pub unsafe extern "C" fn igraph_vector_is_nan(
v: *const igraph_vector_t,
is_nan: *mut igraph_vector_bool_t,
) -> igraph_error_tpub unsafe extern "C" fn igraph_vector_is_nan(
v: *const igraph_vector_t,
is_nan: *mut igraph_vector_bool_t,
) -> igraph_error_t