On Tue, 22 Oct 2002, John Gardiner Myers wrote:
>
>
> Dan Kegel wrote:
>
> > The choice I see is between:
> > 1. re-arming the one-shot notification when the user gets EAGAIN
> > 2. re-arming the one-shot notification when the user reads all the data
> > that was waiting (such that the very next read would return EGAIN).
> >
> > #1 is what Davide wants; I think John and Mark are arguing for #2.
>
> No, this is not what I'm arguing. Once an event arrives for a fd, my
> proposed semantics are no different than Mr. Libenzi's. The only
> difference is what happens upon registration of interest for a fd. With
> my semantics, the kernel guarantees that if the fd is ready then at
> least one event has been generated. With Mr Libenzi's semantics, there
> is no such guarantee and the application is required to behave as if an
> event had been generated upon registration.
sed s/Mr. Libenzi/Davide/g ... I'm not that old :)
There're a couple of reason's why the drop of the initial event is a waste
of time :
1) The I/O write space is completely available at fd creation
2) For sockets it's very likely that the first packet brought something
more than the SYN == The I/O read space might have something for you
I strongly believe that the concept "use the fd until EAGAIN" should be
applied even at creation time, w/out making exceptions to what is the
API's rule to follow.
- Davide
-
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This archive was generated by hypermail 2b29 : Wed Oct 23 2002 - 22:01:00 EST