On 2008 Nov 27, at 8:51, Simon Marlow wrote:
Brandon S. Allbery KF8NH wrote:
On 2008 Nov 10, at 19:04, Jason Dusek wrote:
simple exe bytes args = do
(i, o, e, p) <- runInteractiveProcess exe args Nothing
Nothing
hPut i bytes
s <- hGetContents o
hClose i
return s
Yep, that's your problem. forkIO the hPut.
Maybe I didn't do enough here -- just wrapping in `forkIO`
does not seem to actually help.
*sigh* I hate the ghc runtime... it works in ghci, or compiled with
-threaded.
Would you hate it less if -threaded were the default?
Otherwise you still get the deadlock because it only switches
threads under limited circumstances (garbage collections?)
No, the issue is that without real OS threads, a foreign call can't
be pre-empted (pretty obvious when you think about it).
waitForProcess ends up making a blocking foreign call - non-obvious,
but at least it's documented.
The way this is usually handled in the non-threaded case is to either
use SIGCHLD or non-blocking waitpid() so that "green" threads can
continue running. I'm a little surprised this wasn't done.
--
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED]
system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED]
electrical and computer engineering, carnegie mellon university KF8NH
_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
