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
Retrieves a reference to the underlying std::string
value (unchecked access).
const std::string& get_string() const noexcept;
this->is_string()
== true
(if violated, results in undefined behavior).
No-throw guarantee.
The returned reference is valid as long as *this is alive and no function that invalidates
references is called on *this.