--- size when the `IOMode` is `WriteMode`. Puts the file descriptor
--- into non-blocking mode on Unix systems.
-openFile :: FilePath -> IOMode -> IO (FD,IODeviceType)
-openFile filepath iomode =
+-- size when the `IOMode` is `WriteMode`.
+openFile
+ :: FilePath -- ^ file to open
+ -> IOMode -- ^ mode in which to open the file
+ -> Bool -- ^ open the file in non-blocking mode?
+ -> IO (FD,IODeviceType)
+
+openFile filepath iomode non_blocking =