RE: ThreadId should be Eq and Ord!!!!!

[Simon Peyton-Jones]

> I asked for this months ago (it is after all documented) but 
> nothing seems to have been done.
> It is now extremely urgent that I sort this out if I want 
> UniForM to work.  What am I to do??
> Things are now sufficiently desperate that I will attempt to 
> hack the GHC sources.

George,

Try the module below.  It makes ThreadId an instance of Eq and Ord.

Simon


{-# OPTIONS -fglasgow-exts #-}

module Thread( cmpThread ) where

import PrelConc
import GlaExts

foreign import ccall "cmp_thread" unsafe cmp_thread :: Addr -> Addr -> Int
-- Returns -1, 0, 1

cmpThread :: ThreadId -> ThreadId -> Ordering
cmpThread (ThreadId t1) (ThreadId t2) 
  = case cmp_thread (unsafeCoerce# t1) (unsafeCoerce# t2) of
        -1 -> LT
        0  -> EQ
        1  -> GT

instance Eq ThreadId where
  t1 == t2 = case t1 `cmpThread` t2 of
                EQ    -> True
                other -> False

instance Ord ThreadId where
  cmp = cmpThread