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1 <html>
2 <head>
3 <title>pcrebuild specification</title>
4 </head>
5 <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6 <h1>pcrebuild man page</h1>
7 <p>
8 Return to the <a href="index.html">PCRE index page</a>.
9 </p>
10 <p>
11 This page is part of the PCRE HTML documentation. It was generated automatically
12 from the original man page. If there is any nonsense in it, please consult the
13 man page, in case the conversion went wrong.
14 <br>
15 <ul>
16 <li><a name="TOC1" href="#SEC1">PCRE BUILD-TIME OPTIONS</a>
18 <li><a name="TOC3" href="#SEC3">C++ SUPPORT</a>
19 <li><a name="TOC4" href="#SEC4">UTF-8 SUPPORT</a>
21 <li><a name="TOC6" href="#SEC6">JUST-IN-TIME COMPILER SUPPORT</a>
22 <li><a name="TOC7" href="#SEC7">CODE VALUE OF NEWLINE</a>
23 <li><a name="TOC8" href="#SEC8">WHAT \R MATCHES</a>
24 <li><a name="TOC9" href="#SEC9">POSIX MALLOC USAGE</a>
25 <li><a name="TOC10" href="#SEC10">HANDLING VERY LARGE PATTERNS</a>
26 <li><a name="TOC11" href="#SEC11">AVOIDING EXCESSIVE STACK USAGE</a>
27 <li><a name="TOC12" href="#SEC12">LIMITING PCRE RESOURCE USAGE</a>
28 <li><a name="TOC13" href="#SEC13">CREATING CHARACTER TABLES AT BUILD TIME</a>
29 <li><a name="TOC14" href="#SEC14">USING EBCDIC CODE</a>
31 <li><a name="TOC16" href="#SEC16">PCREGREP BUFFER SIZE</a>
33 <li><a name="TOC18" href="#SEC18">SEE ALSO</a>
34 <li><a name="TOC19" href="#SEC19">AUTHOR</a>
35 <li><a name="TOC20" href="#SEC20">REVISION</a>
36 </ul>
37 <br><a name="SEC1" href="#TOC1">PCRE BUILD-TIME OPTIONS</a><br>
38 <P>
39 This document describes the optional features of PCRE that can be selected when
40 the library is compiled. It assumes use of the <b>configure</b> script, where
41 the optional features are selected or deselected by providing options to
42 <b>configure</b> before running the <b>make</b> command. However, the same
43 options can be selected in both Unix-like and non-Unix-like environments using
44 the GUI facility of <b>cmake-gui</b> if you are using <b>CMake</b> instead of
45 <b>configure</b> to build PCRE.
46 </P>
47 <P>
48 There is a lot more information about building PCRE in non-Unix-like
49 environments in the file called <i>NON_UNIX_USE</i>, which is part of the PCRE
50 distribution. You should consult this file as well as the <i>README</i> file if
51 you are building in a non-Unix-like environment.
52 </P>
53 <P>
54 The complete list of options for <b>configure</b> (which includes the standard
55 ones such as the selection of the installation directory) can be obtained by
56 running
57 <pre>
58 ./configure --help
59 </pre>
60 The following sections include descriptions of options whose names begin with
61 --enable or --disable. These settings specify changes to the defaults for the
62 <b>configure</b> command. Because of the way that <b>configure</b> works,
63 --enable and --disable always come in pairs, so the complementary option always
64 exists as well, but as it specifies the default, it is not described.
65 </P>
66 <br><a name="SEC2" href="#TOC1">BUILDING SHARED AND STATIC LIBRARIES</a><br>
67 <P>
68 The PCRE building process uses <b>libtool</b> to build both shared and static
69 Unix libraries by default. You can suppress one of these by adding one of
70 <pre>
71 --disable-shared
72 --disable-static
73 </pre>
74 to the <b>configure</b> command, as required.
75 </P>
76 <br><a name="SEC3" href="#TOC1">C++ SUPPORT</a><br>
77 <P>
78 By default, the <b>configure</b> script will search for a C++ compiler and C++
79 header files. If it finds them, it automatically builds the C++ wrapper library
80 for PCRE. You can disable this by adding
81 <pre>
82 --disable-cpp
83 </pre>
84 to the <b>configure</b> command.
85 </P>
86 <br><a name="SEC4" href="#TOC1">UTF-8 SUPPORT</a><br>
87 <P>
88 To build PCRE with support for UTF-8 Unicode character strings, add
89 <pre>
90 --enable-utf8
91 </pre>
92 to the <b>configure</b> command. Of itself, this does not make PCRE treat
93 strings as UTF-8. As well as compiling PCRE with this option, you also have
94 have to set the PCRE_UTF8 option when you call the <b>pcre_compile()</b>
95 or <b>pcre_compile2()</b> functions.
