std::regex_constants::match_flag_type

 

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Regular expressions library

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basic_regex (C++11)

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syntax_option_type (C++11)

match_flag_type (C++11)

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Defined in header <regex>
using match_flag_type = /* implementation-defined */;	(1)	(since C++11)
constexpr match_flag_type match_default =     {}; constexpr match_flag_type match_not_bol =     /* unspecified */; constexpr match_flag_type match_not_eol =     /* unspecified */; constexpr match_flag_type match_not_bow =     /* unspecified */; constexpr match_flag_type match_not_eow =     /* unspecified */; constexpr match_flag_type match_any =         /* unspecified */; constexpr match_flag_type match_not_null =    /* unspecified */; constexpr match_flag_type match_continuous =  /* unspecified */; constexpr match_flag_type match_prev_avail =  /* unspecified */; constexpr match_flag_type format_default =    {}; constexpr match_flag_type format_sed =        /* unspecified */; constexpr match_flag_type format_no_copy =    /* unspecified */; constexpr match_flag_type format_first_only = /* unspecified */;	(2)	(since C++11) (inline since C++17)

1) match_flag_type is a BitmaskType that specifies additional regular expression matching options.

Constants

Note: [first, last) refers to the character sequence being matched.

Name	Explanation
match_not_bol	The first character in [first, last) will be treated as if it is not at the beginning of a line (i.e. ^ will not match [first, first)).
match_not_eol	The last character in [first, last) will be treated as if it is not at the end of a line (i.e. $ will not match [last, last)).
match_not_bow	\b will not match [first, first).
match_not_eow	\b will not match [last, last).
match_any	If more than one match is possible, then any match is an acceptable result.
match_not_null	Do not match empty sequences.
match_continuous	Only match a sub-sequence that begins at first.
match_prev_avail	--first is a valid iterator position. When set, causes match_not_bol and match_not_bow to be ignored.
format_default	Use ECMAScript rules to construct strings in std::regex_replace (syntax documentation).
format_sed	Use POSIX sed utility rules in std::regex_replace (syntax documentation).
format_no_copy	Do not copy un-matched strings to the output in std::regex_replace.
format_first_only	Only replace the first match in std::regex_replace.

All constants, except for match_default and format_default, are bitmask elements. The match_default and format_default constants are empty bitmasks.

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 2053	C++11	1. the constants were declared static 2. match_default and format_default were initialized from ​0​	1. removed the static specifier 2. initialized from {}

See also

regex_match (C++11)	attempts to match a regular expression to an entire character sequence (function template)
syntax_option_type (C++11)	general options controlling regex behavior (typedef)
error_type (C++11)	describes different types of matching errors (typedef)