100 lines
3.1 KiB
Groff
100 lines
3.1 KiB
Groff
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.TH PCRESAMPLE 3 "10 January 2012" "PCRE 8.30"
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.SH NAME
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PCRE - Perl-compatible regular expressions
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.SH "PCRE SAMPLE PROGRAM"
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.rs
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.sp
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A simple, complete demonstration program, to get you started with using PCRE,
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is supplied in the file \fIpcredemo.c\fP in the PCRE distribution. A listing of
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this program is given in the
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.\" HREF
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\fBpcredemo\fP
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.\"
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documentation. If you do not have a copy of the PCRE distribution, you can save
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this listing to re-create \fIpcredemo.c\fP.
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.P
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The demonstration program, which uses the original PCRE 8-bit library, compiles
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the regular expression that is its first argument, and matches it against the
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subject string in its second argument. No PCRE options are set, and default
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character tables are used. If matching succeeds, the program outputs the
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portion of the subject that matched, together with the contents of any captured
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substrings.
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.P
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If the -g option is given on the command line, the program then goes on to
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check for further matches of the same regular expression in the same subject
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string. The logic is a little bit tricky because of the possibility of matching
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an empty string. Comments in the code explain what is going on.
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.P
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If PCRE is installed in the standard include and library directories for your
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operating system, you should be able to compile the demonstration program using
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this command:
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.sp
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gcc -o pcredemo pcredemo.c -lpcre
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.sp
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If PCRE is installed elsewhere, you may need to add additional options to the
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command line. For example, on a Unix-like system that has PCRE installed in
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\fI/usr/local\fP, you can compile the demonstration program using a command
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like this:
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.sp
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.\" JOINSH
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gcc -o pcredemo -I/usr/local/include pcredemo.c \e
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-L/usr/local/lib -lpcre
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.sp
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In a Windows environment, if you want to statically link the program against a
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non-dll \fBpcre.a\fP file, you must uncomment the line that defines PCRE_STATIC
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before including \fBpcre.h\fP, because otherwise the \fBpcre_malloc()\fP and
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\fBpcre_free()\fP exported functions will be declared
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\fB__declspec(dllimport)\fP, with unwanted results.
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.P
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Once you have compiled and linked the demonstration program, you can run simple
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tests like this:
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.sp
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./pcredemo 'cat|dog' 'the cat sat on the mat'
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./pcredemo -g 'cat|dog' 'the dog sat on the cat'
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.sp
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Note that there is a much more comprehensive test program, called
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.\" HREF
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\fBpcretest\fP,
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.\"
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which supports many more facilities for testing regular expressions and both
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PCRE libraries. The
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.\" HREF
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\fBpcredemo\fP
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.\"
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program is provided as a simple coding example.
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.P
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If you try to run
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.\" HREF
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\fBpcredemo\fP
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.\"
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when PCRE is not installed in the standard library directory, you may get an
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error like this on some operating systems (e.g. Solaris):
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.sp
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ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or directory
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.sp
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This is caused by the way shared library support works on those systems. You
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need to add
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.sp
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-R/usr/local/lib
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.sp
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(for example) to the compile command to get round this problem.
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.
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.
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.SH AUTHOR
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.rs
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.sp
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.nf
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Philip Hazel
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University Computing Service
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Cambridge CB2 3QH, England.
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.fi
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.
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.
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.SH REVISION
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.rs
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.sp
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.nf
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Last updated: 10 January 2012
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Copyright (c) 1997-2012 University of Cambridge.
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.fi
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