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3  <title>pcrebuild specification</title>  <title>pcrebuild specification</title>
4  </head>  </head>
5  <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">  <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6  This HTML document has been generated automatically from the original man page.  <h1>pcrebuild man page</h1>
7  If there is any nonsense in it, please consult the man page, in case the  <p>
8  conversion went wrong.<br>  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>  <ul>
16  <li><a name="TOC1" href="#SEC1">PCRE BUILD-TIME OPTIONS</a>  <li><a name="TOC1" href="#SEC1">PCRE BUILD-TIME OPTIONS</a>
17  <li><a name="TOC2" href="#SEC2">UTF-8 SUPPORT</a>  <li><a name="TOC2" href="#SEC2">C++ SUPPORT</a>
18  <li><a name="TOC3" href="#SEC3">CODE VALUE OF NEWLINE</a>  <li><a name="TOC3" href="#SEC3">UTF-8 SUPPORT</a>
19  <li><a name="TOC4" href="#SEC4">BUILDING SHARED AND STATIC LIBRARIES</a>  <li><a name="TOC4" href="#SEC4">UNICODE CHARACTER PROPERTY SUPPORT</a>
20  <li><a name="TOC5" href="#SEC5">POSIX MALLOC USAGE</a>  <li><a name="TOC5" href="#SEC5">CODE VALUE OF NEWLINE</a>
21  <li><a name="TOC6" href="#SEC6">LIMITING PCRE RESOURCE USAGE</a>  <li><a name="TOC6" href="#SEC6">BUILDING SHARED AND STATIC LIBRARIES</a>
22  <li><a name="TOC7" href="#SEC7">HANDLING VERY LARGE PATTERNS</a>  <li><a name="TOC7" href="#SEC7">POSIX MALLOC USAGE</a>
23  <li><a name="TOC8" href="#SEC8">AVOIDING EXCESSIVE STACK USAGE</a>  <li><a name="TOC8" href="#SEC8">LIMITING PCRE RESOURCE USAGE</a>
24  <li><a name="TOC9" href="#SEC9">USING EBCDIC CODE</a>  <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">USING EBCDIC CODE</a>
27  </ul>  </ul>
28  <br><a name="SEC1" href="#TOC1">PCRE BUILD-TIME OPTIONS</a><br>  <br><a name="SEC1" href="#TOC1">PCRE BUILD-TIME OPTIONS</a><br>
29  <P>  <P>
30  This document describes the optional features of PCRE that can be selected when  This document describes the optional features of PCRE that can be selected when
31  the library is compiled. They are all selected, or deselected, by providing  the library is compiled. They are all selected, or deselected, by providing
32  options to the <b>configure</b> script which is run before the <b>make</b>  options to the <b>configure</b> script that is run before the <b>make</b>
33  command. The complete list of options for <b>configure</b> (which includes the  command. The complete list of options for <b>configure</b> (which includes the
34  standard ones such as the selection of the installation directory) can be  standard ones such as the selection of the installation directory) can be
35  obtained by running  obtained by running
 </P>  
 <P>  
36  <pre>  <pre>
37    ./configure --help    ./configure --help
38  </PRE>  </pre>
 </P>  
 <P>  
39  The following sections describe certain options whose names begin with --enable  The following sections describe certain options whose names begin with --enable
40  or --disable. These settings specify changes to the defaults for the  or --disable. These settings specify changes to the defaults for the
41  <b>configure</b> command. Because of the way that <b>configure</b> works,  <b>configure</b> command. Because of the way that <b>configure</b> works,
42  --enable and --disable always come in pairs, so the complementary option always  --enable and --disable always come in pairs, so the complementary option always
43  exists as well, but as it specifies the default, it is not described.  exists as well, but as it specifies the default, it is not described.
44  </P>  </P>
45  <br><a name="SEC2" href="#TOC1">UTF-8 SUPPORT</a><br>  <br><a name="SEC2" href="#TOC1">C++ SUPPORT</a><br>
46  <P>  <P>
47  To build PCRE with support for UTF-8 character strings, add  By default, the <b>configure</b> script will search for a C++ compiler and C++
48    header files. If it finds them, it automatically builds the C++ wrapper library
49    for PCRE. You can disable this by adding
50    <pre>
51      --disable-cpp
52    </pre>
53    to the <b>configure</b> command.
