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Document number: N3870

Date: 2014-01-14

Extending make_shared to Support Arrays, Revision 1

by Peter Dimov, Glen Fernandes

Excerpt:

This paper proposes adding array support to make_shared, via the syntax make_shared<T[]> and make_shared<T[N]>.

Changes in Revision 1: This revision of N3641 significantly narrows the scope of the proposal, based on feedback from Jeffrey Yasskin and Stephan T. Lavavej. It cuts down the number of make_shared overloads considerably, leaving only two use cases:

— Value initialization, analogous to new U[N]():

template<class T> shared_ptr<T> make_shared(size_t N); // T is U[]
template<class T> shared_ptr<T> make_shared(); // T is U[N]

— Per-element initialization to a specified value, analogous to the std::vector<U>(N, u) constructor:

template<class T> shared_ptr<T> make_shared(size_t N, const U& u); // T is U[]
template<class T> shared_ptr<T> make_shared(const U& u); // T is U[N]