< cpp‎ | types
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Type support
Basic types
Fundamental types
Fixed width integer types (C++11)
Numeric limits
C numeric limits interface
Runtime type information
Type traits
Primary type categories
Type properties
Supported operations
Relationships and property queries
Type modifications
Type transformations
Type trait constants

Template:ddcl list begin <tr class="t-dsc-header">

Defined in header <type_traits>

<td></td> <td></td> <tr class="t-dcl-sep"><td></td><td></td><td></td></tr>

<tr class="t-dcl ">

<td >
template< class T >
struct is_trivially_copyable;

<td class="t-dcl-nopad"> </td> <td > (since C++11) </td> </tr> Template:ddcl list end

If T is a trivially copyable type, provides the member constant value equal true. For any other type, value is false.

The only trivially copyable types are scalar types, trivially copyable classes, and arrays of such types/classes (possibly cv-qualified).

A trivially copyable class is a class that

1. Has no non-trivial copy constructors (this also requires no virtual functions or virtual bases)

2. Has no non-trivial move constructors

3. Has no non-trivial copy assignment operators

4. Has no non-trivial move assignment operators

5. Has a trivial destructor


Inherited from std::integral_constant

Member constants

true if T is a trivially copyable type , false otherwise
(public static member constant)

Member functions

operator bool
converts the object to bool, returns value
(public member function)

Member types

Type Definition
value_type bool
type std::integral_constant<bool, value>


Objects of trivially-copyable types are the only C++ objects that may be safely copied with std::memcpy or serialized to/from binary files with std::ofstream::write()/std::ifstream::read(). In general, a trivially copyable type is any type for which the underlying bytes can be copied to an array of char or unsigned char and into a new object of the same type, and the resulting object would have the same value as the original.


#include <iostream>
#include <type_traits>
struct A {
    int m;
struct B {
    B(const B&) {}
struct C {
    virtual void foo();
int main()
    std::cout << std::boolalpha;
    std::cout << std::is_trivially_copyable<A>::value << '\n';
    std::cout << std::is_trivially_copyable<B>::value << '\n';
    std::cout << std::is_trivially_copyable<C>::value << '\n';