54  </P>  </P>
55    <br><a name="SEC3" href="#TOC1">UTF-8 SUPPORT</a><br>
56  <P>  <P>
57    To build PCRE with support for UTF-8 character strings, add
58  <pre>  <pre>
59    --enable-utf8    --enable-utf8
60  </PRE>  </pre>
 </P>  
 <P>  
61  to the <b>configure</b> command. Of itself, this does not make PCRE treat  to the <b>configure</b> command. Of itself, this does not make PCRE treat
62  strings as UTF-8. As well as compiling PCRE with this option, you also have  strings as UTF-8. As well as compiling PCRE with this option, you also have
63  have to set the PCRE_UTF8 option when you call the <b>pcre_compile()</b>  have to set the PCRE_UTF8 option when you call the <b>pcre_compile()</b>
64  function.  function.
65  </P>  </P>
66  <br><a name="SEC3" href="#TOC1">CODE VALUE OF NEWLINE</a><br>  <br><a name="SEC4" href="#TOC1">UNICODE CHARACTER PROPERTY SUPPORT</a><br>
67    <P>
68    UTF-8 support allows PCRE to process character values greater than 255 in the
69    strings that it handles. On its own, however, it does not provide any
70    facilities for accessing the properties of such characters. If you want to be
71    able to use the pattern escapes \P, \p, and \X, which refer to Unicode
72    character properties, you must add
73    <pre>
74      --enable-unicode-properties
75    </pre>
76    to the <b>configure</b> command. This implies UTF-8 support, even if you have
77    not explicitly requested it.
78    </P>
79    <P>
80    Including Unicode property support adds around 90K of tables to the PCRE
81    library, approximately doubling its size. Only the general category properties
82    such as <i>Lu</i> and <i>Nd</i> are supported. Details are given in the
83    <a href="pcrepattern.html"><b>pcrepattern</b></a>
84    documentation.
85    </P>
86    <br><a name="SEC5" href="#TOC1">CODE VALUE OF NEWLINE</a><br>
87  <P>  <P>
88  By default, PCRE treats character 10 (linefeed) as the newline character. This  By default, PCRE treats character 10 (linefeed) as the newline character. This
89  is the normal newline character on Unix-like systems. You can compile PCRE to  is the normal newline character on Unix-like systems. You can compile PCRE to
90  use character 13 (carriage return) instead by adding  use character 13 (carriage return) instead by adding
 </P>  
 <P>  
91  <pre>  <pre>
92    --enable-newline-is-cr    --enable-newline-is-cr
93  </PRE>  </pre>
 </P>  
 <P>  
94  to the <b>configure</b> command. For completeness there is also a  to the <b>configure</b> command. For completeness there is also a
95  --enable-newline-is-lf option, which explicitly specifies linefeed as the  --enable-newline-is-lf option, which explicitly specifies linefeed as the
96  newline character.  newline character.
97  </P>  </P>
98  <br><a name="SEC4" href="#TOC1">BUILDING SHARED AND STATIC LIBRARIES</a><br>  <br><a name="SEC6" href="#TOC1">BUILDING SHARED AND STATIC LIBRARIES</a><br>
99  <P>  <P>
100  The PCRE building process uses <b>libtool</b> to build both shared and static  The PCRE building process uses <b>libtool</b> to build both shared and static
101  Unix libraries by default. You can suppress one of these by adding one of  Unix libraries by default. You can suppress one of these by adding one of
 </P>  
 <P>  
102  <pre>  <pre>
103    --disable-shared    --disable-shared
104    --disable-static    --disable-static
105  </PRE>  </pre>
 </P>  
 <P>  
106  to the <b>configure</b> command, as required.  to the <b>configure</b> command, as required.
