/vendor/pcre/doc/html/pcrebuild.html

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  1. <html>
    2. 

  2. <head>
    3. 

  3. <title>pcrebuild specification</title>
    4. 

  4. </head>
    5. 

  5. <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
    6. 

  6. <h1>pcrebuild man page</h1>
    7. 

  7. <p>
    8. 

  8. Return to the <a href="index.html">PCRE index page</a>.
    9. 

  9. </p>
    10. 

  10. <p>
    11. 

  11. This page is part of the PCRE HTML documentation. It was generated automatically
    12. 

  12. from the original man page. If there is any nonsense in it, please consult the
    13. 

  13. man page, in case the conversion went wrong.
    14. 

  14. <br>
    15. 

  15. <ul>
    16. 

  16. <li><a name="TOC1" href="#SEC1">PCRE BUILD-TIME OPTIONS</a>
    17. 

  17. <li><a name="TOC2" href="#SEC2">C++ SUPPORT</a>
    18. 

  18. <li><a name="TOC3" href="#SEC3">UTF-8 SUPPORT</a>
    19. 

  19. <li><a name="TOC4" href="#SEC4">UNICODE CHARACTER PROPERTY SUPPORT</a>
    20. 

  20. <li><a name="TOC5" href="#SEC5">CODE VALUE OF NEWLINE</a>
    21. 

  21. <li><a name="TOC6" href="#SEC6">WHAT \R MATCHES</a>
    22. 

  22. <li><a name="TOC7" href="#SEC7">BUILDING SHARED AND STATIC LIBRARIES</a>
    23. 

  23. <li><a name="TOC8" href="#SEC8">POSIX MALLOC USAGE</a>
    24. 

  24. <li><a name="TOC9" href="#SEC9">HANDLING VERY LARGE PATTERNS</a>
    25. 

  25. <li><a name="TOC10" href="#SEC10">AVOIDING EXCESSIVE STACK USAGE</a>
    26. 

  26. <li><a name="TOC11" href="#SEC11">LIMITING PCRE RESOURCE USAGE</a>
    27. 

  27. <li><a name="TOC12" href="#SEC12">CREATING CHARACTER TABLES AT BUILD TIME</a>
    28. 

  28. <li><a name="TOC13" href="#SEC13">USING EBCDIC CODE</a>
    29. 

  29. <li><a name="TOC14" href="#SEC14">PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT</a>
    30. 

  30. <li><a name="TOC15" href="#SEC15">PCRETEST OPTION FOR LIBREADLINE SUPPORT</a>
    31. 

  31. <li><a name="TOC16" href="#SEC16">SEE ALSO</a>
    32. 

  32. <li><a name="TOC17" href="#SEC17">AUTHOR</a>
    33. 

  33. <li><a name="TOC18" href="#SEC18">REVISION</a>
    34. 

  34. </ul>
    35. 

  35. <br><a name="SEC1" href="#TOC1">PCRE BUILD-TIME OPTIONS</a><br>
    36. 

  36. <P>
    37. 

  37. This document describes the optional features of PCRE that can be selected when
    38. 

  38. the library is compiled. It assumes use of the <b>configure</b> script, where
    39. 

  39. the optional features are selected or deselected by providing options to
    40. 

  40. <b>configure</b> before running the <b>make</b> command. However, the same
    41. 

  41. options can be selected in both Unix-like and non-Unix-like environments using
    42. 

  42. the GUI facility of <b>CMakeSetup</b> if you are using <b>CMake</b> instead of
    43. 

  43. <b>configure</b> to build PCRE.
    44. 

  44. </P>
    45. 

  45. <P>
    46. 

  46. The complete list of options for <b>configure</b> (which includes the standard
    47. 

  47. ones such as the selection of the installation directory) can be obtained by
    48. 

  48. running
    49. 

  49. <pre>
    50. 

  50.   ./configure --help
    51. 

  51. </pre>
    52. 

  52. The following sections include descriptions of options whose names begin with
    53. 

  53. --enable or --disable. These settings specify changes to the defaults for the
    54. 

  54. <b>configure</b> command. Because of the way that <b>configure</b> works,
    55. 

  55. --enable and --disable always come in pairs, so the complementary option always
    56. 

  56. exists as well, but as it specifies the default, it is not described.
    57. 

  57. </P>
    58. 

