Re: [PATCH iproute2-next] rtnetlink: add new function rtnl_echo_talk()

[Hangbin Liu <liuhangbin@gmail.com>]

Hi David,

On Tue, Sep 27, 2022 at 09:12:35PM -0600, David Ahern wrote:
> >  
> > -	if (echo_request)
> > -		ret = rtnl_talk(&rth, &req.n, &answer);
> > -	else
> > -		ret = rtnl_talk(&rth, &req.n, NULL);
> > -
> > -	if (ret < 0)
> > -		return -2;
> > -
> > -	if (echo_request) {
> > -		new_json_obj(json);
> > -		open_json_object(NULL);
> > -		print_addrinfo(answer, stdout);
> > -		close_json_object();
> > -		delete_json_obj();
> > -		free(answer);
> > -	}
> > -
> > -	return 0;
> > +	return rtnl_echo_talk(&rth, &req.n, print_addrinfo);
> 
> I was thinking something more like:
> 
> if (echo_request)
> 	return rtnl_echo_talk(&rth, &req.n, print_addrinfo);
> 
> return rtnl_talk(&rth, &req.n, NULL);

OK, I will update the patch. I have one question about the return value.
In previous code, the function return -2 if rtnl_talk() fails. I don't know
why we use "-2" here. And you suggested to just return rtnl_talk() directly.

Does this means we can ignore the -2 return values for all the places safely,
and just return rtnl_talk()?

Thanks
Hangbin