#2558: re-throwing an asynchronous exception throws it synchronously
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Reporter: simonmar | Owner: simonmar
Type: bug | Status: new
Priority: normal | Milestone: 6.12 branch
Component: Compiler | Version: 6.8.3
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Os: Unknown/Multiple
Architecture: Unknown/Multiple |
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Comment (by int-e):
My first instinct would be to pass a flag to exception handlers (changing
the type of the {{{catch#}}} primitive, and the stack frame creation in
{{{RaiseAsync.c}}} and {{{Exception.cmm}}} accordingly) to sort out at
their leisure. Igloo's idea is similar in that would also pass a flag
along with the exception, although the flag is set at a different point.
I'm not sure which is easier to accomplish.
It's already possible to use such a flag:
{{{
throwAsync :: Exception e => e -> IO ()
throwAsync e = do
target <- myThreadId
throwTo target e
throwSyncOrAsync :: Exception e => Bool -> e -> IO ()
throwSyncOrAsync async = if async then throwAsync else throwIO
}}}
If such a flag is added, I'd also like to have a variant of {{{catch}}}
that gets to see it in {{{Control.Exception}}}, say,
{{{
catchSyncOrAsync :: Exception e => IO a -> (Bool -> e -> IO a) -> IO a
}}}
and possibly {{{catchSync}}} and {{{catchAsync}}}.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2558#comment:5>
GHC <http://www.haskell.org/ghc/>
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