1PCRE(3) Library Functions Manual PCRE(3)
2
6 PCRE - Perl-compatible regular expressions
7 #include <pcre.h>
9
11 pcre16 *pcre16_compile(PCRE_SPTR16 pattern, int options,
13 const char **errptr, int *erroffset,
14 const unsigned char *tableptr);
15 pcre16 *pcre16_compile2(PCRE_SPTR16 pattern, int options,
17 int *errorcodeptr,
18 const char **errptr, int *erroffset,
19 const unsigned char *tableptr);
20 pcre16_extra *pcre16_study(const pcre16 *code, int options,
22 const char **errptr);
23 void pcre16_free_study(pcre16_extra *extra);
25 int pcre16_exec(const pcre16 *code, const pcre16_extra *extra,
27 PCRE_SPTR16 subject, int length, int startoffset,
28 int options, int *ovector, int ovecsize);
29 int pcre16_dfa_exec(const pcre16 *code, const pcre16_extra *extra,
31 PCRE_SPTR16 subject, int length, int startoffset,
32 int options, int *ovector, int ovecsize,
33 int *workspace, int wscount);
34
36 int pcre16_copy_named_substring(const pcre16 *code,
38 PCRE_SPTR16 subject, int *ovector,
39 int stringcount, PCRE_SPTR16 stringname,
40 PCRE_UCHAR16 *buffer, int buffersize);
41 int pcre16_copy_substring(PCRE_SPTR16 subject, int *ovector,
43 int stringcount, int stringnumber, PCRE_UCHAR16 *buffer,
44 int buffersize);
45 int pcre16_get_named_substring(const pcre16 *code,
47 PCRE_SPTR16 subject, int *ovector,
48 int stringcount, PCRE_SPTR16 stringname,
49 PCRE_SPTR16 *stringptr);
50 int pcre16_get_stringnumber(const pcre16 *code,
52 PCRE_SPTR16 name);
53 int pcre16_get_stringtable_entries(const pcre16 *code,
55 PCRE_SPTR16 name, PCRE_UCHAR16 **first, PCRE_UCHAR16 **last);
56 int pcre16_get_substring(PCRE_SPTR16 subject, int *ovector,
58 int stringcount, int stringnumber,
59 PCRE_SPTR16 *stringptr);
60 int pcre16_get_substring_list(PCRE_SPTR16 subject,
62 int *ovector, int stringcount, PCRE_SPTR16 **listptr);
63 void pcre16_free_substring(PCRE_SPTR16 stringptr);
65 void pcre16_free_substring_list(PCRE_SPTR16 *stringptr);
67
69 pcre16_jit_stack *pcre16_jit_stack_alloc(int startsize, int maxsize);
71 void pcre16_jit_stack_free(pcre16_jit_stack *stack);
73 void pcre16_assign_jit_stack(pcre16_extra *extra,
75 pcre16_jit_callback callback, void *data);
76 const unsigned char *pcre16_maketables(void);
78 int pcre16_fullinfo(const pcre16 *code, const pcre16_extra *extra,
80 int what, void *where);
81 int pcre16_refcount(pcre16 *code, int adjust);
83 int pcre16_config(int what, void *where);
85 const char *pcre16_version(void);
87 int pcre16_pattern_to_host_byte_order(pcre16 *code,
89 pcre16_extra *extra, const unsigned char *tables);
90
92 void *(*pcre16_malloc)(size_t);
94 void (*pcre16_free)(void *);
96 void *(*pcre16_stack_malloc)(size_t);
98 void (*pcre16_stack_free)(void *);
100 int (*pcre16_callout)(pcre16_callout_block *);
102
104 int pcre16_utf16_to_host_byte_order(PCRE_UCHAR16 *output,
106 PCRE_SPTR16 input, int length, int *byte_order,
107 int keep_boms);
108
110 Starting with release 8.30, it is possible to compile a PCRE library
112 that supports 16-bit character strings, including UTF-16 strings, as
113 well as or instead of the original 8-bit library. The majority of the
114 work to make this possible was done by Zoltan Herczeg. The two
115 libraries contain identical sets of functions, used in exactly the same
116 way. Only the names of the functions and the data types of their argu‐
117 ments and results are different. To avoid over-complication and reduce
118 the documentation maintenance load, most of the PCRE documentation
119 describes the 8-bit library, with only occasional references to the
120 16-bit library. This page describes what is different when you use the
121 16-bit library.
