Comment by drysine

may I introduce you to the nodiscard attribute[1]?

  enum (class)? [[nodiscard]] Error {
    Ok,
    NoMem,
    ...
  };

[1]: https://en.cppreference.com/w/cpp/language/attributes/nodisc...

Looking at code, it‘s easier to spot the missing check for an error code, than a not catched exceptions.

Also error codes are part of the signature of a function, which exceptions aren‘t.