/etc/portage/package.use: gnome-base/gvfs udisks $ emerge -pv gnome-base/gvfs [ebuild R ] gnome-base/gvfs-1.12.3-r1 USE="cdda fuse http udev -afp -archive -avahi -bluetooth -bluray -doc -gdu -gnome-keyring -gphoto2 -ios -samba (-udisks)" 0 kB According to man emerge 'udisks' USE flag of gnome-base/gvfs is not only turned off, but for installed version it's masked. $ eix -e gvfs [I] gnome-base/gvfs Available versions: 1.12.3-r1 ~1.14.2 [M]~1.16.1 [M]~1.16.2^t {{afp archive avahi bluetooth bluray cdda doc fuse gdu gnome-keyring gnome-online-accounts gphoto2 gtk +http ios mtp samba systemd test +udev udisks}} Installed versions: 1.12.3-r1(09:40:33 10.06.2013)(cdda fuse http udev -afp -archive -avahi -bluetooth -bluray -doc -gdu -gnome-keyring -gphoto2 -ios -samba -udisks) Displays 'udisks' USE _only_ turned off. In conjunction with package.use settings it looks confusing. I expect eix to show mask state of USE in the same way with emerge. I.e. for listed example: ... Installed versions: 1.12.3-r1(09:40:33 10.06.2013)(cdda fuse http udev -afp -archive -avahi -bluetooth -bluray -doc -gdu -gnome-keyring -gphoto2 -ios -samba (-udisks))
USE-Flags and *DEPENDS are only rudimentarily supported by eix: For available versions, eix only shows the IUSE metadata of the ebuild. For installed versions, eix only shows the IUSE/USE data from /var/db. From eix/TODO: > Ambitious tasks [...] > - Full support for USE-Flags. > Although initial implementation is not extremely hard[...]