107  </P>  </P>
108  <br><a name="SEC5" href="#TOC1">POSIX MALLOC USAGE</a><br>  <br><a name="SEC7" href="#TOC1">POSIX MALLOC USAGE</a><br>
109  <P>  <P>
110  When PCRE is called through the POSIX interface (see the <b>pcreposix</b>  When PCRE is called through the POSIX interface (see the
111    <a href="pcreposix.html"><b>pcreposix</b></a>
112  documentation), additional working storage is required for holding the pointers  documentation), additional working storage is required for holding the pointers
113  to capturing substrings because PCRE requires three integers per substring,  to capturing substrings, because PCRE requires three integers per substring,
114  whereas the POSIX interface provides only two. If the number of expected  whereas the POSIX interface provides only two. If the number of expected
115  substrings is small, the wrapper function uses space on the stack, because this  substrings is small, the wrapper function uses space on the stack, because this
116  is faster than using <b>malloc()</b> for each call. The default threshold above  is faster than using <b>malloc()</b> for each call. The default threshold above
117  which the stack is no longer used is 10; it can be changed by adding a setting  which the stack is no longer used is 10; it can be changed by adding a setting
118  such as  such as
 </P>  
 <P>  
119  <pre>  <pre>
120    --with-posix-malloc-threshold=20    --with-posix-malloc-threshold=20
121  </PRE>  </pre>
 </P>  
 <P>  
122  to the <b>configure</b> command.  to the <b>configure</b> command.
123  </P>  </P>
124  <br><a name="SEC6" href="#TOC1">LIMITING PCRE RESOURCE USAGE</a><br>  <br><a name="SEC8" href="#TOC1">LIMITING PCRE RESOURCE USAGE</a><br>
125  <P>  <P>
126  Internally, PCRE has a function called <b>match()</b> which it calls repeatedly  Internally, PCRE has a function called <b>match()</b>, which it calls repeatedly
127  (possibly recursively) when performing a matching operation. By limiting the  (possibly recursively) when matching a pattern with the <b>pcre_exec()</b>
128  number of times this function may be called, a limit can be placed on the  function. By controlling the maximum number of times this function may be
129    called during a single matching operation, a limit can be placed on the
130  resources used by a single call to <b>pcre_exec()</b>. The limit can be changed  resources used by a single call to <b>pcre_exec()</b>. The limit can be changed
131  at run time, as described in the <b>pcreapi</b> documentation. The default is 10  at run time, as described in the
132  million, but this can be changed by adding a setting such as  <a href="pcreapi.html"><b>pcreapi</b></a>
133  </P>  documentation. The default is 10 million, but this can be changed by adding a
134  <P>  setting such as
135  <pre>  <pre>
136    --with-match-limit=500000    --with-match-limit=500000
137  </PRE>  </pre>
138    to the <b>configure</b> command. This setting has no effect on the
139    <b>pcre_dfa_exec()</b> matching function.
140  </P>  </P>
141  <P>  <br><a name="SEC9" href="#TOC1">HANDLING VERY LARGE PATTERNS</a><br>
 to the <b>configure</b> command.  
 </P>  
 <br><a name="SEC7" href="#TOC1">HANDLING VERY LARGE PATTERNS</a><br>  
142  <P>  <P>
143  Within a compiled pattern, offset values are used to point from one part to  Within a compiled pattern, offset values are used to point from one part to
144  another (for example, from an opening parenthesis to an alternation  another (for example, from an opening parenthesis to an alternation
145  metacharacter). By default two-byte values are used for these offsets, leading  metacharacter). By default, two-byte values are used for these offsets, leading
146  to a maximum size for a compiled pattern of around 64K. This is sufficient to  to a maximum size for a compiled pattern of around 64K. This is sufficient to
147  handle all but the most gigantic patterns. Nevertheless, some people do want to  handle all but the most gigantic patterns. Nevertheless, some people do want to
148  process enormous patterns, so it is possible to compile PCRE to use three-byte  process enormous patterns, so it is possible to compile PCRE to use three-byte
149  or four-byte offsets by adding a setting such as  or four-byte offsets by adding a setting such as
 </P>  
 <P>  
150  <pre>  <pre>
151    --with-link-size=3    --with-link-size=3
152  </PRE>  </pre>
 </P>  
 <P>  
153  to the <b>configure</b> command. The value given must be 2, 3, or 4. Using  to the <b>configure</b> command. The value given must be 2, 3, or 4. Using
154  longer offsets slows down the operation of PCRE because it has to load  longer offsets slows down the operation of PCRE because it has to load
155  additional bytes when handling them.  additional bytes when handling them.
