Move constructor for std::string from char*

Question

I have a function f returning a char*. The function documentation says:

The user must delete returned string

I wa

Answer 1

std::string steal_char_buffer( std::unique_ptr buff ) {
  std::string s = buff?buff.get():""; // handle null pointers
  return s;
}
std::string steal_char_buffer( const char* str ) {
  std::unique_ptr buff(str); // manage lifetime
  return steal_char_buffer(std::move(buff));
}

now you can type

std::string s = steal_char_buffer(f());

and you get a std::string out of f().

You may want to make the argument of steal_char_buffer be a const char*&&. It is mostly pointless, but it might lead to some useful errors.

If you can change the interface of f, make it return a std::string directly or a std::unique_ptr.

Another good idea is to wrap f in another function that returns a std::unique_ptr or std::string:

std::unique_ptr good_f() {
  return std::unique_ptr(f());
}

and/or

std::string good_f2() {
  auto s = good_f();
  return steal_char_buffer( std::move(s) );
}