  58. <br><a name="SEC2" href="#TOC1">C++ SUPPORT</a><br>
    59. 

  59. <P>
    60. 

  60. By default, the <b>configure</b> script will search for a C++ compiler and C++
    61. 

  61. header files. If it finds them, it automatically builds the C++ wrapper library
    62. 

  62. for PCRE. You can disable this by adding
    63. 

  63. <pre>
    64. 

  64.   --disable-cpp
    65. 

  65. </pre>
    66. 

  66. to the <b>configure</b> command.
    67. 

  67. </P>
    68. 

  68. <br><a name="SEC3" href="#TOC1">UTF-8 SUPPORT</a><br>
    69. 

  69. <P>
    70. 

  70. To build PCRE with support for UTF-8 character strings, add
    71. 

  71. <pre>
    72. 

  72.   --enable-utf8
    73. 

  73. </pre>
    74. 

  74. to the <b>configure</b> command. Of itself, this does not make PCRE treat
    75. 

  75. strings as UTF-8. As well as compiling PCRE with this option, you also have
    76. 

  76. have to set the PCRE_UTF8 option when you call the <b>pcre_compile()</b>
    77. 

  77. function.
    78. 

  78. </P>
    79. 

  79. <br><a name="SEC4" href="#TOC1">UNICODE CHARACTER PROPERTY SUPPORT</a><br>
    80. 

  80. <P>
    81. 

  81. UTF-8 support allows PCRE to process character values greater than 255 in the
    82. 

  82. strings that it handles. On its own, however, it does not provide any
    83. 

  83. facilities for accessing the properties of such characters. If you want to be
    84. 

  84. able to use the pattern escapes \P, \p, and \X, which refer to Unicode
    85. 

  85. character properties, you must add
    86. 

  86. <pre>
    87. 

  87.   --enable-unicode-properties
    88. 

  88. </pre>
    89. 

  89. to the <b>configure</b> command. This implies UTF-8 support, even if you have
    90. 

  90. not explicitly requested it.
    91. 

  91. </P>
    92. 

  92. <P>
    93. 

  93. Including Unicode property support adds around 30K of tables to the PCRE
    94. 

  94. library. Only the general category properties such as <i>Lu</i> and <i>Nd</i> are
    95. 

  95. supported. Details are given in the
    96. 

  96. <a href="pcrepattern.html"><b>pcrepattern</b></a>
    97. 

  97. documentation.
    98. 

  98. </P>
    99. 

  99. <br><a name="SEC5" href="#TOC1">CODE VALUE OF NEWLINE</a><br>
    100. 

  100. <P>
    101. 

  101. By default, PCRE interprets character 10 (linefeed, LF) as indicating the end
    102. 

  102. of a line. This is the normal newline character on Unix-like systems. You can
    103. 

  103. compile PCRE to use character 13 (carriage return, CR) instead, by adding
    104. 

  104. <pre>
    105. 

  105.   --enable-newline-is-cr
    106. 

  106. </pre>
    107. 

  107. to the <b>configure</b> command. There is also a --enable-newline-is-lf option,
    108. 

  108. which explicitly specifies linefeed as the newline character.
    109. 

  109. <br>
    110. 

  110. <br>
    111. 

  111. Alternatively, you can specify that line endings are to be indicated by the two
    112. 

  112. character sequence CRLF. If you want this, add
    113. 

  113. <pre>
    114. 

  114.   --enable-newline-is-crlf
    115. 

  115. </pre>
    116. 

  116. to the <b>configure</b> command. There is a fourth option, specified by
    117. 

  117. <pre>
    118. 

  118.   --enable-newline-is-anycrlf
    119. 

  119. </pre>
    120. 

  120. which causes PCRE to recognize any of the three sequences CR, LF, or CRLF as
    121. 

  121. indicating a line ending. Finally, a fifth option, specified by
    122. 

  122. <pre>
    123. 

  123.   --enable-newline-is-any
    124. 

  124. </pre>
    125. 

  125. causes PCRE to recognize any Unicode newline sequence.
    126. 

  126. </P>
    127. 

  127. <P>
    128. 

  128. Whatever line ending convention is selected when PCRE is built can be
    129. 

  129. overridden when the library functions are called. At build time it is
    130. 

  130. conventional to use the standard for your operating system.
    131. 

  131. </P>
    132. 

  132. <br><a name="SEC6" href="#TOC1">WHAT \R MATCHES</a><br>
    133. 

