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">C++ SUPPORT</a> 18 <li><a name="TOC3" href="#SEC3">UTF-8 SUPPORT</a> 19 <li><a name="TOC4" href="#SEC4">UNICODE CHARACTER PROPERTY SUPPORT</a> 20 <li><a name="TOC5" href="#SEC5">CODE VALUE OF NEWLINE</a> 21 <li><a name="TOC6" href="#SEC6">WHAT \R MATCHES</a> 22 <li><a name="TOC7" href="#SEC7">BUILDING SHARED AND STATIC LIBRARIES</a> 23 <li><a name="TOC8" href="#SEC8">POSIX MALLOC USAGE</a> 24 <li><a name="TOC9" href="#SEC9">HANDLING VERY LARGE PATTERNS</a> 25 <li><a name="TOC10" href="#SEC10">AVOIDING EXCESSIVE STACK USAGE</a> 26 <li><a name="TOC11" href="#SEC11">LIMITING PCRE RESOURCE USAGE</a> 27 <li><a name="TOC12" href="#SEC12">CREATING CHARACTER TABLES AT BUILD TIME</a> 28 <li><a name="TOC13" href="#SEC13">USING EBCDIC CODE</a> 29 <li><a name="TOC14" href="#SEC14">PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT</a> 30 <li><a name="TOC15" href="#SEC15">PCRETEST OPTION FOR LIBREADLINE SUPPORT</a> 31 <li><a name="TOC16" href="#SEC16">SEE ALSO</a> 32 <li><a name="TOC17" href="#SEC17">AUTHOR</a> 33 <li><a name="TOC18" href="#SEC18">REVISION</a> 34 </ul> 35 <br><a name="SEC1" href="#TOC1">PCRE BUILD-TIME OPTIONS</a><br> 36 <P> 37 This document describes the optional features of PCRE that can be selected when 38 the library is compiled. It assumes use of the <b>configure</b> script, where 39 the optional features are selected or deselected by providing options to 40 <b>configure</b> before running the <b>make</b> command. However, the same 41 options can be selected in both Unix-like and non-Unix-like environments using 42 the GUI facility of <b>cmake-gui</b> if you are using <b>CMake</b> instead of 43 <b>configure</b> to build PCRE. 44 </P> 45 <P> 46 There is a lot more information about building PCRE in non-Unix-like 47 environments in the file called <i>NON_UNIX_USE</i>, which is part of the PCRE 48 distribution. You should consult this file as well as the <i>README</i> file if 49 you are building in a non-Unix-like environment. 50 </P> 51 <P> 52 The complete list of options for <b>configure</b> (which includes the standard 53 ones such as the selection of the installation directory) can be obtained by 54 running 55 <pre> 56 ./configure --help 57 </pre> 58 The following sections include descriptions of options whose names begin with 59 --enable or --disable. These settings specify changes to the defaults for the 60 <b>configure</b> command. Because of the way that <b>configure</b> works, 61 --enable and --disable always come in pairs, so the complementary option always 62 exists as well, but as it specifies the default, it is not described. 63 </P> 64 <br><a name="SEC2" href="#TOC1">C++ SUPPORT</a><br> 65 <P> 66 By default, the <b>configure</b> script will search for a C++ compiler and C++ 67 header files. If it finds them, it automatically builds the C++ wrapper library 68 for PCRE. You can disable this by adding 69 <pre> 70 --disable-cpp 71 </pre> 72 to the <b>configure</b> command. 73 </P> 74 <br><a name="SEC3" href="#TOC1">UTF-8 SUPPORT</a><br> 75 <P> 76 To build PCRE with support for UTF-8 Unicode character strings, add 77 <pre> 78 --enable-utf8 79 </pre> 80 to the <b>configure</b> command. Of itself, this does not make PCRE treat 81 strings as UTF-8. As well as compiling PCRE with this option, you also have 82 have to set the PCRE_UTF8 option when you call the <b>pcre_compile()</b> 83 or <b>pcre_compile2()</b> functions. 84 </P> 85 <P> 86 If you set --enable-utf8 when compiling in an EBCDIC environment, PCRE expects 87 its input to be either ASCII or UTF-8 (depending on the runtime option). It is 88 not possible to support both EBCDIC and UTF-8 codes in the same version of the 89 library. Consequently, --enable-utf8 and --enable-ebcdic are mutually 90 exclusive. 