NAME

PCRE2 - Perl-compatible regular expressions (revised API)

SYNOPSIS

#include <pcre2.h>

pcre2_code *pcre2_compile(PCRE2_SPTR pattern, PCRE2_SIZE length,
  uint32_t options, int *errorcode, PCRE2_SIZE *erroroffset,
  pcre2_compile_context *ccontext);

DESCRIPTION

This function compiles a regular expression pattern into an internal form. Its arguments are:

pattern A string containing expression to be compiled
length The length of the string or PCRE2_ZERO_TERMINATED
options Primary option bits
errorcode Where to put an error code
erroffset Where to put an error offset
ccontext Pointer to a compile context or NULL

The length of the pattern and any error offset that is returned are in code units, not characters. A NULL pattern with zero length is treated as an empty string. A compile context is needed only if you want to provide custom memory allocation functions, or to provide an external function for system stack size checking (see pcre2_set_compile_recursion_guard()), or to change one or more of these parameters:

What \R matches (Unicode newlines, or CR, LF, CRLF only);
PCRE2's character tables;
The newline character sequence;
The compile time nested parentheses limit;
The maximum pattern length (in code units) that is allowed;
The additional options bits.

The primary option bits are:

PCRE2_ANCHORED Force pattern anchoring
PCRE2_ALLOW_EMPTY_CLASS Allow empty classes
PCRE2_ALT_BSUX Alternative handling of \u, \U, and \x
PCRE2_ALT_CIRCUMFLEX Alternative handling of ^ in multiline mode
PCRE2_ALT_VERBNAMES Process backslashes in verb names
PCRE2_AUTO_CALLOUT Compile automatic callouts
PCRE2_CASELESS Do caseless matching
PCRE2_DOLLAR_ENDONLY $ not to match newline at end
PCRE2_DOTALL . matches anything including NL
PCRE2_DUPNAMES Allow duplicate names for subpatterns
PCRE2_ENDANCHORED Pattern can match only at end of subject
PCRE2_EXTENDED Ignore white space and # comments
PCRE2_FIRSTLINE Force matching to be before newline
PCRE2_LITERAL Pattern characters are all literal
PCRE2_MATCH_INVALID_UTF Enable support for matching invalid UTF
PCRE2_MATCH_UNSET_BACKREF Match unset backreferences
PCRE2_MULTILINE ^ and $ match newlines within data
PCRE2_NEVER_BACKSLASH_C Lock out the use of \C in patterns
PCRE2_NEVER_UCP Lock out PCRE2_UCP, e.g. via (*UCP)
PCRE2_NEVER_UTF Lock out PCRE2_UTF, e.g. via (*UTF)
PCRE2_NO_AUTO_CAPTURE Disable numbered capturing paren-
theses (named ones available)
PCRE2_NO_AUTO_POSSESS Disable auto-possessification
PCRE2_NO_DOTSTAR_ANCHOR Disable automatic anchoring for .*
PCRE2_NO_START_OPTIMIZE Disable match-time start optimizations
PCRE2_NO_UTF_CHECK Do not check the pattern for UTF validity
(only relevant if PCRE2_UTF is set)
PCRE2_UCP Use Unicode properties for \d, \w, etc.
PCRE2_UNGREEDY Invert greediness of quantifiers
PCRE2_USE_OFFSET_LIMIT Enable offset limit for unanchored matching
PCRE2_UTF Treat pattern and subjects as UTF strings

PCRE2 must be built with Unicode support (the default) in order to use PCRE2_UTF, PCRE2_UCP and related options.

Additional options may be set in the compile context via the pcre2_set_compile_extra_options function.

If either of errorcode or erroroffset is NULL, the function returns NULL immediately. Otherwise, the yield of this function is a pointer to a private data structure that contains the compiled pattern, or NULL if an error was detected. In the error case, a text error message can be obtained by passing the value returned via the errorcode argument to the pcre2_get_error_message() function. The offset (in code units) where the error was encountered is returned via the erroroffset argument.

If there is no error, the value passed via errorcode returns the message "no error" if passed to pcre2_get_error_message(), and the value passed via erroroffset is zero.

There is a complete description of the PCRE2 native API, with more detail on each option, in the pcre2api page, and a description of the POSIX API in the pcre2posix page.