23 Containers library [containers]

23.2 Requirements [container.requirements]

23.2.1 Preamble [container.requirements.pre]

1
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Containers are objects that store other objects.
They control allocation and deallocation of these objects through constructors, destructors, insert and erase operations.
2
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All of the complexity requirements in this Clause are stated solely in terms of the number of operations on the contained objects.
[Example 1: 
The copy constructor of type vector<vector<int>> has linear complexity, even though the complexity of copying each contained vector<int> is itself linear.
— end example]
3
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Allocator-aware containers ([container.alloc.reqmts]) other than basic_string construct elements using the function allocator_traits<allocator_type>​::​rebind_traits<U>​::​​construct and destroy elements using the function allocator_traits<allocator_type>​::​rebind_traits<U>​::​​destroy ([allocator.traits.members]), where U is either allocator_type​::​value_type or an internal type used by the container.
These functions are called only for the container's element type, not for internal types used by the container.
[Note 1: 
This means, for example, that a node-based container would need to construct nodes containing aligned buffers and call construct to place the element into the buffer.
— end note]