[Haskell-cafe] hugs segmentation fault

Fergus Henderson fjh-mailbox-24 at galois.com
Thu Oct 28 20:51:18 EDT 2004

On 29-Oct-2004, Ben Rudiak-Gould <Benjamin.Rudiak-Gould at cl.cam.ac.uk> wrote:
> Jon Fairbairn wrote:
> >On 2004-10-29 at 00:03BST Ben Rudiak-Gould wrote:
> >
> >>Not much better, though: in my experience this particular
> >>exception leaves ghci in a very peculiar state, and it's
> >>usually necessary to quit and restart it before it will
> >>work again.
> >
> >I don't think I've seen such a problem (maybe I so rarely
> >make that type of mistake?;-). What version? What are the
> >symptoms of this not working of which you speak? It seems
> >OK in ghci 6.2.1

We ran into a related problem recently.  I think the problem may only
show up on Windows, not on Linux.  The problem is that when a loop
occurs, ghc's garbage collection detects that the standard I/O handles
for stdin/stdout/stderr can no longer be referenced and finalizes them,
*before* detecting the loop and throwing an exception.  Subsequent code
may then attempt to use these already-finalized standard I/O handles.
A possible work-around is to create stable pointers to those handles.

But I'm not sure whether this is the same problem that you are

Fergus J. Henderson                 |  "I have always known that the pursuit
Galois Connections, Inc.            |  of excellence is a lethal habit"
Phone: +1 503 626 6616              |     -- the last words of T. S. Garp.

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