Re: Loaded footgun open_datasync on Windows

On Fri, Jun 8, 2018 at 7:48 AM, Laurenz Albe <laurenz.albe@cybertec.at> wrote:

Amit Kapila wrote:
> On Wed, Jun 6, 2018 at 3:06 PM, Kuntal Ghosh <kuntalghosh.2007@gmail.com> wrote:
> > It seems the "#ifndef FRONTEND" restriction was added around
> > pgwin32_open() for building libpq with Visual C++ or Borland C++.  The
> > restriction was added in commit 422d4819 to build libpq with VC++[1].
> > Later, in commit fd7c3f67e0bc4, the support for Borland C++ was also
> > added.
> >
> > So, I'm not sure whether removing that restriction will work for all
> > front-end modules.
> >
>
> Thanks for doing investigation.  I agree with you that it appears from the old
> discussion that we have added this restriction to build libpq/psql (basically frontend)
> modules.  However, I tried to build those modules on windows by removing that
> restriction and it doesn't give me any problem (except one extra argument error,
> which can be easily resolved).  It might be that it gives problem with certain
> version of MSVC.  I think if we want to pursue this direction, one needs to verify
> on various supportted versions (of Windows) to see if things are okay.

That's what the buildfarm is for, right?

> Speaking about the issue at-hand, one way to make pg_test_fsync work in to just
> include c.h and remove inclusion of postgres_fe.h, but not sure if that is the best way.
> I am not sure if we have any other options to proceed in this case.
>
> Thoughts?

I thought of a better way.
pg_test_fsync is properly listed as a server application in the documentation,
so I think it should be built as such, as per the attached patch.

-#include "postgres_fe.h"
+#include "postgres.h"

I don't think that server application can use backend environment unless it is adapted to do so.  I think the application should have the capability to deal with backend stuff like ereport, elog etc, if we don't want to use FRONTEND environment.  The other server applications like pg_ctl.c, initdb.c, etc. also uses FRONTEND environment.