91 </P> 92 <br><a name="SEC4" href="#TOC1">UNICODE CHARACTER PROPERTY SUPPORT</a><br> 93 <P> 94 UTF-8 support allows PCRE to process character values greater than 255 in the 95 strings that it handles. On its own, however, it does not provide any 96 facilities for accessing the properties of such characters. If you want to be 97 able to use the pattern escapes \P, \p, and \X, which refer to Unicode 98 character properties, you must add 99 <pre> 100 --enable-unicode-properties 101 </pre> 102 to the <b>configure</b> command. This implies UTF-8 support, even if you have 103 not explicitly requested it. 104 </P> 105 <P> 106 Including Unicode property support adds around 30K of tables to the PCRE 107 library. Only the general category properties such as <i>Lu</i> and <i>Nd</i> are 108 supported. Details are given in the 109 <a href="pcrepattern.html"><b>pcrepattern</b></a> 110 documentation. 111 </P> 112 <br><a name="SEC5" href="#TOC1">CODE VALUE OF NEWLINE</a><br> 113 <P> 114 By default, PCRE interprets the linefeed (LF) character as indicating the end 115 of a line. This is the normal newline character on Unix-like systems. You can 116 compile PCRE to use carriage return (CR) instead, by adding 117 <pre> 118 --enable-newline-is-cr 119 </pre> 120 to the <b>configure</b> command. There is also a --enable-newline-is-lf option, 121 which explicitly specifies linefeed as the newline character. 122 <br> 123 <br> 124 Alternatively, you can specify that line endings are to be indicated by the two 125 character sequence CRLF. If you want this, add 126 <pre> 127 --enable-newline-is-crlf 128 </pre> 129 to the <b>configure</b> command. There is a fourth option, specified by 130 <pre> 131 --enable-newline-is-anycrlf 132 </pre> 133 which causes PCRE to recognize any of the three sequences CR, LF, or CRLF as 134 indicating a line ending. Finally, a fifth option, specified by 135 <pre> 136 --enable-newline-is-any 137 </pre> 138 causes PCRE to recognize any Unicode newline sequence. 139 </P> 140 <P> 141 Whatever line ending convention is selected when PCRE is built can be 142 overridden when the library functions are called. At build time it is 143 conventional to use the standard for your operating system. 144 </P> 145 <br><a name="SEC6" href="#TOC1">WHAT \R MATCHES</a><br> 146 <P> 147 By default, the sequence \R in a pattern matches any Unicode newline sequence, 148 whatever has been selected as the line ending sequence. If you specify 149 <pre> 150 --enable-bsr-anycrlf 151 </pre> 152 the default is changed so that \R matches only CR, LF, or CRLF. Whatever is 153 selected when PCRE is built can be overridden when the library functions are 154 called. 155 </P> 156 <br><a name="SEC7" href="#TOC1">BUILDING SHARED AND STATIC LIBRARIES</a><br> 157 <P> 158 The PCRE building process uses <b>libtool</b> to build both shared and static 159 Unix libraries by default. You can suppress one of these by adding one of 160 <pre> 161 --disable-shared 162 --disable-static 163 </pre> 164 to the <b>configure</b> command, as required. 165 </P> 166 <br><a name="SEC8" href="#TOC1">POSIX MALLOC USAGE</a><br> 167 <P> 168 When PCRE is called through the POSIX interface (see the 169 <a href="pcreposix.html"><b>pcreposix</b></a> 170 documentation), additional working storage is required for holding the pointers 171 to capturing substrings, because PCRE requires three integers per substring, 172 whereas the POSIX interface provides only two. If the number of expected 173 substrings is small, the wrapper function uses space on the stack, because this 174 is faster than using <b>malloc()</b> for each call. The default threshold above 175 which the stack is no longer used is 10; it can be changed by adding a setting 176 such as 177 <pre> 178 --with-posix-malloc-threshold=20 179 </pre> 180 to the <b>configure</b> command. 