Odd FFI behavior

Donn Cave donn at avvanta.com
Wed Aug 13 15:56:59 UTC 2014

[ ... re -V0 ]
> Thanks, this solved the problem.
> I would like to know more about what the signals are doing, and
> what am I giving up by disabling them?
> My hope is I can then go back to the dll expert and ask why this
> is causing their library a problem and try to see if they can
> solve the problem from their end, etc.

I'm disgracefully ignorant about that.  When I've been forced to
run this way, it doesn't seem to do any very obvious immediate
harm to the application at all, but I could be missing long term

The problem with the library might be easy to fix, and in principle
it's sure worth looking into - while the GHC runtime delivers signals
on an exceptionally massive scale, there are plenty of normal UNIX
applications that use signals, maybe timers just like this for example,
and it's easy to set up a similar test environment using setitimer(2)
to provide the signal bombardment.  (I believe GHC actually uses
SIGVTALRM rather than SIGALRM, but don't think it will make any

But realistically, in the end sometimes we can't get a fix for it,
so it's interesting to know how -V0 works out as a work-around.
I hope you will keep us posted.


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