Re: Reversed sync check in pg_receivewal

Magnus Hagander <magnus(at)hagander(dot)net> writes:
> Something like the attached?

Not sure about

+ * All methods that have a failure path will set errno on failure.

Given that you've got a getlasterror method, I don't think that's really
the API invariant is it? If it were, you'd just have the callers doing
strerror(errno) for themselves. I think maybe a more accurate statement
would be

* All methods that have a failure return indicator will set state
* allowing the getlasterror() method to return a suitable message.
* Commonly, errno is this state (or part of it); so callers must take
* care not to clobber errno between a failed method call and use of
* getlasterror() to retrieve the message.

Also:

* the arguments of open_for_write() could stand to be explained

* what's the return value of finish()?

* wouldn't it be better to declare getlasterror() as returning
"const char *"?

regards, tom lane