template<class FUNC>
struct bslstl::Function_InvokerUtilNullCheck< FUNC >
Provides an isNull
static method that that returns whether or not its argument is "null", i.e., it cannot be invoked. For must FUNC
types isNull
always returns false
as every instance of FUNC
is invocable. However, specializations of this class, especially for pointer types, have isNull
functions that sometimes return true
. This class is a customization point: types outside of this component can (but rarely should) specialize this template. In particular, bslstl_function contains a specialization for bsl::function
.