20 General utilities library [utilities]

20.11 Smart pointers [smartptr]

20.11.4 Class template weak_­ptr [util.smartptr.weak]

20.11.4.5 Modifiers [util.smartptr.weak.mod]

void swap(weak_ptr& r) noexcept;
Effects: Exchanges the contents of *this and r.
void reset() noexcept;
Effects: Equivalent to weak_­ptr().swap(*this).