std::uninitialized_default_construct (3) - Linux Manuals
Defined in header <memory>
template< class ForwardIt > (1) (since C++17)
void uninitialized_default_construct( ForwardIt first, ForwardIt last);
template< class ExecutionPolicy, class ForwardIt > (2) (since C++17)
void uninitialized_default_construct( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last );
1) Constructs objects of type typename iterator_traits<ForwardIt>::value_type in the uninitialized storage designated by the range [first, last) by default-initialization, as if by
If an exception is thrown during the initialization, the objects already constructed are destroyed in an unspecified order.
2) Same as (1), but executed according to policy. This overload does not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true
ForwardIt must meet the requirements of LegacyForwardIterator.
No increment, assignment, comparison, or indirection through valid instances of ForwardIt may throw exceptions.
Linear in the distance between first and last
The overload with a template parameter named ExecutionPolicy reports errors as follows:
* If execution of a function invoked as part of the algorithm throws an exception and ExecutionPolicy is one of the standard_policies, std::terminate is called. For any other ExecutionPolicy, the behavior is implementation-defined.
* If the algorithm fails to allocate memory, std::bad_alloc is thrown.
This section is incomplete
Reason: no example
uninitialized_default_construct_n constructs objects by default-initialization in an uninitialized area of memory, defined by a start and a count
uninitialized_value_construct constructs objects by value-initialization in an uninitialized area of memory, defined by a range