1PCRESAMPLE(3) Library Functions Manual PCRESAMPLE(3)
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6 PCRE - Perl-compatible regular expressions
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9 A simple, complete demonstration program, to get you started with using
11 PCRE, is supplied in the file pcredemo.c in the PCRE distribution. A
12 listing of this program is given in the pcredemo documentation. If you
13 do not have a copy of the PCRE distribution, you can save this listing
14 to re-create pcredemo.c.
15 The program compiles the regular expression that is its first argument,
17 and matches it against the subject string in its second argument. No
18 PCRE options are set, and default character tables are used. If match‐
19 ing succeeds, the program outputs the portion of the subject that
20 matched, together with the contents of any captured substrings.
21 If the -g option is given on the command line, the program then goes on
23 to check for further matches of the same regular expression in the same
24 subject string. The logic is a little bit tricky because of the possi‐
25 bility of matching an empty string. Comments in the code explain what
26 is going on.
27 If PCRE is installed in the standard include and library directories
29 for your operating system, you should be able to compile the demonstra‐
30 tion program using this command:
31 gcc -o pcredemo pcredemo.c -lpcre
33 If PCRE is installed elsewhere, you may need to add additional options
35 to the command line. For example, on a Unix-like system that has PCRE
36 installed in /usr/local, you can compile the demonstration program
37 using a command like this:
38 gcc -o pcredemo -I/usr/local/include pcredemo.c \
40 -L/usr/local/lib -lpcre
41 In a Windows environment, if you want to statically link the program
43 against a non-dll pcre.a file, you must uncomment the line that defines
44 PCRE_STATIC before including pcre.h, because otherwise the pcre_mal‐
45 loc() and pcre_free() exported functions will be declared
46 __declspec(dllimport), with unwanted results.
47 Once you have compiled and linked the demonstration program, you can
49 run simple tests like this:
50 ./pcredemo 'cat|dog' 'the cat sat on the mat'
52 ./pcredemo -g 'cat|dog' 'the dog sat on the cat'
53 Note that there is a much more comprehensive test program, called
55 pcretest, which supports many more facilities for testing regular
56 expressions and the PCRE library. The pcredemo program is provided as a
57 simple coding example.
58 When you try to run pcredemo when PCRE is not installed in the standard
60 library directory, you may get an error like this on some operating
61 systems (e.g. Solaris):
62 ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or
64 directory
65 This is caused by the way shared library support works on those sys‐
67 tems. You need to add
68 -R/usr/local/lib
70 (for example) to the compile command to get round this problem.
72
74 Philip Hazel
76 University Computing Service
77 Cambridge CB2 3QH, England.
78
80 Last updated: 26 May 2010
82 Copyright (c) 1997-2010 University of Cambridge.
83 PCRESAMPLE(3)