[Haskell-cafe] C++ exception (from *.so) catchable by Haskell??

[Brandon Allbery]

On Thu, Feb 13, 2014 at 6:43 AM, Nick Rudnick <nick.rudnick at gmail.com>wrote:

> 3) To my surprise, every time the output stays the same:
>
> terminate called after throwing an instance of 'std::runtime_error'
>   what():  OOOPS.
>

It's calling terminate which calls exit(), in the C++ runtime. You can't
catch it at that level.

set_unexpected() may or may not help you since it's not clear that you can
make it pop back to the FFI call and no further. Maybe you can use
setjmp()/longjmp() or setcontext() and friends, but I'm betting its
interaction with C++ is undefined (and in particular C++
finalizers/destructors don't get called).

Your best bet is to catch the exception in C++, in whatever code you are
invoking from the (C context) FFI call.

Upshot: there is no global concept of exceptions that applies across all
languages unless you're using something like JVM or CLR.

-- 
brandon s allbery kf8nh                               sine nomine associates
allbery.b at gmail.com                                  ballbery at sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net
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