Hi, When using « virsh attach-device ....." to add a channel device to a Guest , I see following entry in libvirt log : 2015-12-07 11:14:47.307+0000: 14551: debug : virDomainAttachDeviceFlags:10433 : dom=0x7f2a58252fc0, ........ Great !! But , when calling virDomainAttachDeviceFlags( ) from a C program , I got return code -1 but nothing appears related to virDomainAttachDeviceFlags( ) in the libvirt log file . Others libvirt calls of this C program are correctly logged . Did I misunderstand something ? To add traces I've added these lines within /etc/libvirt/libvirtd.conf log_level = 1 log_outputs="1:file:/var/log/libvirt/libvirtd.log" Thx for help. Regards, J.P. Ribeauville P: +33.(0).1.47.17.20.49 . Puteaux 3 Etage 5 Bureau 4 jpribeauville@axway.com<mailto:jpribeauville@axway.com> http://www.axway.com<http://www.axway.com/> P Pensez à l'environnement avant d'imprimer.