deduction guides for std::vector
Defined in header <vector>
|
||
|
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
{
}
)
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_containers_ranges |
202202L |
(C++23) | Ranges-aware construction and insertion; overload (2) |
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()}; }