bsl::allocator_traits<std::allocator<ALLOCATOR_TYPE>>

Synopsis

Declared in <bslma_allocatortraits.h>

template<class ALLOCATOR_TYPE>
struct allocator_traits<std::allocator<ALLOCATOR_TYPE>>;

Description

Since C++17 many of the std::allocator members are deprecated (and removed in C++20). C++23 deprecates type name members and C++26 removes them. The clang compiler on Darwin warns about any mention of those names in C++17 so this header file was producing many warnings. The specialization below "disconnects" the allocator traits of std::allocator from our own implementation and so it avoids not only warnings but possible other hassles as the std::allocator interface is morphing.

Note that we are using the standard traits (in place of ours) only on C++17 or later compilers and not C++11 (when std::allocator_traits appeared). The reason for this is that our bsl::allocator_traits supports allocator_traits::is_always_equal from C++17 in a backwards compatible manner so we cannot use pre-C++17 standard implementation that does not have that.

Type Aliases

Name	Description
`rebind_alloc`	Alias template that rebinds the allocator to `ELEMENT_TYPE`.
`rebind_traits`	`allocator_traits` for an allocator rebound to `ELEMENT_TYPE`.

Using Declarations

Name	Description
`allocate`	Allocate uninitialized storage for `n` objects, optionally using `hint`.
`allocator_type`	This `typedef` is an alias to `std::allocator<ALLOCATOR_TYPE>`.
`const_pointer`	This `typedef` is an alias to `allocator_type::const_pointer`.
`const_void_pointer`	This `typedef` is an alias to `allocator_type::const_void_pointer`.
`construct`	Construct an object at the specified uninitialized address.
`deallocate`	Deallocate the storage at `p` for `n` objects.
`destroy`	Destroy the object at the specified address.
`difference_type`	This `typedef` is an alias to `allocator_type::difference_type`.
`is_always_equal`	`true_type` if two allocators always compare equal; else `false_type`.
`max_size`	Return the maximum number of objects `allocate` can return.
`pointer`	This `typedef` is an alias to `allocator_type::pointer`.
`propagate_on_container_copy_assignment`	`true_type` if the allocator propagates on copy assignment.
`propagate_on_container_move_assignment`	`true_type` if the allocator propagates on move assignment.
`propagate_on_container_swap`	`true_type` if the allocator propagates on container swap.
`select_on_container_copy_construction`	Return the allocator to use when copy-constructing a container.
`size_type`	This `typedef` is an alias to `allocator_type::size_type`.
`value_type`	This `typedef` is an alias to `allocator_type::value_type`.
`void_pointer`	This `typedef` is an alias to `allocator_type::void_pointer`.