std::deque<T,Allocator>::clear (3) - Linux Man Pages
void clear(); (until C++11)
void clear() noexcept; (since C++11)
Erases all elements from the container. After this call, size() returns zero.
Invalidates any references, pointers, or iterators referring to contained elements. Any past-the-end iterators are also invalidated.
Linear in the size of the container, i.e., the number of elements.
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR Applied to Behavior as published Correct behavior
LWG_2231 C++11 complexity guarantee was mistakenly omitted in C++11 complexity reaffirmed as linear
erase (public member function)