pcre32(3)
PCRE(3) C LIBRARY FUNCTIONS PCRE(3)
NAME
PCRE - Perl-compatible regular expressions
#include <pcre.h>
PCRE 32-BIT API BASIC FUNCTIONS
pcre32 *pcre32_compile(PCRE_SPTR32 pattern, int options,
const char **errptr, int *erroffset,
const unsigned char *tableptr);
pcre32 *pcre32_compile2(PCRE_SPTR32 pattern, int options,
int *errorcodeptr,
const unsigned char *tableptr);
pcre32_extra *pcre32_study(const pcre32 *code, int options,
const char **errptr);
void pcre32_free_study(pcre32_extra *extra);
int pcre32_exec(const pcre32 *code, const pcre32_extra *extra,
PCRE_SPTR32 subject, int length, int startoffset,
int options, int *ovector, int ovecsize);
int pcre32_dfa_exec(const pcre32 *code, const pcre32_extra *extra,
PCRE_SPTR32 subject, int length, int startoffset,
int options, int *ovector, int ovecsize,
int *workspace, int wscount);
PCRE 32-BIT API STRING EXTRACTION FUNCTIONS
int pcre32_copy_named_substring(const pcre32 *code,
PCRE_SPTR32 subject, int *ovector,
int stringcount, PCRE_SPTR32 stringname,
PCRE_UCHAR32 *buffer, int buffersize);
int pcre32_copy_substring(PCRE_SPTR32 subject, int *ovector,
int stringcount, int stringnumber, PCRE_UCHAR32 *buffer,
int buffersize);
int pcre32_get_named_substring(const pcre32 *code,
PCRE_SPTR32 subject, int *ovector,
int stringcount, PCRE_SPTR32 stringname,
PCRE_SPTR32 *stringptr);
int pcre32_get_stringnumber(const pcre32 *code,
PCRE_SPTR32 name);
int pcre32_get_stringtable_entries(const pcre32 *code,
PCRE_SPTR32 name, PCRE_UCHAR32 **first, PCRE_UCHAR32 **last);
int pcre32_get_substring(PCRE_SPTR32 subject, int *ovector,
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PCRE(3) C LIBRARY FUNCTIONS PCRE(3)
int stringcount, int stringnumber,
PCRE_SPTR32 *stringptr);
int pcre32_get_substring_list(PCRE_SPTR32 subject,
int *ovector, int stringcount, PCRE_SPTR32 **listptr);
void pcre32_free_substring(PCRE_SPTR32 stringptr);
void pcre32_free_substring_list(PCRE_SPTR32 *stringptr);
PCRE 32-BIT API AUXILIARY FUNCTIONS
pcre32_jit_stack *pcre32_jit_stack_alloc(int startsize, int maxsize);
void pcre32_jit_stack_free(pcre32_jit_stack *stack);
void pcre32_assign_jit_stack(pcre32_extra *extra,
pcre32_jit_callback callback, void *data);
const unsigned char *pcre32_maketables(void);
int pcre32_fullinfo(const pcre32 *code, const pcre32_extra *extra,
int what, void *where);
int pcre32_refcount(pcre32 *code, int adjust);
int pcre32_config(int what, void *where);
const char *pcre32_version(void);
int pcre32_pattern_to_host_byte_order(pcre32 *code,
pcre32_extra *extra, const unsigned char *tables);
PCRE 32-BIT API INDIRECTED FUNCTIONS
void *(*pcre32_malloc)(size_t);
void (*pcre32_free)(void *);
void *(*pcre32_stack_malloc)(size_t);
void (*pcre32_stack_free)(void *);
int (*pcre32_callout)(pcre32_callout_block *);
PCRE 32-BIT API 32-BIT-ONLY FUNCTION
int pcre32_utf32_to_host_byte_order(PCRE_UCHAR32 *output,
PCRE_SPTR32 input, int length, int *byte_order,
int keep_boms);
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PCRE(3) C LIBRARY FUNCTIONS PCRE(3)
THE PCRE 32-BIT LIBRARY
Starting with release 8.32, it is possible to compile a PCRE
library that supports 32-bit character strings, including
UTF-32 strings, as well as or instead of the original 8-bit
library. This work was done by Christian Persch, based on
the work done by Zoltan Herczeg for the 16-bit library. All
three libraries contain identical sets of functions, used in
exactly the same way. Only the names of the functions and
the data types of their arguments and results are different.
