lookupSymbol :: String -> IO (Maybe (Ptr a))
lookupSymbol str_in = do
   let str = prefixUnderscore str_in
   withCAString str $ \c_str -> do
     addr <- c_lookupSymbol c_str
     if addr == nullPtr
        then return Nothing
        else return (Just addr)
lookupSymbol :: String -> IO (Maybe (Ptr a))
lookupSymbol str_in = do
   let str = prefixUnderscore str_in
   withCAString str $ \c_str -> do
     addr <- c_lookupSymbol c_str
     if addr == nullPtr
        then return Nothing
        else return (Just addr)
lookupSymbol str_in = do
   let str = prefixUnderscore str_in
   withCAString str $ \c_str -> do
     addr <- c_lookupSymbol c_str
     if addr == nullPtr
        then return Nothing
        else return (Just addr)