  133. <P>
    134. 

  134. By default, the sequence \R in a pattern matches any Unicode newline sequence,
    135. 

  135. whatever has been selected as the line ending sequence. If you specify
    136. 

  136. <pre>
    137. 

  137.   --enable-bsr-anycrlf
    138. 

  138. </pre>
    139. 

  139. the default is changed so that \R matches only CR, LF, or CRLF. Whatever is
    140. 

  140. selected when PCRE is built can be overridden when the library functions are
    141. 

  141. called.
    142. 

  142. </P>
    143. 

  143. <br><a name="SEC7" href="#TOC1">BUILDING SHARED AND STATIC LIBRARIES</a><br>
    144. 

  144. <P>
    145. 

  145. The PCRE building process uses <b>libtool</b> to build both shared and static
    146. 

  146. Unix libraries by default. You can suppress one of these by adding one of
    147. 

  147. <pre>
    148. 

  148.   --disable-shared
    149. 

  149.   --disable-static
    150. 

  150. </pre>
    151. 

  151. to the <b>configure</b> command, as required.
    152. 

  152. </P>
    153. 

  153. <br><a name="SEC8" href="#TOC1">POSIX MALLOC USAGE</a><br>
    154. 

  154. <P>
    155. 

  155. When PCRE is called through the POSIX interface (see the
    156. 

  156. <a href="pcreposix.html"><b>pcreposix</b></a>
    157. 

  157. documentation), additional working storage is required for holding the pointers
    158. 

  158. to capturing substrings, because PCRE requires three integers per substring,
    159. 

  159. whereas the POSIX interface provides only two. If the number of expected
    160. 

  160. substrings is small, the wrapper function uses space on the stack, because this
    161. 

  161. is faster than using <b>malloc()</b> for each call. The default threshold above
    162. 

  162. which the stack is no longer used is 10; it can be changed by adding a setting
    163. 

  163. such as
    164. 

  164. <pre>
    165. 

  165.   --with-posix-malloc-threshold=20
    166. 

  166. </pre>
    167. 

  167. to the <b>configure</b> command.
    168. 

  168. </P>
    169. 

  169. <br><a name="SEC9" href="#TOC1">HANDLING VERY LARGE PATTERNS</a><br>
    170. 

  170. <P>
    171. 

  171. Within a compiled pattern, offset values are used to point from one part to
    172. 

  172. another (for example, from an opening parenthesis to an alternation
    173. 

  173. metacharacter). By default, two-byte values are used for these offsets, leading
    174. 

  174. to a maximum size for a compiled pattern of around 64K. This is sufficient to
    175. 

  175. handle all but the most gigantic patterns. Nevertheless, some people do want to
    176. 

  176. process enormous patterns, so it is possible to compile PCRE to use three-byte
    177. 

  177. or four-byte offsets by adding a setting such as
    178. 

  178. <pre>
    179. 

  179.   --with-link-size=3
    180. 

  180. </pre>
    181. 

  181. to the <b>configure</b> command. The value given must be 2, 3, or 4. Using
    182. 

  182. longer offsets slows down the operation of PCRE because it has to load
    183. 

  183. additional bytes when handling them.
    184. 

  184. </P>
    185. 

  185. <br><a name="SEC10" href="#TOC1">AVOIDING EXCESSIVE STACK USAGE</a><br>
    186. 

  186. <P>
    187. 

  187. When matching with the <b>pcre_exec()</b> function, PCRE implements backtracking
    188. 

  188. by making recursive calls to an internal function called <b>match()</b>. In
    189. 

  189. environments where the size of the stack is limited, this can severely limit
    190. 

  190. PCRE's operation. (The Unix environment does not usually suffer from this
    191. 

  191. problem, but it may sometimes be necessary to increase the maximum stack size.
    192. 

  192. There is a discussion in the
    193. 

  193. <a href="pcrestack.html"><b>pcrestack</b></a>
    194. 

  194. documentation.) An alternative approach to recursion that uses memory from the
    195. 

  195. heap to remember data, instead of using recursive function calls, has been
    196. 

  196. implemented to work round the problem of limited stack size. If you want to
    197. 

  197. build a version of PCRE that works this way, add
    198. 

  198. <pre>
    199. 

  199.   --disable-stack-for-recursion
    200. 

  200. </pre>
    201. 

