how to
1968    do this in the
1969    .\" HREF
1970    \fBpcredemo\fP
1971    .\"
1972    sample program. In the most general case, you have to check to see if the
1973    newline convention recognizes CRLF as a newline, and if so, and the current
1974    character is CR followed by LF, advance the starting offset by two characters
1975    instead of one.
1976    .P
1977  If a non-zero starting offset is passed when the pattern is anchored, one  If a non-zero starting offset is passed when the pattern is anchored, one
1978  attempt to match at the given offset is made. This can only succeed if the  attempt to match at the given offset is made. This can only succeed if the
1979  pattern does not require the match to be at the start of the subject.  pattern does not require the match to be at the start of the subject.
1980  .  .
1981    .
1982  .SS "How \fBpcre_exec()\fP returns captured substrings"  .SS "How \fBpcre_exec()\fP returns captured substrings"
1983  .rs  .rs
1984  .sp  .sp
# Line 1150  pattern. Following the usage in Jeffrey Line 1989  pattern. Following the usage in Jeffrey
1989  a fragment of a pattern that picks out a substring. PCRE supports several other  a fragment of a pattern that picks out a substring. PCRE supports several other
1990  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1991  .P  .P
1992  Captured substrings are returned to the caller via a vector of integer offsets  Captured substrings are returned to the caller via a vector of integers whose
1993  whose address is passed in \fIovector\fP. The number of elements in the vector  address is passed in \fIovector\fP. The number of elements in the vector is
1994  is passed in \fIovecsize\fP, which must be a non-negative number. \fBNote\fP:  passed in \fIovecsize\fP, which must be a non-negative number. \fBNote\fP: this
1995  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1996  .P  .P
1997  The first two-thirds of the vector is used to pass back captured substrings,  The first two-thirds of the vector is used to pass back captured substrings,
1998  each substring using a pair of integers. The remaining third of the vector is  each substring using a pair of integers. The remaining third of the vector is
1999  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
2000  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
2001  \fIovecsize\fP should always be a multiple of three. If it is not, it is  \fIovecsize\fP should always be a multiple of three. If it is not, it is
2002  rounded down.  rounded down.
2003  .P  .P
2004  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
2005  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
2006  continuing up to two-thirds of its length at the most. The first element of a  continuing up to two-thirds of its length at the most. The first element of
2007  pair is set to the offset of the first character in a substring, and the second  each pair is set to the byte offset of the first character in a substring, and
2008  is set to the offset of the first character after the end of a substring. The  the second is set to the byte offset of the first character after the end of a
2009  first pair, \fIovector[0]\fP and \fIovector[1]\fP, identify the portion of the  substring. \fBNote\fP: these values are always byte offsets, even in UTF-8
2010  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
2011  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
2012  is the number of pairs that have been set. If there are no capturing  The first pair of integers, \fIovector[0]\fP and \fIovector[1]\fP, identify the
2013  subpatterns, the return value from a successful match is 1, indicating that  portion of the subject string matched by the entire pattern. The next pair is
2014  just the first pair of offsets has been set.  used for the first capturing subpattern, and so on. The value returned by
2015  .P  \fBpcre_exec()\fP is one more than the highest numbered pair that has been set.
2016  Some convenience functions are provided for extracting the captured substrings  For example, if two substrings have been captured, the returned value is 3. If
2017  as separate strings. These are described in the following section.  there are no capturing subpatterns, the return value from a successful match is
2018  .P  1, indicating that just the first pair of offsets has been set.
 It is possible for an capturing subpattern number \fIn+1\fP to match some  
 part of the subject when subpattern \fIn\fP has not been used at all. For  
 example, if the string "abc" is matched against the pattern (a|(z))(bc)  
 subpatterns 1 and 3 are matched, but 2 is not. When this happens, both offset  
 values corresponding to the unused subpattern are set to -1.  
2019  .P  .P
2020  If a capturing subpattern is matched repeatedly, it is the last portion of the  If a capturing subpattern is matched repeatedly, it is the last portion of the
2021  string that it matched that is returned.  string that it matched that is returned.
2022  .P  .P
2023  If the vector is too small to hold all the captured substring offsets, it is  If the vector is too small to hold all the captured substring offsets, it is
2024  used as far as possible (up to two-thirds of its length), and the function  used as far as possible (up to two-thirds of its length), and the function
2025  returns a value of zero. In particular, if the substring offsets are not of  returns a value of zero. If neither the actual string matched nor any captured
2026  interest, \fBpcre_exec()\fP may be called with \fIovector\fP passed as NULL and  substrings are of interest, \fBpcre_exec()\fP may be called with \fIovector\fP
2027  \fIovecsize\fP as zero. However, if the pattern contains back references and  passed as NULL and \fIovecsize\fP as zero. However, if the pattern contains
2028  the \fIovector\fP is not big enough to remember the related substrings, PCRE  back references and the \fIovector\fP is not big enough to remember the related
2029  has to get additional memory for use during matching. Thus it is usually  substrings, PCRE has to get additional memory for use during matching. Thus it
2030  advisable to supply an \fIovector\fP.  is usually advisable to supply an \fIovector\fP of reasonable size.
