| Home | Libraries | People | FAQ | More

### is_pod

    template <class T>
    struct is_pod : public true_type-or-false_type {};

Inherits: If T is a (possibly cv-qualified) POD type then inherits from true_type, otherwise inherits from false_type.

POD stands for "Plain old data". Arithmetic types, and enumeration types, a pointers and pointer to members are all PODs. Classes and unions can also be POD's if they have no non-static data members that are of reference or non-POD type, no user defined constructors, no user defined assignment operators, no private or protected non-static data members, no virtual functions and no base classes. Finally, a cv-qualified POD is still a POD, as is an array of PODs.

C++ Standard Reference: 3.9p10 and 9p4 (Note that POD's are also aggregates, see 8.5.1).

Compiler Compatibility: Without some (as yet unspecified) help from the compiler, is_pod will never report that a class or struct is a POD; this is always safe, if possibly sub-optimal. Currently (June 2015) compilers more recent than Visual C++ 8, Clang-3, GCC-4.3, Greenhills 6.0, Intel-11.0, and Codegear have the necessary compiler intrinsics to ensure that this trait "just works". You may also test to see if the necessary intrinsics are available by checking to see if the macro `BOOST_IS_POD` is defined.

Header: `#include <boost/type_traits/is_pod.hpp>` or `#include <boost/type_traits.hpp>`

Examples:

> `is_pod<int>` inherits from `true_type`.

> `is_pod<char*>::type` is the type `true_type`.

> `is_pod<int (*)(long)>::value` is an integral constant expression that evaluates to true.

> `is_pod<MyClass>::value` is an integral constant expression that evaluates to false.

> `is_pod<T>::value_type` is the type `bool`.