Function igraph_transitivity_barrat 

pub unsafe extern "C" fn igraph_transitivity_barrat(
    graph: *const igraph_t,
    res: *mut igraph_vector_t,
    vids: igraph_vs_t,
    weights: *const igraph_vector_t,
    mode: igraph_transitivity_mode_t,
) -> igraph_error_t