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Documentation updates.

1 ph10 846 .TH PCRE 3
2     .SH NAME
3     PCRE - Perl-compatible regular expressions
4 ph10 856 .sp
5     .B #include <pcre.h>
6     .
7     .
8 ph10 855 .SH "PCRE 16-BIT API BASIC FUNCTIONS"
9     .rs
10     .sp
11     .SM
12     .B pcre16 *pcre16_compile(PCRE_SPTR16 \fIpattern\fP, int \fIoptions\fP,
13     .ti +5n
14     .B const char **\fIerrptr\fP, int *\fIerroffset\fP,
15     .ti +5n
16     .B const unsigned char *\fItableptr\fP);
17     .PP
18     .B pcre16 *pcre16_compile2(PCRE_SPTR16 \fIpattern\fP, int \fIoptions\fP,
19     .ti +5n
20     .B int *\fIerrorcodeptr\fP,
21     .ti +5n
22     .B const char **\fIerrptr\fP, int *\fIerroffset\fP,
23     .ti +5n
24     .B const unsigned char *\fItableptr\fP);
25     .PP
26     .B pcre16_extra *pcre16_study(const pcre16 *\fIcode\fP, int \fIoptions\fP,
27     .ti +5n
28     .B const char **\fIerrptr\fP);
29     .PP
30     .B void pcre16_free_study(pcre16_extra *\fIextra\fP);
31     .PP
32     .B int pcre16_exec(const pcre16 *\fIcode\fP, "const pcre16_extra *\fIextra\fP,"
33     .ti +5n
34     .B "PCRE_SPTR16 \fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
35     .ti +5n
36     .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);
37     .PP
38     .B int pcre16_dfa_exec(const pcre16 *\fIcode\fP, "const pcre16_extra *\fIextra\fP,"
39     .ti +5n
40     .B "PCRE_SPTR16 \fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
41     .ti +5n
42     .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP,
43     .ti +5n
44     .B int *\fIworkspace\fP, int \fIwscount\fP);
45 ph10 856 .
46     .
47     .SH "PCRE 16-BIT API STRING EXTRACTION FUNCTIONS"
48     .rs
49     .sp
50 ph10 855 .B int pcre16_copy_named_substring(const pcre16 *\fIcode\fP,
51     .ti +5n
52     .B PCRE_SPTR16 \fIsubject\fP, int *\fIovector\fP,
53     .ti +5n
54     .B int \fIstringcount\fP, PCRE_SPTR16 \fIstringname\fP,
55     .ti +5n
56     .B PCRE_SCHAR16 *\fIbuffer\fP, int \fIbuffersize\fP);
57     .PP
58     .B int pcre16_copy_substring(PCRE_SPTR16 \fIsubject\fP, int *\fIovector\fP,
59     .ti +5n
60     .B int \fIstringcount\fP, int \fIstringnumber\fP, PCRE_SCHAR16 *\fIbuffer\fP,
61     .ti +5n
62     .B int \fIbuffersize\fP);
63     .PP
64     .B int pcre16_get_named_substring(const pcre16 *\fIcode\fP,
65     .ti +5n
66     .B PCRE_SPTR16 \fIsubject\fP, int *\fIovector\fP,
67     .ti +5n
68     .B int \fIstringcount\fP, PCRE_SPTR16 \fIstringname\fP,
69     .ti +5n
70     .B PCRE_SPTR16 *\fIstringptr\fP);
71     .PP
72     .B int pcre16_get_stringnumber(const pcre16 *\fIcode\fP,
73     .ti +5n
74     .B PCRE_SPTR16 \fIname\fP);
75     .PP
76     .B int pcre16_get_stringtable_entries(const pcre16 *\fIcode\fP,
77     .ti +5n
78     .B PCRE_SPTR16 \fIname\fP, PCRE_SCHAR16 **\fIfirst\fP, PCRE_SCHAR16 **\fIlast\fP);
79     .PP
80     .B int pcre16_get_substring(PCRE_SPTR16 \fIsubject\fP, int *\fIovector\fP,
81     .ti +5n
82     .B int \fIstringcount\fP, int \fIstringnumber\fP,
83     .ti +5n
84     .B PCRE_SPTR16 *\fIstringptr\fP);
85     .PP
86     .B int pcre16_get_substring_list(PCRE_SPTR16 \fIsubject\fP,
87     .ti +5n
88     .B int *\fIovector\fP, int \fIstringcount\fP, "PCRE_SPTR16 **\fIlistptr\fP);"
89     .PP
90     .B void pcre16_free_substring(PCRE_SPTR16 \fIstringptr\fP);
91     .PP
92     .B void pcre16_free_substring_list(PCRE_SPTR16 *\fIstringptr\fP);
93 ph10 856 .
