template <class T>
struct add_lvalue_reference
{
   typedef see-below type;
};

type: If T names an object or function type then the member typedef type shall name T&; otherwise, if T names a type rvalue reference to U then the member typedef type shall name U&; otherwise, type shall name T.

C++ Standard Reference: 20.7.6.2.

Compiler Compatibility: If the compiler does not support partial specialization of class-templates then this template will compile, but the member type will always be the same as type T except where compiler workarounds have been applied.

Header: #include <boost/type_traits/add_lvalue_reference.hpp> or #include <boost/type_traits.hpp>