Would you mind filing a ticket for this as well now when the trac instance is working? Thanks a lot! -- Johan On Mon, Nov 30, 2009 at 3:49 PM, Valery V. Vorotyntsev wrote:

See http://is.gd/57Ptu (Network.Socket.setSocketOption).

`setSocketOption' uses FFI binding to setsockopt(2), named `c_setsockopt'.

...

foreign import CALLCONV unsafe "setsockopt"   c_setsockopt :: CInt -> CInt -> CInt -> Ptr CInt -> CInt -> IO CInt

The binding treats OPTVAL (4th argument) as a pointer to `int'. This is mostly fine but not when `SO_LINGER' option is being set. In the latter case OPTVAL must be a pointer to `struct linger'. [1]

 [1] http://www.gnu.org/s/libc/manual/html_node/Socket_002dLevel-Options.html

Haskell programs trying to set SO_LINGER socket option will successfully compile but fail in runtime.

   $ runhaskell socket-linger.hs || echo X    $ runhaskell -DLINGER socket-linger.hs || echo X    socket-linger.hs: setSocketOption: invalid argument (Invalid argument)    X

   $ gcc -g -Wall -W -o /tmp/1 socket-linger.c && /tmp/1 || echo X    $ gcc -g -DLINGER_AS_INT -Wall -W -o /tmp/1 socket-linger.c && /tmp/1 || echo X    setsockopt: Invalid argument    X

(See attached files `socket-linger.c', `socket-linger.hs'.)

The necessity of `SO_LINGER' option is controversial (see [2]). I think it is better to comment the `Linger' constructor out of Network/Socket.hsc.

 [2] http://www.developerweb.net/forum/archive/index.php/t-2982.html

Cheers.

-- vvv