# pcre2_compile man page

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## 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_EXTENDED_CLASS Alternative extended character class syntax
      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.

Return to the PCRE2 index page.