Function igraph_rng_sample_sphere_volume 

pub unsafe extern "C" fn igraph_rng_sample_sphere_volume(
    rng: *mut igraph_rng_t,
    dim: igraph_int_t,
    n: igraph_int_t,
    radius: igraph_real_t,
    positive: igraph_bool_t,
    res: *mut igraph_matrix_t,
) -> igraph_error_t