2031    .P
2032    There are some cases where zero is returned (indicating vector overflow) when
2033    in fact the vector is exactly the right size for the final match. For example,
2034    consider the pattern
2035    .sp
2036      (a)(?:(b)c|bd)
2037    .sp
2038    If a vector of 6 elements (allowing for only 1 captured substring) is given
2039    with subject string "abd", \fBpcre_exec()\fP will try to set the second
2040    captured string, thereby recording a vector overflow, before failing to match
2041    "c" and backing up to try the second alternative. The zero return, however,
2042    does correctly indicate that the maximum number of slots (namely 2) have been
2043    filled. In similar cases where there is temporary overflow, but the final
2044    number of used slots is actually less than the maximum, a non-zero value is
2045    returned.
2046  .P  .P
2047  Note that \fBpcre_info()\fP can be used to find out how many capturing  The \fBpcre_fullinfo()\fP function can be used to find out how many capturing
2048  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
2049  \fIovector\fP that will allow for \fIn\fP captured substrings, in addition to  \fIovector\fP that will allow for \fIn\fP captured substrings, in addition to
2050  the offsets of the substring matched by the whole pattern, is (\fIn\fP+1)*3.  the offsets of the substring matched by the whole pattern, is (\fIn\fP+1)*3.
2051    .P
2052    It is possible for capturing subpattern number \fIn+1\fP to match some part of
2053    the subject when subpattern \fIn\fP has not been used at all. For example, if
2054    the string "abc" is matched against the pattern (a|(z))(bc) the return from the
2055    function is 4, and subpatterns 1 and 3 are matched, but 2 is not. When this
2056    happens, both values in the offset pairs corresponding to unused subpatterns
2057    are set to -1.
2058    .P
2059    Offset values that correspond to unused subpatterns at the end of the
2060    expression are also set to -1. For example, if the string "abc" is matched
2061    against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The
2062    return from the function is 2, because the highest used capturing subpattern
2063    number is 1, and the offsets for for the second and third capturing subpatterns
2064    (assuming the vector is large enough, of course) are set to -1.
2065    .P
2066    \fBNote\fP: Elements in the first two-thirds of \fIovector\fP that do not
2067    correspond to capturing parentheses in the pattern are never changed. That is,
2068    if a pattern contains \fIn\fP capturing parentheses, no more than
2069    \fIovector[0]\fP to \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other
2070    elements (in the first two-thirds) retain whatever values they previously had.
2071    .P
2072    Some convenience functions are provided for extracting the captured substrings
2073    as separate strings. These are described below.
2074    .
2075  .  .
2076  .\" HTML <a name="errorlist"></a>  .\" HTML <a name="errorlist"></a>
2077  .SS "Return values from \fBpcre_exec()\fP"  .SS "Error return values from \fBpcre_exec()\fP"
2078  .rs  .rs
2079  .sp  .sp
2080  If \fBpcre_exec()\fP fails, it returns a negative number. The following are  If \fBpcre_exec()\fP fails, it returns a negative number. The following are
# Line 1228  compiled in an environment of one endian Line 2101  compiled in an environment of one endian
2101  other endianness. This is the error that PCRE gives when the magic number is  other endianness. This is the error that PCRE gives when the magic number is
2102  not present.  not present.
2103  .sp  .sp
2104    PCRE_ERROR_UNKNOWN_NODE   (-5)    PCRE_ERROR_UNKNOWN_OPCODE (-5)
2105  .sp  .sp
2106  While running the pattern match, an unknown item was encountered in the  While running the pattern match, an unknown item was encountered in the
2107  compiled pattern. This error could be caused by a bug in PCRE or by overwriting  compiled pattern. This error could be caused by a bug in PCRE or by overwriting
# Line 1241  If a pattern contains back references, b Line 2114  If a pattern contains back references, b
2114  gets a block of memory at the start of matching to use for this purpose. If the  gets a block of memory at the start of matching to use for this purpose. If the
2115  call via \fBpcre_malloc()\fP fails, this error is given. The memory is  call via \fBpcre_malloc()\fP fails, this error is given. The memory is
2116  automatically freed at the end of matching.  automatically freed at the end of matching.
2117    .P
2118    This error is also given if \fBpcre_stack_malloc()\fP fails in
2119    \fBpcre_exec()\fP. This can happen only when PCRE has been compiled with
2120    \fB--disable-stack-for-recursion\fP.
2121  .sp  .sp
2122    PCRE_ERROR_NOSUBSTRING    (-7)    PCRE_ERROR_NOSUBSTRING    (-7)
2123  .sp  .sp
# Line 1250  below). It is never returned by \fBpcre_ Line 2127  below). It is never returned by \fBpcre_
2127  .sp  .sp
2128    PCRE_ERROR_MATCHLIMIT     (-8)    PCRE_ERROR_MATCHLIMIT     (-8)
2129  .sp  .sp
2130  The recursion and backtracking limit, as specified by the \fImatch_limit\fP  The backtracking limit, as specified by the \fImatch_limit\fP field in a
2131  field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the  \fBpcre_extra\fP structure (or defaulted) was reached. See the description
2132  description above.  above.
2133  .sp  .sp
2134    PCRE_ERROR_CALLOUT        (-9)    PCRE_ERROR_CALLOUT        (-9)
2135  .sp  .sp
# Line 1265  documentation for details. Line 2142  documentation for details.
2142  .sp  .sp
2143    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
2144  .sp  .sp
2145  A string that contains an invalid UTF-8 byte sequence was passed as a subject.  A string that contains an invalid UTF-8 byte sequence was passed as a subject,
2146    and the PCRE_NO_UTF8_CHECK option was not set. If the size of the output vector
2147    (\fIovecsize\fP) is at least 2, the byte offset to the start of the the invalid
2148    UTF-8 character is placed in the first element, and a reason code is placed in
2149    the second element. The reason codes are listed in the
2150    .\" HTML <a href="#badutf8reasons">
2151    .\" </a>
2152    following section.
