PCRE(3)                   OpenBSD Programmer's Manual                  PCRE(3)



NAME
       PCRE - Perl-compatible regular expressions

       #include <pcre.h>

PCRE 16-BIT API BASIC FUNCTIONS

       pcre16 *pcre16_compile(PCRE_SPTR16 pattern, int options,
            const char **errptr, int *erroffset,
            const unsigned char *tableptr);

       pcre16 *pcre16_compile2(PCRE_SPTR16 pattern, int options,
            int *errorcodeptr,
            const char **errptr, int *erroffset,
            const unsigned char *tableptr);

       pcre16_extra *pcre16_study(const pcre16 *code, int options,
            const char **errptr);

       void pcre16_free_study(pcre16_extra *extra);

       int pcre16_exec(const pcre16 *code, const pcre16_extra *extra,
            PCRE_SPTR16 subject, int length, int startoffset,
            int options, int *ovector, int ovecsize);

       int pcre16_dfa_exec(const pcre16 *code, const pcre16_extra *extra,
            PCRE_SPTR16 subject, int length, int startoffset,
            int options, int *ovector, int ovecsize,
            int *workspace, int wscount);

PCRE 16-BIT API STRING EXTRACTION FUNCTIONS

       int pcre16_copy_named_substring(const pcre16 *code,
            PCRE_SPTR16 subject, int *ovector,
            int stringcount, PCRE_SPTR16 stringname,
            PCRE_UCHAR16 *buffer, int buffersize);

       int pcre16_copy_substring(PCRE_SPTR16 subject, int *ovector,
            int stringcount, int stringnumber, PCRE_UCHAR16 *buffer,
            int buffersize);

       int pcre16_get_named_substring(const pcre16 *code,
            PCRE_SPTR16 subject, int *ovector,
            int stringcount, PCRE_SPTR16 stringname,
            PCRE_SPTR16 *stringptr);

       int pcre16_get_stringnumber(const pcre16 *code,
            PCRE_SPTR16 name);

       int pcre16_get_stringtable_entries(const pcre16 *code,
            PCRE_SPTR16 name, PCRE_UCHAR16 **first, PCRE_UCHAR16 **last);

       int pcre16_get_substring(PCRE_SPTR16 subject, int *ovector,
            int stringcount, int stringnumber,
            PCRE_SPTR16 *stringptr);

       int pcre16_get_substring_list(PCRE_SPTR16 subject,
            int *ovector, int stringcount, PCRE_SPTR16 **listptr);

       void pcre16_free_substring(PCRE_SPTR16 stringptr);

       void pcre16_free_substring_list(PCRE_SPTR16 *stringptr);

PCRE 16-BIT API AUXILIARY FUNCTIONS

       pcre16_jit_stack *pcre16_jit_stack_alloc(int startsize, int maxsize);

       void pcre16_jit_stack_free(pcre16_jit_stack *stack);

       void pcre16_assign_jit_stack(pcre16_extra *extra,
            pcre16_jit_callback callback, void *data);

       const unsigned char *pcre16_maketables(void);

       int pcre16_fullinfo(const pcre16 *code, const pcre16_extra *extra,
            int what, void *where);

       int pcre16_refcount(pcre16 *code, int adjust);

       int pcre16_config(int what, void *where);

       const char *pcre16_version(void);

       int pcre16_pattern_to_host_byte_order(pcre16 *code,
            pcre16_extra *extra, const unsigned char *tables);

PCRE 16-BIT API INDIRECTED FUNCTIONS

       void *(*pcre16_malloc)(size_t);

       void (*pcre16_free)(void *);

       void *(*pcre16_stack_malloc)(size_t);

       void (*pcre16_stack_free)(void *);

       int (*pcre16_callout)(pcre16_callout_block *);

PCRE 16-BIT API 16-BIT-ONLY FUNCTION

       int pcre16_utf16_to_host_byte_order(PCRE_UCHAR16 *output,
            PCRE_SPTR16 input, int length, int *byte_order,
            int keep_boms);

THE PCRE 16-BIT LIBRARY

       Starting with release 8.30, it is possible to compile a PCRE library
       that supports 16-bit character strings, including UTF-16 strings, as
       well as or instead of the original 8-bit library. The majority of the
       work to make this possible was done by Zoltan Herczeg. The two
       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 library. This page describes what is different
       when you use the 16-bit library.

