NAME¶

std::regex_constants::match_flag_type - std::regex_constants::match_flag_type

Synopsis¶

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*/; (since C++11)
constexpr match_flag_type match_not_null = /*unspecified*/; (until C++17)
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*/;
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*/; (since C++17)
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*/;

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
The first character in [first,last) will be treated as if it is
match_not_bol 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
match_flag_type could not be a scoped
LWG 2053 C++11 enumeration because made initialized from
match_default and format_default was empty braces
required to be initialized from 0

See also¶

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