2153    .\"
2154    For backward compatibility, if PCRE_PARTIAL_HARD is set and the problem is a
2155    truncated UTF-8 character at the end of the subject (reason codes 1 to 5),
2156    PCRE_ERROR_SHORTUTF8 is returned instead of PCRE_ERROR_BADUTF8.
2157  .sp  .sp
2158    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
2159  .sp  .sp
2160  The UTF-8 byte sequence that was passed as a subject was valid, but the value  The UTF-8 byte sequence that was passed as a subject was checked and found to
2161  of \fIstartoffset\fP did not point to the beginning of a UTF-8 character.  be valid (the PCRE_NO_UTF8_CHECK option was not set), but the value of
2162    \fIstartoffset\fP did not point to the beginning of a UTF-8 character or the
2163    end of the subject.
2164  .sp  .sp
2165    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
2166  .sp  .sp
# Line 1282  documentation for details of partial mat Line 2172  documentation for details of partial mat
2172  .sp  .sp
2173    PCRE_ERROR_BADPARTIAL     (-13)    PCRE_ERROR_BADPARTIAL     (-13)
2174  .sp  .sp
2175  The PCRE_PARTIAL option was used with a compiled pattern containing items that  This code is no longer in use. It was formerly returned when the PCRE_PARTIAL
2176  are not supported for partial matching. See the  option was used with a compiled pattern containing items that were not
2177  .\" HREF  supported for partial matching. From release 8.00 onwards, there are no
2178  \fBpcrepartial\fP  restrictions on partial matching.
 .\"  
 documentation for details of partial matching.  
2179  .sp  .sp
2180    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
2181  .sp  .sp
# Line 1297  in PCRE or by overwriting of the compile Line 2185  in PCRE or by overwriting of the compile
2185    PCRE_ERROR_BADCOUNT       (-15)    PCRE_ERROR_BADCOUNT       (-15)
2186  .sp  .sp
2187  This error is given if the value of the \fIovecsize\fP argument is negative.  This error is given if the value of the \fIovecsize\fP argument is negative.
2188    .sp
2189      PCRE_ERROR_RECURSIONLIMIT (-21)
2190    .sp
2191    The internal recursion limit, as specified by the \fImatch_limit_recursion\fP
2192    field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the
2193    description above.
2194    .sp
2195      PCRE_ERROR_BADNEWLINE     (-23)
2196    .sp
2197    An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
2198    .sp
2199      PCRE_ERROR_BADOFFSET      (-24)
2200    .sp
2201    The value of \fIstartoffset\fP was negative or greater than the length of the
2202    subject, that is, the value in \fIlength\fP.
2203    .sp
2204      PCRE_ERROR_SHORTUTF8      (-25)
2205    .sp
2206    This error is returned instead of PCRE_ERROR_BADUTF8 when the subject string
2207    ends with a truncated UTF-8 character and the PCRE_PARTIAL_HARD option is set.
2208    Information about the failure is returned as for PCRE_ERROR_BADUTF8. It is in
2209    fact sufficient to detect this case, but this special error code for
2210    PCRE_PARTIAL_HARD precedes the implementation of returned information; it is
2211    retained for backwards compatibility.
2212    .sp
2213      PCRE_ERROR_RECURSELOOP    (-26)
2214    .sp
2215    This error is returned when \fBpcre_exec()\fP detects a recursion loop within
2216    the pattern. Specifically, it means that either the whole pattern or a
2217    subpattern has been called recursively for the second time at the same position
2218    in the subject string. Some simple patterns that might do this are detected and
2219    faulted at compile time, but more complicated cases, in particular mutual
2220    recursions between two different subpatterns, cannot be detected until run
2221    time.
2222    .sp
2223      PCRE_ERROR_JIT_STACKLIMIT (-27)
2224    .sp
2225    This error is returned when a pattern that was successfully studied using a
2226    JIT compile option is being matched, but the memory available for the
2227    just-in-time processing stack is not large enough. See the
2228    .\" HREF
2229    \fBpcrejit\fP
2230    .\"
2231    documentation for more details.
2232    .sp
2233      PCRE_ERROR_BADMODE        (-28)
2234    .sp
2235    This error is given if a pattern that was compiled by the 8-bit library is
2236    passed to a 16-bit or 32-bit library function, or vice versa.
2237    .sp
2238      PCRE_ERROR_BADENDIANNESS  (-29)
2239    .sp
2240    This error is given if a pattern that was compiled and saved is reloaded on a
2241    host with different endianness. The utility function
2242    \fBpcre_pattern_to_host_byte_order()\fP can be used to convert such a pattern
2243    so that it runs on the new host.
2244    .P
2245    Error numbers -16 to -20, -22, and -30 are not used by \fBpcre_exec()\fP.
2246    .
2247    .
2248    .\" HTML <a name="badutf8reasons"></a>
2249    .SS "Reason codes for invalid UTF-8 strings"
2250    .rs
2251    .sp
2252    This section applies only to the 8-bit library. The corresponding information
2253    for the 16-bit library is given in the
2254    .\" HREF
2255    \fBpcre16\fP
2256    .\"
2257    page. The corresponding information for the 32-bit library is given in the
2258    .\" HREF
2259    \fBpcre32\fP
2260    .\"
2261    page.
