GV_TODISABLE
if (v->gv_flags & GV_TODISABLE)
if (!satbility || v->gv_flags & GV_TODISABLE)
vertex->gv_flags &= ~GV_TODISABLE;
vertex->gv_flags |= GV_TODISABLE;
((v->gv_flags & GV_TODISABLE) || \
if (v->gv_flags & GV_TODISABLE)
v->gv_flags &= ~GV_TODISABLE;
if (v->gv_flags & GV_TODISABLE) {
v->gv_flags &= ~GV_TODISABLE;