Hmm, I thought so as well, you know. But actually, error
conditions are flagged by excptions, so we would not return
errors anyway. So it does not matter if e.g. mkdir_sync ()
returns a task: it would not be used anyway. (If the task
gets returned it is Finished. If it failes, an error is
thrown.)
OTOH, for calls which do return infos this is different:
directory.ls (); would normally return a list of strings I
guess. With the proposed model, the list would need to be
returned in I/O parameters, such as:
std::list<string> l;
d.ls_sync (&l);
So, the problems are not error conditions, but return values
I guess.
However, similar considerations hold for the other task
models: at least the signature of the method calls might
look different for synchroneous and asynchroneous calls:
sync in version B:
std::list<string> l = d.sync.ls ();
async in version B:
std::list<string> l;
saga::task t = d.sync.ls (&l);
I created some more verbose examples at
http://wiki.cct.lsu.edu/saga/space/Task+Models
(see bottom of page) -- I hope that helps the discussion.
Feel free to change/edit/correct them, and in fact to edit
that page.
Again: the cuurent discussion does ONLY affect the C++
language binding for now!
Cheers, Andre.
Quoting [Hartmut Kaiser] (Nov 08 2005):
>
> The main question is, do we need to have different return values from
> sync/async operations or not. It's kind of unusual to get a task from a
> 'normal' sync operation, even more because this task is usable for return
> value retrieval only.
>
> Regards Hartmut
--
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| Andre Merzky | phon: +31 - 20 - 598 - 7759 |
| Vrije Universiteit Amsterdam (VU) | fax : +31 - 20 - 598 - 7653 |
| Dept. of Computer Science | mail: merzky at cs.vu.nl |
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