To avoid over-complication and reduce the documentation
maintenance load, most of the PCRE documentation describes
the 8-bit library, with only occasional references to the
16-bit and 32-bit libraries. This page describes what is
different when you use the 32-bit library. WARNING: A sin-
gle application can be linked with all or any of the three
libraries, but you must take care when processing any par-
ticular pattern to use functions from just one library. For
example, if you want to study a pattern that was compiled
with pcre32_compile(), you must do so with pcre32_study(),
not pcre_study(), and you must free the study data with
pcre32_free_study().
THE HEADER FILE
There is only one header file, pcre.h. It contains proto-
types for all the functions in all libraries, as well as
definitions of flags, structures, error codes, etc.
THE LIBRARY NAME
In Unix-like systems, the 32-bit library is called libp-
cre32, and can normally be accesss by adding -lpcre32 to the
command for linking an application that uses PCRE.
STRING TYPES
In the 8-bit library, strings are passed to PCRE library
functions as vectors of bytes with the C type "char *". In
the 32-bit library, strings are passed as vectors of
unsigned 32-bit quantities. The macro PCRE_UCHAR32 specifies
an appropriate data type, and PCRE_SPTR32 is defined as
"const PCRE_UCHAR32 *". In very many environments, "unsigned
int" is a 32-bit data type. When PCRE is built, it defines
PCRE_UCHAR32 as "unsigned int", but checks that it really is
a 32-bit data type. If it is not, the build fails with an
error message telling the maintainer to modify the defini-
tion appropriately.
STRUCTURE TYPES
The types of the opaque structures that are used for
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PCRE(3) C LIBRARY FUNCTIONS PCRE(3)
compiled 32-bit patterns and JIT stacks are pcre32 and
pcre32_jit_stack respectively. The type of the user-
accessible structure that is returned by pcre32_study() is
pcre32_extra, and the type of the structure that is used for
passing data to a callout function is pcre32_callout_block.
These structures contain the same fields, with the same
names, as their 8-bit counterparts. The only difference is
that pointers to character strings are 32-bit instead of 8-
bit types.
32-BIT FUNCTIONS
For every function in the 8-bit library there is a
corresponding function in the 32-bit library with a name
that starts with pcre32_ instead of pcre_. The prototypes
are listed above. In addition, there is one extra function,
pcre32_utf32_to_host_byte_order(). This is a utility func-
tion that converts a UTF-32 character string to host byte
order if necessary. The other 32-bit functions expect the
strings they are passed to be in host byte order. The input
and output arguments of pcre32_utf32_to_host_byte_order()
may point to the same address, that is, conversion in place
is supported. The output buffer must be at least as long as
the input. The length argument specifies the number of 32-
bit data units in the input string; a negative value speci-
fies a zero-terminated string. If byte_order is NULL, it is
assumed that the string starts off in host byte order. This
may be changed by byte-order marks (BOMs) anywhere in the
string (commonly as the first character). If byte_order is
not NULL, a non-zero value of the integer to which it points
means that the input starts off in host byte order, other-
wise the opposite order is assumed. Again, BOMs in the
string can change this. The final byte order is passed back
at the end of processing. If keep_boms is not zero, byte-
order mark characters (0xfeff) are copied into the output
string. Otherwise they are discarded. The result of the
function is the number of 32-bit units placed into the out-
put buffer, including the zero terminator if the string was
zero-terminated.
SUBJECT STRING OFFSETS
The lengths and starting offsets of subject strings must be
specified in 32-bit data units, and the offsets within sub-
ject strings that are returned by the matching functions are
in also 32-bit units rather than bytes.
