NAME¶

deductionguidesforstd::unordered_multiset - deductionguidesforstd::unordered_multiset

Synopsis¶

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

class Hash = std::hash<T>,
class Pred = std::equal_to<T>,
class Alloc = std::allocator<T>> (2) (since C++17)
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>;
template<class InputIt, class Alloc>

unordered_multiset(InputIt, InputIt, typename /*see
below*/::size_type, Alloc)
-> unordered_multiset<typename (3) (since C++17)
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>;
template<class InputIt, class Hash, class Alloc>

unordered_multiset(InputIt, InputIt, typename /*see
below*/::size_type, Hash, Alloc)
-> unordered_multiset<typename (4) (since C++17)
std::iterator_traits<InputIt>::value_type, Hash,

std::equal_to<typename std::iterator_traits<InputIt>::value_type>,
Allocator>;
template<class T, class Allocator>

unordered_multiset(std::initializer_list<T>, typename /*see (5) (since C++17)
below*/::size_type, Allocator)

-> unordered_multiset<T, std::hash<T>, std::equal_to<T>, Alloc>;
template<class T, class Hash, class Alloc>

unordered_multiset(std::initializer_list<T>, typename /*see (6) (since C++17)
below*/::size_type, Hash, Alloc)

-> unordered_multiset<T, Hash, std::equal_to<T>, Alloc>;

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

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.

Example¶

// Run this code

#include <unordered_set>
int main() {
std::unordered_multiset s = {1,2,3,4}; // guide #2 deduces std::unordered_multiset<int>
std::unordered_multiset s2(s.begin(), s.end()); // guide #1 deduces std::unordered_multiset<int>
}