Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for an old version of Boost. Click here to view this page for the latest version.


template <class T>
struct is_final : public true_type-or-false_type {};

Inherits: If T is a (possibly cv-qualified) class type declared with the final specifier type then inherits from true_type, otherwise inherits from false_type. Currently requires some kind of compiler support.

C++ Standard Reference: 9p3.

Compiler Compatibility: Without (some as yet unspecified) help from the compiler, we cannot detect class types declared with the final specifier using only standard C++, as a result this type will never inherit from true_type, unless the user explicitly specializes the template for their user-defined final class types, or unless the compiler supplies some unspecified intrinsic that implements this functionality. Currently (Aug 2014) compilers more recent than GCC-4.7, and Clang have the necessary compiler intrinsics to ensure that this trait "just works". You may also test to see if the necessary intrinsics are available by checking to see if the macro BOOST_IS_FINAL is defined.

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


Given struct my_final final {}; then:

is_final<my_final> inherits from true_type.

is_final<const my_final>::type is the type true_type.

is_final<my_final>::value is an integral constant expression that evaluates to true.

is_final<my_final*>::value is an integral constant expression that evaluates to false.

is_final<T>::value_type is the type bool.