deduction guides for std::list
Defined in header <list>
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template< class InputIt, class Alloc = std::allocator< |
(1) | (since C++17) |
template< ranges::input_range R, class Alloc = std::allocator<ranges::range_value_t<R>> > |
(2) | (since C++23) |
InputIt
satisfies LegacyInputIterator and Alloc
satisfies Allocator.input_range
.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.
[edit] Notes
Feature-test macro | Value | Std | Feature |
---|---|---|---|
__cpp_lib_containers_ranges |
202202L |
(C++23) | Ranges-aware construction and insertion; overload (2) |
[edit] Example
#include <list> #include <vector> int main() { std::vector<int> v = {1, 2, 3, 4}; // uses explicit deduction guide to deduce std::list<int> std::list x(v.begin(), v.end()); // deduces std::list<std::vector<int>::iterator> // first phase of overload resolution for list-initialization selects the candidate // synthesized from the initializer-list constructor; second phase is not performed // and deduction guide has no effect std::list y{v.begin(), v.end()}; }