On 25/06/10 16:06, Dimitry Golubovsky wrote:
Should an implementation of GHC.IO.Device expect the `ready' method to be called from a thread different than one waiting for an I/O operation on a handle to complete, while that operation is in progress?
As a more general question, are GHC Handles (and underlying implementations of GHC.IO.Device and GHC.IO.BufferedIO) expected to be thread-safe?
I would be happy to store the id of the thread that calls mkFileHandle somewhere in the underlying `dev' and simply reject all I/O requests that come from other threads, but is this correct/permitted behavior?
The Handle layer implements its own mutual exclusion (a Handle is an MVar), so you only need to worry about thread-safety for your device if you expose it some other way, or make it accessible from multiple Handles. FD for example does no additional locking. Cheers, Simon