deduction guides for std::set

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

priority_queue

span (C++20)

 

std::set

Member functions

set::set

set::~set

set::operator=

set::get_allocator

Iterators

set::beginset::cbegin (C++11)

set::endset::cend (C++11)

set::rbeginset::crbegin (C++11)

set::rendset::crend (C++11)

Capacity

set::empty

set::size

set::max_size

Modifiers

set::clear

set::insert

set::emplace (C++11)

set::emplace_hint (C++11)

set::erase

set::swap

set::extract (C++17)

set::merge (C++17)

Lookup

set::count

set::find

set::contains (C++20)

set::equal_range

set::lower_bound

set::upper_bound

Observers

set::key_comp

set::value_comp

Deduction guides(C++17)

 

Defined in header <set>
template<class InputIt,          class Comp = std::less<typename std::iterator_traits<InputIt>::value_type>,          class Alloc = std::allocator<typename std::iterator_traits<InputIt>::value_type>> set(InputIt, InputIt, Comp = Comp(), Alloc = Alloc())   -> set<typename std::iterator_traits<InputIt>::value_type, Comp, Alloc>;	(1)	(since C++17)
template<class Key, class Comp = std::less<Key>, class Alloc = std::allocator<Key>> set(std::initializer_list<Key>, Comp = Comp(), Alloc = Alloc())   -> set<Key, Comp, Alloc>;	(2)	(since C++17)
template<class InputIt, class Alloc> set(InputIt, InputIt, Alloc)   -> set<typename std::iterator_traits<InputIt>::value_type,            std::less<typename std::iterator_traits<InputIt>::value_type>, Alloc>;	(3)	(since C++17)
template<class Key, class Alloc> set(std::initializer_list<Key>, Alloc)   -> set<Key, std::less<Key>, Alloc>;	(4)	(since C++17)

These deduction guides are provided for set to allow deduction from an iterator range (overloads (1,3)) and std::initializer_list (overloads (2,4)). These overloads only participate in overload resolution if InputIt satisfies LegacyInputIterator, Alloc satisfies Allocator, and Comp does not satisfy Allocator.

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.

Example

Run this code

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