Hi,
Amirouche Boubekki <[email protected]> writes:
> I have a program that try to download hackernews locally.
>
> What it does is simple, it fetch the max identifier and
> http-get each json value starting with the most recent
> item. I use n-for-each-par-map with 16 threads I have
> 8 cores.
>
> Here is the full program:
[...]
> (define (store pair)
> (if (null? pair)
> (format #t "X\n")
> (let ((port (open-file "hn.scm" "a")))
> (format #t "~a\n" (car pair))
These calls to (format #t ...), which write to a port that is shared by
multiple threads, should be performed while holding a mutex to prevent
concurrent writes to the same port.
I/O operations in Guile do not include built-in thread synchronization,
at least not in the fast path cases. However, an effort was made to
avoid _crashes_ on common architectures in the event of concurrent use
of the same port. Our hope was that the worst that would typically
happen is garbled I/O. Perhaps we failed to realize that hope.
> How can I debug this?
It would be helpful to see a GDB backtrace from a crash in this program.
Does it help to protect the shared port with a mutex?
Thanks,
Mark
