[GHC] #1177: All I/O requests must complete before shutdown on Windows

[GHC]

#1177: All I/O requests must complete before shutdown on Windows
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    Reporter:  simonmar        |       Owner:  simonmar
        Type:  bug             |      Status:  new     
    Priority:  normal          |   Milestone:  6.6.2   
   Component:  Runtime System  |     Version:  6.6     
    Severity:  normal          |    Keywords:          
  Difficulty:  Unknown         |    Testcase:          
Architecture:  Multiple        |          Os:  Windows 
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In the non-threaded RTS, in order to fix problems with shutdown of DLLs we
 made it so that the RTS would wait for any outstanding IO request threads
 to exit before the RTS exits (otherwise the threads return later to find
 the DLL is missing and crash).

 Unfortunately this means if you fire off a long threadDelay and then the
 program ends, the RTS won't exit until the threadDelay expires, even if
 the original Haskell thread has been killed.  In the threaded RTS, we
 don't have the threadDelay problem (any more) because of the IO manager
 thread, but we do have a similar problem with outstanding I/O requests
 (untested).

 It's perhaps worse in the threaded RTS, because we don't wait for these
 I/O requests to exit - they are in foreign calls, and we don't currently
 wait for foreign calls to complete before exiting (this is a bug, in fact,
 similar to the original DLL shutdown bug).

 I'm not sure what to do, here are some options:

  * the I/O request threads should be terminated, somehow.

  * maybe we need two ways to shut down the RTS: forcibly, for program
 exit,
    and more carefully, for DLL shutdown.

  * when shutting down a DLL, we should wait for and/or terminate
 outstanding
    foreign call threads.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1177>
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