Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for a snapshot of the master branch, built from commit 3768da8c7d.


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

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

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

These two traits are synonyms for each other.

If a type has a trivial copy-constructor then the constructor has the same effect as copying the bits of one object to the other: calls to the constructor can be safely replaced with a call to memcpy.

Compiler Compatibility: Without some (as yet unspecified) help from the compiler, has_trivial_copy will never report that a user-defined class or struct has a trivial constructor; this is always safe, if possibly sub-optimal. In addition, in order to correctly handle deleted or private copy-constructors then C++11's dectype is required. Currently (May 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_COPY is defined.

C++ Standard Reference: 12.8p6.

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


has_trivial_copy<int> inherits from true_type.

has_trivial_copy<char*>::type is the type true_type.

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

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

has_trivial_copy<T>::value_type is the type bool.