Xref: utzoo comp.sys.att:7242 unix-pc.general:3533
Path: utzoo!utgpu!watmath!uunet!tut.cis.ohio-state.edu!n8emr!uncle!jbm
From: jbm@uncle.UUCP (John B. Milton)
Newsgroups: comp.sys.att,unix-pc.general
Subject: Re: sockets & ptys
Keywords: PD socket & PD pty
Message-ID: <589@uncle.UUCP>
Date: 9 Aug 89 05:47:02 GMT
References: <637@holin.ATT.COM> <2229@umbc3.UMBC.EDU>
Reply-To: jbm@uncle.UUCP (John B. Milton)
Organization: U.N.C.L.E.
Lines: 39

In article <2229@umbc3.UMBC.EDU> alex@umbc3.umbc.edu.UMBC.EDU (Alex S. Crain) writes:
>In article <637@holin.ATT.COM> bes@holin.ATT.COM (Bradley Smith) writes:
>>Now a question. I want select to work on the /dev/window as well
>>(like stdin, stdout) but you can't access data in other loadable
>>devices.  I thought of find out what address the struct tty is at
>>and looking at it that way.  Does anyone have an idea?
>	You can access data in loadable devices, *if you know the address*.
>One way of doing this is to link with /etc/lddrv/ifile.wind and assume that
>this info will not change. Another way would be to have uipcinit() read
>/etc/ldrv/ifile.wind (yuk). Since its reasonable to assume that wind.o
>will always be the first driver loaded, then there is no reason that the
>addresses should change, ever, so using that ifile is a reasonably good
>way of doing it. You could justify it by assuming that the window driver 
>will someday be replaced, so this is only temporary :-).
>
>	ld -r -o uipc.o /etc/lddrv/ifile.wind *.o 
>
>should give you what you want.

There is one minor problem. Everytime you change the version of the kernel
you're using, each ifile.driver gets regenerated. The file /etc/.drvload does
this:
---
find . -name unix.sym ! -newer /unix -exec rm {} \; 
if [ ! -r unix.sym ]
then
	echo creating unix.sym 
	./mkifile /unix unix.sym 
fi
----
and lddrv checks unix.sym to make sure it's older than the driver file

So, you would have to at least regenerate the addresses everytime you change
the kernel.

John
-- 
John Bly Milton IV, jbm@uncle.UUCP, n8emr!uncle!jbm@osu-cis.cis.ohio-state.edu
(614) h:294-4823, w:785-1110; N8KSN, AMPR: 44.70.0.52; Don't FLAME, inform!