       WARNING: A single application can be linked with both 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 pcre16_compile(), you must do so with
       pcre16_study(), not pcre_study(), and you must free the study data with
       pcre16_free_study().

THE HEADER FILE

       There is only one header file, pcre.h. It contains prototypes for all
       the functions in both libraries, as well as definitions of flags,
       structures, error codes, etc.

THE LIBRARY NAME

       In Unix-like systems, the 16-bit library is called libpcre16, and can
       normally be accesss by adding -lpcre16 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 16-bit library,
       strings are passed as vectors of unsigned 16-bit quantities. The macro
       PCRE_UCHAR16 specifies an appropriate data type, and PCRE_SPTR16 is
       defined as "const PCRE_UCHAR16 *". In very many environments, "short
       int" is a 16-bit data type. When PCRE is built, it defines PCRE_UCHAR16
       as "short int", but checks that it really is a 16-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 16-bit
       patterns and JIT stacks are pcre16 and pcre16_jit_stack respectively.
       The type of the user-accessible structure that is returned by
       pcre16_study() is pcre16_extra, and the type of the structure that is
       used for passing data to a callout function is pcre16_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 16-bit instead of 8-bit types.

16-BIT FUNCTIONS

       For every function in the 8-bit library there is a corresponding
       function in the 16-bit library with a name that starts with pcre16_
       instead of pcre_. The prototypes are listed above. In addition, there
       is one extra function, pcre16_utf16_to_host_byte_order(). This is a
       utility function that converts a UTF-16 character string to host byte
       order if necessary. The other 16-bit functions expect the strings they
       are passed to be in host byte order.

       The input and output arguments of pcre16_utf16_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 16-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 16-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 16-bit units rather than bytes.

NAMED SUBPATTERNS

       The name-to-number translation table that is maintained for named
       subpatterns uses 16-bit characters. The
       pcre16_get_stringtable_entries() function returns the length of each
       entry in the table as the number of 16-bit data units.

OPTION NAMES

       There are two new general option names, PCRE_UTF16 and
       PCRE_NO_UTF16_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.

       For the pcre16_config() function there is an option PCRE_CONFIG_UTF16
       that returns 1 if UTF-16 support is configured, otherwise 0. If this
       option is given to pcre_config(), or if the PCRE_CONFIG_UTF8 option is
       given to pcre16_config(), the result is the PCRE_ERROR_BADOPTION error.

CHARACTER CODES

       In 16-bit mode, when PCRE_UTF16 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 0xffff 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-16 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 used in pairs to encode
       values greater than 0xffff.

       A UTF-16 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
       pcre16_utf16_to_host_byte_order() is provided to help with this (see
       above).

ERROR NAMES

       The errors PCRE_ERROR_BADUTF16_OFFSET and PCRE_ERROR_SHORTUTF16
       correspond to their 8-bit counterparts. 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 pcre16_exec().

       There are new error codes whose names begin with PCRE_UTF16_ERR for
       invalid UTF-16 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-16 errors
       are:

         PCRE_UTF16_ERR1  Missing low surrogate at end of string
         PCRE_UTF16_ERR2  Invalid low surrogate follows high surrogate
         PCRE_UTF16_ERR3  Isolated low surrogate
         PCRE_UTF16_ERR4  Invalid character 0xfffe

ERROR TEXTS

       If there is an error while compiling a pattern, the error text that is
       passed back by pcre16_compile() or pcre16_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 16-bit vectors.

TESTING

       The pcretest program continues to operate with 8-bit input and output
       files, but it can be used for testing the 16-bit library. If it is run
       with the command line option -16, patterns and subject strings are
       converted from 8-bit to 16-bit before being passed to PCRE, and the
       16-bit library functions are used instead of the 8-bit ones. Returned
       16-bit strings are converted to 8-bit for output. If the 8-bit library
       was not compiled, pcretest defaults to 16-bit and the -16 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 and
       16-bit libraries has been built, and runs the tests appropriately.

NOT SUPPORTED IN 16-BIT MODE

       Not all the features of the 8-bit library are available with the 16-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 January 2012
       Copyright (c) 1997-2012 University of Cambridge.



                                                                       PCRE(3)
