This metafunction yields bsl::true_type if the specified template-parameter TYPE has a nested type named allocator_type that meets the requirements for a C++11 allocator, and bsl::false_type otherwise. This primary template, yielding false_type, is instantiated for types for which allocator_type does not exist or is not an allocator type. Note that instantiation will fail if allocator_type exists but is not public within TYPE or if any of the required members of TYPE::allocator_type exist but are not public (though only value_type and allocate are tested at present).
Declared in <bslma_hasallocatortype.h>
template<
class TYPE,
class = void>
struct HasAllocatorType
: bsl::false_type| Name | Description |
|---|---|
bsl::false_type | Metafunction representing the boolean constant false. |
| Name | Description |
|---|---|
HasAllocatorType<TYPE, bsl::void_t<TYPE::allocator_type>> | Partial specialization of HasAllocatorType yielding true_type is instantiated for TYPEs that do have an allocator_type member that meets the requirements of a C++11 allocator type. |