On Thu, Feb 23, 2012 at 07:14:03PM +0900, Kyotaro HORIGUCHI wrote:
> Hello, this is new version of the patch.
Looks good.
> By the way, I would like to ask you one question. What is the
> reason why void* should be head or tail of the parameter list?
Aesthetical reasons:
1) PGresult and PGrowValue belong together.
2) void* is probably the context object for handler. When doing object-oriented programming in C the main object is
usuallyfirst. Like libpq does - PGconn is always first argument.
But as libpq does not know the actual meaning of void* for handler,
is can be last param as well.
When I wrote the demo code, I noticed that it is unnatural to have
void* in the middle.
Last comment - if we drop the plan to make PQsetRowProcessorErrMsg()
usable outside of handler, we can simplify internal usage as well:
the PGresult->rowProcessorErrMsg can be dropped and let's use
->errMsg to transport the error message.
The PGresult is long-lived structure and adding fields for such
temporary usage feels wrong. There is no other libpq code between
row processor and getAnotherTuple, so the use is safe.
--
marko