NAMED SUBPATTERNS
The name-to-number translation table that is maintained for
named subpatterns uses 32-bit characters. The
pcre32_get_stringtable_entries() function returns the length
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PCRE(3) C LIBRARY FUNCTIONS PCRE(3)
of each entry in the table as the number of 32-bit data
units.
OPTION NAMES
There are two new general option names, PCRE_UTF32 and
PCRE_NO_UTF32_CHECK, which correspond to PCRE_UTF8 and
PCRE_NO_UTF8_CHECK in the 8-bit library. In fact, these new
options define the same bits in the options word. There is a
discussion about the validity of UTF-32 strings in the
pcreunicode page. For the pcre32_config() function there is
an option PCRE_CONFIG_UTF32 that returns 1 if UTF-32 support
is configured, otherwise 0. If this option is given to
pcre_config() or pcre16_config(), or if the PCRE_CONFIG_UTF8
or PCRE_CONFIG_UTF16 option is given to pcre32_config(), the
result is the PCRE_ERROR_BADOPTION error.
CHARACTER CODES
In 32-bit mode, when PCRE_UTF32 is not set, character values
are treated in the same way as in 8-bit, non UTF-8 mode,
except, of course, that they can range from 0 to 0x7fffffff
instead of 0 to 0xff. Character types for characters less
than 0xff can therefore be influenced by the locale in the
same way as before. Characters greater than 0xff have only
one case, and no "type" (such as letter or digit). In UTF-
32 mode, the character code is Unicode, in the range 0 to
0x10ffff, with the exception of values in the range 0xd800
to 0xdfff because those are "surrogate" values that are
ill-formed in UTF-32. A UTF-32 string can indicate its
endianness by special code knows as a byte-order mark (BOM).
The PCRE functions do not handle this, expecting strings to
be in host byte order. A utility function called
pcre32_utf32_to_host_byte_order() is provided to help with
this (see above).
ERROR NAMES
The error PCRE_ERROR_BADUTF32 corresponds to its 8-bit coun-
terpart. The error PCRE_ERROR_BADMODE is given when a com-
piled pattern is passed to a function that processes pat-
terns in the other mode, for example, if a pattern compiled
with pcre_compile() is passed to pcre32_exec(). There are
new error codes whose names begin with PCRE_UTF32_ERR for
invalid UTF-32 strings, corresponding to the PCRE_UTF8_ERR
codes for UTF-8 strings that are described in the section
entitled "Reason codes for invalid UTF-8 strings" in the
main pcreapi page. The UTF-32 errors are:
PCRE_UTF32_ERR1 Surrogate character (range from 0xd800 to
0xdfff)
PCRE_UTF32_ERR2 Non-character
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PCRE(3) C LIBRARY FUNCTIONS PCRE(3)
PCRE_UTF32_ERR3 Character > 0x10ffff
ERROR TEXTS
If there is an error while compiling a pattern, the error
text that is passed back by pcre32_compile() or
pcre32_compile2() is still an 8-bit character string, zero-
terminated.
CALLOUTS
The subject and mark fields in the callout block that is
passed to a callout function point to 32-bit vectors.
TESTING
The pcretest program continues to operate with 8-bit input
and output files, but it can be used for testing the 32-bit
library. If it is run with the command line option -32, pat-
terns and subject strings are converted from 8-bit to 32-bit
before being passed to PCRE, and the 32-bit library func-
tions are used instead of the 8-bit ones. Returned 32-bit
strings are converted to 8-bit for output. If both the 8-bit
and the 16-bit libraries were not compiled, pcretest
defaults to 32-bit and the -32 option is ignored. When PCRE
is being built, the RunTest script that is called by "make
check" uses the pcretest -C option to discover which of the
8-bit, 16-bit and 32-bit libraries has been built, and runs
the tests appropriately.
NOT SUPPORTED IN 32-BIT MODE
Not all the features of the 8-bit library are available with
the 32-bit library. The C++ and POSIX wrapper functions sup-
port only the 8-bit library, and the pcregrep program is at
present 8-bit only.
AUTHOR
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
REVISION
Last updated: 12 May 2013
Copyright (c) 1997-2013 University of Cambridge.
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