deduction guides for std::vector
<vector>
class Alloc = std::allocator <
typename std::iterator_traits <InputIt>::value_type> >
vector( InputIt, InputIt, Alloc = Alloc() )
class Alloc = std::allocator <ranges::range_value_t <R>> >
vector( std::from_range_t, R&&, Alloc = Alloc() )
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 <vector> int main() { std::vector <int> v = {1, 2, 3, 4}; // uses explicit deduction guide to deduce std::vector<int> std::vector x(v.begin(), v.end()); // deduces std::vector<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::vector y{v.begin(), v.end()}; }