pub unsafe extern "C" fn igraph_vector_char_difference_and_intersection_sorted(
v1: *const igraph_vector_char_t,
v2: *const igraph_vector_char_t,
vdiff12: *mut igraph_vector_char_t,
vdiff21: *mut igraph_vector_char_t,
vinter: *mut igraph_vector_char_t,
) -> igraph_error_t