Type tag for types that take a bslma::Allocator* as the second argument of their constructors, following an argument of type bsl::allocator_arg_t.
bslma::Allocator*
bsl::allocator_arg_t
Declared in <bslstl_pair.h>
<bslstl_pair.h>
typedef bsl::integral_constant<int, 2> Pair_BslmaIdiomAllocatorArgT;