  201. to the <b>configure</b> command. With this configuration, PCRE will use the
    202. 

  202. <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> variables to call memory
    203. 

  203. management functions. By default these point to <b>malloc()</b> and
    204. 

  204. <b>free()</b>, but you can replace the pointers so that your own functions are
    205. 

  205. used.
    206. 

  206. </P>
    207. 

  207. <P>
    208. 

  208. Separate functions are provided rather than using <b>pcre_malloc</b> and
    209. 

  209. <b>pcre_free</b> because the usage is very predictable: the block sizes
    210. 

  210. requested are always the same, and the blocks are always freed in reverse
    211. 

  211. order. A calling program might be able to implement optimized functions that
    212. 

  212. perform better than <b>malloc()</b> and <b>free()</b>. PCRE runs noticeably more
    213. 

  213. slowly when built in this way. This option affects only the <b>pcre_exec()</b>
    214. 

  214. function; it is not relevant for the the <b>pcre_dfa_exec()</b> function.
    215. 

  215. </P>
    216. 

  216. <br><a name="SEC11" href="#TOC1">LIMITING PCRE RESOURCE USAGE</a><br>
    217. 

  217. <P>
    218. 

  218. Internally, PCRE has a function called <b>match()</b>, which it calls repeatedly
    219. 

  219. (sometimes recursively) when matching a pattern with the <b>pcre_exec()</b>
    220. 

  220. function. By controlling the maximum number of times this function may be
    221. 

  221. called during a single matching operation, a limit can be placed on the
    222. 

  222. resources used by a single call to <b>pcre_exec()</b>. The limit can be changed
    223. 

  223. at run time, as described in the
    224. 

  224. <a href="pcreapi.html"><b>pcreapi</b></a>
    225. 

  225. documentation. The default is 10 million, but this can be changed by adding a
    226. 

  226. setting such as
    227. 

  227. <pre>
    228. 

  228.   --with-match-limit=500000
    229. 

  229. </pre>
    230. 

  230. to the <b>configure</b> command. This setting has no effect on the
    231. 

  231. <b>pcre_dfa_exec()</b> matching function.
    232. 

  232. </P>
    233. 

  233. <P>
    234. 

  234. In some environments it is desirable to limit the depth of recursive calls of
    235. 

  235. <b>match()</b> more strictly than the total number of calls, in order to
    236. 

  236. restrict the maximum amount of stack (or heap, if --disable-stack-for-recursion
    237. 

  237. is specified) that is used. A second limit controls this; it defaults to the
    238. 

  238. value that is set for --with-match-limit, which imposes no additional
    239. 

  239. constraints. However, you can set a lower limit by adding, for example,
    240. 

  240. <pre>
    241. 

  241.   --with-match-limit-recursion=10000
    242. 

  242. </pre>
    243. 

  243. to the <b>configure</b> command. This value can also be overridden at run time.
    244. 

  244. </P>
    245. 

  245. <br><a name="SEC12" href="#TOC1">CREATING CHARACTER TABLES AT BUILD TIME</a><br>
    246. 

  246. <P>
    247. 

  247. PCRE uses fixed tables for processing characters whose code values are less
    248. 

  248. than 256. By default, PCRE is built with a set of tables that are distributed
    249. 

  249. in the file <i>pcre_chartables.c.dist</i>. These tables are for ASCII codes
    250. 

  250. only. If you add
    251. 

  251. <pre>
    252. 

  252.   --enable-rebuild-chartables
    253. 

  253. </pre>
    254. 

  254. to the <b>configure</b> command, the distributed tables are no longer used.
    255. 

  255. Instead, a program called <b>dftables</b> is compiled and run. This outputs the
    256. 

  256. source for new set of tables, created in the default locale of your C runtime
    257. 

  257. system. (This method of replacing the tables does not work if you are cross
    258. 

  258. compiling, because <b>dftables</b> is run on the local host. If you need to
    259. 

  259. create alternative tables when cross compiling, you will have to do so "by
    260. 

  260. hand".)
    261. 

  261. </P>
    262. 

  262. <br><a name="SEC13" href="#TOC1">USING EBCDIC CODE</a><br>
    263. 

  263. <P>
    264. 

  264. PCRE assumes by default that it will run in an environment where the character
    265. 

  265. code is ASCII (or Unicode, which is a superset of ASCII). This is the case for
    266. 

