Hi Bernd, On Fri, 08 Dec 2006 14:20:15 +0100 Bernd Holzmüller <[EMAIL PROTECTED]> wrote:
> I would like to use the function > > treeCtrlHitTest :: TreeCtrl a -> Point -> Ptr CInt -> IO TreeItem > > but I cannot find out from the wxHaskell documentation how to create / > use the Ptr argument, which stands for an "out" parameter. You can create a pointer using functions from Foreign.Marshal.Alloc, and read/write it using functions from Foreign.Marshal.Storable. For example, using alloca and peek, you can write a simple wrapper around treeCtrlHitTest, which returns a pair instead of requiring a Ptr. myHitTest :: TreeCtrl a -> Point -> IO (TreeItem, CInt) myHitTest w point = alloca $ \ptr -> do r <- treeCtrlHitTest w point ptr flags <- peek ptr return (r, flags) Regards, Takano Akio ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ wxhaskell-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/wxhaskell-users
