Created by: wangkuiyi

In old Unix world, errors are represented by a non-zero integer.

In the Web world, errors are often represented by an integer and a message string. TensorFlow adopted this idea and have Status:

class Status {
...
 private:
  static const string& empty_string();
  struct State {
    tensorflow::error::Code code;
    string msg;
  };
  // OK status has a `NULL` state_.  Otherwise, `state_` points to
  // a `State` structure containing the error code and message(s)
  State* state_;
...
};

Go represents an error by a string.

I personally prefer Go's approach because integers are not readable and the integer-plus-string approach is redundant. What do you think, dear PaddlePaddle authors?