std::is_compound
Defined in header <type_traits> |
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|---|---|---|
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(since C++11) |
std::is_compound is a UnaryTypeTrait.
If T is a compound type (that is, array, function, object pointer, function pointer, member object pointer, member function pointer, reference, class, union, or enumeration, including any cv-qualified variants), provides the member constant value equal true. For any other type, value is false.
The behavior of a program that adds specializations for std::is_compound or std::is_compound_v is undefined.
Template parameters
| T | - | a type to check |
Helper variable template
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(since C++17) |
Inherited from std::integral_constant
Member constants
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value
[static]
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true if T is a compound type, false otherwise (public static member constant) |
Member functions
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operator bool
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converts the object to bool, returns value (public member function) |
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operator()
(C++14)
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returns value (public member function) |
Member types
| Type | Definition |
|---|---|
value_type |
bool |
type |
std::integral_constant<bool, value> |
Notes
Compound types are the types that are constructed from fundamental types. Any C++ type is either fundamental or compound.
Possible implementation
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Example
#include <type_traits>
static_assert(not std::is_compound_v<int>);
static_assert(std::is_compound_v<int*>);
static_assert(std::is_compound_v<int&>);
void f();
static_assert(std::is_compound_v<decltype(f)>);
static_assert(std::is_compound_v<decltype(&f)>);
static_assert(std::is_compound_v<char['a']>);
class C {};
static_assert(std::is_compound_v<C>);
union U {};
static_assert(std::is_compound_v<U>);
enum struct E { e };
static_assert(std::is_compound_v<E>);
static_assert(std::is_compound_v<decltype(E::e)>);
struct S
{
int i : 8;
int j;
void foo();
};
static_assert(not std::is_compound_v<decltype(S::i)>);
static_assert(not std::is_compound_v<decltype(S::j)>);
static_assert(std::is_compound_v<decltype(&S::j)>);
static_assert(std::is_compound_v<decltype(&S::foo)>);
int main() {}See also
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(C++11)
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checks if a type is a fundamental type (class template) |
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(C++11)
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checks if a type is a scalar type (class template) |
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(C++11)
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checks if a type is an object type (class template) |
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(C++11)
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checks if a type is an array type (class template) |
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https://en.cppreference.com/w/cpp/types/is_compound