From: wolfgang <unknown>
Date: Wed, 1 Oct 2003 10:57:44 +0000 (+0000)
Subject: [project @ 2003-10-01 10:57:44 by wolfgang]
X-Git-Tag: nhc98-1-18-release~486
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=221834f61e883a17db96bb8b8c0157a3de626738;p=ghc-base.git

[project @ 2003-10-01 10:57:44 by wolfgang]
New implementation & changed type signature of forkProcess

forkProcess now has the following type:
forkProcess :: IO () -> IO ProcessID

forkProcessAll has been removed as it is unimplementable in the threaded RTS.

forkProcess using the old type (IO (Maybe ProcessID)) was impossible to
implement correctly in the non-threaded RTS and very hard to implement
in the threaded RTS.
The new type signature allows a clean and simple implementation.
---

diff --git a/GHC/Conc.lhs b/GHC/Conc.lhs
index 279681b..2a24fa5 100644
--- a/GHC/Conc.lhs
+++ b/GHC/Conc.lhs
@@ -26,7 +26,6 @@ module GHC.Conc
 	, pseq 		-- :: a -> b -> b
 	, yield         -- :: IO ()
 	, labelThread	-- :: ThreadId -> String -> IO ()
-	, forkProcessPrim -- :: IO Int
 
 	-- Waiting
 	, threadDelay	  	-- :: Int -> IO ()
@@ -154,29 +153,6 @@ labelThread (ThreadId t) str = IO $ \ s ->
        adr = byteArrayContents# ps in
      case (labelThread# t adr s) of s1 -> (# s1, () #)
 
-{- | This function is a replacement for 'System.Posix.Process.forkProcessAll':
-This implementation /will stop all other Concurrent Haskell threads/ in the
-(heavyweight) forked copy.
-'forkProcessPrim' returns the pid of the child process to the parent, 0 to the
-child, and a value less than 0 in case of errors. See also:
-'System.Posix.Process.forkProcess' in package @unix@.
-
-Without this function, you need excessive and often impractical
-explicit synchronization using the regular Concurrent Haskell constructs to assure
-that only the desired thread is running after the fork().
-
-The stopped threads are /not/ garbage collected! This behaviour may change in
-future releases.
-
-NOTE: currently, main threads are not stopped in the child process.
-To work around this problem, call 'forkProcessPrim' from the main thread. 
--}
-
--- XXX RTS should know about 'pid_t'.
-
-forkProcessPrim :: IO Int
-forkProcessPrim = IO $ \s -> case (forkProcess# s) of (# s1, id #) -> (# s1, (I# id) #)
-
 -- 	Nota Bene: 'pseq' used to be 'seq'
 --		   but 'seq' is now defined in PrelGHC
 --