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PCRE(3) Library Functions Manual 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 char **errptr, int *erroffset,
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,
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);
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 argu-
ments 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 dif-
ferent 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_com-
pile(), 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 prototypes 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 libpcre32, 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 definition appropriately.
STRUCTURE TYPES
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 struc-
ture 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 function that converts a UTF-32 character string to host byte order if neces-
sary. 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 nega-
tive 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 pro-
cessing.
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.
SUBJECT STRING OFFSETS
The offsets within subject strings that are returned by the matching functions are in
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 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 corre-
spond 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 excep-
tion 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 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
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 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 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 support 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: 08 November 2012
Copyright (c) 1997-2012 University of Cambridge.
PCRE 8.32 08 November 2012 PCRE(3)
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On Apache/2.4.6 (CentOS)
Under GNU General Public License
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