...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Determine whether the address is unspecified.
bool is_unspecified() const;
This function tests whether the address is the unspecified address 0.0.0.0
.
to_uint()
== 0
.