| Home | Libraries | People | FAQ | More

### has_trivial_destructor

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

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

If a type has a trivial destructor then the destructor has no effect: calls to the destructor can be safely omitted. Note that using meta-programming to omit a call to a single trivial-constructor call is of no benefit whatsoever. However, if loops and/or exception handling code can also be omitted, then some benefit in terms of code size and speed can be obtained.

Compiler Compatibility: Without some (as yet unspecified) help from the compiler, has_trivial_destructor will never report that a user-defined class or struct has a trivial destructor; this is always safe, if possibly sub-optimal. In addition, in order to correctly handle deleted or private destructors then support for C++11's `decltype` is required. Currently (June 2015) compilers more recent than Visual C++ 8, 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_HAS_TRIVIAL_DESTRUCTOR` is defined.

C++ Standard Reference: 12.4p3.

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

Examples:

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

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

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

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

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