Function igraph_connected_components 

pub unsafe extern "C" fn igraph_connected_components(
    graph: *const igraph_t,
    membership: *mut igraph_vector_int_t,
    csize: *mut igraph_vector_int_t,
    no: *mut igraph_int_t,
    mode: igraph_connectedness_t,
) -> igraph_error_t