"Francisco Figueiredo Jr." <fxjrlists@yahoo.com.br> writes:
> I'm finishing the implementation of the protocol 3.0 and now I'm working
> in how to connect to server using protocol 3.0 when the server doesn't
> support it 7.3- .
I'd suggest using the same methods libpq does. You do have to be
prepared to accept an old-format error message.
regards, tom lane