96 </P>
97 <P>
98 If you set --enable-utf8 when compiling in an EBCDIC environment, PCRE expects
99 its input to be either ASCII or UTF-8 (depending on the runtime option). It is
100 not possible to support both EBCDIC and UTF-8 codes in the same version of the
101 library. Consequently, --enable-utf8 and --enable-ebcdic are mutually
102 exclusive.
103 </P>
104 <br><a name="SEC5" href="#TOC1">UNICODE CHARACTER PROPERTY SUPPORT</a><br>
105 <P>
106 UTF-8 support allows PCRE to process character values greater than 255 in the
107 strings that it handles. On its own, however, it does not provide any
108 facilities for accessing the properties of such characters. If you want to be
109 able to use the pattern escapes \P, \p, and \X, which refer to Unicode
110 character properties, you must add
111 <pre>
112 --enable-unicode-properties
113 </pre>
114 to the <b>configure</b> command. This implies UTF-8 support, even if you have
115 not explicitly requested it.
116 </P>
117 <P>
118 Including Unicode property support adds around 30K of tables to the PCRE
119 library. Only the general category properties such as <i>Lu</i> and <i>Nd</i> are
120 supported. Details are given in the
121 <a href="pcrepattern.html"><b>pcrepattern</b></a>
122 documentation.
123 </P>
124 <br><a name="SEC6" href="#TOC1">JUST-IN-TIME COMPILER SUPPORT</a><br>
125 <P>
126 Just-in-time compiler support is included in the build by specifying
127 <pre>
128 --enable-jit
129 </pre>
130 This support is available only for certain hardware architectures. If this
131 option is set for an unsupported architecture, a compile time error occurs.
132 See the
133 <a href="pcrejit.html"><b>pcrejit</b></a>
134 documentation for a discussion of JIT usage. When JIT support is enabled,
135 pcregrep automatically makes use of it, unless you add
136 <pre>
137 --disable-pcregrep-jit
138 </pre>
139 to the "configure" command.
140 </P>
141 <br><a name="SEC7" href="#TOC1">CODE VALUE OF NEWLINE</a><br>
142 <P>
143 By default, PCRE interprets the linefeed (LF) character as indicating the end
144 of a line. This is the normal newline character on Unix-like systems. You can
145 compile PCRE to use carriage return (CR) instead, by adding
146 <pre>
147 --enable-newline-is-cr
148 </pre>
149 to the <b>configure</b> command. There is also a --enable-newline-is-lf option,
150 which explicitly specifies linefeed as the newline character.
151 <br>
152 <br>
153 Alternatively, you can specify that line endings are to be indicated by the two
154 character sequence CRLF. If you want this, add
155 <pre>
156 --enable-newline-is-crlf
157 </pre>
158 to the <b>configure</b> command. There is a fourth option, specified by
159 <pre>
160 --enable-newline-is-anycrlf
161 </pre>
162 which causes PCRE to recognize any of the three sequences CR, LF, or CRLF as
163 indicating a line ending. Finally, a fifth option, specified by
164 <pre>
165 --enable-newline-is-any
166 </pre>
167 causes PCRE to recognize any Unicode newline sequence.
168 </P>
169 <P>
170 Whatever line ending convention is selected when PCRE is built can be
171 overridden when the library functions are called. At build time it is
172 conventional to use the standard for your operating system.
173 </P>
174 <br><a name="SEC8" href="#TOC1">WHAT \R MATCHES</a><br>
175 <P>
176 By default, the sequence \R in a pattern matches any Unicode newline sequence,
177 whatever has been selected as the line ending sequence. If you specify
178 <pre>
179 --enable-bsr-anycrlf
180 </pre>
181 the default is changed so that \R matches only CR, LF, or CRLF. Whatever is
182 selected when PCRE is built can be overridden when the library functions are
183 called.
184 </P>
185 <br><a name="SEC9" href="#TOC1">POSIX MALLOC USAGE</a><br>
186 <P>
187 When PCRE is called through the POSIX interface (see the
188 <a href="pcreposix.html"><b>pcreposix</b></a>
189 documentation), additional working storage is required for holding the pointers
190 to capturing substrings, because PCRE requires three integers per substring,
191 whereas the POSIX interface provides only two. If the number of expected
192 substrings is small, the wrapper function uses space on the stack, because this
193 is faster than using <b>malloc()</b> for each call. The default threshold above
194 which the stack is no longer used is 10; it can be changed by adding a setting
195 such as
196 <pre>
197 --with-posix-malloc-threshold=20
198 </pre>
199 to the <b>configure</b> command.
