virDomainPtr	virDomainMigrate	(virDomainPtr domain, 

					 virConnectPtr dconn, 
					 unsigned long flags, 
					 const char * dname, 
					 const char * uri, 
					 unsigned long bandwidth)

to achieve the domain to the remote host. I set the "const char * uri" as "qemu+ssh://root@116.56.142.199/system".

But the Error "libvir: QEMU error : invalid argument in only tcp URIs are supported for KVM/QEMU migrations" happened.

I want to know when i want the migrate ,how can i set the URI ? offer a example is better.   :-)