Deduce the template parameters KEY and VALUE from the value_type of the initializer_list supplied to the constructor of unordered_map. Deduce the template parameters HASH, EQUAL and ALLOCATOR from the other parameters supplied to the constructor of unordered_map. This deduction guide does not participate unless: (1) the supplied HASH is invokable with a KEY, (2) the supplied EQUAL is invokable with two KEYs, and (3) the supplied allocator meets the requirements of a standard allocator.
Declared in <bslstl_unorderedmap.h>
template<
class KEY,
class VALUE,
class HASH = bsl::hash<KEY>,
class EQUAL = bsl::equal_to<KEY>,
class ALLOCATOR = bsl::allocator<bsl::pair<KEY const, VALUE>>>
requires std::is_invocable_v<HASH, const KEY &> && std::is_invocable_v<EQUAL, const KEY &, const KEY &> && bsl::IsStdAllocator_v<ALLOCATOR>
unordered_map<KEY, VALUE, HASH, EQUAL, ALLOCATOR>(
std::initializer_list<bsl::pair<KEY const, VALUE>>,
bsl::allocator_traits<ALLOCATOR>::size_type,
HASH,
EQUAL,
ALLOCATOR) -> unordered_map<KEY, VALUE, HASH, EQUAL, ALLOCATOR>;