pcre16(3) — Linux manual page

NAME | PCRE 16-BIT API BASIC FUNCTIONS | PCRE 16-BIT API STRING EXTRACTION FUNCTIONS | PCRE 16-BIT API AUXILIARY FUNCTIONS | PCRE 16-BIT API INDIRECTED FUNCTIONS | PCRE 16-BIT API 16-BIT-ONLY FUNCTION | THE PCRE 16-BIT LIBRARY | THE HEADER FILE | THE LIBRARY NAME | STRING TYPES | STRUCTURE TYPES | 16-BIT FUNCTIONS | SUBJECT STRING OFFSETS | NAMED SUBPATTERNS | OPTION NAMES | CHARACTER CODES | ERROR NAMES | ERROR TEXTS | CALLOUTS | TESTING | NOT SUPPORTED IN 16-BIT MODE | AUTHOR | REVISION | COLOPHON

PCRE(3)                 Library Functions Manual                 PCRE(3)

NAME         top

       PCRE - Perl-compatible regular expressions

       #include <pcre.h>

PCRE 16-BIT API BASIC FUNCTIONS         top


       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         top


       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         top


       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         top


       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         top


       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         top


       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         top


       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         top


       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         top


       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 "unsigned 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         top


       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         top


       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         top


       The lengths and starting offsets of subject strings must be
       specified in 16-bit data units, and the offsets within subject
       strings that are returned by the matching functions are in also
       16-bit units rather than bytes.

NAMED SUBPATTERNS         top


       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         top


       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. There is a
       discussion about the validity of UTF-16 strings in the
       pcreunicode page.

       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
       pcre32_config(), or if the PCRE_CONFIG_UTF8 or PCRE_CONFIG_UTF32
       option is given to pcre16_config(), the result is the
       PCRE_ERROR_BADOPTION error.

CHARACTER CODES         top


       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         top


       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  Non-character

ERROR TEXTS         top


       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         top


       The subject and mark fields in the callout block that is passed
       to a callout function point to 16-bit vectors.

TESTING         top


       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 both the 8-bit and the 32-bit libraries were 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, 16-bit and 32-bit libraries has been built, and runs the
       tests appropriately.

NOT SUPPORTED IN 16-BIT MODE         top


       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         top


       Philip Hazel
       University Computing Service
       Cambridge CB2 3QH, England.

REVISION         top


       Last updated: 12 May 2013
       Copyright (c) 1997-2013 University of Cambridge.

COLOPHON         top

       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-8.44.tar.gz fetched from
       ⟨ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/⟩ on
       2021-04-01.  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)