-- * Basic concurrency operations
-#ifndef __HUGS__
ThreadId,
+#ifdef __GLASGOW_HASKELL__
myThreadId,
#endif
forkIO,
-#ifndef __HUGS__
+#ifdef __GLASGOW_HASKELL__
killThread,
throwTo,
#endif
import Control.Concurrent.QSemN
import Control.Concurrent.SampleVar
+#ifdef __HUGS__
+type ThreadId = ()
+#endif
+
{- $conc_intro
The concurrency extension for Haskell is described in the paper
Haskell threads can communicate via 'MVar's, a kind of synchronised
mutable variable (see "Control.Concurrent.MVar"). Several common
concurrency abstractions can be built from 'MVar's, and these are
-provided by the "Concurrent" library. Threads may also communicate
-via exceptions.
+provided by the "Control.Concurrent" library.
+In GHC, threads may also communicate via exceptions.
-}
{- $conc_scheduling
> return mvar
Note that we use 'finally' from the
- "Exception" module to make sure that the
+ "Control.Exception" module to make sure that the
'MVar' is written to even if the thread dies or
is killed for some reason.
The rescheduling timer runs on a 20ms granularity by
default, but this may be altered using the
- @-i<n>@ RTS option. After a rescheduling
+ @-i\<n\>@ RTS option. After a rescheduling
\"tick\" the running thread is pre-empted as soon as
possible.
One final note: the
@aaaa@ @bbbb@ example may not
work too well on GHC (see Scheduling, above), due
- to the locking on a 'Handle'. Only one thread
- may hold the lock on a 'Handle' at any one
+ to the locking on a 'System.IO.Handle'. Only one thread
+ may hold the lock on a 'System.IO.Handle' at any one
time, so if a reschedule happens while a thread is holding the
lock, the other thread won't be able to run. The upshot is that
the switch from @aaaa@ to