Deduction guides¶
Where possible, constructors of concurrent_unordered_multimap support
class template argument deduction (since C++17):
template <typename InputIterator,
typename Hash = std::hash<iterator_key_t<InputIterator>>,
typename KeyEqual = std::equal_to<iterator_key_t<InputIterator>>,
typename Allocator = tbb_allocator<iterator_alloc_value_t<InputIterator>>>
concurrent_unordered_multimap( InputIterator, InputIterator,
map_size_type = /*implementation_defined*/,
Hash = Hash(), KeyEqual = KeyEqual(),
Allocator = Allocator() )
-> concurrent_unordered_multimap<iterator_key_t<InputIterator>,
iterator_mapped_t<InputIterator>,
Hash, KeyEqual, Allocator>;
template <typename InputIterator,
typename Allocator>
concurrent_unordered_multimap( InputIterator, InputIterator,
map_size_type,
Allocator )
-> concurrent_unordered_multimap<iterator_key_t<InputIterator>,
iterator_mapped_t<InputIterator>,
std::hash<iterator_key_t<InputIterator>>,
std::equal_to<iterator_key_t<InputIterator>>,
Allocator>;
template <typename InputIterator,
typename Allocator>
concurrent_unordered_multimap( InputIterator, InputIterator, Allocator )
-> concurrent_unordered_multimap<iterator_key_t<InputIterator>,
iterator_mapped_t<InputIterator>,
std::hash<iterator_key_t<InputIterator>>,
std::equal_to<iterator_key_t<InputIterator>>,
Allocator>;
template <typename InputIterator,
typename Hash,
typename Allocator>
concurrent_unordered_multimap( InputIterator, InputIterator,
Hash, Allocator )
-> concurrent_unordered_multimap<iterator_key_t<InputIterator>,
iterator_mapped_t<InputIterator>,
Hash,
std::equal_to<iterator_key_t<InputIterator>>,
Allocator>;
template <typename Key,
typename T,
typename Hash = std::hash<Key>,
typename KeyEqual = std::equal_to<Key>,
typename Allocator = tbb_allocator<std::pair<Key, T>>>
concurrent_unordered_multimap( std::initializer_list<value_type>,
map_size_type = /*implementation-defined*/,
Hash = Hash(),
KeyEqual = KeyEqual(),
Allocator = Allocator() )
-> concurrent_unordered_multimap<Key, T,
Hash,
KeyEqual,
Allocator>;
template <typename Key,
typename T,
typename Allocator>
concurrent_unordered_multimap( std::initializer_list<value_type>,
map_size_type, Allocator )
-> concurrent_unordered_multimap<Key, T,
std::hash<Key>,
std::equal_to<Key>,
Allocator>;
template <typename Key,
typename T,
typename Hash,
typename Allocator>
concurrent_unordered_multimap( std::initializer_list<value_type>,
map_size_type, Hash, Allocator )
-> concurrent_unordered_multimap<Key, T,
Hash,
std::equal_to<Key>,
Allocator>;
Where the type map_size_type refers to the size_type member type of the deduced concurrent_multimap
and the type aliases iterator_key_t, iterator_mapped_t and iterator_alloc_value_t
are defined as follows:
template <typename InputIterator>
using iterator_key_t = std::remove_const_t<typename std::iterator_traits<InputIterator>::value_type::first_type>;
template <typename InputIterator>
using iterator_mapped_t = typename std::iterator_traits<InputIterator>::value_type::second_type;
template <typename InputIterator>
using iterator_alloc_value_t = std::pair<std::add_const_t<iterator_key_t<InputIterator>,
iterator_mapped_t<InputIterator>>>;
Example
#include <tbb/concurrent_unordered_map.h>
#include <vector>
#include <functional>
struct CustomHasher {...};
int main() {
std::vector<std::pair<int, float>> v;
// Deduces m1 as concurrent_unordered_multimap<int, float>
tbb::concurrent_unordered_multimap m1(v.begin(), v.end());
// Deduces m2 as concurrent_unordered_multimap<int, float, CustomHasher>;
tbb::concurrent_unordered_multimap m2(v.begin(), v.end(), CustomHasher{});
}