is_pod Class

2018-01-02

The latest version of this topic can be found at is_pod Class.

Tests if type is POD.

Syntax

template <class Ty>
struct is_pod;

Parameters

Ty
The type to query.

Remarks

is_pod<Ty>::value is true if the type Ty is Plain Old Data (POD). Otherwise it is false.

Arithmetic types, enumeration types, pointer types, and pointer to member types are POD.

A cv-qualified version of a POD type is itself a POD type.

An array of POD is itself POD.

A struct or union, all of whose non-static data members are POD, is itself POD if it has:

No user-declared constructors.
No private or protected non-static data members.
No base classes.
No virtual functions.
No non-static data members of reference type.
No user-defined copy assignment operator.
No user-defined destructor.

Therefore, you can recursively build POD structs and arrays that contain POD structs and arrays.

Example

// std_tr1__type_traits__is_pod.cpp   
// compile with: /EHsc   
#include <type_traits>   
#include <iostream>   
  
struct trivial   
    {   
    int val;   
    };   
  
struct throws   
    {   
    throws() throw(int)   
        {   
        }   
  
    throws(const throws&) throw(int)   
        {   
        }   
  
    throws& operator=(const throws&) throw(int)   
        {   
        }   
  
    int val;   
    };   
  
int main()   
    {   
    std::cout << "is_pod<trivial> == " << std::boolalpha   
        << std::is_pod<trivial>::value << std::endl;   
    std::cout << "is_pod<int> == " << std::boolalpha   
        << std::is_pod<int>::value << std::endl;   
    std::cout << "is_pod<throws> == " << std::boolalpha   
        << std::is_pod<throws>::value << std::endl;   
  
    return (0);   
    }   
    /* Output:  
    is_pod<trivial> == true  
is_pod<int> == true  
is_pod<throws> == false  
*/

Requirements

Header: <type_traits>

Namespace: std

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