# Line 144  If you build PCRE with an increased link Line 159  If you build PCRE with an increased link
159  using UTF-8) will fail. Part of the output of these tests is a representation  using UTF-8) will fail. Part of the output of these tests is a representation
160  of the compiled pattern, and this changes with the link size.  of the compiled pattern, and this changes with the link size.
161  </P>  </P>
162  <br><a name="SEC8" href="#TOC1">AVOIDING EXCESSIVE STACK USAGE</a><br>  <br><a name="SEC10" href="#TOC1">AVOIDING EXCESSIVE STACK USAGE</a><br>
 <P>  
 PCRE implements backtracking while matching by making recursive calls to an  
 internal function called <b>match()</b>. In environments where the size of the  
 stack is limited, this can severely limit PCRE's operation. (The Unix  
 environment does not usually suffer from this problem.) An alternative approach  
 that uses memory from the heap to remember data, instead of using recursive  
 function calls, has been implemented to work round this problem. If you want to  
 build a version of PCRE that works this way, add  
 </P>  
163  <P>  <P>
164    When matching with the <b>pcre_exec()</b> function, PCRE implements backtracking
165    by making recursive calls to an internal function called <b>match()</b>. In
166    environments where the size of the stack is limited, this can severely limit
167    PCRE's operation. (The Unix environment does not usually suffer from this
168    problem.) An alternative approach that uses memory from the heap to remember
169    data, instead of using recursive function calls, has been implemented to work
170    round this problem. If you want to build a version of PCRE that works this way,
171    add
172  <pre>  <pre>
173    --disable-stack-for-recursion    --disable-stack-for-recursion
174  </PRE>  </pre>
 </P>  
 <P>  
175  to the <b>configure</b> command. With this configuration, PCRE will use the  to the <b>configure</b> command. With this configuration, PCRE will use the
176  <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> variables to call memory  <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> variables to call memory
177  management functions. Separate functions are provided because the usage is very  management functions. Separate functions are provided because the usage is very
# Line 167  predictable: the block sizes requested a Line 179  predictable: the block sizes requested a
179  always freed in reverse order. A calling program might be able to implement  always freed in reverse order. A calling program might be able to implement
180  optimized functions that perform better than the standard <b>malloc()</b> and  optimized functions that perform better than the standard <b>malloc()</b> and
181  <b>free()</b> functions. PCRE runs noticeably more slowly when built in this  <b>free()</b> functions. PCRE runs noticeably more slowly when built in this
182  way.  way. This option affects only the <b>pcre_exec()</b> function; it is not
183    relevant for the the <b>pcre_dfa_exec()</b> function.
184  </P>  </P>
185  <br><a name="SEC9" href="#TOC1">USING EBCDIC CODE</a><br>  <br><a name="SEC11" href="#TOC1">USING EBCDIC CODE</a><br>
186  <P>  <P>
187  PCRE assumes by default that it will run in an environment where the character  PCRE assumes by default that it will run in an environment where the character
188  code is ASCII (or UTF-8, which is a superset of ASCII). PCRE can, however, be  code is ASCII (or Unicode, which is a superset of ASCII). PCRE can, however, be
189  compiled to run in an EBCDIC environment by adding  compiled to run in an EBCDIC environment by adding
 </P>  
 <P>  
190  <pre>  <pre>
191    --enable-ebcdic    --enable-ebcdic
192  </PRE>  </pre>
 </P>  
 <P>  
193  to the <b>configure</b> command.  to the <b>configure</b> command.
194  </P>  </P>
195  <P>  <P>
196  Last updated: 09 December 2003  Last updated: 15 August 2005
197  <br>  <br>
198  Copyright &copy; 1997-2003 University of Cambridge.  Copyright &copy; 1997-2005 University of Cambridge.
199    <p>
200    Return to the <a href="index.html">PCRE index page</a>.
201    </p>

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