122 WARNING: A single application can be linked with both libraries, but
124 you must take care when processing any particular pattern to use func‐
125 tions from just one library. For example, if you want to study a pat‐
126 tern that was compiled with pcre16_compile(), you must do so with
127 pcre16_study(), not pcre_study(), and you must free the study data with
128 pcre16_free_study().
129
131 There is only one header file, pcre.h. It contains prototypes for all
133 the functions in all libraries, as well as definitions of flags, struc‐
134 tures, error codes, etc.
135
137 In Unix-like systems, the 16-bit library is called libpcre16, and can
139 normally be accesss by adding -lpcre16 to the command for linking an
140 application that uses PCRE.
141
143 In the 8-bit library, strings are passed to PCRE library functions as
145 vectors of bytes with the C type "char *". In the 16-bit library,
146 strings are passed as vectors of unsigned 16-bit quantities. The macro
147 PCRE_UCHAR16 specifies an appropriate data type, and PCRE_SPTR16 is
148 defined as "const PCRE_UCHAR16 *". In very many environments, "short
149 int" is a 16-bit data type. When PCRE is built, it defines PCRE_UCHAR16
150 as "unsigned short int", but checks that it really is a 16-bit data
151 type. If it is not, the build fails with an error message telling the
152 maintainer to modify the definition appropriately.
153
155 The types of the opaque structures that are used for compiled 16-bit
157 patterns and JIT stacks are pcre16 and pcre16_jit_stack respectively.
158 The type of the user-accessible structure that is returned by
159 pcre16_study() is pcre16_extra, and the type of the structure that is
160 used for passing data to a callout function is pcre16_callout_block.
161 These structures contain the same fields, with the same names, as their
162 8-bit counterparts. The only difference is that pointers to character
163 strings are 16-bit instead of 8-bit types.
164
166 For every function in the 8-bit library there is a corresponding func‐
168 tion in the 16-bit library with a name that starts with pcre16_ instead
169 of pcre_. The prototypes are listed above. In addition, there is one
170 extra function, pcre16_utf16_to_host_byte_order(). This is a utility
171 function that converts a UTF-16 character string to host byte order if
172 necessary. The other 16-bit functions expect the strings they are
173 passed to be in host byte order.
174 The input and output arguments of pcre16_utf16_to_host_byte_order() may
176 point to the same address, that is, conversion in place is supported.
177 The output buffer must be at least as long as the input.
178 The length argument specifies the number of 16-bit data units in the
180 input string; a negative value specifies a zero-terminated string.
181 If byte_order is NULL, it is assumed that the string starts off in host
183 byte order. This may be changed by byte-order marks (BOMs) anywhere in
184 the string (commonly as the first character).
185 If byte_order is not NULL, a non-zero value of the integer to which it
187 points means that the input starts off in host byte order, otherwise
188 the opposite order is assumed. Again, BOMs in the string can change
189 this. The final byte order is passed back at the end of processing.
190 If keep_boms is not zero, byte-order mark characters (0xfeff) are
192 copied into the output string. Otherwise they are discarded.
193 The result of the function is the number of 16-bit units placed into
195 the output buffer, including the zero terminator if the string was
196 zero-terminated.
197
199 The lengths and starting offsets of subject strings must be specified
201 in 16-bit data units, and the offsets within subject strings that are
202 returned by the matching functions are in also 16-bit units rather than
203 bytes.
204
206 The name-to-number translation table that is maintained for named sub‐
208 patterns uses 16-bit characters. The pcre16_get_stringtable_entries()
209 function returns the length of each entry in the table as the number of
210 16-bit data units.
