[GHC] #13497: GHC does not use select()/poll() correctly on non-Linux platforms

[GHC]

#13497: GHC does not use select()/poll() correctly on non-Linux platforms
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        Reporter:  nh2               |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Runtime System    |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #8684, #12912     |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by nh2):

 Hmm looks like I also discovered that `fdReady()` doesn't work at all on
 Windows for the `case FILE_TYPE_PIPE`.

 This example file

 {{{
 import System.IO

 main = hWaitForInput stdin (5 * 1000)
 }}}


 when compiled with `ghc --make -O -fforce-recomp ../example-windows-
 pipe.hs && time ../example-windows-pipe.hs` terminates immediately instead
 of waiting for 5 seconds.

 The reason seems to be that the `PeekNamedPipe( hFile, NULL, 0, NULL,
 &avail, NULL )`, which is called only once in `fdReady()`, doesn't have
 any blocking feature.

 From the docs https://msdn.microsoft.com/en-
 us/library/windows/desktop/aa365779(v=vs.85).aspx

 > The function always returns immediately in a single-threaded
 application, even if there is no data in the pipe

 (Not sure why it says "in a single-threaded application"; the same problem
 happens with `-threaded` and `+RTS -N2`.)

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13497#comment:17>
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