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

value::emplace_null

`value::emplace_null`

Replace with a null value.

void
emplace_null() noexcept;

The current value is destroyed and the kind is changed to kind::null. The associated memeory resource is kept unchanged.

Linear in the size of *this.

No-throw guarantee.