From 3a21a064deb60983eeeb521e9c68316d0e8cb3fa Mon Sep 17 00:00:00 2001
From: sof <unknown>
Date: Fri, 14 May 1999 19:49:23 +0000
Subject: [PATCH] [project @ 1999-05-14 19:49:22 by sof] Added (yield :: IO
 ()) - the underlying bits were already there, really.

---
 ghc/lib/concurrent/Concurrent.lhs |    2 ++
 ghc/lib/std/PrelConc.lhs          |    6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/ghc/lib/concurrent/Concurrent.lhs b/ghc/lib/concurrent/Concurrent.lhs
index 2fe58d3..c9c2240 100644
--- a/ghc/lib/concurrent/Concurrent.lhs
+++ b/ghc/lib/concurrent/Concurrent.lhs
@@ -29,6 +29,8 @@ module Concurrent (
 	, par  		-- :: a -> b -> b
 	, seq  		-- :: a -> b -> b
 	, fork  	-- :: a -> b -> b
+	, yield         -- :: IO ()
+
 	{-threadDelay, threadWaitRead, threadWaitWrite,-}
 
 	-- MVars
diff --git a/ghc/lib/std/PrelConc.lhs b/ghc/lib/std/PrelConc.lhs
index 10ebbe4..c23e8d8 100644
--- a/ghc/lib/std/PrelConc.lhs
+++ b/ghc/lib/std/PrelConc.lhs
@@ -18,6 +18,8 @@ module PrelConc
 	, raiseInThread -- :: ThreadId -> Exception -> IO ()
 	, par  		-- :: a -> b -> b
 	, seq  		-- :: a -> b -> b
+	, yield         -- :: IO ()
+
 	{-threadDelay, threadWaitRead, threadWaitWrite,-}
 
 	-- MVars
@@ -68,6 +70,10 @@ myThreadId :: IO ThreadId
 myThreadId = IO $ \s ->
    case (myThreadId# s) of (# s1, id #) -> (# s1, ThreadId id #)
 
+yield :: IO ()
+yield = IO $ \s -> 
+   case (yield# s) of s1 -> (# s1, () #)
+
 -- "seq" is defined a bit wierdly (see below)
 --
 -- The reason for the strange "0# -> parError" case is that
-- 
1.7.10.4