Annotation of embedaddon/pcre/doc/html/pcrebuild.html, revision 1.1.1.1
1.1 misho 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>
17: <li><a name="TOC2" href="#SEC2">BUILDING SHARED AND STATIC LIBRARIES</a>
18: <li><a name="TOC3" href="#SEC3">C++ SUPPORT</a>
19: <li><a name="TOC4" href="#SEC4">UTF-8 SUPPORT</a>
20: <li><a name="TOC5" href="#SEC5">UNICODE CHARACTER PROPERTY 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>
30: <li><a name="TOC15" href="#SEC15">PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT</a>
31: <li><a name="TOC16" href="#SEC16">PCREGREP BUFFER SIZE</a>
32: <li><a name="TOC17" href="#SEC17">PCRETEST OPTION FOR LIBREADLINE SUPPORT</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>
308: <br><a name="SEC15" href="#TOC1">PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT</a><br>
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 © 1997-2011 University of Cambridge.
385: <br>
386: <p>
387: Return to the <a href="index.html">PCRE index page</a>.
388: </p>
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/cvsweb/back.gif){kind=icon}
Return to pcrebuild.html CVS log ![[TXT]](/icons/cvsweb/text.gif){kind=icon}
![[DIR]](/icons/cvsweb/dir.gif){kind=icon}
Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / pcre / doc / html