ipv6 default route cannot be set

[JM-Lemmi]

using the ip command to set an IPv6 address works, but the gateway is ignored completely. Pinging anything outside the L2 network fails to find the route.

PC1> version

Welcome to Virtual PC Simulator, version 0.8.2
Dedicated to Daling.
Build time: Aug 23 2021 11:15:00
Copyright (c) 2007-2015, Paul Meng (mirnshi@gmail.com)
All rights reserved.

VPCS is free software, distributed under the terms of the "BSD" licence.
Source code and license can be found at vpcs.sf.net.
For more information, please visit wiki.freecode.com.cn.

PC1> ip fd00:1::2/64 fd00:2::1
PC1 : fd00:1::2/64

PC1> ping fd00:1::1

fd00:1::1 icmp6_seq=1 ttl=64 time=0.725 ms
^C
PC1> ping fd00::2

host (fd00::2) not reachable

PC1> show ipv6

NAME              : PC1[1]
LINK-LOCAL SCOPE  : fe80::250:79ff:fe66:6801/64
GLOBAL SCOPE      : fd00:1::2/64
DNS               :
ROUTER LINK-LAYER :
MAC               : 00:50:79:66:68:01
LPORT             : 20008
RHOST:PORT        : 127.0.0.1:20009
MTU:              : 1500

[fpemud]

I have encountered the same problem. it's strange that the command doesn't show any error.
my vpcs version is 0.8.3

[fpemud]

This is what deepwiki.com answers after parsing this project:

The IPv6 gateway is being ignored because VPCS's IPv6 implementation doesn't support manually configured gateways - it only learns routes through Router Discovery (Router Advertisements). command6.c:319-388

Why the Gateway is Ignored
When you run ip fd00:1::2/64 fd00:2::1, the run_ipset6 function in src/command6.c only processes the IPv6 address and CIDR, but doesn't store the gateway address anywhere in the pcs structure. command6.c:319-388