problem with FFI and libsane

Ganesh Sittampalam ganesh at
Thu Jun 7 23:25:49 CEST 2012

On 07/06/2012 12:08, Simon Marlow wrote:

> I don't completely understand what is going wrong here, but it looks
> like an interaction between the RTS's use of a timer signal and the
> libsane library.  You can make it work by turning off GHC's timer with
> +RTS -V0.
> The signal has always been SIGVTALRM, as far as I can tell.  Which is
> confusing - if the signal had changed, I could understand that being the
> cause of the difference in behaviour.  Perhaps it is just that system
> calls are being interrupted by the signal more often than they were
> before, and libsane does not properly handle EINTR.  I looked at the
> strace output and can't see any use of a signal by libsane.

I see, thanks. I'll do some digging into libsane and see if I can work
out more details.



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