is a library callback function that puts a clone of into *.
- Used in C/C++ code in a library function called from Mathematica.
- A nonzero error code value will be returned if there is not sufficient memory.
- The destination *r should either be null (0) or an MSparseArray object.
- A new MSparseArray is always created. If *r is not null then the memory will be freed before creating the new result.