94     .
95     .SH "PCRE 16-BIT API AUXILIARY FUNCTIONS"
96     .rs
97     .sp
98     .B pcre16_jit_stack *pcre16_jit_stack_alloc(int \fIstartsize\fP, int \fImaxsize\fP);
99 ph10 855 .PP
100 ph10 856 .B void pcre16_jit_stack_free(pcre16_jit_stack *\fIstack\fP);
101     .PP
102     .B void pcre16_assign_jit_stack(pcre16_extra *\fIextra\fP,
103     .ti +5n
104     .B pcre16_jit_callback \fIcallback\fP, void *\fIdata\fP);
105     .PP
106 ph10 855 .B const unsigned char *pcre16_maketables(void);
107     .PP
108     .B int pcre16_fullinfo(const pcre16 *\fIcode\fP, "const pcre16_extra *\fIextra\fP,"
109     .ti +5n
110     .B int \fIwhat\fP, void *\fIwhere\fP);
111     .PP
112     .B int pcre16_refcount(pcre16 *\fIcode\fP, int \fIadjust\fP);
113     .PP
114     .B int pcre16_config(int \fIwhat\fP, void *\fIwhere\fP);
115     .PP
116     .B const char *pcre16_version(void);
117 ph10 856 .PP
118     .B int pcre16_pattern_to_host_byte_order(pcre16 *\fIcode\fP,
119     .ti +5n
120     .B pcre16_extra *\fIextra\fP, const unsigned char *\fItables\fP);
121 ph10 855 .
122     .
123     .SH "PCRE 16-BIT API INDIRECTED FUNCTIONS"
124     .rs
125     .sp
126     .B void *(*pcre16_malloc)(size_t);
127     .PP
128     .B void (*pcre16_free)(void *);
129     .PP
130     .B void *(*pcre16_stack_malloc)(size_t);
131     .PP
132     .B void (*pcre16_stack_free)(void *);
133     .PP
134     .B int (*pcre16_callout)(pcre16_callout_block *);
135     .
136     .
137     .SH "PCRE 16-BIT API 16-BIT-ONLY FUNCTION"
138     .rs
139     .sp
140     .B int pcre16_utf16_to_host_byte_order(PCRE_SCHAR16 *\fIoutput\fP,
141     .ti +5n
142     .B PCRE_SPTR16 \fIinput\fP, int \fIlength\fP, int *\fIbyte_order\fP,
143     .ti +5n
144     .B int \fIkeep_boms\fP);
145     .
146     .
147 ph10 846 .SH "THE PCRE 16-BIT LIBRARY"
148     .rs
149     .sp
150     Starting with release 8.30, it is possible to compile a PCRE library that
151     supports 16-bit character strings, including UTF-16 strings, as well as or
152     instead of the original 8-bit library. The majority of the work to make this
153     possible was done by Zoltan Herczeg. The two libraries contain identical sets
154     of functions, used in exactly the same way. Only the names of the functions and
155 ph10 855 the data types of their arguments and results are different. To avoid
156 ph10 846 over-complication and reduce the documentation maintenance load, most of the
157 ph10 855 PCRE documentation describes the 8-bit library, with only occasional references
158     to the 16-bit library. This page describes what is different when you use the
159 ph10 846 16-bit library.
160     .P
161     WARNING: A single application can be linked with both libraries, but you must
162     take care when processing any particular pattern to use functions from just one
163     library. For example, if you want to study a pattern that was compiled with
164     \fBpcre16_compile()\fP, you must do so with \fBpcre16_study()\fP, not
165     \fBpcre_study()\fP, and you must free the study data with
166     \fBpcre16_free_study()\fP.
167     .
168     .
169     .SH "THE HEADER FILE"
170     .rs
171     .sp
172     There is only one header file, \fBpcre.h\fP. It contains prototypes for all the
173 ph10 855 functions in both libraries, as well as definitions of flags, structures, error
174     codes, etc.
175 ph10 846 .
176     .
177 ph10 855 .SH "THE LIBRARY NAME"
178     .rs
179     .sp
180     In Unix-like systems, the 16-bit library is called \fBlibpcre16\fP, and can
181     normally be accesss by adding \fB-lpcre16\fP to the command for linking an
182     application that uses PCRE.
183     .
184     .
