#8286: fdToHandle docs are wrong about non-blocking mode ------------------------------------+------------------------------------- Reporter: duncan | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: libraries/unix | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- The docs for System.Posix.IO.fdToHandle state: {{{ fdToHandle :: Fd -> IO HandleSource Converts an Fd into a Handle that can be used with the standard Haskell IO library (see System.IO). GHC only: this function has the side effect of putting the Fd into non-blocking mode (O_NONBLOCK) due to the way the standard IO library implements multithreaded I/O. }}} The final paragraph is wrong. The code no longer does this. System.Posix.IO.fdToHandle ends up calling GHC.IO.Handle.FD.fdToHandle which has this comment: {{{ fdToHandle :: Posix.FD -> IO Handle fdToHandle fdint = do iomode <- Posix.fdGetMode fdint (fd,fd_type) <- FD.mkFD fdint iomode Nothing False{-is_socket-} -- NB. the is_socket flag is False, meaning that: -- on Windows we're guessing this is not a socket (XXX) False{-is_nonblock-} -- file descriptors that we get from external sources are -- not put into non-blocking mode, because that would affect -- other users of the file descriptor }}} So clearly, it is now deliberately not putting it into non-blocking mode. This can trip people up who expect that it does put it into non-blocking mode, when in fact they now have to do that manually. Fix is trivial: delete that paragraph from the docs for that function. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8286 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler