#2363: getChar cannot be interrupted with -threaded
----------------------------+-----------------------------------------------
Reporter: simonmar | Owner:
Type: bug | Status: new
Priority: high | Milestone: 6.10 branch
Component: libraries/base | Version: 6.8.2
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Architecture: Unknown
Os: Unknown |
----------------------------+-----------------------------------------------
Comment (by judah):
I was the original reporter of this problem. I have worked around it by
rewriting `myGetChar`:
{{{
myGetChar mv = do
Control.Concurrent.threadWaitRead System.Posix.IO.stdInput
c <- getChar
putMVar mv (Just c)
}}}
The problem with the original code was that `getChar` (and
`hWaitForInput`) wrap foreign calls, which block the subthread they're run
in and thus cannot be halted by `killThread`. In contrast,
`threadWaitRead` wraps a primop, so it does not have that problem.
This workaround is OK for now, but in my opinion all of the IO functions
should be interruptible by default. (And `threadWaitRead` uses `Fd`
instead of `Handle` which is more convenient/portable.)
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2363#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler_______________________________________________
Glasgow-haskell-bugs mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
