c++11 - Why does std::make_shared<class T, class...Args>(Args&&... args) require T to have copy constructor? -

i don't understand why class has deleted copy constructor (or contains member, ifstream, has deleted copy constructor , there it, too, has deleted copy constructor) can't used make_shared()? code shows i'm talking

class x {  private:      x(const x&) = delete;      int x;  public:      x(int an_int)  : x{an_int} {};      x() : x{10} {}  }; int main(int argc, char** argv)  {    // fails because x has no copy constructor     shared_ptr<x> ptr { make_shared<x>( x{8} ) };     shared_ptr<x> ptr2 { new x{10} };// works fine     return 0; } 

you may missing fact make_shared forward arguments constructor of x. in case passing x{8} constructor argument, make_shared forced attempt copy or move construction.

in particular example, deleting copy constructor has implicitly deleted move constructor, preventing construction temporary x{8}.

what want write this:

shared_ptr<x> ptr { make_shared<x>(8) };