Sync now, damnit!

[John R. Brinkema]

I know this question has been asked a billion times but ... is there any way
to force the equivalent of an fsync on UNIX V.3 (in particular ISC UNIX 2.2).
If yes, do I have to *open* the file in this mode (I'm thinking of the imple-
mentation of dir) or can I simply grab the fd and have my way?

Right now, I'm writing to a raw file partition, but this is definitly a
kludge.