--- `exitWith code' terminates the program, returning `code' to the
--- program's caller. Before it terminates, any open or semi-closed
--- handles are first closed.
-
-#ifdef __GLASGOW_HASKELL__
+-- | Computation 'exitWith' @code@ throws 'ExitCode' @code@.
+-- Normally this terminates the program, returning @code@ to the
+-- program's caller.
+--
+-- On program termination, the standard 'Handle's 'stdout' and
+-- 'stderr' are flushed automatically; any other buffered 'Handle's
+-- need to be flushed manually, otherwise the buffered data will be
+-- discarded.
+--
+-- A program that fails in any other way is treated as if it had
+-- called 'exitFailure'.
+-- A program that terminates successfully without calling 'exitWith'
+-- explicitly is treated as it it had called 'exitWith' 'ExitSuccess'.
+--
+-- As an 'ExitCode' is not an 'IOError', 'exitWith' bypasses
+-- the error handling in the 'IO' monad and cannot be intercepted by
+-- 'catch' from the "Prelude". However it is a 'SomeException', and can
+-- be caught using the functions of "Control.Exception". This means
+-- that cleanup computations added with 'Control.Exception.bracket'
+-- (from "Control.Exception") are also executed properly on 'exitWith'.
+--
+-- Note: in GHC, 'exitWith' should be called from the main program
+-- thread in order to exit the process. When called from another
+-- thread, 'exitWith' will throw an 'ExitException' as normal, but the
+-- exception will not cause the process itself to exit.
+--
+#ifndef __NHC__