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From Greg Stein <>
Subject Re: filtered I/O ordering
Date Thu, 01 Jun 2000 21:05:44 GMT
On Thu, 1 Jun 2000, Paul J. Reder wrote:
> Greg Stein wrote:
> > 1) the hook scheme tries very hard to *avoid* ordering. much of the
> >    documentation, the _FIRST and _LAST type stuff, etc is all written with
> >    the point of view that ordering is Badness.
> Not that I am an expert, but I thought the idea behind the current hook design
> was as follows:
>    1) Ordering for hooks is usually unimportant so allow easy definition of
>       hooks with little or no granularity (NULL predecessor or successor values
>       and 3 levels of ordering _FIRST, _MIDDLE, _LAST).
>    2) In the event where finer control is required you can specify _MIDDLE+1
>       or _MIDDLE-1, etc.
>    3) Where ordering is important due to an interdependance between modules
>       you can specify predecessors or successors to the hook.
> This doesn't seem to avoid ordering, it just makes the assumed lack of
> required ordering easy to implement while providing the ability to precisely
> control ordering where required.

Sorry if I was unclear. Yes: all the capability for ordering is present.
I'm simply trying to say that the hooks basic design is to attempt to
avoid ordering. It is a "broadcast" to all that will listen.

Where the broadcast concept breaks down, there are provided mechanisms for


Greg Stein,

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