Boost C++ Libraries

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

This is an older version of Boost and was released in 2017. The current version is 1.90.0.

Header <boost/optional/optional_fwd.hpp>

Header <boost/optional/optional_fwd.hpp>

Synopsis

namespace boost {

template <class T> class optional ;

template <class T> void swap ( optional<T>& , optional<T>& );

template <class T> struct optional_swap_should_use_default_constructor ;

} // namespace boost

This header only contains declarations.