2262    .P
2263    When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or
2264    PCRE_ERROR_SHORTUTF8, and the size of the output vector (\fIovecsize\fP) is at
2265    least 2, the offset of the start of the invalid UTF-8 character is placed in
2266    the first output vector element (\fIovector[0]\fP) and a reason code is placed
2267    in the second element (\fIovector[1]\fP). The reason codes are given names in
2268    the \fBpcre.h\fP header file:
2269    .sp
2270      PCRE_UTF8_ERR1
2271      PCRE_UTF8_ERR2
2272      PCRE_UTF8_ERR3
2273      PCRE_UTF8_ERR4
2274      PCRE_UTF8_ERR5
2275    .sp
2276    The string ends with a truncated UTF-8 character; the code specifies how many
2277    bytes are missing (1 to 5). Although RFC 3629 restricts UTF-8 characters to be
2278    no longer than 4 bytes, the encoding scheme (originally defined by RFC 2279)
2279    allows for up to 6 bytes, and this is checked first; hence the possibility of
2280    4 or 5 missing bytes.
2281    .sp
2282      PCRE_UTF8_ERR6
2283      PCRE_UTF8_ERR7
2284      PCRE_UTF8_ERR8
2285      PCRE_UTF8_ERR9
2286      PCRE_UTF8_ERR10
2287    .sp
2288    The two most significant bits of the 2nd, 3rd, 4th, 5th, or 6th byte of the
2289    character do not have the binary value 0b10 (that is, either the most
2290    significant bit is 0, or the next bit is 1).
2291    .sp
2292      PCRE_UTF8_ERR11
2293      PCRE_UTF8_ERR12
2294    .sp
2295    A character that is valid by the RFC 2279 rules is either 5 or 6 bytes long;
2296    these code points are excluded by RFC 3629.
2297    .sp
2298      PCRE_UTF8_ERR13
2299    .sp
2300    A 4-byte character has a value greater than 0x10fff; these code points are
2301    excluded by RFC 3629.
2302    .sp
2303      PCRE_UTF8_ERR14
2304    .sp
2305    A 3-byte character has a value in the range 0xd800 to 0xdfff; this range of
2306    code points are reserved by RFC 3629 for use with UTF-16, and so are excluded
2307    from UTF-8.
2308    .sp
2309      PCRE_UTF8_ERR15
2310      PCRE_UTF8_ERR16
2311      PCRE_UTF8_ERR17
2312      PCRE_UTF8_ERR18
2313      PCRE_UTF8_ERR19
2314    .sp
2315    A 2-, 3-, 4-, 5-, or 6-byte character is "overlong", that is, it codes for a
2316    value that can be represented by fewer bytes, which is invalid. For example,
2317    the two bytes 0xc0, 0xae give the value 0x2e, whose correct coding uses just
2318    one byte.
2319    .sp
2320      PCRE_UTF8_ERR20
2321    .sp
2322    The two most significant bits of the first byte of a character have the binary
2323    value 0b10 (that is, the most significant bit is 1 and the second is 0). Such a
2324    byte can only validly occur as the second or subsequent byte of a multi-byte
2325    character.
2326    .sp
2327      PCRE_UTF8_ERR21
2328    .sp
2329    The first byte of a character has the value 0xfe or 0xff. These values can
2330    never occur in a valid UTF-8 string.
2331    .sp
2332      PCRE_UTF8_ERR2
2333    .sp
2334    Non-character. These are the last two characters in each plane (0xfffe, 0xffff,
2335    0x1fffe, 0x1ffff .. 0x10fffe, 0x10ffff), and the characters 0xfdd0..0xfdef.
2336  .  .
2337  .  .
2338  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1308  This error is given if the value of the Line 2344  This error is given if the value of the
2344  .ti +5n  .ti +5n
2345  .B int \fIbuffersize\fP);  .B int \fIbuffersize\fP);
2346  .PP  .PP
 .br  
2347  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,
2348  .ti +5n  .ti +5n
2349  .B int \fIstringcount\fP, int \fIstringnumber\fP,  .B int \fIstringcount\fP, int \fIstringnumber\fP,
2350  .ti +5n  .ti +5n
2351  .B const char **\fIstringptr\fP);  .B const char **\fIstringptr\fP);
2352  .PP  .PP
 .br  
2353  .B int pcre_get_substring_list(const char *\fIsubject\fP,  .B int pcre_get_substring_list(const char *\fIsubject\fP,
2354  .ti +5n  .ti +5n
2355  .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"  .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"
# Line 1326  Captured substrings can be accessed dire Line 2360  Captured substrings can be accessed dire
2360  \fBpcre_get_substring_list()\fP are provided for extracting captured substrings  \fBpcre_get_substring_list()\fP are provided for extracting captured substrings
2361  as new, separate, zero-terminated strings. These functions identify substrings  as new, separate, zero-terminated strings. These functions identify substrings
2362  by number. The next section describes functions for extracting named  by number. The next section describes functions for extracting named
2363  substrings. A substring that contains a binary zero is correctly extracted and  substrings.
2364  has a further zero added on the end, but the result is not, of course,  .P
2365  a C string.  A substring that contains a binary zero is correctly extracted and has a
2366    further zero added on the end, but the result is not, of course, a C string.
