Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
template <class T>
struct is_class : public true_type-or-false_type {};
Inherits: If T is a (possibly cv-qualified) class type (and not a union type) then inherits from true_type, otherwise inherits from false_type.
C++ Standard Reference: 3.9.2 and 9.2.
Header: #include
<boost/type_traits/is_class.hpp>
or #include <boost/type_traits.hpp>
Compiler Compatibility: This trait works
correctly for almost all current compilers (as of June 2015), with just a
minority of older compilers not correctly detecting all the corner cases.
You can check the macro BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION
which is defined to 1 when the class works correctly in all cases.
Examples:
Given:
class MyClass;then:
is_class<MyClass>inherits fromtrue_type.
is_class<MyClass const>::typeis the typetrue_type.
is_class<MyClass>::valueis an integral constant expression that evaluates to true.
is_class<MyClass&>::valueis an integral constant expression that evaluates to false.
is_class<MyClass*>::valueis an integral constant expression that evaluates to false.
is_class<T>::value_typeis the typebool.