200 </P>
201 <br><a name="SEC10" href="#TOC1">HANDLING VERY LARGE PATTERNS</a><br>
202 <P>
203 Within a compiled pattern, offset values are used to point from one part to
204 another (for example, from an opening parenthesis to an alternation
205 metacharacter). By default, two-byte values are used for these offsets, leading
206 to a maximum size for a compiled pattern of around 64K. This is sufficient to
207 handle all but the most gigantic patterns. Nevertheless, some people do want to
208 process truyl enormous patterns, so it is possible to compile PCRE to use
209 three-byte or four-byte offsets by adding a setting such as
210 <pre>
211 --with-link-size=3
212 </pre>
213 to the <b>configure</b> command. The value given must be 2, 3, or 4. Using
214 longer offsets slows down the operation of PCRE because it has to load
215 additional bytes when handling them.
216 </P>
217 <br><a name="SEC11" href="#TOC1">AVOIDING EXCESSIVE STACK USAGE</a><br>
218 <P>
219 When matching with the <b>pcre_exec()</b> function, PCRE implements backtracking
220 by making recursive calls to an internal function called <b>match()</b>. In
221 environments where the size of the stack is limited, this can severely limit
222 PCRE's operation. (The Unix environment does not usually suffer from this
223 problem, but it may sometimes be necessary to increase the maximum stack size.
224 There is a discussion in the
225 <a href="pcrestack.html"><b>pcrestack</b></a>
226 documentation.) An alternative approach to recursion that uses memory from the
227 heap to remember data, instead of using recursive function calls, has been
228 implemented to work round the problem of limited stack size. If you want to
229 build a version of PCRE that works this way, add
230 <pre>
231 --disable-stack-for-recursion
232 </pre>
233 to the <b>configure</b> command. With this configuration, PCRE will use the
234 <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> variables to call memory
235 management functions. By default these point to <b>malloc()</b> and
236 <b>free()</b>, but you can replace the pointers so that your own functions are
237 used instead.
238 </P>
239 <P>
240 Separate functions are provided rather than using <b>pcre_malloc</b> and
241 <b>pcre_free</b> because the usage is very predictable: the block sizes
242 requested are always the same, and the blocks are always freed in reverse
243 order. A calling program might be able to implement optimized functions that
244 perform better than <b>malloc()</b> and <b>free()</b>. PCRE runs noticeably more
245 slowly when built in this way. This option affects only the <b>pcre_exec()</b>
246 function; it is not relevant for <b>pcre_dfa_exec()</b>.
247 </P>
248 <br><a name="SEC12" href="#TOC1">LIMITING PCRE RESOURCE USAGE</a><br>
249 <P>
250 Internally, PCRE has a function called <b>match()</b>, which it calls repeatedly
251 (sometimes recursively) when matching a pattern with the <b>pcre_exec()</b>
252 function. By controlling the maximum number of times this function may be
253 called during a single matching operation, a limit can be placed on the
254 resources used by a single call to <b>pcre_exec()</b>. The limit can be changed
255 at run time, as described in the
256 <a href="pcreapi.html"><b>pcreapi</b></a>
257 documentation. The default is 10 million, but this can be changed by adding a
258 setting such as
259 <pre>
260 --with-match-limit=500000
261 </pre>
262 to the <b>configure</b> command. This setting has no effect on the
263 <b>pcre_dfa_exec()</b> matching function.
264 </P>
265 <P>
266 In some environments it is desirable to limit the depth of recursive calls of
267 <b>match()</b> more strictly than the total number of calls, in order to
268 restrict the maximum amount of stack (or heap, if --disable-stack-for-recursion
269 is specified) that is used. A second limit controls this; it defaults to the
270 value that is set for --with-match-limit, which imposes no additional
271 constraints. However, you can set a lower limit by adding, for example,
272 <pre>
273 --with-match-limit-recursion=10000
274 </pre>
275 to the <b>configure</b> command. This value can also be overridden at run time.
276 </P>
277 <br><a name="SEC13" href="#TOC1">CREATING CHARACTER TABLES AT BUILD TIME</a><br>
278 <P>
279 PCRE uses fixed tables for processing characters whose code values are less
280 than 256. By default, PCRE is built with a set of tables that are distributed
281 in the file <i>pcre_chartables.c.dist</i>. These tables are for ASCII codes
282 only. If you add
283 <pre>
284 --enable-rebuild-chartables
285 </pre>
286 to the <b>configure</b> command, the distributed tables are no longer used.
