[Haskell-cafe] strange hangs with -threaded runtime (now with test case)

Joey Hess joey at kitenet.net
Sat Jul 14 21:28:33 CEST 2012

Antoine Latter wrote:
> Well, hPipeFrom does indeed call forkProcess internally. I don't fully
> understand when it is and is not safe to use 'forkProcess' with the
> threaded runtime of GHC.
> Which version of GHC are you using?

I've reproduced the problem with 7.4.2, and 7.4.1.

Just tried 6.12.1, which is interesting.. after around the same number of iterations
at which it hangs with the newer ghcs, it instead does this:

"pipeRead in [\"hello\",\"world\"]"
"pipeRead getcontents"
test: internal error: MUT_ARR_PTRS_FROZEN object entered!
    (GHC version 6.12.1 for i386_unknown_linux)
    Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
"got: "
"pipeRead out"

see shy jo

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