[libvirt-users] How to use "virDomainMemoryStats"? I got 0 result.

I use like this; int n = virDomainMemoryStats(dom, stats, 4, 0); I want to get men used and not used. If can , I want to get all output in stats. but "n" result is always 0. 非淡泊無以明志，非寧靜無以致遠