2367    However, you can process such a string by referring to the length that is
2368    returned by \fBpcre_copy_substring()\fP and \fBpcre_get_substring()\fP.
2369    Unfortunately, the interface to \fBpcre_get_substring_list()\fP is not adequate
2370    for handling strings containing binary zeros, because the end of the final
2371    string is not independently indicated.
2372  .P  .P
2373  The first three arguments are the same for all three of these functions:  The first three arguments are the same for all three of these functions:
2374  \fIsubject\fP is the subject string that has just been successfully matched,  \fIsubject\fP is the subject string that has just been successfully matched,
# Line 1348  the string is placed in \fIbuffer\fP, wh Line 2388  the string is placed in \fIbuffer\fP, wh
2388  \fIbuffersize\fP, while for \fBpcre_get_substring()\fP a new block of memory is  \fIbuffersize\fP, while for \fBpcre_get_substring()\fP a new block of memory is
2389  obtained via \fBpcre_malloc\fP, and its address is returned via  obtained via \fBpcre_malloc\fP, and its address is returned via
2390  \fIstringptr\fP. The yield of the function is the length of the string, not  \fIstringptr\fP. The yield of the function is the length of the string, not
2391  including the terminating zero, or one of  including the terminating zero, or one of these error codes:
2392  .sp  .sp
2393    PCRE_ERROR_NOMEMORY       (-6)    PCRE_ERROR_NOMEMORY       (-6)
2394  .sp  .sp
# Line 1364  and builds a list of pointers to them. A Line 2404  and builds a list of pointers to them. A
2404  memory that is obtained via \fBpcre_malloc\fP. The address of the memory block  memory that is obtained via \fBpcre_malloc\fP. The address of the memory block
2405  is returned via \fIlistptr\fP, which is also the start of the list of string  is returned via \fIlistptr\fP, which is also the start of the list of string
2406  pointers. The end of the list is marked by a NULL pointer. The yield of the  pointers. The end of the list is marked by a NULL pointer. The yield of the
2407  function is zero if all went well, or  function is zero if all went well, or the error code
2408  .sp  .sp
2409    PCRE_ERROR_NOMEMORY       (-6)    PCRE_ERROR_NOMEMORY       (-6)
2410  .sp  .sp
# Line 1383  a previous call of \fBpcre_get_substring Line 2423  a previous call of \fBpcre_get_substring
2423  \fBpcre_get_substring_list()\fP, respectively. They do nothing more than call  \fBpcre_get_substring_list()\fP, respectively. They do nothing more than call
2424  the function pointed to by \fBpcre_free\fP, which of course could be called  the function pointed to by \fBpcre_free\fP, which of course could be called
2425  directly from a C program. However, PCRE is used in some situations where it is  directly from a C program. However, PCRE is used in some situations where it is
2426  linked via a special interface to another programming language which cannot use  linked via a special interface to another programming language that cannot use
2427  \fBpcre_free\fP directly; it is for these cases that the functions are  \fBpcre_free\fP directly; it is for these cases that the functions are
2428  provided.  provided.
2429  .  .
# Line 1395  provided. Line 2435  provided.
2435  .ti +5n  .ti +5n
2436  .B const char *\fIname\fP);  .B const char *\fIname\fP);
2437  .PP  .PP
 .br  
2438  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,
2439  .ti +5n  .ti +5n
2440  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 1404  provided. Line 2443  provided.
2443  .ti +5n  .ti +5n
2444  .B char *\fIbuffer\fP, int \fIbuffersize\fP);  .B char *\fIbuffer\fP, int \fIbuffersize\fP);
2445  .PP  .PP
 .br  
2446  .B int pcre_get_named_substring(const pcre *\fIcode\fP,  .B int pcre_get_named_substring(const pcre *\fIcode\fP,
2447  .ti +5n  .ti +5n
2448  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 1418  For example, for this pattern Line 2456  For example, for this pattern
2456  .sp  .sp
2457    (a+)b(?<xxx>\ed+)...    (a+)b(?<xxx>\ed+)...
2458  .sp  .sp
2459  the number of the subpattern called "xxx" is 2. You can find the number from  the number of the subpattern called "xxx" is 2. If the name is known to be
2460  the name by calling \fBpcre_get_stringnumber()\fP. The first argument is the  unique (PCRE_DUPNAMES was not set), you can find the number from the name by
2461  compiled pattern, and the second is the name. The yield of the function is the  calling \fBpcre_get_stringnumber()\fP. The first argument is the compiled
2462    pattern, and the second is the name. The yield of the function is the
2463  subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no subpattern of  subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no subpattern of
2464  that name.  that name.
2465  .P  .P
# Line 1428  Given the number, you can extract the su Line 2467  Given the number, you can extract the su
2467  functions described in the previous section. For convenience, there are also  functions described in the previous section. For convenience, there are also
2468  two functions that do the whole job.  two functions that do the whole job.
2469  .P  .P
2470  Most of the arguments of \fIpcre_copy_named_substring()\fP and  Most of the arguments of \fBpcre_copy_named_substring()\fP and
2471  \fIpcre_get_named_substring()\fP are the same as those for the similarly named  \fBpcre_get_named_substring()\fP are the same as those for the similarly named
2472  functions that extract by number. As these are described in the previous  functions that extract by number. As these are described in the previous
2473  section, they are not re-described here. There are just two differences:  section, they are not re-described here. There are just two differences:
2474  .P  .P
# Line 1439  pattern. This is needed in order to gain Line 2478  pattern. This is needed in order to gain
2478  translation table.  translation table.
