std::is_pointer
From cppreference.com
Defined in header
<type_traits>
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||
template< class T >
struct is_pointer; |
(since C++11) | |
Checks whether T
is a pointer to object or a pointer to function (but not a pointer to member/member function). Provides the member constant value
which is equal to true, if T
is a object/function pointer type. Otherwise, value
is equal to false.
Contents |
[edit] Template parameters
T | - | a type to check |
Inherited from std::integral_constant
Member constants
value
[static]
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true if T is a pointer type , false otherwise (public static member constant) |
Member functions
operator bool |
converts the object to bool, returns value (public member function) |
operator()
(C++14)
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returns value (public member function) |
Member types
Type | Definition |
value_type
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bool
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type
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std::integral_constant<bool, value> |
[edit] Possible implementation
template< class T > struct is_pointer_helper : std::false_type {}; template< class T > struct is_pointer_helper<T*> : std::true_type {}; template< class T > struct is_pointer : is_pointer_helper<typename std::remove_cv<T>::type> {}; |
[edit] Example
Run this code
#include <iostream> #include <type_traits> class A {}; int main() { std::cout << std::boolalpha; std::cout << std::is_pointer<A>::value << '\n'; std::cout << std::is_pointer<A *>::value << '\n'; std::cout << std::is_pointer<A &>::value << '\n'; std::cout << std::is_pointer<int>::value << '\n'; std::cout << std::is_pointer<int *>::value << '\n'; std::cout << std::is_pointer<int **>::value << '\n'; std::cout << std::is_pointer<int[10]>::value << '\n'; std::cout << std::is_pointer<std::nullptr_t>::value << '\n'; }
Output:
false true false false true true false false
[edit] See also
(C++11)
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checks if a type is a pointer to a non-static member function or object (class template) |
(C++11)
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checks if a type is a pointer to a non-static member object (class template) |
(C++11)
|
checks if a type is a pointer to a non-static member function (class template) |
(C++11)
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checks if a type is an array type (class template) |
(C++11)
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checks if a type is scalar type (class template) |
(library fundamentals TS)
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variable template alias of std::is_pointer::value (variable template) |