211
213 There are two new general option names, PCRE_UTF16 and
215 PCRE_NO_UTF16_CHECK, which correspond to PCRE_UTF8 and
216 PCRE_NO_UTF8_CHECK in the 8-bit library. In fact, these new options
217 define the same bits in the options word. There is a discussion about
218 the validity of UTF-16 strings in the pcreunicode page.
219 For the pcre16_config() function there is an option PCRE_CONFIG_UTF16
221 that returns 1 if UTF-16 support is configured, otherwise 0. If this
222 option is given to pcre_config() or pcre32_config(), or if the
223 PCRE_CONFIG_UTF8 or PCRE_CONFIG_UTF32 option is given to pcre16_con‐
224 fig(), the result is the PCRE_ERROR_BADOPTION error.
225
227 In 16-bit mode, when PCRE_UTF16 is not set, character values are
229 treated in the same way as in 8-bit, non UTF-8 mode, except, of course,
230 that they can range from 0 to 0xffff instead of 0 to 0xff. Character
231 types for characters less than 0xff can therefore be influenced by the
232 locale in the same way as before. Characters greater than 0xff have
233 only one case, and no "type" (such as letter or digit).
234 In UTF-16 mode, the character code is Unicode, in the range 0 to
236 0x10ffff, with the exception of values in the range 0xd800 to 0xdfff
237 because those are "surrogate" values that are used in pairs to encode
238 values greater than 0xffff.
239 A UTF-16 string can indicate its endianness by special code knows as a
241 byte-order mark (BOM). The PCRE functions do not handle this, expecting
242 strings to be in host byte order. A utility function called
243 pcre16_utf16_to_host_byte_order() is provided to help with this (see
244 above).
245
247 The errors PCRE_ERROR_BADUTF16_OFFSET and PCRE_ERROR_SHORTUTF16 corre‐
249 spond to their 8-bit counterparts. The error PCRE_ERROR_BADMODE is
250 given when a compiled pattern is passed to a function that processes
251 patterns in the other mode, for example, if a pattern compiled with
252 pcre_compile() is passed to pcre16_exec().
253 There are new error codes whose names begin with PCRE_UTF16_ERR for
255 invalid UTF-16 strings, corresponding to the PCRE_UTF8_ERR codes for
256 UTF-8 strings that are described in the section entitled "Reason codes
257 for invalid UTF-8 strings" in the main pcreapi page. The UTF-16 errors
258 are:
259 PCRE_UTF16_ERR1 Missing low surrogate at end of string
261 PCRE_UTF16_ERR2 Invalid low surrogate follows high surrogate
262 PCRE_UTF16_ERR3 Isolated low surrogate
263 PCRE_UTF16_ERR4 Non-character
264
266 If there is an error while compiling a pattern, the error text that is
268 passed back by pcre16_compile() or pcre16_compile2() is still an 8-bit
269 character string, zero-terminated.
270
272 The subject and mark fields in the callout block that is passed to a
274 callout function point to 16-bit vectors.
275
277 The pcretest program continues to operate with 8-bit input and output
279 files, but it can be used for testing the 16-bit library. If it is run
280 with the command line option -16, patterns and subject strings are con‐
281 verted from 8-bit to 16-bit before being passed to PCRE, and the 16-bit
282 library functions are used instead of the 8-bit ones. Returned 16-bit
283 strings are converted to 8-bit for output. If both the 8-bit and the
284 32-bit libraries were not compiled, pcretest defaults to 16-bit and the
285 -16 option is ignored.
286 When PCRE is being built, the RunTest script that is called by "make
288 check" uses the pcretest -C option to discover which of the 8-bit,
289 16-bit and 32-bit libraries has been built, and runs the tests appro‐
290 priately.
291
293 Not all the features of the 8-bit library are available with the 16-bit
295 library. The C++ and POSIX wrapper functions support only the 8-bit
296 library, and the pcregrep program is at present 8-bit only.
297
299 Philip Hazel
301 University Computing Service
302 Cambridge CB2 3QH, England.
303
305 Last updated: 12 May 2013
307 Copyright (c) 1997-2013 University of Cambridge.
308PCRE 8.33 12 May 2013 PCRE(3)