函数中类实例的生命周期

如何解决函数中类实例的生命周期

以下最少的代码说明了我的困惑。应该在函数 a(x) 中销毁 create() 吗？为什么 m 和 a 完全一样。为什么从不调用复制构造函数？

#include <iostream>
using namespace std;
class Board{
 public:
  int a[10000];
  int s = sizeof(a)/sizeof(a[0]);
  Board(int x){
    for(size_t i=0; i < s; ++i){
      a[i] = x;
    }
  };

  Board(const Board& other){
    memcpy(a,other.a,sizeof(int)*s);
    cout << "copy constructor called" << endl;
  };

  Board& operator=(const Board&) = default;
   ~Board(){
     cout << "board destroyed" << endl;
   };
};

Board create(int x){
  Board a(x);
  cout << &a << endl;
  return a;
}

Board mycreate(int x){
  return create(x);
}

int main(){
  auto m=create(3);
  cout << &m << endl;
  auto m2(mycreate(3));
  cout << &m2 << endl;
}

输出：

0x7ffee7f18cf8
0x7ffee7f18cf8
0x7ffee7f0f0a8
0x7ffee7f0f0a8
board destroyed
board destroyed