PCRE_DFA_EXEC(3)

NAME
PCRE - Perl-compatible regular expressions

SYNOPSIS

#include <pcre.h>

int pcre_dfa_exec(const pcre *code, const pcre_extra *extra,
const char *subject, int length, int startoffset,
int options, int *ovector, int ovecsize,
int *workspace, int wscount);

DESCRIPTION

This function matches a compiled regular expression against a given subject string, using an alternative matching algorithm that scans the subject string just once (not Perl-compatible). Note that the main, Perl-compatible, matching function is pcre_exec(). The arguments for this function are:

  code Points to the compiled pattern
  extra Points to an associated pcre_extra structure,
                 or is NULL
  subject Points to the subject string
  length Length of the subject string, in bytes
  startoffset Offset in bytes in the subject at which to
                 start matching
  options Option bits
  ovector Points to a vector of ints for result offsets
  ovecsize Number of elements in the vector
  workspace Points to a vector of ints used as working space
  wscount Number of elements in the vector

The options are:

  PCRE_ANCHORED Match only at the first position
  PCRE_BSR_ANYCRLF \R matches only CR, LF, or CRLF
  PCRE_BSR_UNICODE \R matches all Unicode line endings
  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_NOTBOL Subject is not the beginning of a line
  PCRE_NOTEOL Subject is not the end of a line
  PCRE_NOTEMPTY An empty string is not a valid match
  PCRE_NO_START_OPTIMIZE Do not do "start-match" optimizations
  PCRE_NO_UTF8_CHECK Do not check the subject for UTF-8
                       validity (only relevant if PCRE_UTF8
                       was set at compile time)
  PCRE_PARTIAL Return PCRE_ERROR_PARTIAL for a partial match
  PCRE_DFA_SHORTEST Return only the shortest match
  PCRE_DFA_RESTART This is a restart after a partial match

There are restrictions on what may appear in a pattern when using this matching function. Details are given in the pcrematching documentation.

A pcre_extra structure contains the following fields:

  flags Bits indicating which fields are set
  study_data Opaque data from pcre_study()
  match_limit Limit on internal resource use
  match_limit_recursion Limit on internal recursion depth
  callout_data Opaque data passed back to callouts
  tables Points to character tables or is NULL

The flag bits are PCRE_EXTRA_STUDY_DATA, PCRE_EXTRA_MATCH_LIMIT, PCRE_EXTRA_MATCH_LIMIT_RECURSION, PCRE_EXTRA_CALLOUT_DATA, and PCRE_EXTRA_TABLES. For this matching function, the match_limit and match_limit_recursion fields are not used, and must not be set.

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.