BloombergLP::bslma::AAModelIsSupported

Predicate metafunction that determines if the specified TYPE supports the specified MODEL AA model. It yields (i.e., is derived from) bsl:true_type if type TYPE supports AA model MODEL; otherwise it yields false_type. MODEL Must be one of AAModelNone, AAModelLegacy, AAModelBsl, AAModelPmr, or AAModelStl. This metafunction can yield true_type for more than one type MODEL type, e.g., it will yield true_type if TYPE is bsl-AA, and MODEL is either AAModelBsl or AAModelLegacy, since TYPE can be constructed with either allocator type.

Synopsis

Declared in <bslma_aamodel.h>

template<
    class TYPE,
    class MODEL>
struct AAModelIsSupported
    : bsl::false_type

Base Classes

Name	Description
`bsl::false_type`	Metafunction representing the boolean constant `false`.

Specializations

Name	Description
`AAModelIsSupported<TYPE, AAModelBsl>`	Specialization of `AAModelIsSupported` for `MODEL == AAModelBsl`, yielding `true_type` if `TYPE::allocator_type` exists and is convertible from `bsl::allocator<char>`.
`AAModelIsSupported<TYPE, AAModelLegacy>`	Specialization of `AAModelIsSupported` for `MODEL == AAModelStl`, yielding `true_type` if `TYPE` can use `bslma::Allocator ` as its memory resource. Specifically, it is true if `UsesBslmaAllocator<TYPE>` is true or if `TYPE::allocator_type` exists and is convertible from `bslma::Allocator `.
`AAModelIsSupported<TYPE, AAModelNone>`	Specialization of `AAModelIsSupported` for `MODEL == AAModelNone`, always yielding `true_type`.
`AAModelIsSupported<TYPE, AAModelPmr>`	Specialization of `AAModelIsSupported` for `MODEL == AAModelPmr`, yielding `true_type` if `TYPE::allocator_type` exists and is convertible from `bsl::polymorphic_allocator<char>`.
`AAModelIsSupported<TYPE, AAModelStl>`	Specialization of `AAModelIsSupported` for `MODEL == AAModelStl`, yielding `true_type` if `TYPE::allocator_type` exists; otherwise, yielding `false_type` unless `AAModelIsSupported<TYPE, AAModelBsl>` is true. The latter condition exists so that bsl-AA always implies stl-AA even if `AAModelIsSupported<TYPE, AAModelBsl>` is explicitly specialized to true for a type that does not have an `allocator_type` member.