For instance:

hellolibvirt/hellolibvirt.c: In function 'showDomains':
hellolibvirt/hellolibvirt.c:100:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < numNames; i++) {
                   ^
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>