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.

     9 .P

    10 The program compiles the regular expression that is its first argument, and

    11 matches it against the subject string in its second argument. No PCRE options

    12 are set, and default character tables are used. If matching succeeds, the

    13 program outputs the portion of the subject that matched, together with the

    14 contents of any captured substrings.

    15 .P

    16 If the -g option is given on the command line, the program then goes on to

    17 check for further matches of the same regular expression in the same subject

    18 string. The logic is a little bit tricky because of the possibility of matching

    19 an empty string. Comments in the code explain what is going on.

    20 .P

    21 If PCRE is installed in the standard include and library directories for your

    22 system, you should be able to compile the demonstration program using this

    23 command:

    24 .sp

    25   gcc -o pcredemo pcredemo.c -lpcre

    26 .sp

    27 If PCRE is installed elsewhere, you may need to add additional options to the

    28 command line. For example, on a Unix-like system that has PCRE installed in

    29 \fI/usr/local\fP, you can compile the demonstration program using a command

    30 like this:

    31 .sp

    32 .\" JOINSH

    33   gcc -o pcredemo -I/usr/local/include pcredemo.c \e

    34       -L/usr/local/lib -lpcre

    35 .sp

    36 Once you have compiled the demonstration program, you can run simple tests like

    37 this:

    38 .sp

    39   ./pcredemo 'cat|dog' 'the cat sat on the mat'

    40   ./pcredemo -g 'cat|dog' 'the dog sat on the cat'

    41 .sp

    42 Note that there is a much more comprehensive test program, called

    43 .\" HREF

    44 \fBpcretest\fP,

    45 .\"

    46 which supports many more facilities for testing regular expressions and the

    47 PCRE library. The \fBpcredemo\fP program is provided as a simple coding

    48 example.

    49 .P

    50 On some operating systems (e.g. Solaris), when PCRE is not installed in the

    51 standard library directory, you may get an error like this when you try to run

    52 \fBpcredemo\fP:

    53 .sp

    54   ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or directory

    55 .sp

    56 This is caused by the way shared library support works on those systems. You

    57 need to add

    58 .sp

    59   -R/usr/local/lib

    60 .sp

    61 (for example) to the compile command to get round this problem.

    62 .

    63 .

    64 .SH AUTHOR

    65 .rs

    66 .sp

    67 .nf

    68 Philip Hazel

    69 University Computing Service

    70 Cambridge CB2 3QH, England.

    71 .fi

    72 .

    73 .

    74 .SH REVISION

    75 .rs

    76 .sp

    77 .nf

    78 Last updated: 23 January 2008

    79 Copyright (c) 1997-2008 University of Cambridge.

    80 .fi