Function igraph_distances_bellman_ford 

pub unsafe extern "C" fn igraph_distances_bellman_ford(
    graph: *const igraph_t,
    res: *mut igraph_matrix_t,
    from: igraph_vs_t,
    to: igraph_vs_t,
    weights: *const igraph_vector_t,
    mode: igraph_neimode_t,
) -> igraph_error_t