deduction guides for std::unordered_multiset

From cppreference.com

C++
Containers library
std::unordered_multiset
Member types
Member functions
Non-member functions
Deduction guides (C++17)
Defined in header <unordered_set>
template <

class InputIt,
class Hash = std:: hash < typename std:: iterator_traits < InputIt > :: value_type > ,
class Pred = std:: equal_to < typename std:: iterator_traits < InputIt > :: value_type > ,
class Alloc = std:: allocator < typename std:: iterator_traits < InputIt > :: value_type > >
unordered_multiset ( InputIt, InputIt,
typename /* see below */ :: size_type = /* see below */ ,
Hash = Hash ( ) , Pred = Pred ( ) , Alloc = Alloc ( ) )
- > unordered_multiset < typename std:: iterator_traits < InputIt > :: value_type ,

Hash, Pred, Alloc > ;
(1) (since C++17)
template < class T,

class Hash = std:: hash < T > ,
class Pred = std:: equal_to < T > ,
class Alloc = std:: allocator < T > >
unordered_multiset ( std:: initializer_list < T > ,
typename /* see below */ :: size_type = /* see below */ ,
Hash = Hash ( ) , Pred = Pred ( ) , Alloc = Alloc ( ) )

- > unordered_multiset < T, Hash, Pred, Alloc > ;
(2) (since C++17)
template < class InputIt, class Alloc >

unordered_multiset ( InputIt, InputIt, typename /* see below */ :: size_type , Alloc )
- > unordered_multiset < typename std:: iterator_traits < InputIt > :: value_type ,
std:: hash < typename std:: iterator_traits < InputIt > :: value_type > ,
std:: equal_to < typename std:: iterator_traits < InputIt > :: value_type > ,

Alloc > ;
(3) (since C++17)
template < class InputIt, class Hash, class Alloc >

unordered_multiset ( InputIt, InputIt, typename /* see below */ :: size_type , Hash, Alloc )
- > unordered_multiset < typename std:: iterator_traits < InputIt > :: value_type , Hash,
std:: equal_to < typename std:: iterator_traits < InputIt > :: value_type > ,

Alloc > ;
(4) (since C++17)
template < class T, class Alloc >

unordered_multiset ( std:: initializer_list < T > , typename /* see below */ :: size_type , Alloc )

- > unordered_multiset < T, std:: hash < T > , std:: equal_to < T > , Alloc > ;
(5) (since C++17)
template < class T, class Hash, class Alloc >

unordered_multiset ( std:: initializer_list < T > , typename /* see below */ :: size_type ,
Hash, Alloc )

- > unordered_multiset < T, Hash, std:: equal_to < T > , Alloc > ;
(6) (since C++17)
template < ranges:: input_range R,

class Hash = std:: hash < ranges:: range_value_t < R >> ,
class Pred = std:: equal_to < ranges:: range_value_t < R >> ,
class Alloc = std:: allocator < ranges:: range_value_t < R >> >
unordered_multiset ( std:: from_range_t , R && ,
typename /* see below */ :: size_type = /* see below */ ,
Hash = Hash ( ) , Pred = Pred ( ) , Alloc = Alloc ( ) )

- > unordered_multiset < ranges:: range_value_t < R > , Hash, Pred, Alloc > ;
(7) (since C++23)
template < ranges:: input_range R, class Alloc >

unordered_multiset ( std:: from_range_t , R && ,
typename /* see below */ :: size_type , Alloc )
- > unordered_multiset < ranges:: range_value_t < R > , hash < ranges:: range_value_t < R >> ,

std:: equal_to < ranges:: range_value_t < R >> , Alloc > ;
(8) (since C++23)
template < ranges:: input_range R, class Alloc >

unordered_multiset ( std:: from_range_t , R && , Alloc )
- > unordered_multiset < ranges:: range_value_t < R > , hash < ranges:: range_value_t < R >> ,

std:: equal_to < ranges:: range_value_t < R >> , Alloc > ;
(9) (since C++23)
template < ranges:: input_range R, class Hash, class Alloc >

unordered_multiset ( std:: from_range_t , R && ,
typename /* see below */ :: size_type , Hash, Alloc )
- > unordered_multiset < ranges:: range_value_t < R > , Hash,

std:: equal_to < ranges:: range_value_t < R >> , Alloc > ;
(10) (since C++23)
1-6) These deduction guides are provided for unordered_multiset to allow deduction from an iterator range (overloads (1,3,4) ) and std::initializer_list (overloads (2,5,6) ). This overload participates in overload resolution only if InputIt satisfies LegacyInputIterator , Alloc satisfies Allocator , neither Hash nor Pred satisfy Allocator , Hash is not an integral type.
7-10) These deduction guides are provided for unordered_multiset to allow deduction from a std::from_range_t tag and an input_range .

Note: the extent to which the library determines that a type does not satisfy LegacyInputIterator is unspecified, except that as a minimum integral types do not qualify as input iterators. Likewise, the extent to which it determines that a type does not satisfy Allocator is unspecified, except that as a minimum the member type Alloc::value_type must exist and the expression std:: declval < Alloc & > ( ) . allocate ( std:: size_t { } ) must be well-formed when treated as an unevaluated operand.

The size_type parameter type in these guides refers to the size_type member type of the type deduced by the deduction guide.

Notes

Feature-test macro Value Std Feature
__cpp_lib_containers_ranges 202202L (C++23) Ranges-aware construction and insertion; overloads (7-10)

Example

Run this code 
#include <unordered_set>
 
int main()
{
    // guide #2 deduces std::unordered_multiset<int>
    std::unordered_multiset s = {1, 2, 3, 4};
 
    // guide #1 deduces std::unordered_multiset<int>
    std::unordered_multiset s2(s.begin(), s.end());
}
Retrieved from " https://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_multiset/deduction_guides&oldid=135886 "