181 </P> 182 <br><a name="SEC9" href="#TOC1">HANDLING VERY LARGE PATTERNS</a><br> 183 <P> 184 Within a compiled pattern, offset values are used to point from one part to 185 another (for example, from an opening parenthesis to an alternation 186 metacharacter). By default, two-byte values are used for these offsets, leading 187 to a maximum size for a compiled pattern of around 64K. This is sufficient to 188 handle all but the most gigantic patterns. Nevertheless, some people do want to 189 process truyl enormous patterns, so it is possible to compile PCRE to use 190 three-byte or four-byte offsets by adding a setting such as 191 <pre> 192 --with-link-size=3 193 </pre> 194 to the <b>configure</b> command. The value given must be 2, 3, or 4. Using 195 longer offsets slows down the operation of PCRE because it has to load 196 additional bytes when handling them. 197 </P> 198 <br><a name="SEC10" href="#TOC1">AVOIDING EXCESSIVE STACK USAGE</a><br> 199 <P> 200 When matching with the <b>pcre_exec()</b> function, PCRE implements backtracking 201 by making recursive calls to an internal function called <b>match()</b>. In 202 environments where the size of the stack is limited, this can severely limit 203 PCRE's operation. (The Unix environment does not usually suffer from this 204 problem, but it may sometimes be necessary to increase the maximum stack size. 205 There is a discussion in the 206 <a href="pcrestack.html"><b>pcrestack</b></a> 207 documentation.) An alternative approach to recursion that uses memory from the 208 heap to remember data, instead of using recursive function calls, has been 209 implemented to work round the problem of limited stack size. If you want to 210 build a version of PCRE that works this way, add 211 <pre> 212 --disable-stack-for-recursion 213 </pre> 214 to the <b>configure</b> command. With this configuration, PCRE will use the 215 <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> variables to call memory 216 management functions. By default these point to <b>malloc()</b> and 217 <b>free()</b>, but you can replace the pointers so that your own functions are 218 used instead. 219 </P> 220 <P> 221 Separate functions are provided rather than using <b>pcre_malloc</b> and 222 <b>pcre_free</b> because the usage is very predictable: the block sizes 223 requested are always the same, and the blocks are always freed in reverse 224 order. A calling program might be able to implement optimized functions that 225 perform better than <b>malloc()</b> and <b>free()</b>. PCRE runs noticeably more 226 slowly when built in this way. This option affects only the <b>pcre_exec()</b> 227 function; it is not relevant for <b>pcre_dfa_exec()</b>. 228 </P> 229 <br><a name="SEC11" href="#TOC1">LIMITING PCRE RESOURCE USAGE</a><br> 230 <P> 231 Internally, PCRE has a function called <b>match()</b>, which it calls repeatedly 232 (sometimes recursively) when matching a pattern with the <b>pcre_exec()</b> 233 function. By controlling the maximum number of times this function may be 234 called during a single matching operation, a limit can be placed on the 235 resources used by a single call to <b>pcre_exec()</b>. The limit can be changed 236 at run time, as described in the 237 <a href="pcreapi.html"><b>pcreapi</b></a> 238 documentation. The default is 10 million, but this can be changed by adding a 239 setting such as 240 <pre> 241 --with-match-limit=500000 242 </pre> 243 to the <b>configure</b> command. This setting has no effect on the 244 <b>pcre_dfa_exec()</b> matching function. 245 </P> 246 <P> 247 In some environments it is desirable to limit the depth of recursive calls of 248 <b>match()</b> more strictly than the total number of calls, in order to 249 restrict the maximum amount of stack (or heap, if --disable-stack-for-recursion 250 is specified) that is used. A second limit controls this; it defaults to the 251 value that is set for --with-match-limit, which imposes no additional 252 constraints. However, you can set a lower limit by adding, for example, 253 <pre> 254 --with-match-limit-recursion=10000 255 </pre> 256 to the <b>configure</b> command. This value can also be overridden at run time. 257 </P> 258 <br><a name="SEC12" href="#TOC1">CREATING CHARACTER TABLES AT BUILD TIME</a><br> 259 <P> 260 PCRE uses fixed tables for processing characters whose code values are less 261 than 256. By default, PCRE