##### A.1.6.3 Using Sparse Matrices in Oct-Files

Most of the same operators and functions on sparse matrices that are available from the Octave are equally available with oct-files. The basic means of extracting a sparse matrix from an `octave_value` and returning them as an `octave_value`, can be seen in the following example.

         octave_value_list retval;

         SparseMatrix sm = args(0).sparse_matrix_value ();
         SparseComplexMatrix scm =
             args(1).sparse_complex_matrix_value ();
         SparseBoolMatrix sbm = args(2).sparse_bool_matrix_value ();
         ...
         retval(2) = sbm;
         retval(1) = scm;
         retval(0) = sm;

The conversion to an octave-value is handled by the sparse `octave_value` constructors, and so no special care is needed.