[GHC] #9945: export list for System.Posix.Internals breaking the build on Windows

[GHC]

#9945: export list for System.Posix.Internals breaking the build on Windows
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        Reporter:  MartinF           |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.11
      Resolution:                    |                Keywords:
Operating System:  Windows           |            Architecture:
 Type of failure:  Building GHC      |  Unknown/Multiple
  failed                             |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:  #9852             |  Differential Revisions:
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Comment (by MartinF):

 I've noticed something strange while looking into `peekFilePathLen` - this
 is where it's defined:

 {{{#!hs
 #ifdef mingw32_HOST_OS
 withFilePath :: FilePath -> (CWString -> IO a) -> IO a
 withFilePath = withCWString

 newFilePath :: FilePath -> IO CWString
 newFilePath = newCWString

 peekFilePath :: CWString -> IO FilePath
 peekFilePath = peekCWString
 #else

 withFilePath :: FilePath -> (CString -> IO a) -> IO a
 newFilePath :: FilePath -> IO CString
 peekFilePath :: CString -> IO FilePath
 peekFilePathLen :: CStringLen -> IO FilePath

 withFilePath fp f = getFileSystemEncoding >>= \enc -> GHC.withCString enc
 fp f
 newFilePath fp = getFileSystemEncoding >>= \enc -> GHC.newCString enc fp
 peekFilePath fp = getFileSystemEncoding >>= \enc -> GHC.peekCString enc fp
 peekFilePathLen fp = getFileSystemEncoding >>= \enc -> GHC.peekCStringLen
 enc fp

 #endif
 }}}

 So, `#ifdef mingw32_HOST_OS`, those three related functions all have types
 involving `CWString` - but if not, their types have `CString` instead.

 If CPP-conditional exports are generally wrong, would the same be true for
 exports with CPP-conditional types?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9945#comment:12>
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