std::unordered_multimap<Key,T,Hash,KeyEqual,Allocator>::unordered_multimap
unordered_multimap() : unordered_multimap( size_type(/*implementation-defined*/) ) {} explicit unordered_multimap( size_type bucket_count, const Hash& hash = Hash(), const key_equal& equal = key_equal(), const Allocator& alloc = Allocator() ); | (1) | (since C++11) |
unordered_multimap( size_type bucket_count, const Allocator& alloc ) : unordered_multimap(bucket_count, Hash(), key_equal(), alloc) {} unordered_multimap( size_type bucket_count, const Hash& hash, const Allocator& alloc ) : unordered_multimap(bucket_count, hash, key_equal(), alloc) {} | (1) | (since C++14) |
explicit unordered_multimap( const Allocator& alloc ); | (1) | (since C++11) |
template< class InputIt > unordered_multimap( InputIt first, InputIt last, size_type bucket_count = /*implementation-defined*/, const Hash& hash = Hash(), const key_equal& equal = key_equal(), const Allocator& alloc = Allocator() ); | (2) | (since C++11) |
template< class InputIt > unordered_multimap( InputIt first, InputIt last, size_type bucket_count, const Allocator& alloc ) : unordered_multimap(first, last, bucket_count, Hash(), key_equal(), alloc) {} | (2) | (since C++14) |
template< class InputIt > unordered_multimap( InputIt first, InputIt last, size_type bucket_count, const Hash& hash, const Allocator& alloc ) : unordered_multimap(first, last, bucket_count, hash, key_equal(), alloc) {} | (2) | (since C++14) |
unordered_multimap( const unordered_multimap& other ); | (3) | (since C++11) |
unordered_multimap( const unordered_multimap& other, const Allocator& alloc ); | (3) | (since C++11) |
unordered_multimap( unordered_multimap&& other ); | (4) | (since C++11) |
unordered_multimap( unordered_multimap&& other, const Allocator& alloc ); | (4) | (since C++11) |
unordered_multimap( std::initializer_list<value_type> init, size_type bucket_count = /*implementation-defined*/, const Hash& hash = Hash(), const key_equal& equal = key_equal(), const Allocator& alloc = Allocator() ); | (5) | (since C++11) |
unordered_multimap( std::initializer_list<value_type> init, size_type bucket_count, const Allocator& alloc ) : unordered_multimap(init, bucket_count, Hash(), key_equal(), alloc) {} | (5) | (since C++14) |
unordered_multimap( std::initializer_list<value_type> init, size_type bucket_count, const Hash& hash, const Allocator& alloc ) : unordered_multimap(init, bucket_count, hash, key_equal(), alloc) {} | (5) | (since C++14) |
Constructs new container from a variety of data sources. Optionally uses user supplied bucket_count
as a minimal number of buckets to create, hash
as the hash function, equal
as the function to compare keys and alloc
as the allocator.
1) Constructs empty container. Sets
max_load_factor()
to 1.0. For the default constructor, the number of buckets is implementation-defined.
2) constructs the container with the contents of the range
[first, last)
. Sets max_load_factor()
to 1.0.
3) copy constructor. Constructs the container with the copy of the contents of
other
, copies the load factor, the predicate, and the hash function as well. If alloc
is not provided, allocator is obtained by calling std::allocator_traits<allocator_type>::select_on_container_copy_construction(other.get_allocator())
.
4) move constructor. Constructs the container with the contents of
other
using move semantics. If alloc
is not provided, allocator is obtained by move-construction from the allocator belonging to other
.
5) constructs the container with the contents of the initializer list
init
, same as unordered_multimap(init.begin(), init.end()).Parameters
alloc | - | allocator to use for all memory allocations of this container |
bucket_count | - | minimal number of buckets to use on initialization. If it is not specified, implementation-defined default value is used |
hash | - | hash function to use |
equal | - | comparison function to use for all key comparisons of this container |
first, last | - | the range to copy the elements from |
other | - | another container to be used as source to initialize the elements of the container with |
init | - | initializer list to initialize the elements of the container with |
Type requirements | ||
-InputIt must meet the requirements of LegacyInputIterator. |
Complexity
1) constant
2) average case linear worst case quadratic in distance between
first
and last
3) linear in size of
other
4) constant. If
alloc
is given and alloc != other.get_allocator()
, then linear.
5) average case linear worst case quadratic in size of
init
Exceptions
Calls to Allocator::allocate
may throw.
Notes
After container move construction (overload (4)), references, pointers, and iterators (other than the end iterator) toother
remain valid, but refer to elements that are now in *this
. The current standard makes this guarantee via the blanket statement in §23.2.1[container.requirements.general]/12, and a more direct guarantee is under consideration via LWG 2321. Example
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR | Applied to | Behavior as published | Correct behavior |
---|---|---|---|
LWG 2193 | C++11 | the default constructor is explicit | made non-explicit |
See also
assigns values to the container (public member function) |
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