gistfile1.hs

ncInq :: NCID -> IO (Int, Int, Int, Int)
ncInq ncid = do
    alloca $ \ndims_ptr -> do
        alloca $ \nvars_ptr -> do
            alloca $ \natts_ptr -> do
                alloca $ \unlimdimid_ptr -> do
                    status     <- nc_inq ncid ndims_ptr nvars_ptr natts_ptr unlimdimid_ptr 
                    ndims      <- peek ndims_ptr
                    nvars      <- peek nvars_ptr
                    natts      <- peek natts_ptr
                    unlimdimid <- peek unlimdimid_ptr
                    return (fromEnum ndims, fromEnum nvars, fromEnum natts, fromEnum unlimdimid)

-- looks to me to be equivalent to this
ncInq :: NCID -> IO (Int, Int, Int, Int)
ncInq ncid = do
    ndims_ptr <- alloca
    nvars_ptr <- alloca
    natts_ptr <- alloca
    unlimdimid <- alloca_ptr
    status <- nc_inq ncid ndims_ptr nvars_ptr natts_ptr unlimdimid_ptr
    ndims <- peek ndims_ptr
    nvars <- peek nvars_ptr
    natts <- peek natts_ptr
    unlimdimid <- peek unlimdimid_ptr
    return (fromEnum ndims, fromEnum nvars, fromEnum natts, fromEnum unlimdimid)

@tonymorris:

That is not equivalent. alloca takes a function as a parameter. See my last fork for an example using ContT that looks more like your version, though.

Ah yeah duh@me.