PCRE(3) Library Functions Manual PCRE(3)
PCRE - Perl-compatible regular expressions
#include <pcre.h>
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);
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,
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);
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);
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 *);
int pcre32_utf32_to_host_byte_order(PCRE_UCHAR32 *output,
PCRE_SPTR32 input, int length, int *byte_order,
int keep_boms);
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 single application can be linked with all or any of
the three libraries, but you must take care when processing any
particular 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().
There is only one header file, pcre.h. It contains prototypes for
all the functions in all libraries, as well as definitions of
flags, structures, error codes, etc.
In Unix-like systems, the 32-bit library is called libpcre32, and
can normally be accesss by adding -lpcre32 to the command for
linking an application that uses PCRE.
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 definition appropriately.
The types of the opaque structures that are used for 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.
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 function
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 specifies 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, otherwise 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 output buffer, including the zero terminator if the
string was zero-terminated.
The lengths and starting offsets of subject strings must be
specified in 32-bit data units, and the offsets within subject
strings that are returned by the matching functions are in also
32-bit units rather than bytes.
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 of
each entry in the table as the number of 32-bit data units.
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.
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).
The error PCRE_ERROR_BADUTF32 corresponds to its 8-bit
counterpart. The error PCRE_ERROR_BADMODE is given when a
compiled pattern is passed to a function that processes patterns
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
PCRE_UTF32_ERR3 Character > 0x10ffff
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.
The subject and mark fields in the callout block that is passed
to a callout function point to 32-bit vectors.
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, patterns and
subject strings are converted from 8-bit to 32-bit before being
passed to PCRE, and the 32-bit library functions 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 all the features of the 8-bit library are available with the
32-bit library. The C++ and POSIX wrapper functions support only
the 8-bit library, and the pcregrep program is at present 8-bit
only.
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
Last updated: 12 May 2013
Copyright (c) 1997-2013 University of Cambridge.
This page is part of the PCRE (Perl Compatible Regular
Expressions) project. Information about the project can be found
at ⟨http://www.pcre.org/⟩. If you have a bug report for this
manual page, see
⟨http://bugs.exim.org/enter_bug.cgi?product=PCRE⟩. This page was
obtained from the tarball pcre-8.45.tar.gz fetched from
⟨ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/⟩ on
2021-08-27. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
PCRE 8.33 12 May 2013 PCRE(3)
Pages that refer to this page: pcretest(1), pcreapi(3), pcrepattern(3)
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