Specifies that an instance of the type can be default-constructed in-place by a given allocator.
The type T
is DefaultInsertable into the Container X
whose value_type
is identical to T
if, given.
A | an allocator type |
m | an lvalue of type A |
p | the pointer of type T* prepared by the container |
where X::allocator_type
is identical to std::allocator_traits<A>::rebind_alloc<T>
,
the following expression is well-formed:
std::allocator_traits<A>::construct(m, p);
If X
is not allocator-aware, the term is defined as if A
were std::allocator<T>
, except that no allocator object needs to be created, and user-defined specializations of std::allocator
are not instantiated.
By default, this will call placement-new, as by ::new((void*)p) T()
(that is, value-initialize the object pointed to by p
). If value-initialization is undesirable, for example, if the object is of non-class type and zeroing out is not needed, it can be avoided by providing a custom Allocator::construct.
DefaultConstructible | |
CopyInsertable | |
MoveInsertable | |
EmplaceConstructible | |
Erasable |
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