On Thu, Jun 10, 2010 at 05:34:23AM -0400, bugzilla(a)redhat.com wrote: Unfortunately although this looks temptingly simple, it doesn't work for a variety of reasons. (1) $g is captured by the closure and so prevents implicit closure. Of course you can explicitly close the handle now, but it's still very counter-intuitive. (2) Even if you explicitly close the handle, the closure will still capture $g and prevent the handle from being freed (the reasons are this are quite subtle -- see perlcall(3) discussion of call_sv for the full details). (3) Whatever you do, you end up with a static array in the XS code storing SVs which has all sorts of horrible thread safety issues. Again, see perlcall(3) for the details. (4) guestfs_close can be called from exit (via an atexit handler) and it's not at all clear that the Perl interpreter won't have been shut down by the time we try to invoke the closure, resulting in hilarity. Since it's now possible to store user data in the Perl handle, I suggest pursuing a Perl-based solution to all this. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into Xen guests. http://et.redhat.com/~rjones/virt-p2v