On Wed, 2012-07-18 at 18:22 +0200, Simon Peter Nicholls wrote: > Some "sending" code: > > Foreign.C.String.withCWString "frustrator" $ \s -> do > let wParam = System.Win32.Types.castPtrToUINT s :: > System.Win32.Types.WPARAM > Graphics.Win32.sendMessage wnd Graphics.Win32.wM_APP wParam 0 > > wndProc "receiving" code: > > | wmsg == Graphics.Win32.wM_APP = do > s <- peekCWString $ System.Win32.Types.castUINTToPtr wParam > putStrLn s > return 0 >
>From the docs ( http://hackage.haskell.org/packages/archive/base/4.5.1.0/doc/html/Foreign-C-String.html#v:withCWString ): > the memory is freed when the subcomputation terminates (either normally or via an exception), so the pointer to the temporary storage must not be used after this I'm noy a windows guru, but I assume that `sendMessage` just puts the message into a queue and exits. So, you receive a pointer to already deallocated memory. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
