^^&&^^

Edit File: pcre16.html

<html>
<head>
<title>pcre16 specification</title>
</head>
<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
<h1>pcre16 man page</h1>

Return to the <a href="index.html">PCRE index page</a>.


This page is part of the PCRE HTML documentation. It was generated automatically
from the original man page. If there is any nonsense in it, please consult the
man page, in case the conversion went wrong.
 
<ul>
<li><a name="TOC1" href="#SEC1">PCRE 16-BIT API BASIC FUNCTIONS</a>
<li><a name="TOC2" href="#SEC2">PCRE 16-BIT API STRING EXTRACTION FUNCTIONS</a>
<li><a name="TOC3" href="#SEC3">PCRE 16-BIT API AUXILIARY FUNCTIONS</a>
<li><a name="TOC4" href="#SEC4">PCRE 16-BIT API INDIRECTED FUNCTIONS</a>
<li><a name="TOC5" href="#SEC5">PCRE 16-BIT API 16-BIT-ONLY FUNCTION</a>
<li><a name="TOC6" href="#SEC6">THE PCRE 16-BIT LIBRARY</a>
<li><a name="TOC7" href="#SEC7">THE HEADER FILE</a>
<li><a name="TOC8" href="#SEC8">THE LIBRARY NAME</a>
<li><a name="TOC9" href="#SEC9">STRING TYPES</a>
<li><a name="TOC10" href="#SEC10">STRUCTURE TYPES</a>
<li><a name="TOC11" href="#SEC11">16-BIT FUNCTIONS</a>
<li><a name="TOC12" href="#SEC12">SUBJECT STRING OFFSETS</a>
<li><a name="TOC13" href="#SEC13">NAMED SUBPATTERNS</a>
<li><a name="TOC14" href="#SEC14">OPTION NAMES</a>
<li><a name="TOC15" href="#SEC15">CHARACTER CODES</a>
<li><a name="TOC16" href="#SEC16">ERROR NAMES</a>
<li><a name="TOC17" href="#SEC17">ERROR TEXTS</a>
<li><a name="TOC18" href="#SEC18">CALLOUTS</a>
<li><a name="TOC19" href="#SEC19">TESTING</a>
<li><a name="TOC20" href="#SEC20">NOT SUPPORTED IN 16-BIT MODE</a>
<li><a name="TOC21" href="#SEC21">AUTHOR</a>
<li><a name="TOC22" href="#SEC22">REVISION</a>
</ul>

#include &#60;pcre.h&#62;

 <a name="SEC1" href="#TOC1">PCRE 16-BIT API BASIC FUNCTIONS</a> 

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);

 <a name="SEC2" href="#TOC1">PCRE 16-BIT API STRING EXTRACTION FUNCTIONS</a> 

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);

 <a name="SEC3" href="#TOC1">PCRE 16-BIT API AUXILIARY FUNCTIONS</a> 

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);

 <a name="SEC4" href="#TOC1">PCRE 16-BIT API INDIRECTED FUNCTIONS</a> 

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 *);

 <a name="SEC5" href="#TOC1">PCRE 16-BIT API 16-BIT-ONLY FUNCTION</a> 

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

 <a name="SEC6" href="#TOC1">THE PCRE 16-BIT LIBRARY</a> 

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().

 <a name="SEC7" href="#TOC1">THE HEADER FILE</a> 

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.

 <a name="SEC8" href="#TOC1">THE LIBRARY NAME</a> 

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.

 <a name="SEC9" href="#TOC1">STRING TYPES</a> 

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.

 <a name="SEC10" href="#TOC1">STRUCTURE TYPES</a> 

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.

 <a name="SEC11" href="#TOC1">16-BIT FUNCTIONS</a> 

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.

 <a name="SEC12" href="#TOC1">SUBJECT STRING OFFSETS</a> 

The offsets within subject strings that are returned by the matching functions
are in 16-bit units rather than bytes.

 <a name="SEC13" href="#TOC1">NAMED SUBPATTERNS</a> 

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.

 <a name="SEC14" href="#TOC1">OPTION NAMES</a> 

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
<a href="pcreunicode.html#utf16strings">validity of UTF-16 strings</a>
in the
<a href="pcreunicode.html">pcreunicode</a>
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.

 <a name="SEC15" href="#TOC1">CHARACTER CODES</a> 

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).

 <a name="SEC16" href="#TOC1">ERROR NAMES</a> 

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
<a href="pcreapi.html#badutf8reasons">"Reason codes for invalid UTF-8 strings"</a>
in the main
<a href="pcreapi.html">pcreapi</a>
page. The UTF-16 errors are:
<pre>
 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
</PRE>

 <a name="SEC17" href="#TOC1">ERROR TEXTS</a> 

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.

 <a name="SEC18" href="#TOC1">CALLOUTS</a> 

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

 <a name="SEC19" href="#TOC1">TESTING</a> 

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.

 <a name="SEC20" href="#TOC1">NOT SUPPORTED IN 16-BIT MODE</a> 

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.

 <a name="SEC21" href="#TOC1">AUTHOR</a> 

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

 <a name="SEC22" href="#TOC1">REVISION</a> 

Last updated: 08 November 2012
 
Copyright &copy; 1997-2012 University of Cambridge.
 

Return to the <a href="index.html">PCRE index page</a>.