# deduction guides for `std::flat_set`

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< cpp‎ | container‎ | flat set

Defined in header `<flat_set>` |  |
template< class KeyContainer, class Compare = std::less <typename KeyContainer::value_type> > flat_set( KeyContainer, Compare = Compare() ) -> flat_set<typename KeyContainer::value_type, Compare, KeyContainer>; | (1) | (since C++23)
template< class KeyContainer, class Allocator > flat_set( KeyContainer, Allocator ) -> flat_set<typename KeyContainer::value_type, std::less <typename KeyContainer::value_type>, KeyContainer>; | (2) | (since C++23)
template< class KeyContainer, class Compare, class Allocator > flat_set( KeyContainer, Compare, Allocator ) -> flat_set<typename KeyContainer::value_type, Compare, KeyContainer>; | (3) | (since C++23)
template< class KeyContainer, class Compare = std::less <typename KeyContainer::value_type> > flat_set( std::sorted_unique_t, KeyContainer, Compare = Compare() ) -> flat_set<typename KeyContainer::value_type, Compare, KeyContainer>; | (4) | (since C++23)
template< class KeyContainer, class Allocator > flat_set( std::sorted_unique_t, KeyContainer, Allocator ) -> flat_set<typename KeyContainer::value_type, std::less <typename KeyContainer::value_type>, KeyContainer>; | (5) | (since C++23)
template< class KeyContainer, class Compare, class Allocator > flat_set( std::sorted_unique_t, KeyContainer, Compare, Allocator ) -> flat_set<typename KeyContainer::value_type, Compare, KeyContainer>; | (6) | (since C++23)
template< class InputIter, class Compare = std::less </*iter-value-type*/<InputIter>> > flat_set( InputIter, InputIter, Compare = Compare() ) -> flat_set</*iter-value-type*/<InputIter>, Compare>; | (7) | (since C++23)
template< class InputIter, class Compare = std::less </*iter-value-type*/<InputIter>> > flat_set( std::sorted_unique_t, InputIter, InputIter, Compare = Compare() ) -> flat_set</*iter-value-type*/<InputIter>, Compare>; | (8) | (since C++23)

template< ranges::input_range R,

class Compare = std::less < ranges::range_value_t <R>>,
class Allocator = std::allocator < ranges::range_value_t <R>> >
flat_set( std::from_range_t, R&&, Compare = Compare(), Allocator = Allocator() )
-> flat_set< ranges::range_value_t <R>, Compare,
std::vector < ranges::range_value_t <R>,

/*alloc-rebind*/<Allocator, ranges::range_value_t <R>>>>;

(9)

(since C++23)

template< ranges::input_range R, class Allocator > flat_set( std::from_range_t, R&&, Allocator ) -> flat_set< ranges::range_value_t <R>, std::less < ranges::range_value_t <R>>, std::vector < ranges::range_value_t <R>, /*alloc-rebind*/<Allocator, ranges::range_value_t <R>>>>; | (10) | (since C++23)
template< class Key, class Compare = std::less <Key> > flat_set( std::initializer_list <Key>, Compare = Compare() ) -> flat_set<Key, Compare>; | (11) | (since C++23)
template< class Key, class Compare = std::less <Key> > flat_set( std::sorted_unique_t, std::initializer_list <Key>, Compare = Compare() ) -> flat_set<Key, Compare>; | (12) | (since C++23)

These deduction guides are provided for `` to allow deduction from:

1) A container and a comparator.
2) A container and an allocator.
3) A container, a comparator and an allocator.
4) The std::sorted_unique_t tag, a container and a comparator.
5) The std::sorted_unique_t tag, a container and an allocator.
6) The std::sorted_unique_t tag, a container, a comparator and an allocator.
7) An iterator range and a comparator.
8) The std::sorted_unique_t tag, an iterator range and a comparator.
9) The std::from_range_t tag, an `input_range` range, a comparator and an allocator.
10) The std::from_range_t tag, an `input_range` range and an allocator.
11) The std::initializer_list and a comparator.
12) The std::sorted_unique_t tag, the std::initializer_list and a comparator.

These overloads participate in overload resolution only 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

| This section is incomplete Reason: no example

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