  266. most computer operating systems. PCRE can, however, be compiled to run in an
    267. 

  267. EBCDIC environment by adding
    268. 

  268. <pre>
    269. 

  269.   --enable-ebcdic
    270. 

  270. </pre>
    271. 

  271. to the <b>configure</b> command. This setting implies
    272. 

  272. --enable-rebuild-chartables. You should only use it if you know that you are in
    273. 

  273. an EBCDIC environment (for example, an IBM mainframe operating system).
    274. 

  274. </P>
    275. 

  275. <br><a name="SEC14" href="#TOC1">PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT</a><br>
    276. 

  276. <P>
    277. 

  277. By default, <b>pcregrep</b> reads all files as plain text. You can build it so
    278. 

  278. that it recognizes files whose names end in <b>.gz</b> or <b>.bz2</b>, and reads
    279. 

  279. them with <b>libz</b> or <b>libbz2</b>, respectively, by adding one or both of
    280. 

  280. <pre>
    281. 

  281.   --enable-pcregrep-libz
    282. 

  282.   --enable-pcregrep-libbz2
    283. 

  283. </pre>
    284. 

  284. to the <b>configure</b> command. These options naturally require that the
    285. 

  285. relevant libraries are installed on your system. Configuration will fail if
    286. 

  286. they are not.
    287. 

  287. </P>
    288. 

  288. <br><a name="SEC15" href="#TOC1">PCRETEST OPTION FOR LIBREADLINE SUPPORT</a><br>
    289. 

  289. <P>
    290. 

  290. If you add
    291. 

  291. <pre>
    292. 

  292.   --enable-pcretest-libreadline
    293. 

  293. </pre>
    294. 

  294. to the <b>configure</b> command, <b>pcretest</b> is linked with the
    295. 

  295. <b>libreadline</b> library, and when its input is from a terminal, it reads it
    296. 

  296. using the <b>readline()</b> function. This provides line-editing and history
    297. 

  297. facilities. Note that <b>libreadline</b> is GPL-licenced, so if you distribute a
    298. 

  298. binary of <b>pcretest</b> linked in this way, there may be licensing issues.
    299. 

  299. </P>
    300. 

  300. <P>
    301. 

  301. Setting this option causes the <b>-lreadline</b> option to be added to the
    302. 

  302. <b>pcretest</b> build. In many operating environments with a sytem-installed
    303. 

  303. <b>libreadline</b> this is sufficient. However, in some environments (e.g.
    304. 

  304. if an unmodified distribution version of readline is in use), some extra
    305. 

  305. configuration may be necessary. The INSTALL file for <b>libreadline</b> says
    306. 

  306. this:
    307. 

  307. <pre>
    308. 

  308.   "Readline uses the termcap functions, but does not link with the
    309. 

  309.   termcap or curses library itself, allowing applications which link
    310. 

  310.   with readline the to choose an appropriate library."
    311. 

  311. </pre>
    312. 

  312. If your environment has not been set up so that an appropriate library is
    313. 

  313. automatically included, you may need to add something like
    314. 

  314. <pre>
    315. 

  315.   LIBS="-ncurses"
    316. 

  316. </pre>
    317. 

  317. immediately before the <b>configure</b> command.
    318. 

  318. </P>
    319. 

  319. <br><a name="SEC16" href="#TOC1">SEE ALSO</a><br>
    320. 

  320. <P>
    321. 

  321. <b>pcreapi</b>(3), <b>pcre_config</b>(3).
    322. 

  322. </P>
    323. 

  323. <br><a name="SEC17" href="#TOC1">AUTHOR</a><br>
    324. 

  324. <P>
    325. 

  325. Philip Hazel
    326. 

  326. <br>
    327. 

  327. University Computing Service
    328. 

  328. <br>
    329. 

  329. Cambridge CB2 3QH, England.
    330. 

  330. <br>
    331. 

  331. </P>
    332. 

  332. <br><a name="SEC18" href="#TOC1">REVISION</a><br>
    333. 

  333. <P>
    334. 

  334. Last updated: 13 April 2008
    335. 

  335. <br>
    336. 

  336. Copyright &copy; 1997-2008 University of Cambridge.
    337. 

  337. <br>
    338. 

  338. <p>
    339. 

  339. Return to the <a href="index.html">PCRE index page</a>.
    340. 

  340. </p>
    341.