trunk/doc/pcresample.3

.TH PCRESAMPLE 3
.SH NAME
PCRE - Perl-compatible regular expressions
.SH "PCRE SAMPLE PROGRAM"
.rs
.sp
A simple, complete demonstration program, to get you started with using PCRE,
is supplied in the file \fIpcredemo.c\fP in the PCRE distribution. A listing of
this program is given in the
.\" HREF
\fBpcredemo\fP
.\"
documentation. If you do not have a copy of the PCRE distribution, you can save 
this listing to re-create \fIpcredemo.c\fP.
.P
The program compiles the regular expression that is its first argument, and
matches it against the subject string in its second argument. No PCRE options
are set, and default character tables are used. If matching succeeds, the
program outputs the portion of the subject that matched, together with the
contents of any captured substrings.
.P
If the -g option is given on the command line, the program then goes on to
check for further matches of the same regular expression in the same subject
string. The logic is a little bit tricky because of the possibility of matching
an empty string. Comments in the code explain what is going on.
.P
If PCRE is installed in the standard include and library directories for your
system, you should be able to compile the demonstration program using this
command:
.sp
  gcc -o pcredemo pcredemo.c -lpcre
.sp
If PCRE is installed elsewhere, you may need to add additional options to the
command line. For example, on a Unix-like system that has PCRE installed in
\fI/usr/local\fP, you can compile the demonstration program using a command
like this:
.sp
.\" JOINSH
  gcc -o pcredemo -I/usr/local/include pcredemo.c \e
      -L/usr/local/lib -lpcre
.sp
Once you have compiled the demonstration program, you can run simple tests like
this:
.sp
  ./pcredemo 'cat|dog' 'the cat sat on the mat'
  ./pcredemo -g 'cat|dog' 'the dog sat on the cat'
.sp
Note that there is a much more comprehensive test program, called
.\" HREF
\fBpcretest\fP,
.\"
which supports many more facilities for testing regular expressions and the
PCRE library. The 
.\" HREF
\fBpcredemo\fP
.\"
program is provided as a simple coding example.
.P
When you try to run
.\" HREF
\fBpcredemo\fP
.\"
when PCRE is not installed in the standard library directory, you may get an
error like this on some operating systems (e.g. Solaris):
.sp
  ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or directory
.sp
This is caused by the way shared library support works on those systems. You
need to add
.sp
  -R/usr/local/lib
.sp
(for example) to the compile command to get round this problem.
.
.
.SH AUTHOR
.rs
.sp
.nf
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
.fi
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 01 September 2009
Copyright (c) 1997-2009 University of Cambridge.
.fi
1	.TH PCRESAMPLE 3
2	.SH NAME
3	PCRE - Perl-compatible regular expressions
4	.SH "PCRE SAMPLE PROGRAM"
5	.rs
6	.sp
7	A simple, complete demonstration program, to get you started with using PCRE,
8	is supplied in the file \fIpcredemo.c\fP in the PCRE distribution. A listing of
9	this program is given in the
10	.\" HREF
11	\fBpcredemo\fP
12	.\"
13	documentation. If you do not have a copy of the PCRE distribution, you can save
14	this listing to re-create \fIpcredemo.c\fP.
15	.P
16	The program compiles the regular expression that is its first argument, and
17	matches it against the subject string in its second argument. No PCRE options
18	are set, and default character tables are used. If matching succeeds, the
19	program outputs the portion of the subject that matched, together with the
20	contents of any captured substrings.
21	.P
22	If the -g option is given on the command line, the program then goes on to
23	check for further matches of the same regular expression in the same subject
24	string. The logic is a little bit tricky because of the possibility of matching
25	an empty string. Comments in the code explain what is going on.
26	.P
27	If PCRE is installed in the standard include and library directories for your
28	system, you should be able to compile the demonstration program using this
29	command:
30	.sp
31	gcc -o pcredemo pcredemo.c -lpcre
32	.sp
33	If PCRE is installed elsewhere, you may need to add additional options to the
34	command line. For example, on a Unix-like system that has PCRE installed in
35	\fI/usr/local\fP, you can compile the demonstration program using a command
36	like this:
37	.sp
38	.\" JOINSH
39	gcc -o pcredemo -I/usr/local/include pcredemo.c \e
40	-L/usr/local/lib -lpcre
41	.sp
42	Once you have compiled the demonstration program, you can run simple tests like
43	this:
44	.sp
45	./pcredemo 'cat\|dog' 'the cat sat on the mat'
46	./pcredemo -g 'cat\|dog' 'the dog sat on the cat'
47	.sp
48	Note that there is a much more comprehensive test program, called
49	.\" HREF
50	\fBpcretest\fP,
51	.\"
52	which supports many more facilities for testing regular expressions and the
53	PCRE library. The
54	.\" HREF
55	\fBpcredemo\fP
56	.\"
57	program is provided as a simple coding example.
58	.P
59	When you try to run
60	.\" HREF
61	\fBpcredemo\fP
62	.\"
63	when PCRE is not installed in the standard library directory, you may get an
64	error like this on some operating systems (e.g. Solaris):
65	.sp
66	ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or directory
67	.sp
68	This is caused by the way shared library support works on those systems. You
69	need to add
70	.sp
71	-R/usr/local/lib
72	.sp
73	(for example) to the compile command to get round this problem.
74	.
75	.
76	.SH AUTHOR
77	.rs
78	.sp
79	.nf
80	Philip Hazel
81	University Computing Service
82	Cambridge CB2 3QH, England.
83	.fi
84	.
85	.
86	.SH REVISION
87	.rs
88	.sp
89	.nf
90	Last updated: 01 September 2009
91	Copyright (c) 1997-2009 University of Cambridge.
92	.fi
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