PCRE - Perl-compatible regular expressions

       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.

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

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

       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).

       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

       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.

       PCRE - Perl-compatible regular expressions

       #include<pcre.h>

       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.

       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.

       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.

intpcre16_utf16_to_host_byte_order(PCRE_UCHAR16*output,PCRE_SPTR16input,intlength,int*byte_order,intkeep_boms);

pcre16_jit_stack*pcre16_jit_stack_alloc(intstartsize,intmaxsize);voidpcre16_jit_stack_free(pcre16_jit_stack*stack);voidpcre16_assign_jit_stack(pcre16_extra*extra,pcre16_jit_callbackcallback,void*data);constunsignedchar*pcre16_maketables(void);intpcre16_fullinfo(constpcre16*code,constpcre16_extra*extra,intwhat,void*where);intpcre16_refcount(pcre16*code,intadjust);intpcre16_config(intwhat,void*where);constchar*pcre16_version(void);intpcre16_pattern_to_host_byte_order(pcre16*code,pcre16_extra*extra,constunsignedchar*tables);

pcre16*pcre16_compile(PCRE_SPTR16pattern,intoptions,constchar**errptr,int*erroffset,constunsignedchar*tableptr);pcre16*pcre16_compile2(PCRE_SPTR16pattern,intoptions,int*errorcodeptr,constchar**errptr,int*erroffset,constunsignedchar*tableptr);pcre16_extra*pcre16_study(constpcre16*code,intoptions,constchar**errptr);voidpcre16_free_study(pcre16_extra*extra);intpcre16_exec(constpcre16*code,constpcre16_extra*extra,PCRE_SPTR16subject,intlength,intstartoffset,intoptions,int*ovector,intovecsize);intpcre16_dfa_exec(constpcre16*code,constpcre16_extra*extra,PCRE_SPTR16subject,intlength,intstartoffset,intoptions,int*ovector,intovecsize,int*workspace,intwscount);

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*);

intpcre16_copy_named_substring(constpcre16*code,PCRE_SPTR16subject,int*ovector,intstringcount,PCRE_SPTR16stringname,PCRE_UCHAR16*buffer,intbuffersize);intpcre16_copy_substring(PCRE_SPTR16subject,int*ovector,intstringcount,intstringnumber,PCRE_UCHAR16*buffer,intbuffersize);intpcre16_get_named_substring(constpcre16*code,PCRE_SPTR16subject,int*ovector,intstringcount,PCRE_SPTR16stringname,PCRE_SPTR16*stringptr);intpcre16_get_stringnumber(constpcre16*code,PCRE_SPTR16name);intpcre16_get_stringtable_entries(constpcre16*code,PCRE_SPTR16name,PCRE_UCHAR16**first,PCRE_UCHAR16**last);intpcre16_get_substring(PCRE_SPTR16subject,int*ovector,intstringcount,intstringnumber,PCRE_SPTR16*stringptr);intpcre16_get_substring_list(PCRE_SPTR16subject,int*ovector,intstringcount,PCRE_SPTR16**listptr);voidpcre16_free_substring(PCRE_SPTR16stringptr);voidpcre16_free_substring_list(PCRE_SPTR16*stringptr);

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

PCRE 8.33                                          12 May 2013                                           PCRE(3)

       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.

       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.

       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.

       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.

       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  16-bit  library  is called libpcre16, and can normally be accesss by adding
       -lpcre16 to the command for linking an application that uses PCRE.

       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().