2479  .P  .P
2480  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they
2481  then call \fIpcre_copy_substring()\fP or \fIpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
2482  appropriate.  appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,
2483    the behaviour may not be what you want (see the next section).
2484    .P
2485    \fBWarning:\fP If the pattern uses the (?| feature to set up multiple
2486    subpatterns with the same number, as described in the
2487    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
2488    .\" </a>
2489    section on duplicate subpattern numbers
2490    .\"
2491    in the
2492    .\" HREF
2493    \fBpcrepattern\fP
2494    .\"
2495    page, you cannot use names to distinguish the different subpatterns, because
2496    names are not included in the compiled code. The matching process uses only
2497    numbers. For this reason, the use of different names for subpatterns of the
2498    same number causes an error at compile time.
2499    .
2500    .
2501    .SH "DUPLICATE SUBPATTERN NAMES"
2502    .rs
2503    .sp
2504    .B int pcre_get_stringtable_entries(const pcre *\fIcode\fP,
2505    .ti +5n
2506    .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
2507    .PP
2508    When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns
2509    are not required to be unique. (Duplicate names are always allowed for
2510    subpatterns with the same number, created by using the (?| feature. Indeed, if
2511    such subpatterns are named, they are required to use the same names.)
2512    .P
2513    Normally, patterns with duplicate names are such that in any one match, only
2514    one of the named subpatterns participates. An example is shown in the
2515    .\" HREF
2516    \fBpcrepattern\fP
2517    .\"
2518    documentation.
2519    .P
2520    When duplicates are present, \fBpcre_copy_named_substring()\fP and
2521    \fBpcre_get_named_substring()\fP return the first substring corresponding to
2522    the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
2523    returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
2524    returns one of the numbers that are associated with the name, but it is not
2525    defined which it is.
2526    .P
2527    If you want to get full details of all captured substrings for a given name,
2528    you must use the \fBpcre_get_stringtable_entries()\fP function. The first
2529    argument is the compiled pattern, and the second is the name. The third and
2530    fourth are pointers to variables which are updated by the function. After it
2531    has run, they point to the first and last entries in the name-to-number table
2532    for the given name. The function itself returns the length of each entry, or
2533    PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is
2534    described above in the section entitled \fIInformation about a pattern\fP
2535    .\" HTML <a href="#infoaboutpattern">
2536    .\" </a>
2537    above.
2538    .\"
2539    Given all the relevant entries for the name, you can extract each of their
2540    numbers, and hence the captured data, if any.
2541  .  .
2542  .  .
2543  .SH "FINDING ALL POSSIBLE MATCHES"  .SH "FINDING ALL POSSIBLE MATCHES"
# Line 1465  other alternatives. Ultimately, when it Line 2562  other alternatives. Ultimately, when it
2562  will yield PCRE_ERROR_NOMATCH.  will yield PCRE_ERROR_NOMATCH.
2563  .  .
2564  .  .
2565    .SH "OBTAINING AN ESTIMATE OF STACK USAGE"
2566    .rs
2567    .sp
2568    Matching certain patterns using \fBpcre_exec()\fP can use a lot of process
2569    stack, which in certain environments can be rather limited in size. Some users
2570    find it helpful to have an estimate of the amount of stack that is used by
2571    \fBpcre_exec()\fP, to help them set recursion limits, as described in the
2572    .\" HREF
2573    \fBpcrestack\fP
2574    .\"
2575    documentation. The estimate that is output by \fBpcretest\fP when called with
2576    the \fB-m\fP and \fB-C\fP options is obtained by calling \fBpcre_exec\fP with
2577    the values NULL, NULL, NULL, -999, and -999 for its first five arguments.
2578    .P
2579    Normally, if its first argument is NULL, \fBpcre_exec()\fP immediately returns
2580    the negative error code PCRE_ERROR_NULL, but with this special combination of
2581    arguments, it returns instead a negative number whose absolute value is the
2582    approximate stack frame size in bytes. (A negative number is used so that it is
2583    clear that no match has happened.) The value is approximate because in some
2584    cases, recursive calls to \fBpcre_exec()\fP occur when there are one or two
2585    additional variables on the stack.
2586    .P
2587    If PCRE has been compiled to use the heap instead of the stack for recursion,
2588    the value returned is the size of each block that is obtained from the heap.
2589    .
2590    .
2591  .\" HTML <a name="dfamatch"></a>  .\" HTML <a name="dfamatch"></a>
2592  .SH "MATCHING A PATTERN: THE ALTERNATIVE FUNCTION"  .SH "MATCHING A PATTERN: THE ALTERNATIVE FUNCTION"
