According to the C spec, this is expression is undefined for v == 0. So it might return true, or return false, or start NetHack, or wipe your disk. In other wo

According to the C spec, this is expression is undefined for v == 0. So it might return true, or return false, or start NetHack, or wipe your disk. In other words: Strictly speaken, that function is not allowed to be called for v == 0.