Yes I didn't read your specification accurately... However I would argue such a constraint on the problem domain is artificial as operating systems exist. At the end of the day it is the job of the OS to manage such one-shot hardware inits, not application code. (As the OS is the only thing that can manage resources accross multiple programs)... What did you think of the code example given where the one-shot nature is provided by a 'C' wrapper around the FFI function. I think this is the best solution... Keean. Adrian Hey wrote:
On Monday 08 Nov 2004 6:48 pm, Keean Schupke wrote:
Adrian Hey wrote:
The problem is simple enough to restate for anyone who's interested. "Provide a simple reliable mechanism to ensure that in a given program run one particular top level IO operation cannot be executed more than once."
No language can guarantee this - all I have to do is run 2 copies of the executable at once... or wven sequentially!
Read what I wrote :-)
Regards -- Adrian Hey _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe