On Feb 8, 2008 10:57 AM, Galchin Vasili
basically I am trying to implement ioctl for the Posix library .. so a possible signtaure would be:
fdIoctl :: Fd -> Int -> Ptr Word 8 -> IO( Ptr Word8) ????
Ah, ok. You could cover many of the ioctls (the ones which only take a single primitive) by using the Storable class and the types CInt etc. Define the FFI call to ioctl with a type of CInt -> Int -> Ptr () -> IO CInt and then ioctlCInt :: CInt -> CInt -> CInt -> IO CInt ioctlCInt fd call arg = do allocaBytes $ \ptr -> do poke ptr arg result <- ioctl fd call (cast ptr) when (result < 0) $ fail "ioctl error" peek ptr (untested, might work ;) ... and likewise for the other C types. However, for those ioctls which take a complex structure (e.g. many of the networking ones), you'll need to marshal yourself: data SomeIOCtlStruct = CInt CInt CInt ioctlSomeIOCtlStruct :: CInt -> CInt -> SomeIOCtlStruct -> IO () ioctlSomeIOCtlStruct = do ... (see the above linked to pointers to hsc2hs and c2hs about how to write this function) AGL -- Adam Langley agl@imperialviolet.org http://www.imperialviolet.org 650-283-9641