On Mon, Jul 22, 2019 at 08:13:12AM -0500, Eric Blake wrote: > On 7/22/19 6:50 AM, Richard W.M. Jones wrote: > > On Mon, Jul 22, 2019 at 10:08:25AM +0100, Richard W.M. Jones wrote: > >> On Sat, Jul 20, 2019 at 07:38:45AM +0100, Richard W.M. Jones wrote: > >>> More thoughts on callbacks, etc. following on from: > >>> https://www.redhat.com/archives/libguestfs/2019-July/thread.html#00184 > >>> > >>> Closure lifetimes > >>> ----------------- > > > > Here's a possibly better idea which still changes the API a bit but > > not as invasively. > > > > We overload the callback so that it can either be a callback function > > or a "free function". They are distinguished by an extra flag > > argument passed to the callback: > > > > extern int nbd_set_debug_callback ( > > struct nbd_handle *h, > > int (*debug_fn) (int valid_flag, // <-- note > > void *user_data, > > const char *context, const char *msg), > > void *user_data); > > Would the 'valid_flag' be presented to non-C bindings, or is it only > needed for C code?
C only. It's not needed for languages which have garbage collection. For non-C languages without GC, well I guess we can decide on a case-by-case basis. > At any rate, the idea makes sense as a lighter-weight > way for libnbd to always inform the callback about the last invocation. I've almost got a working implementation. Will post it for review as soon as I can. [..] Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top _______________________________________________ Libguestfs mailing list Libguestfs@redhat.com https://www.redhat.com/mailman/listinfo/libguestfs
