Function igraph_bfs 

pub unsafe extern "C" fn igraph_bfs(
    graph: *const igraph_t,
    root: igraph_int_t,
    roots: *const igraph_vector_int_t,
    mode: igraph_neimode_t,
    unreachable: igraph_bool_t,
    restricted: *const igraph_vector_int_t,
    order: *mut igraph_vector_int_t,
    rank: *mut igraph_vector_int_t,
    parents: *mut igraph_vector_int_t,
    pred: *mut igraph_vector_int_t,
    succ: *mut igraph_vector_int_t,
    dist: *mut igraph_vector_int_t,
    callback: igraph_bfshandler_t,
    extra: *mut c_void,
) -> igraph_error_t