is built with a set of tables that are distributed 262 in the file <i>pcre_chartables.c.dist</i>. These tables are for ASCII codes 263 only. If you add 264 <pre> 265 --enable-rebuild-chartables 266 </pre> 267 to the <b>configure</b> command, the distributed tables are no longer used. 268 Instead, a program called <b>dftables</b> is compiled and run. This outputs the 269 source for new set of tables, created in the default locale of your C runtime 270 system. (This method of replacing the tables does not work if you are cross 271 compiling, because <b>dftables</b> is run on the local host. If you need to 272 create alternative tables when cross compiling, you will have to do so "by 273 hand".) 274 </P> 275 <br><a name="SEC13" href="#TOC1">USING EBCDIC CODE</a><br> 276 <P> 277 PCRE assumes by default that it will run in an environment where the character 278 code is ASCII (or Unicode, which is a superset of ASCII). This is the case for 279 most computer operating systems. PCRE can, however, be compiled to run in an 280 EBCDIC environment by adding 281 <pre> 282 --enable-ebcdic 283 </pre> 284 to the <b>configure</b> command. This setting implies 285 --enable-rebuild-chartables. You should only use it if you know that you are in 286 an EBCDIC environment (for example, an IBM mainframe operating system). The 287 --enable-ebcdic option is incompatible with --enable-utf8. 288 </P> 289 <br><a name="SEC14" href="#TOC1">PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT</a><br> 290 <P> 291 By default, <b>pcregrep</b> reads all files as plain text. You can build it so 292 that it recognizes files whose names end in <b>.gz</b> or <b>.bz2</b>, and reads 293 them with <b>libz</b> or <b>libbz2</b>, respectively, by adding one or both of 294 <pre> 295 --enable-pcregrep-libz 296 --enable-pcregrep-libbz2 297 </pre> 298 to the <b>configure</b> command. These options naturally require that the 299 relevant libraries are installed on your system. Configuration will fail if 300 they are not. 301 </P> 302 <br><a name="SEC15" href="#TOC1">PCRETEST OPTION FOR LIBREADLINE SUPPORT</a><br> 303 <P> 304 If you add 305 <pre> 306 --enable-pcretest-libreadline 307 </pre> 308 to the <b>configure</b> command, <b>pcretest</b> is linked with the 309 <b>libreadline</b> library, and when its input is from a terminal, it reads it 310 using the <b>readline()</b> function. This provides line-editing and history 311 facilities. Note that <b>libreadline</b> is GPL-licensed, so if you distribute a 312 binary of <b>pcretest</b> linked in this way, there may be licensing issues. 313 </P> 314 <P> 315 Setting this option causes the <b>-lreadline</b> option to be added to the 316 <b>pcretest</b> build. In many operating environments with a sytem-installed 317 <b>libreadline</b> this is sufficient. However, in some environments (e.g. 318 if an unmodified distribution version of readline is in use), some extra 319 configuration may be necessary. The INSTALL file for <b>libreadline</b> says 320 this: 321 <pre> 322 "Readline uses the termcap functions, but does not link with the 323 termcap or curses library itself, allowing applications which link 324 with readline the to choose an appropriate library." 325 </pre> 326 If your environment has not been set up so that an appropriate library is 327 automatically included, you may need to add something like 328 <pre> 329 LIBS="-ncurses" 330 </pre> 331 immediately before the <b>configure</b> command. 332 </P> 333 <br><a name="SEC16" href="#TOC1">SEE ALSO</a><br> 334 <P> 335 <b>pcreapi</b>(3), <b>pcre_config</b>(3). 336 </P> 337 <br><a name="SEC17" href="#TOC1">AUTHOR</a><br> 338 <P> 339 Philip Hazel 340 <br> 341 University Computing Service 342 <br> 343 Cambridge CB2 3QH, England. 344 <br> 345 </P> 346 <br><a name="SEC18" href="#TOC1">REVISION</a><br> 347 <P> 348 Last updated: 29 September 2009 349 <br> 350 Copyright © 1997-2009 University of Cambridge. 351 <br> 352 <p> 353 Return to the <a href="index.html">PCRE index page</a>. 354 </p> 355
