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<title>pcre2sample specification</title>
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<h1>pcre2sample man page</h1>

Return to the <a href="index.html">PCRE2 index page</a>.


This page is part of the PCRE2 HTML documentation. It was generated
automatically from the original man page. If there is any nonsense in it,
please consult the man page, in case the conversion went wrong.
 
 
PCRE2 SAMPLE PROGRAM
 

A simple, complete demonstration program to get you started with using PCRE2 is
supplied in the file pcre2demo.c in the src directory in the PCRE2
distribution. A listing of this program is given in the
<a href="pcre2demo.html">pcre2demo</a>
documentation. If you do not have a copy of the PCRE2 distribution, you can
save this listing to re-create the contents of pcre2demo.c.


The demonstration program compiles the regular expression that is its
first argument, and matches it against the subject string in its second
argument. No PCRE2 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.


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.


The code in pcre2demo.c is an 8-bit program that uses the PCRE2 8-bit
library. It handles strings and characters that are stored in 8-bit code units.
By default, one character corresponds to one code unit, but if the pattern
starts with "(*UTF)", both it and the subject are treated as UTF-8 strings,
where characters may occupy multiple code units.


If PCRE2 is installed in the standard include and library directories for your
operating system, you should be able to compile the demonstration program using
a command like this:
<pre>
 cc -o pcre2demo pcre2demo.c -lpcre2-8
</pre>
If PCRE2 is installed elsewhere, you may need to add additional options to the
command line. For example, on a Unix-like system that has PCRE2 installed in
/usr/local, you can compile the demonstration program using a command
like this:
<pre>
 cc -o pcre2demo -I/usr/local/include pcre2demo.c -L/usr/local/lib -lpcre2-8
</pre>
Once you have built the demonstration program, you can run simple tests like
this:
<pre>
 ./pcre2demo 'cat|dog' 'the cat sat on the mat'
 ./pcre2demo -g 'cat|dog' 'the dog sat on the cat'
</pre>
Note that there is a much more comprehensive test program, called
<a href="pcre2test.html">pcre2test,</a>
which supports many more facilities for testing regular expressions using all
three PCRE2 libraries (8-bit, 16-bit, and 32-bit, though not all three need be
installed). The
<a href="pcre2demo.html">pcre2demo</a>
program is provided as a relatively simple coding example.


If you try to run
<a href="pcre2demo.html">pcre2demo</a>
when PCRE2 is not installed in the standard library directory, you may get an
error like this on some operating systems (e.g. Solaris):
<pre>
 ld.so.1: pcre2demo: fatal: libpcre2-8.so.0: open failed: No such file or directory
</pre>
This is caused by the way shared library support works on those systems. You
need to add
<pre>
 -R/usr/local/lib
</pre>
(for example) to the compile command to get round this problem.

 
AUTHOR
 

Philip Hazel
 
University Computing Service
 
Cambridge, England.
 

 
REVISION
 

Last updated: 02 February 2016
 
Copyright &copy; 1997-2016 University of Cambridge.
 

Return to the <a href="index.html">PCRE2 index page</a>.

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NON-AUTOTOOLS-BUILD.txt	Edit
README.txt	Edit
index.html	Edit
pcre2-config.html	Edit
pcre2.html	Edit
pcre2_callout_enumerate.html	Edit
pcre2_code_copy.html	Edit
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pcre2_code_free.html	Edit
pcre2_compile.html	Edit
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pcre2_compile_context_create.html	Edit
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pcre2_config.html	Edit
pcre2_convert_context_copy.html	Edit
pcre2_convert_context_create.html	Edit
pcre2_convert_context_free.html	Edit
pcre2_converted_pattern_free.html	Edit
pcre2_dfa_match.html	Edit
pcre2_general_context_copy.html	Edit
pcre2_general_context_create.html	Edit
pcre2_general_context_free.html	Edit
pcre2_get_error_message.html	Edit
pcre2_get_mark.html	Edit
pcre2_get_match_data_size.html	Edit
pcre2_get_ovector_count.html	Edit
pcre2_get_ovector_pointer.html	Edit
pcre2_get_startchar.html	Edit
pcre2_jit_compile.html	Edit
pcre2_jit_free_unused_memory.html	Edit
pcre2_jit_match.html	Edit
pcre2_jit_stack_assign.html	Edit
pcre2_jit_stack_create.html	Edit
pcre2_jit_stack_free.html	Edit
pcre2_maketables.html	Edit
pcre2_maketables_free.html	Edit
pcre2_match.html	Edit
pcre2_match_context_copy.html	Edit
pcre2_match_context_create.html	Edit
pcre2_match_context_free.html	Edit
pcre2_match_data_create.html	Edit
pcre2_match_data_create_from_pattern.html	Edit
pcre2_match_data_free.html	Edit
pcre2_pattern_convert.html	Edit
pcre2_pattern_info.html	Edit
pcre2_serialize_decode.html	Edit
pcre2_serialize_encode.html	Edit
pcre2_serialize_free.html	Edit
pcre2_serialize_get_number_of_codes.html	Edit
pcre2_set_bsr.html	Edit
pcre2_set_callout.html	Edit
pcre2_set_character_tables.html	Edit
pcre2_set_compile_extra_options.html	Edit
pcre2_set_compile_recursion_guard.html	Edit
pcre2_set_depth_limit.html	Edit
pcre2_set_glob_escape.html	Edit
pcre2_set_glob_separator.html	Edit
pcre2_set_heap_limit.html	Edit
pcre2_set_match_limit.html	Edit
pcre2_set_max_pattern_length.html	Edit
pcre2_set_newline.html	Edit
pcre2_set_offset_limit.html	Edit
pcre2_set_parens_nest_limit.html	Edit
pcre2_set_recursion_limit.html	Edit
pcre2_set_recursion_memory_management.html	Edit
pcre2_set_substitute_callout.html	Edit
pcre2_substitute.html	Edit
pcre2_substring_copy_byname.html	Edit
pcre2_substring_copy_bynumber.html	Edit
pcre2_substring_free.html	Edit
pcre2_substring_get_byname.html	Edit
pcre2_substring_get_bynumber.html	Edit
pcre2_substring_length_byname.html	Edit
pcre2_substring_length_bynumber.html	Edit
pcre2_substring_list_free.html	Edit
pcre2_substring_list_get.html	Edit
pcre2_substring_nametable_scan.html	Edit
pcre2_substring_number_from_name.html	Edit
pcre2api.html	Edit
pcre2build.html	Edit
pcre2callout.html	Edit
pcre2compat.html	Edit
pcre2convert.html	Edit
pcre2demo.html	Edit
pcre2grep.html	Edit
pcre2jit.html	Edit
pcre2limits.html	Edit
pcre2matching.html	Edit
pcre2partial.html	Edit
pcre2pattern.html	Edit
pcre2perform.html	Edit
pcre2posix.html	Edit
pcre2sample.html	Edit
pcre2serialize.html	Edit
pcre2syntax.html	Edit
pcre2test.html	Edit
pcre2unicode.html	Edit