#5553: sendWakeup error in simple test program with MVars and killThread
-----------------------+----------------------------------------------------
Reporter: bit | Owner: tibbe
Type: bug | Status: new
Priority: normal | Component: Runtime System
Version: 7.2.1 | Keywords:
Testcase: | Blockedby:
Os: Linux | Blocking:
Architecture: x86 | Failure: Incorrect result at runtime
-----------------------+----------------------------------------------------
Changes (by tibbe):
* owner: => tibbe
Comment:
I've assigned the ticket to myself but I'm pretty swamped right now so if
someone else has time feel free to take a look.
`sendWakeup` is defined in `GHC/Event/Control.hs` and is used to wake up
the I/O manager every time a new file descriptor or timeout (i.e.
`threadDelay`) is added. Here's the relevant code:
{{{
sendWakeup :: Control -> IO ()
#if defined(HAVE_EVENTFD)
sendWakeup c = alloca $ \p -> do
poke p (1 :: Word64)
throwErrnoIfMinus1_ "sendWakeup" $
c_write (fromIntegral (controlEventFd c)) (castPtr p) 8
#else
sendWakeup c = do
n <- sendMessage (wakeupWriteFd c) CMsgWakeup
case n of
_ | n /= -1 -> return ()
| otherwise -> do
errno <- getErrno
when (errno /= eAGAIN && errno /= eWOULDBLOCK) $
throwErrno "sendWakeup"
#endif
}}}
Since you're on Linux the first `#if` case applies.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5553#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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