std:: basic_regex

Defined in header <regex>
template < class CharT, class Traits = std:: regex_traits < CharT > > class basic_regex ;		(since C++11)

The class template basic_regex provides a general framework for holding regular expressions.

Several typedefs for common character types are provided:

Defined in header <regex>
Type	Definition
std::regex	std :: basic_regex < char >
std::wregex	std :: basic_regex < wchar_t >

Member types

Member type	Definition
value_type	CharT
traits_type	Traits
string_type	Traits::string_type
locale_type	Traits::locale_type
flag_type	std::regex_constants::syntax_option_type

Member functions

(constructor)	constructs the regex object (public member function)
(destructor)	destructs the regex object (public member function)
operator=	assigns the contents (public member function)
assign	assigns the contents (public member function)
Observers
mark_count	returns the number of marked sub-expressions within the regular expression (public member function)
flags	returns the syntax flags (public member function)
Locale
getloc	get locale information (public member function)
imbue	set locale information (public member function)
Modifiers
swap	swaps the contents (public member function)
Constants

Grammar option	Effect(s)
ECMAScript	Use the Modified ECMAScript regular expression grammar .
basic	Use the basic POSIX regular expression grammar ( grammar 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 ).
grep	Use the regular expression grammar used by the grep utility in POSIX. This is effectively the same as the basic option with the addition of newline ' \n ' as an alternation separator.
egrep	Use the regular expression grammar used by the grep utility, with 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.
nosubs	When performing matches, all marked sub-expressions ( expr ) are treated as non-marking sub-expressions (?: expr ) . No matches are stored in the supplied std::regex_match structure and mark_count() is zero.
optimize	Instructs the regular expression engine to make matching faster, with the potential cost of making construction slower. For example, this might mean converting a non-deterministic 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 , extended , awk , grep , egrep . If no grammar is chosen, ECMAScript is assumed to be selected. The other options serve as variations, such that std :: regex ( "meow" , std :: regex :: icase ) is equivalent to std :: regex ( "meow" , std :: regex :: ECMAScript | std :: regex :: icase ) .

The member constants in basic_regex are duplicates of the syntax_option_type constants defined in the namespace std::regex_constants .

Non-member functions

std::swap (std::basic_regex) (C++11)

specializes the std::swap algorithm (function template)

Deduction guides (since C++17)