Subject: Re: DHCP client, integration with ifconfig, etc.
To: Bill Sommerfeld <>
From: Perry E. Metzger <>
List: tech-kern
Date: 02/10/1997 11:23:12
Bill Sommerfeld writes:
>    It turns out that when you're mobile, some daemons don't behave
>    properly, so another thing this script might do is to shut down
>    some daemons and restart them when the IP address changes.
> An idea which has occurred to me was to add a new signal,
> SIGIFCH, analogous to SIGWINCH, which is delivered to user
> processes expressing interest in it when the "local address set" of a
> system changes.

There are a bunch of things that one might want to signal -- window
size changes, IP changes, wakeups following an APM sleep, etc.

I wish kill() had a richer interface so one could pass data along with
a signal and have one generic "something has changed" signal and tell
what has changed in the passed data.  I believe the kernel can sort of
do this right now for some signals...