[#BloombergLP-bslma-UsesBslmaAllocator_Sniff-0d]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslma.adoc[bslma]::UsesBslmaAllocator_Sniff
:relfileprefix: ../../
:mrdocs:

This class has a constant `value` that is `true` if the specified `TYPE` is implicitly convertible from `bslma::Allocator *`. It thus "sniffs" whether `UsesBslmaAllocator<TYPE>::value` should be `true`. If the specified `BYPASS` parameter is `true`, the conversion check is skipped and `value` is hard‐coded to `true`. The bypass is needed because the xlC compiler will sometimes instantiate the copy constructor for `TYPE`, leading to compilation errors if `TYPE` is not copy constructible. This automatic sniffing is deprecated; having a type implicitly convertible from an allocator pointer is discouraged.

== Synopsis

Declared in `<bslma_usesbslmaallocator.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class TYPE,
    bool BYPASS>
struct UsesBslmaAllocator_Sniff;
----

== Enums

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/UsesBslmaAllocator_Sniff-0d/_04enum.adoc[`Unnamed enum`] 
| Public constants.
|===


== Specializations

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/UsesBslmaAllocator_Sniff-0e.adoc[`UsesBslmaAllocator_Sniff<TYPE, true>`] 
| Specialization of `UsesBslmaAllocator_Sniff` for which `BYPASS` is `true`.
|===



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