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756. Container adaptors push

Section: 23.6 [container.adaptors] Status: Resolved Submitter: Paolo Carlini Opened: 2007-10-31 Last modified: 2016-01-28

Priority: Not Prioritized

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Discussion:

After n2369 we have a single push_back overload in the sequence containers, of the "emplace" type. At variance with that, still in n2461, we have two separate overloads, the C++03 one + one taking an rvalue reference in the container adaptors. Therefore, simply from a consistency point of view, I was wondering whether the container adaptors should be aligned with the specifications of the sequence container themselves: thus have a single push along the lines:

template<typename... _Args>
void
push(_Args&&... __args)
  { c.push_back(std::forward<_Args>(__args)...); }

[ Related to 767⁽ⁱ⁾ ]

Proposed resolution:

Change 23.6.3.1 [queue.defn]:

void push(const value_type& x) { c.push_back(x); }
void push(value_type&& x) { c.push_back(std::move(x)); }
template<class... Args> void push(Args&&... args) { c.push_back(std::forward<Args>(args)...); }

Change 23.6.4 [priority.queue]:

void push(const value_type& x) { c.push_back(x); }
void push(value_type&& x) { c.push_back(std::move(x)); }
template<class... Args> void push(Args&&... args) { c.push_back(std::forward<Args>(args)...); }

Change 23.6.4.4 [priqueue.members]:

void push(const value_type& x);

Effects:

c.push_back(x);
push_heap(c.begin(), c.end(), comp);

template<class... Args> void push(value_type Args&&... x args);

Effects:

c.push_back(std::moveforward<Args>(x args)...);
push_heap(c.begin(), c.end(), comp);

Change 23.6.6.2 [stack.defn]:

void push(const value_type& x) { c.push_back(x); }
void push(value_type&& x) { c.push_back(std::move(x)); }
template<class... Args> void push(Args&&... args) { c.push_back(std::forward<Args>(args)...); }

Rationale:

Addressed by N2680 Proposed Wording for Placement Insert (Revision 1).