1 {-# OPTIONS -#include "PrelIOUtils.h" #-}
2 -- -----------------------------------------------------------------------------
4 -- (c) The University of Glasgow, 1994-
8 -- 'Top-level' IO actions want to catch exceptions (e.g., forkIO and
9 -- PrelMain.mainIO) and report them - topHandler is the exception
10 -- handler they should use for this:
12 -- make sure we handle errors while reporting the error!
13 -- (e.g. evaluating the string passed to 'error' might generate
14 -- another error, etc.)
16 -- These functions can't go in PrelMain, because PrelMain isn't
17 -- included in HSstd.o (because PrelMain depends on Main, which
18 -- doesn't exist yet...).
20 -- Note: used to be called PrelTopHandler.lhs, so if you're looking
21 -- for CVS info, try 'cvs log'ging it too.
22 module PrelTopHandler (
23 topHandler, reportStackOverflow, reportError
33 topHandler :: Exception -> IO ()
34 topHandler err = catchException (real_handler err) topHandler
36 real_handler :: Exception -> IO ()
39 AsyncException StackOverflow -> reportStackOverflow True
41 -- only the main thread gets ExitException exceptions
42 ExitException ExitSuccess -> shutdownHaskellAndExit 0
43 ExitException (ExitFailure n) -> shutdownHaskellAndExit n
45 ErrorCall s -> reportError True s
46 other -> reportError True (showsPrec 0 other "\n")
48 -- NOTE: shutdownHaskellAndExit must be called "safe", because it *can*
49 -- re-enter Haskell land through finalizers.
50 foreign import ccall "shutdownHaskellAndExit"
51 shutdownHaskellAndExit :: Int -> IO ()
53 reportStackOverflow :: Bool -> IO ()
54 reportStackOverflow bombOut = do
55 (hFlush stdout) `catchException` (\ _ -> return ())
62 reportError :: Bool -> String -> IO ()
63 reportError bombOut str = do
64 (hFlush stdout) `catchException` (\ _ -> return ())
65 withCStringLen str $ \(cstr,len) -> do
66 writeErrString errorHdrHook cstr len
72 foreign label "ErrorHdrHook" errorHdrHook :: Ptr ()
74 foreign import "_ErrorHdrHook" errorHdrHook :: Ptr ()
77 foreign import ccall "writeErrString__" unsafe
78 writeErrString :: Ptr () -> CString -> Int -> IO ()
80 -- SUP: Are the hooks allowed to re-enter Haskell land? If so, remove
82 foreign import ccall "stackOverflow" unsafe
83 callStackOverflowHook :: IO ()
85 foreign import ccall "stg_exit" unsafe
86 stg_exit :: Int -> IO ()