Deduction guides

Where possible, constructors of concurrent_unordered_set support class template argument deduction (since C++17):

template <typename InputIterator,
          typename Hash = std::hash<iterator_value_t<InputIterator>>,
          typename KeyEqual = std::equal_to<iterator_value_t<InputIterator>>,
          typename Allocator = tbb_allocator<iterator_value_t<InputIterator>>>
concurrent_unordered_set( InputIterator, InputIterator,
                          map_size_type = /*implementation_defined*/,
                          Hash = Hash(), KeyEqual = KeyEqual(),
                          Allocator = Allocator() )
-> concurrent_unordered_set<iterator_value_t<InputIterator>,
                            Hash, KeyEqual, Allocator>;

template <typename InputIterator,
          typename Allocator>
concurrent_unordered_set( InputIterator, InputIterator,
                          map_size_type,
                          Allocator )
-> concurrent_unordered_set<iterator_value_t<InputIterator>,
                            std::hash<iterator_value_t<InputIterator>>,
                            std::equal_to<iterator_value_t<InputIterator>>,
                            Allocator>;

template <typename InputIterator,
          typename Allocator>
concurrent_unordered_set( InputIterator, InputIterator, Allocator )
-> concurrent_unordered_set<iterator_value_t<InputIterator>,
                            std::hash<iterator_value_t<InputIterator>>,
                            std::equal_to<iterator_key_t<InputIterator>>,
                            Allocator>;

template <typename InputIterator,
          typename Hash,
          typename Allocator>
concurrent_unordered_set( InputIterator, InputIterator,
                          Hash, Allocator )
-> concurrent_unordered_set<iterator_value_t<InputIterator>,
                            Hash,
                            std::equal_to<iterator_value_t<InputIterator>>,
                            Allocator>;

template <typename T,
          typename Hash = std::hash<Key>,
          typename KeyEqual = std::equal_to<Key>,
          typename Allocator = tbb_allocator<std::pair<Key, T>>>
concurrent_unordered_set( std::initializer_list<value_type>,
                          map_size_type = /*implementation-defined*/,
                          Hash = Hash(),
                          KeyEqual = KeyEqual(),
                          Allocator = Allocator() )
-> concurrent_unordered_set<T,
                            Hash,
                            KeyEqual,
                            Allocator>;

template <typename T,
          typename Allocator>
concurrent_unordered_set( std::initializer_list<value_type>,
                          map_size_type, Allocator )
-> concurrent_unordered_set<T,
                            std::hash<Key>,
                            std::equal_to<Key>,
                            Allocator>;

template <typename T,
          typename Hash,
          typename Allocator>
concurrent_unordered_set( std::initializer_list<value_type>,
                          map_size_type, Hash, Allocator )
-> concurrent_unordered_set<T,
                            Hash,
                            std::equal_to<Key>,
                            Allocator>;

Where the type map_size_type refers to the size_type member type of the deduced concurrent_unordered_set and the type alias iterator_value_t is defined as follows:

template <typename InputIterator>
using iterator_value_t = typename std::iterator_traits<InputIterator>::value_type;

Example

#include <tbb/concurrent_unordered_set.h>
#include <vector>
#include <functional>

struct CustomHasher {...};

int main() {
    std::vector<int> v;

    // Deduces s1 as concurrent_unordered_set<int>
    tbb::concurrent_unordered_set s1(v.begin(), v.end());

    // Deduces s2 as concurrent_unordered_set<int, CustomHasher>;
    tbb::concurrent_unordered_set s2(v.begin(), v.end(), CustomHasher{});
}