Thanks for pointing out the mistake.I will move the check in qemuConnectGetAllDomainStats, this won't make a old client cannot use the future server and will give a good error when use future client to connect to old server. Thanks, Luyao Huang ----- Original Message ----- From: "Eric Blake" <eblake@xxxxxxxxxx> To: "Luyao Huang" <lhuang@xxxxxxxxxx>, libvir-list@xxxxxxxxxx Sent: Tuesday, November 4, 2014 7:19:41 PM Subject: Re: [PATCH] domain: Improve error output for virDomainListGetStats On 11/04/2014 07:51 AM, Luyao Huang wrote: > When pass flags --domain and --list-* to cmdDomstats, > a unsupport error will output from qemuConnectGetAllDomainStats. > > error: unsupported flags (0x1) in function qemuConnectGetAllDomainStats > >>From manual of virsh: The approaches can't be combined. NACK. While they cannot be combined in the current implementation, I see nothing that would prohibit a future implementation from allowing the combination (for example, show me all stats for a given domain, but only if the domain is running). Prohibiting in libvirt-domian.c would prevent an older RPC client from talking to a newer server that supports the combination. We should only prohibit combinations in libvirt-*.c if there is no chance we will ever extend things to allow the combination. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list