diff options
| -rw-r--r-- | System/Posix/Process.hsc | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/System/Posix/Process.hsc b/System/Posix/Process.hsc index ec0bc33..5549d23 100644 --- a/System/Posix/Process.hsc +++ b/System/Posix/Process.hsc @@ -17,7 +17,8 @@ module System.Posix.Process ( -- * Processes -- ** Forking and executing - forkProcess, executeFile, + forkProcess, forkProcessAll, + executeFile, -- ** Exiting exitImmediately, @@ -62,6 +63,7 @@ module System.Posix.Process ( #include "HsUnix.h" +import GHC.Conc ( forkProcessPrim ) import Foreign import Foreign.C import System.IO @@ -199,8 +201,32 @@ foreign import ccall unsafe "setpriority" -- ----------------------------------------------------------------------------- -- Forking, execution +{- | 'forkProcess' is a wrapper around "GHC.Conc.forkProcessPrim" similar to +'forkProcessAll' which returns a Maybe-type. The child receives @Nothing@, +the parent @Just (pid::ProcessID)@. In case of an error, an exception is thrown. + +NOTE: currently, main threads are not stopped in the child process. +To work around this problem, call 'forkProcess' from the main thread. + +If you really want to copy all threads into the new process, use +'forkProcessAll' instead. +-} + forkProcess :: IO (Maybe ProcessID) forkProcess = do + pid <- throwErrnoIfMinus1 "forkProcess" forkProcessPrim + case pid of + 0 -> return Nothing + _ -> return (Just (fromIntegral pid)) + +{- | 'forkProcessAll' is the low-level wrapper for the @fork@ system-call. +Standard disclaimer for lazy I\/O, shared file handles etc. apply. Notice that +all Concurrent Haskell threads will be copied into the new process. See +'forkProcess' on how to start a new process with only one active thread. +-} + +forkProcessAll :: IO (Maybe ProcessID) +forkProcessAll = do r <- throwErrnoIfMinus1 "forkProcess" c_fork case r of 0 -> return Nothing @@ -209,7 +235,6 @@ forkProcess = do foreign import ccall unsafe "fork" c_fork :: IO CInt - executeFile :: FilePath -- Command -> Bool -- Search PATH? -> [String] -- Arguments |