std::regex_constants::match_flag_type

 

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Regular expressions library

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basic_regex (C++11)

sub_match (C++11)

match_results (C++11)

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regex_match (C++11)

regex_search (C++11)

regex_replace (C++11)

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regex_iterator (C++11)

regex_token_iterator (C++11)

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regex_error (C++11)

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regex_traits (C++11)

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syntax_option_type (C++11)

match_flag_type (C++11)

error_type (C++11)

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Modified ECMAScript-262 (C++11)

 

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

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

Constants

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

Constant	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	match_flag_type could not be a scoped enumeration because match_default and format_default was required to be initialized from ​0​	made initialized from empty braces

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)