[Haskell-cafe] Compiling Setup.hs with -threaded

[Brandon Allbery]

On Thu, Jan 29, 2015 at 5:59 PM, Michael Orlitzky <michael at orlitzky.com>
wrote:

> and we want to run its test suite. Basically:
>
>   * If you run the test suite using runghc, then it works fine.
>   * If you compile Setup.hs to setup, then the test suite hangs.
>   * But if you compile Setup.hs to setup using -threaded, it works?
>

IIRC bytecode (runghc, ghci) always uses the threaded runtime, and this
problem can be a symptom of an FFI call that can block but wasn't declared
as potentially blocking; so the runtime calls it expecting it to not block
and the program freezes when it does block. In the threaded runtime, other
OS threads can continue executing in this case; in the non-threaded
runtime, this will block the "green" thread scheduler.

-- 
brandon s allbery kf8nh                               sine nomine associates
allbery.b at gmail.com                                  ballbery at sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20150129/4cbfb039/attachment.html>