185 ph10 846 .SH "STRING TYPES"
186     .rs
187     .sp
188     In the 8-bit library, strings are passed to PCRE library functions as vectors
189     of bytes with the C type "char *". In the 16-bit library, strings are passed as
190     vectors of unsigned 16-bit quantities. The macro PCRE_SCHAR16 specifies an
191     appropriate data type, and PCRE_SPTR16 is defined as "const PCRE_SCHAR16 *". In
192     very many environments, "short int" is a 16-bit data type. When PCRE is built,
193     it defines PCRE_SCHAR16 as "short int", but checks that it really is a 16-bit
194     data type. If it is not, the build fails with an error message telling the
195     maintainer to modify the definition appropriately.
196     .
197     .
198 ph10 855 .SH "STRUCTURE TYPES"
199 ph10 846 .rs
200     .sp
201 ph10 855 The types of the opaque structures that are used for compiled 16-bit patterns
202     and JIT stacks are \fBpcre16\fP and \fBpcre16_jit_stack\fP respectively. The
203     type of the user-accessible structure that is returned by \fBpcre16_study()\fP
204     is \fBpcre16_extra\fP, and the type of the structure that is used for passing
205     data to a callout function is \fBpcre16_callout_block\fP. These structures
206     contain the same fields, with the same names, as their 8-bit counterparts. The
207     only difference is that pointers to character strings are 16-bit instead of
208     8-bit types.
209     .
210     .
211     .SH "16-BIT FUNCTIONS"
212     .rs
213     .sp
214 ph10 846 For every function in the 8-bit library there is a corresponding function in
215     the 16-bit library with a name that starts with \fBpcre16_\fP instead of
216 ph10 855 \fBpcre_\fP. The prototypes are listed above. In addition, there is one extra
217     function, \fBpcre16_utf16_to_host_byte_order()\fP. This is a utility function
218     that converts a UTF-16 character string to host byte order if necessary. The
219     other 16-bit functions expect the strings they are passed to be in host byte
220     order.
221     .P
222 ph10 856 The \fIlength\fP argument of \fBpcre16_utf16_to_host_byte_order()\fP specifies
223     the number of 16-bit data units in the input string; a negative value specifies
224     a zero-terminated string.
225 ph10 855 .P
226     If \fIbyte_order\fP is NULL, it is assumed that the string starts off in host
227     byte order. This may be changed by byte-order marks (BOMs) anywhere in the
228     string (commonly as the first character).
229     .P
230     If \fIbyte_order\fP is not NULL, a non-zero value of the integer to which it
231     points means that the input starts off in host byte order, otherwise the
232     opposite order is assumed. Again, BOMs in the string can change this. The final
233     byte order is passed back at the end of processing.
234     .P
235     If \fIkeep_boms\fP is non zero, byte-order mark characters (0xfeff) are copied
236     into the output string. Otherwise they are discarded.
237     .P
238     The result of the function is the number of 16-bit units placed into the output
239     buffer, including the zero terminator if the string was zero-terminated.
240 ph10 846 .
241     .
242     .SH "SUBJECT STRING OFFSETS"
243     .rs
244     .sp
245     The offsets within subject strings that are returned by the matching functions
246     are in 16-bit units rather than bytes.
247     .
248     .
249     .SH "NAMED SUBPATTERNS"
250     .rs
251     .sp
252     The name-to-number translation table that is maintained for named subpatterns
253     uses 16-bit characters. The \fBpcre16_get_stringtable_entries()\fP function
254     returns the length of each entry in the table as the number of 16-bit data
255 ph10 855 units.
256 ph10 846 .
257     .
258     .SH "OPTION NAMES"
259     .rs
260     .sp
261     There are two new general option names, PCRE_UTF16 and PCRE_NO_UTF16_CHECK,
262     which correspond to PCRE_UTF8 and PCRE_NO_UTF8_CHECK in the 8-bit library. In
263     fact, these new options define the same bits in the options word.
264     .P
265     For the \fBpcre16_config()\fP function there is an option PCRE_CONFIG_UTF16
266     that returns 1 if UTF-16 support is configured, otherwise 0. If this option is
267     given to \fBpcre_config()\fP, or if the PCRE_CONFIG_UTF8 option is given to
268     \fBpcre16_config()\fP, the result is the PCRE_ERROR_BADOPTION error.
269     .
270     .
