Move Eq, Ord, Show instances for ThreadId to GHC.Conc

[haskell-directory.git] / GHC / Conc.lhs

diff --git a/GHC/Conc.lhs b/GHC/Conc.lhs
index 11d78b8..f3c57cc 100644 (file)
--- a/GHC/Conc.lhs
+++ b/GHC/Conc.lhs
@@ -99,6 +99,7 @@ import GHC.Exception    ( catchException, Exception(..), AsyncException(..) )
 import GHC.Pack                ( packCString# )
 import GHC.Ptr          ( Ptr(..), plusPtr, FunPtr(..) )
 import GHC.STRef
+import GHC.Show                ( Show(..), showString )
 import Data.Typeable
 
 infixr 0 `par`, `pseq`
@@ -133,6 +134,35 @@ This misfeature will hopefully be corrected at a later date.
 it defines 'ThreadId' as a synonym for ().
 -}
 
+instance Show ThreadId where
+   showsPrec d t = 
+       showString "ThreadId " . 
+        showsPrec d (getThreadId (id2TSO t))
+
+foreign import ccall unsafe "rts_getThreadId" getThreadId :: ThreadId# -> Int
+
+id2TSO :: ThreadId -> ThreadId#
+id2TSO (ThreadId t) = t
+
+foreign import ccall unsafe "cmp_thread" cmp_thread :: ThreadId# -> ThreadId# -> CInt
+-- Returns -1, 0, 1
+
+cmpThread :: ThreadId -> ThreadId -> Ordering
+cmpThread t1 t2 = 
+   case cmp_thread (id2TSO t1) (id2TSO t2) of
+      -1 -> LT
+      0  -> EQ
+      _  -> GT -- must be 1
+
+instance Eq ThreadId where
+   t1 == t2 = 
+      case t1 `cmpThread` t2 of
+         EQ -> True
+         _  -> False
+
+instance Ord ThreadId where
+   compare = cmpThread
+
 {- |
 This sparks off a new thread to run the 'IO' computation passed as the
 first argument, and returns the 'ThreadId' of the newly created