[Haskell-cafe] Re: ACIO versus Execution Contexts
k.schupke at imperial.ac.uk
Wed Dec 1 12:23:52 EST 2004
Adrian Hey wrote:
>Oh yes, so you did. Sorry. What alternative would you propose?
>Something like Keeans thread talking to the rest of the
>world by channels?
>When Keean suggested this I objected that there was still
>no way to prevent accidental forking of multiple copies
>of this supposedly unique resource manager thread. (To enforce
>safety you still need to use oneShot or similar mechanism).
The top level loader controls how many times a device in
initialised, and forks the manager thread. The "user" program
is not given control until after all drivers are initialised, so there
is no chance of the user being able to fork such a thread.
Either way the point is moot, as I have shown how to start
two copies of the driver even if it is protected with your
onShot function (by replacing the MVar module) ... So I am
now happy that the two proposals are equivalent.
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