2593  .rs  .rs
# Line 1478  will yield PCRE_ERROR_NOMATCH. Line 2601  will yield PCRE_ERROR_NOMATCH.
2601  .B int *\fIworkspace\fP, int \fIwscount\fP);  .B int *\fIworkspace\fP, int \fIwscount\fP);
2602  .P  .P
2603  The function \fBpcre_dfa_exec()\fP is called to match a subject string against  The function \fBpcre_dfa_exec()\fP is called to match a subject string against
2604  a compiled pattern, using a "DFA" matching algorithm. This has different  a compiled pattern, using a matching algorithm that scans the subject string
2605  characteristics to the normal algorithm, and is not compatible with Perl. Some  just once, and does not backtrack. This has different characteristics to the
2606  of the features of PCRE patterns are not supported. Nevertheless, there are  normal algorithm, and is not compatible with Perl. Some of the features of PCRE
2607  times when this kind of matching can be useful. For a discussion of the two  patterns are not supported. Nevertheless, there are times when this kind of
2608  matching algorithms, see the  matching can be useful. For a discussion of the two matching algorithms, and a
2609    list of features that \fBpcre_dfa_exec()\fP does not support, see the
2610  .\" HREF  .\" HREF
2611  \fBpcrematching\fP  \fBpcrematching\fP
2612  .\"  .\"
# Line 1497  here. Line 2621  here.
2621  The two additional arguments provide workspace for the function. The workspace  The two additional arguments provide workspace for the function. The workspace
2622  vector should contain at least 20 elements. It is used for keeping track of  vector should contain at least 20 elements. It is used for keeping track of
2623  multiple paths through the pattern tree. More workspace will be needed for  multiple paths through the pattern tree. More workspace will be needed for
2624  patterns and subjects where there are a lot of possible matches.  patterns and subjects where there are a lot of potential matches.
2625  .P  .P
2626  Here is an example of a simple call to \fBpcre_exec()\fP:  Here is an example of a simple call to \fBpcre_dfa_exec()\fP:
2627  .sp  .sp
2628    int rc;    int rc;
2629    int ovector[10];    int ovector[10];
2630    int wspace[20];    int wspace[20];
2631    rc = pcre_exec(    rc = pcre_dfa_exec(
2632      re,             /* result of pcre_compile() */      re,             /* result of pcre_compile() */
2633      NULL,           /* we didn't study the pattern */      NULL,           /* we didn't study the pattern */
2634      "some string",  /* the subject string */      "some string",  /* the subject string */
# Line 1520  Here is an example of a simple call to \ Line 2644  Here is an example of a simple call to \
2644  .rs  .rs
2645  .sp  .sp
2646  The unused bits of the \fIoptions\fP argument for \fBpcre_dfa_exec()\fP must be  The unused bits of the \fIoptions\fP argument for \fBpcre_dfa_exec()\fP must be
2647  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NOTBOL,  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
2648  PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
2649  PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last three of these are  PCRE_NO_UTF8_CHECK, PCRE_BSR_ANYCRLF, PCRE_BSR_UNICODE, PCRE_NO_START_OPTIMIZE,
2650  the same as for \fBpcre_exec()\fP, so their description is not repeated here.  PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART.
2651  .sp  All but the last four of these are exactly the same as for \fBpcre_exec()\fP,
2652    PCRE_PARTIAL  so their description is not repeated here.
2653  .sp  .sp
2654  This has the same general effect as it does for \fBpcre_exec()\fP, but the    PCRE_PARTIAL_HARD
2655  details are slightly different. When PCRE_PARTIAL is set for    PCRE_PARTIAL_SOFT
2656  \fBpcre_dfa_exec()\fP, the return code PCRE_ERROR_NOMATCH is converted into  .sp
2657  PCRE_ERROR_PARTIAL if the end of the subject is reached, there have been no  These have the same general effect as they do for \fBpcre_exec()\fP, but the
2658  complete matches, but there is still at least one matching possibility. The  details are slightly different. When PCRE_PARTIAL_HARD is set for
2659  portion of the string that provided the partial match is set as the first  \fBpcre_dfa_exec()\fP, it returns PCRE_ERROR_PARTIAL if the end of the subject
2660  matching string.  is reached and there is still at least one matching possibility that requires
2661    additional characters. This happens even if some complete matches have also
2662    been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
2663    is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
2664    there have been no complete matches, but there is still at least one matching
2665    possibility. The portion of the string that was inspected when the longest
2666    partial match was found is set as the first matching string in both cases.
2667    There is a more detailed discussion of partial and multi-segment matching, with
2668    examples, in the
2669    .\" HREF
2670    \fBpcrepartial\fP
2671    .\"
2672    documentation.
2673  .sp  .sp
2674    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
2675  .sp  .sp
2676  Setting the PCRE_DFA_SHORTEST option causes the matching algorithm to stop as  Setting the PCRE_DFA_SHORTEST option causes the matching algorithm to stop as
2677  soon as it has found one match. Because of the way the DFA algorithm works,  soon as it has found one match. Because of the way the alternative algorithm
2678  this is necessarily the shortest possible match at the first possible matching  works, this is necessarily the shortest possible match at the first possible
2679  point in the subject string.  matching point in the subject string.
2680  .sp  .sp
2681    PCRE_DFA_RESTART    PCRE_DFA_RESTART
2682  .sp  .sp
2683  When \fBpcre_dfa_exec()\fP is called with the PCRE_PARTIAL option, and returns  When \fBpcre_dfa_exec()\fP returns a partial match, it is possible to call it
2684  a partial match, it is possible to call it again, with additional subject  again, with additional subject characters, and have it continue with the same
2685  characters, and have it continue with the same match. The PCRE_DFA_RESTART  match. The PCRE_DFA_RESTART option requests this action; when it is set, the
2686  option requests this action; when it is set, the \fIworkspace\fP and  \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
2687  \fIwscount\fP options must reference the same vector as before because data  before because data about the match so far is left in them after a partial
2688  about the match so far is left in them after a partial match. There is more  match. There is more discussion of this facility in the
 discussion of this facility in the  
2689  .\" HREF  .\" HREF
2690  \fBpcrepartial\fP  \fBpcrepartial\fP
2691  .\"  .\"
2692  documentation.  documentation.
