/[pcre]/code/trunk/doc/pcrebuild.3
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revision 93 by nigel, Sat Feb 24 21:41:42 2007 UTC revision 195 by ph10, Mon Jul 30 13:23:28 2007 UTC
# Line 13  obtained by running Line 13  obtained by running
13  .sp  .sp
14    ./configure --help    ./configure --help
15  .sp  .sp
16  The following sections describe certain options whose names begin with --enable  The following sections include descriptions of options whose names begin with
17  or --disable. These settings specify changes to the defaults for the  --enable or --disable. These settings specify changes to the defaults for the
18  \fBconfigure\fP command. Because of the way that \fBconfigure\fP works,  \fBconfigure\fP command. Because of the way that \fBconfigure\fP works,
19  --enable and --disable always come in pairs, so the complementary option always  --enable and --disable always come in pairs, so the complementary option always
20  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.
# Line 56  character properties, you must add Line 56  character properties, you must add
56  to the \fBconfigure\fP command. This implies UTF-8 support, even if you have  to the \fBconfigure\fP command. This implies UTF-8 support, even if you have
57  not explicitly requested it.  not explicitly requested it.
58  .P  .P
59  Including Unicode property support adds around 90K of tables to the PCRE  Including Unicode property support adds around 30K of tables to the PCRE
60  library, approximately doubling its size. Only the general category properties  library. Only the general category properties such as \fILu\fP and \fINd\fP are
61  such as \fILu\fP and \fINd\fP are supported. Details are given in the  supported. Details are given in the
62  .\" HREF  .\" HREF
63  \fBpcrepattern\fP  \fBpcrepattern\fP
64  .\"  .\"
# Line 83  character sequence CRLF. If you want thi Line 83  character sequence CRLF. If you want thi
83  .sp  .sp
84  to the \fBconfigure\fP command. There is a fourth option, specified by  to the \fBconfigure\fP command. There is a fourth option, specified by
85  .sp  .sp
86      --enable-newline-is-anycrlf
87    .sp
88    which causes PCRE to recognize any of the three sequences CR, LF, or CRLF as
89    indicating a line ending. Finally, a fifth option, specified by
90    .sp
91    --enable-newline-is-any    --enable-newline-is-any
92  .sp  .sp
93  which causes PCRE to recognize any Unicode newline sequence.  causes PCRE to recognize any Unicode newline sequence.
94  .P  .P
95  Whatever line ending convention is selected when PCRE is built can be  Whatever line ending convention is selected when PCRE is built can be
96  overridden when the library functions are called. At build time it is  overridden when the library functions are called. At build time it is
# Line 137  or four-byte offsets by adding a setting Line 142  or four-byte offsets by adding a setting
142  to the \fBconfigure\fP command. The value given must be 2, 3, or 4. Using  to the \fBconfigure\fP command. The value given must be 2, 3, or 4. Using
143  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
144  additional bytes when handling them.  additional bytes when handling them.
 .P  
 If you build PCRE with an increased link size, test 2 (and test 5 if you are  
 using UTF-8) will fail. Part of the output of these tests is a representation  
 of the compiled pattern, and this changes with the link size.  
145  .  .
146  .SH "AVOIDING EXCESSIVE STACK USAGE"  .SH "AVOIDING EXCESSIVE STACK USAGE"
147  .rs  .rs
# Line 163  build a version of PCRE that works this Line 164  build a version of PCRE that works this
164  .sp  .sp
165  to the \fBconfigure\fP command. With this configuration, PCRE will use the  to the \fBconfigure\fP command. With this configuration, PCRE will use the
166  \fBpcre_stack_malloc\fP and \fBpcre_stack_free\fP variables to call memory  \fBpcre_stack_malloc\fP and \fBpcre_stack_free\fP variables to call memory
167  management functions. Separate functions are provided because the usage is very  management functions. By default these point to \fBmalloc()\fP and
168  predictable: the block sizes requested are always the same, and the blocks are  \fBfree()\fP, but you can replace the pointers so that your own functions are
169  always freed in reverse order. A calling program might be able to implement  used.
