[SAGA-RG] blocking/nonblocking I/O on files?

[John Shalf]

On Aug 29, 2007, at 11:19 AM, Andre Merzky wrote:
> Hi,
> Ole and Hartmut raised the point that the attribute
> interface on files is actaully useless.
>
> Formerly, we had a number of attributes on files defined -
> in the latest version of the spec, only one remaines:

Where did they all go?

> 'Blocking'.  That atgtribute however does not make much
> sense, as we have explicit versions for sync and async file
> I/O.

My original recollection of the "attributes" interface was that it  
allowed us to smuggle in file behaviors that would otherwise be  
accessed via the ioctl() and fcntl() interfaces.  Perhaps we haven't  
found any ioctls that we really need right now, but you should keep  
the attributes interface around so that you can add such capabilities  
in an as-needed basis.  That is certainly the case with ioctl()  (you  
rarely use that interface, when when you need it, that capability is  
essential).

> Yes, yes, sync/async and blocking/non-blocking is not
> exactly the same, but (a) the difference is small for our
> use cases AFAICS (thats different for streams), and (b) the
> spec does not define the behaviour for blocking/non-blocking
> files anyway.

I thought it was assumed that the POSIX spec for blocking/nonblocking  
(which would be enabled via ioctl()) would be in effect.

> So the proposal is to remove that attribute, and the
> attribute interface on files altogether.
>
> Any comments?
>
> Thanks, Andre.
>
>
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