271     .SH "CHARACTER CODES"
272     .rs
273     .sp
274     In 16-bit mode, when PCRE_UTF16 is not set, character values are treated in the
275     same way as in 8-bit, non UTF-8 mode, except, of course, that they can range
276 ph10 855 from 0 to 0xffff instead of 0 to 0xff. Character types for characters less than
277     0xff can therefore be influenced by the locale in the same way as before.
278     Characters greater than 0xff have only one case, and no "type" (such as letter
279 ph10 846 or digit).
280     .P
281 ph10 855 In UTF-16 mode, the character code is Unicode, in the range 0 to 0x10ffff, with
282     the exception of values in the range 0xd800 to 0xdfff because those are
283     "surrogate" values that are used in pairs to encode values greater than 0xffff.
284 ph10 846 .P
285 ph10 855 A UTF-16 string can indicate its endianness by special code knows as a
286     byte-order mark (BOM). The PCRE functions do not handle this, expecting strings
287     to be in host byte order. A utility function called
288     \fBpcre16_utf16_to_host_byte_order()\fP is provided to help with this (see
289     above).
290 ph10 846 .
291     .
292     .SH "ERROR NAMES"
293     .rs
294     .sp
295     The errors PCRE_ERROR_BADUTF16_OFFSET and PCRE_ERROR_SHORTUTF16 correspond to
296     their 8-bit counterparts. The error PCRE_ERROR_BADMODE is given when a compiled
297     pattern is passed to a function that processes patterns in the other
298     mode, for example, if a pattern compiled with \fBpcre_compile()\fP is passed to
299     \fBpcre16_exec()\fP.
300     .P
301     There are new error codes whose names begin with PCRE_UTF16_ERR for invalid
302 ph10 855 UTF-16 strings, corresponding to the PCRE_UTF8_ERR codes for UTF-8 strings that
303     are described in the section entitled
304     .\" HTML <a href="pcreapi.html#badutf8reasons">
305     .\" </a>
306     "Reason codes for invalid UTF-8 strings"
307     .\"
308     in the main
309 ph10 846 .\" HREF
310     \fBpcreapi\fP
311     .\"
312 ph10 855 page. The UTF-16 errors are:
313     .sp
314     PCRE_UTF16_ERR1 Missing low surrogate at end of string
315     PCRE_UTF16_ERR2 Invalid low surrogate follows high surrogate
316     PCRE_UTF16_ERR3 Isolated low surrogate
317     PCRE_UTF16_ERR4 Invalid character 0xfffe
318 ph10 846 .
319     .
320     .SH "ERROR TEXTS"
321     .rs
322     .sp
323     If there is an error while compiling a pattern, the error text that is passed
324     back by \fBpcre16_compile()\fP or \fBpcre16_compile2()\fP is still an 8-bit
325     character string, zero-terminated.
326     .
327     .
328     .SH "CALLOUTS"
329     .rs
330     .sp
331     The \fIsubject\fP and \fImark\fP fields in the callout block that is passed to
332     a callout function point to 16-bit vectors.
333     .
334     .
335     .SH "TESTING"
336     .rs
337     .sp
338     The \fBpcretest\fP program continues to operate with 8-bit input and output
339     files, but it can be used for testing the 16-bit library. If it is run with the
340     command line option \fB-16\fP, patterns and subject strings are converted from
341     8-bit to 16-bit before being passed to PCRE, and the 16-bit library functions
342     are used instead of the 8-bit ones. Returned 16-bit strings are converted to
343     8-bit for output. If the 8-bit library was not compiled, \fBpcretest\fP
344     defaults to 16-bit and the \fB-16\fP option is ignored.
345     .P
346     When PCRE is being built, the \fBRunTest\fP script that is called by "make
347     check" uses the \fBpcretest\fP \fB-C\fP option to discover which of the 8-bit
348     and 16-bit libraries has been built, and runs the tests appropriately.
349     .
350     .
351     .SH "NOT SUPPORTED IN 16-BIT MODE"
352     .rs
353     .sp
354     Not all the features of the 8-bit library are available with the 16-bit
355     library. The C++ and POSIX wrapper functions support only the 8-bit library,
356     and the \fBpcregrep\fP program is at present 8-bit only.
357     .
358     .
359     .SH AUTHOR
360     .rs
361     .sp
362     .nf
363     Philip Hazel
364     University Computing Service
365     Cambridge CB2 3QH, England.
366     .fi
367     .
368     .
369     .SH REVISION
370     .rs
371     .sp
372     .nf
373 ph10 856 Last updated: 07 January 2012
374 ph10 846 Copyright (c) 1997-2012 University of Cambridge.
375     .fi

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