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PCRE(3) 							       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 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 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 func- tions from just one library. For example, if you want to study a pat- tern 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 all libraries, as well as definitions of flags, struc- tures, 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 "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

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 func- tion 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 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

The name-to-number translation table that is maintained for named sub- patterns 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. 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_con- fig(), 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 corre- spond 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

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 con- verted 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 appro- priately. 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: 12 May 2013 Copyright (c) 1997-2013 University of Cambridge. PCRE 8.33 12 May 2013 PCRE(3) PCRE_COMPILE(3) PCRE_COMPILE(3)

NAME

PCRE - Perl-compatible regular expressions

SYNOPSIS

#include <pcre.h> pcre *pcre_compile(const char *pattern, int options, const char **errptr, int *erroffset, const unsigned char *tableptr); pcre16 *pcre16_compile(PCRE_SPTR16 pattern, int options, const char **errptr, int *erroffset, const unsigned char *tableptr); pcre32 *pcre32_compile(PCRE_SPTR32 pattern, int options, const char **errptr, int *erroffset, const unsigned char *tableptr);

DESCRIPTION

This function compiles a regular expression into an internal form. It is the same as pcre[16|32]_compile2(), except for the absence of the errorcodeptr argument. Its arguments are: pattern A zero-terminated string containing the regular expression to be compiled options Zero or more option bits errptr Where to put an error message erroffset Offset in pattern where error was found tableptr Pointer to character tables, or NULL to use the built-in default The option bits are: PCRE_ANCHORED Force pattern anchoring PCRE_AUTO_CALLOUT Compile automatic callouts PCRE_BSR_ANYCRLF \R matches only CR, LF, or CRLF PCRE_BSR_UNICODE \R matches all Unicode line endings PCRE_CASELESS Do caseless matching PCRE_DOLLAR_ENDONLY $ not to match newline at end PCRE_DOTALL . matches anything including NL PCRE_DUPNAMES Allow duplicate names for subpatterns PCRE_EXTENDED Ignore white space and # comments PCRE_EXTRA PCRE extra features (not much use currently) PCRE_FIRSTLINE Force matching to be before newline PCRE_JAVASCRIPT_COMPAT JavaScript compatibility PCRE_MULTILINE ^ and $ match newlines within data PCRE_NEVER_UTF Lock out UTF, e.g. via (*UTF) PCRE_NEWLINE_ANY Recognize any Unicode newline sequence PCRE_NEWLINE_ANYCRLF Recognize CR, LF, and CRLF as newline sequences PCRE_NEWLINE_CR Set CR as the newline sequence PCRE_NEWLINE_CRLF Set CRLF as the newline sequence PCRE_NEWLINE_LF Set LF as the newline sequence PCRE_NO_AUTO_CAPTURE Disable numbered capturing paren- theses (named ones available) PCRE_NO_AUTO_POSSESS Disable auto-possessification PCRE_NO_START_OPTIMIZE Disable match-time start optimizations PCRE_NO_UTF16_CHECK Do not check the pattern for UTF-16 validity (only relevant if PCRE_UTF16 is set) PCRE_NO_UTF32_CHECK Do not check the pattern for UTF-32 validity (only relevant if PCRE_UTF32 is set) PCRE_NO_UTF8_CHECK Do not check the pattern for UTF-8 validity (only relevant if PCRE_UTF8 is set) PCRE_UCP Use Unicode properties for \d, \w, etc. PCRE_UNGREEDY Invert greediness of quantifiers PCRE_UTF16 Run in pcre16_compile() UTF-16 mode PCRE_UTF32 Run in pcre32_compile() UTF-32 mode PCRE_UTF8 Run in pcre_compile() UTF-8 mode PCRE must be built with UTF support in order to use PCRE_UTF8/16/32 and PCRE_NO_UTF8/16/32_CHECK, and with UCP support if PCRE_UCP is used. The yield of the function is a pointer to a private data structure that contains the compiled pattern, or NULL if an error was detected. Note that compiling regular expressions with one version of PCRE for use with a different version is not guaranteed to work and may cause crashes. There is a complete description of the PCRE native API in the pcreapi page and a description of the POSIX API in the pcreposix page. PCRE 8.34 01 October 2013 PCRE_COMPILE(3)

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