...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_const : public true_type-or-false_type
{};
Inherits: If T is a (top level) const-qualified type then inherits from true_type, otherwise inherits from false_type.
C++ Standard Reference: 3.9.3.
Header: #include
<boost/type_traits/is_const.hpp>
or #include <boost/type_traits.hpp>
Compiler Compatibility: All current compilers are supported by this trait.
Examples:
is_const<int const>
inherits fromtrue_type
.
is_const<int const volatile>::type
is the typetrue_type
.
is_const<int* const>::value
is an integral constant expression that evaluates to true.
is_const<int const*>::value
is an integral constant expression that evaluates to false: the const-qualifier is not at the top level in this case.
is_const<int const&>::value
is an integral constant expression that evaluates to false: the const-qualifier is not at the top level in this case.
is_const<int>::value
is an integral constant expression that evaluates to false.
is_const<T>::value_type
is the typebool
.