How to determine cluster rotation around z-axis?

I have a <PointXYZ> cloud that needs to be clustered. I've used pcl::EuclideanClusterExtraction to extract the clusters, Also, I've used pcl::computeCentroid(*(cluster),centroid) to get the centroid x,y,z values. I am asking if there is a function like computeCentroid in pcl that can compute the rotation around the z-axis. If it is not implemented, may I know how to manually calculate it from the cluster points? ps: I know that manual calculation may slow the overall performance since I am not doing any optimizations. Thanks.