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std::basic_regexconstants(3)   C++ Standard Libary  std::basic_regexconstants(3)

NAME
     std::basic_regexconstants - std::basic_regexconstants

Synopsis
	Defined in header <regex>
	static constexpr std::regex_constants::syntax_option_type icase =

	    std::regex_constants::icase;
	static constexpr std::regex_constants::syntax_option_type nosubs =
	    std::regex_constants::nosubs;
	static constexpr std::regex_constants::syntax_option_type optimize =
	    std::regex_constants::optimize;
	static constexpr std::regex_constants::syntax_option_type collate =
	    std::regex_constants::collate;
	static constexpr std::regex_constants::syntax_option_type ECMAScript
	=
	    std::regex_constants::ECMAScript;
	static constexpr std::regex_constants::syntax_option_type basic =
	    std::regex_constants::basic;
	static constexpr std::regex_constants::syntax_option_type extended =
	    std::regex_constants::extended;
	static constexpr std::regex_constants::syntax_option_type awk =
	    std::regex_constants::awk;
	static constexpr std::regex_constants::syntax_option_type grep =
	    std::regex_constants::grep;
	static constexpr std::regex_constants::syntax_option_type egrep =

	    std::regex_constants::egrep;
	static	constexpr  std::regex_constants::syntax_option_type  multiline =
     (since C++17)
	    std::regex_constants::multiline;

	std::basic_regex defines several constants  that  govern  general  regex
     matching
	syntax.

	These constants are duplicated from std::regex_constants:

	Grammar option	  Effect(s)
	ECMAScript	   Use	the Modified ECMAScript regular expression gram-
     mar.
	basic		  Use the basic POSIX regular expression grammar  (gram-
     mar
			  documentation).
	extended	   Use	the  extended  POSIX  regular expression grammar
     (grammar
			  documentation).
	awk		  Use the regular expression grammar  used  by	the  awk
     utility in
			  POSIX (grammar documentation).
			  Use  the  regular  expression grammar used by the grep
     utility in
	grep		  POSIX. This is effectively the same as the  basic  op-
     tion with the
			  addition of newline '\n' as an alternation separator.
			  Use  the  regular  expression grammar used by the grep
     utility, with
	egrep		  the -E option, in POSIX. This is effectively the  same
     as the
			  extended  option  with the addition of newline '\n' as
     an
			  alternation separator in addition to '|'.
	Grammar variation Effect(s)
	icase		  Character matching should be performed without  regard
     to case.
			  When	performing  matches,  all marked sub-expressions
     (expr) are
	nosubs		  treated as non-marking  sub-expressions  (?:expr).  No
     matches are
			  stored  in the supplied std::regex_match structure and
     mark_count()
			  is zero.
			  Instructs the regular expression engine to make match-
     ing faster,
	optimize	  with the potential cost of making construction slower.
     For
			  example, this might mean converting a  non-determinis-
     tic FSA to a
			  deterministic FSA.
	collate 	   Character  ranges  of the form "[a-b]" will be locale
     sensitive.
	multiline (C++17) Specifies that ^ shall match the beginning of  a  line
     and $ shall
			  match  the  end of a line, if the ECMAScript engine is
     selected.

	At most one grammar option can be chosen out of ECMAScript,  basic,  ex-
     tended, awk,
	grep,  egrep.  If  no grammar is chosen, ECMAScript is assumed to be se-
     lected. The
	other  options	serve  as  variations,	such   that   std::regex("meow",
     std::regex::icase)
	is	 equivalent	 to	 std::regex("meow",	 std::regex::EC-
     MAScript|std::regex::icase).

See also
	syntax_option_type general options controlling regex behavior
	(C++11) 	   (typedef)

http://cppreference.com 	   2024.06.10	    std::basic_regexconstants(3)
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