NAME¶

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

Synopsis¶

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 = /* (since C++11)
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 = (2)
{};

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 = (since C++17)
/* 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 */;

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.

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)).
The last character in [first, last) will be treated as if it is
match_not_eol 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
1. the constants were declared static 1. removed the static
LWG 2053 C++11 2. match_default and format_default were specifier
initialized from 0 2. initialized from {}

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)