After a singular point has been detected and located a singular point data structure will be created and initialized as described in section 4.2. If there are some special data (like eigenvalues) which may be of interest for a particular singular point then a call to [failed,s] = feval(cds.curve_process,i,x,v,s) should store this data in the s.data field. Here i indicates which singularity was detected and x and v are the point and tangent vector where this singularity was detected.