Posix.sync

[Simon Marlow]

> > > Rather than patching the Posix library to include stuff like
> > > O_SYNC, I'd like to see a Haskell binding to the Single
> > > UNIX (aka Unix98) instead - it subsumes the
> > > POSIX.1 APIs (and you can get at the specs without having
> > > to pay the extortionate rates that IEEE charges). Feel free
> > > to contribute such a binding!
> >=20
> > I'm afraid I will not. There is pretty huge number of
> > functions to bind, and I'm afraid to miss some. Then I'm not
> > wery good Haskeller.
> >=20
> > Moreover, I could not see the Single Unix features in the
> > linux-2.2 (at least that nice O_DSYNC flag). Maybe they are
> > presented in 2.4, but I have no plan to use it.
>=20
> AFAIK no OS implements all of the Single Unix specification.
> Nevertheless, I think, Sigbjorn is right.  Ideally, we
> should have a binding for Single Unix and on any particular
> OS, you will have a subset of it available (that's the same
> situation as you have with any other programming language).
>=20
> As is pointed out in the open(2) man page, O_SYNC, O_DSYNC,
> and O_RSYNC are synonymous in Linux 2.2.  In 2.4, at least
> with some file systems (eg, XFS) you can choose which
> behaviour O_SYNC should have.

I'd like to see a full SUS binding too.  I also think that POSIX is a
useful subset, because as Manuel says nobody implements the full SUS but
pretty much everyone implements full POSIX (not always with the same
semantics though :-).  So my preferred solution would be a Unix library,
from which Posix re-exports a subset.

I started rewriting GHC's Posix library a while back - I got about half
way though, and I'll get back onto it when I turn my attention to the
new libraries again.  I've kept all the suggestions from people on the
lists regarding the Posix interface, and I'll put together a proposal
for the new interface at some point.  Discussion about the interface
should probably move to libraries@haskell.org.

Cheers,
	Simon