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Linux 2.6 - man page for pcre_dfa_exec (linux section 3)


       PCRE - Perl-compatible regular expressions


       #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);


       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-com-
       patible). Note that the main, Perl-compatible, matching function is pcre_exec(). The argu-
       ments 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, & CRLF as newline sequences
	 PCRE_NEWLINE_CR	Recognize CR as the only newline sequence
	 PCRE_NEWLINE_CRLF	Recognize CRLF as the only newline sequence
	 PCRE_NEWLINE_LF	Recognize LF as the only 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_NOTEMPTY_ATSTART	An empty string at the start of the subject
				  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
	 PCRE_PARTIAL_SOFT	)   match if no full matches are found
	 PCRE_PARTIAL_HARD	Return PCRE_ERROR_PARTIAL for a partial match
				  even if there is a full match as well
	 PCRE_DFA_SHORTEST	Return only the shortest match
	 PCRE_DFA_RESTART	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. For details of partial matching, see
       the pcrepartial page.

       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,
       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 descrip-
       tion of the POSIX API in the pcreposix page.


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