170  optimized functions that perform better than the standard \fBmalloc()\fP and  .P
171  \fBfree()\fP functions. PCRE runs noticeably more slowly when built in this  Separate functions are provided rather than using \fBpcre_malloc\fP and
172  way. This option affects only the \fBpcre_exec()\fP function; it is not  \fBpcre_free\fP because the usage is very predictable: the block sizes
173  relevant for the the \fBpcre_dfa_exec()\fP function.  requested are always the same, and the blocks are always freed in reverse
174    order. A calling program might be able to implement optimized functions that
175    perform better than \fBmalloc()\fP and \fBfree()\fP. PCRE runs noticeably more
176    slowly when built in this way. This option affects only the \fBpcre_exec()\fP
177    function; it is not relevant for the the \fBpcre_dfa_exec()\fP function.
178  .  .
179  .SH "LIMITING PCRE RESOURCE USAGE"  .SH "LIMITING PCRE RESOURCE USAGE"
180  .rs  .rs
# Line 202  constraints. However, you can set a lowe Line 207  constraints. However, you can set a lowe
207  .sp  .sp
208  to the \fBconfigure\fP command. This value can also be overridden at run time.  to the \fBconfigure\fP command. This value can also be overridden at run time.
209  .  .
210    .SH "CREATING CHARACTER TABLES AT BUILD TIME"
211    .rs
212    .sp
213    PCRE uses fixed tables for processing characters whose code values are less
214    than 256. By default, PCRE is built with a set of tables that are distributed
215    in the file \fIpcre_chartables.c.dist\fP. These tables are for ASCII codes
216    only. If you add
217    .sp
218      --enable-rebuild-chartables
219    .sp
220    to the \fBconfigure\fP command, the distributed tables are no longer used.
221    Instead, a program called \fBdftables\fP is compiled and run. This outputs the
222    source for new set of tables, created in the default locale of your C runtime
223    system. (This method of replacing the tables does not work if you are cross
224    compiling, because \fBdftables\fP is run on the local host. If you need to
225    create alternative tables when cross compiling, you will have to do so "by
226    hand".)
227    .
228  .SH "USING EBCDIC CODE"  .SH "USING EBCDIC CODE"
229  .rs  .rs
230  .sp  .sp
231  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
232  code is ASCII (or Unicode, which is a superset of ASCII). PCRE can, however, be  code is ASCII (or Unicode, which is a superset of ASCII). This is the case for
233  compiled to run in an EBCDIC environment by adding  most computer operating systems. PCRE can, however, be compiled to run in an
234    EBCDIC environment by adding
235  .sp  .sp
236    --enable-ebcdic    --enable-ebcdic
237  .sp  .sp
238  to the \fBconfigure\fP command.  to the \fBconfigure\fP command. This setting implies
239    --enable-rebuild-chartables. You should only use it if you know that you are in
240    an EBCDIC environment (for example, an IBM mainframe operating system).
241  .  .
242  .  .
243  .SH "SEE ALSO"  .SH "SEE ALSO"
244  .rs  .rs
245  .sp  .sp
246  \fBpcreapi\fP(3), \fBpcre_config\fP(3).  \fBpcreapi\fP(3), \fBpcre_config\fP(3).
247  .P  .
248  .in 0  .
249  Last updated: 30 November 2006  .SH AUTHOR
250  .br  .rs
251  Copyright (c) 1997-2006 University of Cambridge.  .sp
252    .nf
253    Philip Hazel
254    University Computing Service
255    Cambridge CB2 3QH, England.
256    .fi
257    .
258    .
259    .SH REVISION
260    .rs
261    .sp
262    .nf
263    Last updated: 30 July 2007
264    Copyright (c) 1997-2007 University of Cambridge.
265    .fi

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