Fine grained sync policy control (was: What I want in GNU OS)
Tim Oldham
tjo at Fulcrum.BT.CO.UK
Sat Jul 8 02:52:33 AEST 1989
In article <18410 at mimsy.UUCP> chris at mimsy.UUCP (Chris Torek) writes:
>SysV has an open() flag that causes writes to be immediate. Presumably
>this can also be set and cleared with fcntl(F_SETFL). [yes - Tim]
Not a correction, but an addition and word of warning-ish. O_SYNC, the
flag in question, is only defined in the SVID addendum (V.3).
The word of warning, at the risk of teaching grandma to suck eggs: many
companies say "hey, we're SVID conformant". But check the SVID conformance
level. Sometimes it's without the addendum features. Even then, check the
kernel extensions conformance, otherwise you might be in for a shock when
you come to use things like ptrace(2). This is particularly true of
systems that aren't derived from AT&T source, and just look like SysV *IX.
As a quick question, why does the SVID say that the sticky bit is
`reserved'? Usually this means that "no, you're not allowed to use that -
we're going to say what it's for later". They seem to mean "do what you
want to with this bit", which is usually described as `undefined'.
Comments?
Tim.
--
Tim Oldham tjo at fulcrum.bt.co.uk or ...!mcvax!ukc!axion!fulcrum!tjo
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Why have coffee, when caffeine tastes this good?
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