Is there a way to prevent calling the constructor without assigning it to a variable?

Question

i.e. this should be ok:

Object obj("param");

but this should not:

Object("param");

Is there a way to prevent the second scenario from being done?

Answer 1

You can use the nodiscard attribute for a type (with C++17 or later).

struct [[nodiscard]] Object {};

auto main() -> int {
  Object{}; // error
  return 0;
}