Function igraph_get_adjacency_sparse 

pub unsafe extern "C" fn igraph_get_adjacency_sparse(
    graph: *const igraph_t,
    res: *mut igraph_sparsemat_t,
    type_: igraph_get_adjacency_t,
    weights: *const igraph_vector_t,
    loops: igraph_loops_t,
) -> igraph_error_t