287 Instead, a program called <b>dftables</b> is compiled and run. This outputs the
288 source for new set of tables, created in the default locale of your C runtime
289 system. (This method of replacing the tables does not work if you are cross
290 compiling, because <b>dftables</b> is run on the local host. If you need to
291 create alternative tables when cross compiling, you will have to do so "by
292 hand".)
293 </P>
294 <br><a name="SEC14" href="#TOC1">USING EBCDIC CODE</a><br>
295 <P>
296 PCRE assumes by default that it will run in an environment where the character
297 code is ASCII (or Unicode, which is a superset of ASCII). This is the case for
298 most computer operating systems. PCRE can, however, be compiled to run in an
299 EBCDIC environment by adding
300 <pre>
301 --enable-ebcdic
302 </pre>
303 to the <b>configure</b> command. This setting implies
304 --enable-rebuild-chartables. You should only use it if you know that you are in
305 an EBCDIC environment (for example, an IBM mainframe operating system). The
306 --enable-ebcdic option is incompatible with --enable-utf8.
307 </P>
309 <P>
310 By default, <b>pcregrep</b> reads all files as plain text. You can build it so
311 that it recognizes files whose names end in <b>.gz</b> or <b>.bz2</b>, and reads
312 them with <b>libz</b> or <b>libbz2</b>, respectively, by adding one or both of
313 <pre>
314 --enable-pcregrep-libz
315 --enable-pcregrep-libbz2
316 </pre>
317 to the <b>configure</b> command. These options naturally require that the
318 relevant libraries are installed on your system. Configuration will fail if
319 they are not.
320 </P>
321 <br><a name="SEC16" href="#TOC1">PCREGREP BUFFER SIZE</a><br>
322 <P>
323 <b>pcregrep</b> uses an internal buffer to hold a "window" on the file it is
324 scanning, in order to be able to output "before" and "after" lines when it
325 finds a match. The size of the buffer is controlled by a parameter whose
326 default value is 20K. The buffer itself is three times this size, but because
327 of the way it is used for holding "before" lines, the longest line that is
328 guaranteed to be processable is the parameter size. You can change the default
329 parameter value by adding, for example,
330 <pre>
331 --with-pcregrep-bufsize=50K
332 </pre>
333 to the <b>configure</b> command. The caller of \fPpcregrep\fP can, however,
334 override this value by specifying a run-time option.
335 </P>
336 <br><a name="SEC17" href="#TOC1">PCRETEST OPTION FOR LIBREADLINE SUPPORT</a><br>
337 <P>
338 If you add
339 <pre>
340 --enable-pcretest-libreadline
341 </pre>
342 to the <b>configure</b> command, <b>pcretest</b> is linked with the
343 <b>libreadline</b> library, and when its input is from a terminal, it reads it
344 using the <b>readline()</b> function. This provides line-editing and history
345 facilities. Note that <b>libreadline</b> is GPL-licensed, so if you distribute a
346 binary of <b>pcretest</b> linked in this way, there may be licensing issues.
347 </P>
348 <P>
349 Setting this option causes the <b>-lreadline</b> option to be added to the
350 <b>pcretest</b> build. In many operating environments with a sytem-installed
351 <b>libreadline</b> this is sufficient. However, in some environments (e.g.
352 if an unmodified distribution version of readline is in use), some extra
353 configuration may be necessary. The INSTALL file for <b>libreadline</b> says
354 this:
355 <pre>
356 "Readline uses the termcap functions, but does not link with the
357 termcap or curses library itself, allowing applications which link
358 with readline the to choose an appropriate library."
359 </pre>
360 If your environment has not been set up so that an appropriate library is
361 automatically included, you may need to add something like
362 <pre>
363 LIBS="-ncurses"
364 </pre>
365 immediately before the <b>configure</b> command.
366 </P>
367 <br><a name="SEC18" href="#TOC1">SEE ALSO</a><br>
368 <P>
369 <b>pcreapi</b>(3), <b>pcre_config</b>(3).
370 </P>
371 <br><a name="SEC19" href="#TOC1">AUTHOR</a><br>
372 <P>
373 Philip Hazel
374 <br>
375 University Computing Service
376 <br>
377 Cambridge CB2 3QH, England.
378 <br>
379 </P>
380 <br><a name="SEC20" href="#TOC1">REVISION</a><br>
381 <P>
382 Last updated: 06 September 2011
383 <br>
384 Copyright &copy; 1997-2011 University of Cambridge.
385 <br>
386 <p>
387 Return to the <a href="index.html">PCRE index page</a>.
388 </p>


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