#include #include #define LOG \ if (false) { \ } else \ puts(__PRETTY_FUNCTION__) /// A helper sruct to count instances, copy- and move constructions. struct m { m() { LOG; ++cnt; } ~m() { LOG; --cnt; } m(const m&) { LOG; ++cnt; ++cpy; } m(m&&) noexcept { LOG; ++cnt; ++mov; } m& operator=(const m&) = delete; m& operator=(m&&) = delete; static std::size_t cnt; static std::size_t mov; static std::size_t cpy; }; std::size_t m::cnt = 0; std::size_t m::mov = 0; std::size_t m::cpy = 0; int main() { { ring r; assert(r.size() == 0); assert(r.is_empty()); assert(!r.is_full()); for (int i = 0; i < 10; ++i) { bool ok = r.emplace(); i < 8 ? assert(ok) : assert(!ok); } assert(r.size() == 8); assert(!r.is_empty()); assert(r.is_full()); #if __cplusplus >= 201703L auto v = r.take(); assert(v.has_value()); assert(r.size() == 7); assert(!r.is_empty()); assert(!r.is_full()); #endif assert(m::cnt == 8); } assert(m::cnt == 0); m::mov = 0; m::cpy = 0; { ring r; // Move construct m from an m rvalue reference. assert(m::mov == 0); r.push(m{}); assert(m::mov == 1); // Copy construct m from an m lvalue reference. m m; assert(m::cpy == 0); r.push(m); assert(m::cpy == 1); assert(m::cnt == 3); } assert(m::cnt == 0); }