2693  .  .
2694    .
2695  .SS "Successful returns from \fBpcre_dfa_exec()\fP"  .SS "Successful returns from \fBpcre_dfa_exec()\fP"
2696  .rs  .rs
2697  .sp  .sp
# Line 1579  the three matched strings are Line 2715  the three matched strings are
2715  On success, the yield of the function is a number greater than zero, which is  On success, the yield of the function is a number greater than zero, which is
2716  the number of matched substrings. The substrings themselves are returned in  the number of matched substrings. The substrings themselves are returned in
2717  \fIovector\fP. Each string uses two elements; the first is the offset to the  \fIovector\fP. Each string uses two elements; the first is the offset to the
2718  start, and the second is the offset to the end. All the strings have the same  start, and the second is the offset to the end. In fact, all the strings have
2719  start offset. (Space could have been saved by giving this only once, but it was  the same start offset. (Space could have been saved by giving this only once,
2720  decided to retain some compatibility with the way \fBpcre_exec()\fP returns  but it was decided to retain some compatibility with the way \fBpcre_exec()\fP
2721  data, even though the meaning of the strings is different.)  returns data, even though the meaning of the strings is different.)
2722  .P  .P
2723  The strings are returned in reverse order of length; that is, the longest  The strings are returned in reverse order of length; that is, the longest
2724  matching string is given first. If there were too many matches to fit into  matching string is given first. If there were too many matches to fit into
2725  \fIovector\fP, the yield of the function is zero, and the vector is filled with  \fIovector\fP, the yield of the function is zero, and the vector is filled with
2726  the longest matches.  the longest matches. Unlike \fBpcre_exec()\fP, \fBpcre_dfa_exec()\fP can use
2727    the entire \fIovector\fP for returning matched strings.
2728    .
2729  .  .
2730  .SS "Error returns from \fBpcre_dfa_exec()\fP"  .SS "Error returns from \fBpcre_dfa_exec()\fP"
2731  .rs  .rs
# Line 1609  that it does not support, for instance, Line 2747  that it does not support, for instance,
2747  .sp  .sp
2748    PCRE_ERROR_DFA_UCOND      (-17)    PCRE_ERROR_DFA_UCOND      (-17)
2749  .sp  .sp
2750  This return is given if \fBpcre_dfa_exec()\fP encounters a condition item in a  This return is given if \fBpcre_dfa_exec()\fP encounters a condition item that
2751  pattern that uses a back reference for the condition. This is not supported.  uses a back reference for the condition, or a test for recursion in a specific
2752    group. These are not supported.
2753  .sp  .sp
2754    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
2755  .sp  .sp
2756  This return is given if \fBpcre_dfa_exec()\fP is called with an \fIextra\fP  This return is given if \fBpcre_dfa_exec()\fP is called with an \fIextra\fP
2757  block that contains a setting of the \fImatch_limit\fP field. This is not  block that contains a setting of the \fImatch_limit\fP or
2758  supported (it is meaningless).  \fImatch_limit_recursion\fP fields. This is not supported (these fields are
2759    meaningless for DFA matching).
2760  .sp  .sp
2761    PCRE_ERROR_DFA_WSSIZE     (-19)    PCRE_ERROR_DFA_WSSIZE     (-19)
2762  .sp  .sp
# Line 1629  When a recursive subpattern is processed Line 2769  When a recursive subpattern is processed
2769  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This
2770  error is given if the output vector is not large enough. This should be  error is given if the output vector is not large enough. This should be
2771  extremely rare, as a vector of size 1000 is used.  extremely rare, as a vector of size 1000 is used.
2772  .P  .sp
2773  .in 0    PCRE_ERROR_DFA_BADRESTART (-30)
2774  Last updated: 16 May 2005  .sp
2775  .br  When \fBpcre_dfa_exec()\fP is called with the \fBPCRE_DFA_RESTART\fP option,
2776  Copyright (c) 1997-2005 University of Cambridge.  some plausibility checks are made on the contents of the workspace, which
2777    should contain data about the previous partial match. If any of these checks
2778    fail, this error is given.
2779    .
2780    .
2781    .SH "SEE ALSO"
2782    .rs
2783    .sp
2784    \fBpcre16\fP(3), \fBpcre32\fP(3), \fBpcrebuild\fP(3), \fBpcrecallout\fP(3),
2785    \fBpcrecpp(3)\fP(3), \fBpcrematching\fP(3), \fBpcrepartial\fP(3),
2786    \fBpcreposix\fP(3), \fBpcreprecompile\fP(3), \fBpcresample\fP(3),
2787    \fBpcrestack\fP(3).
2788    .
2789    .
2790    .SH AUTHOR
2791    .rs
2792    .sp
2793    .nf
2794    Philip Hazel
2795    University Computing Service
2796    Cambridge CB2 3QH, England.
2797    .fi
2798    .
2799    .
2800    .SH REVISION
2801    .rs
2802    .sp
2803    .nf
2804    Last updated: 07 September 2012
2805    Copyright (c) 1997-2012 University of Cambridge.
2806    .fi

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