Path: utzoo!attcan!uunet!mcvax!kth!draken!larss
From: larss@nada.kth.se (Lars Schylberg)
Newsgroups: comp.sys.apollo
Subject: fifo files on Apollo-systems.
Keywords: fifo files, interprocess communication
Message-ID: <1176@draken.nada.kth.se>
Date: 8 Jun 89 12:17:06 GMT
Organization: Royal Institute Of Technology, Stockholm, Sweden
Lines: 53

A problem for unix programmers.

I have a problem how to create fifo files on the Apollo
system.  We are currently running BSD4.2 and 9.7.1.

We are trying to port a public domain software called GRASS
(Geographic Resoures Analysis Support System) to Apollo, which prior
have been running on SUN and MASSCOMP.  The interprocess communication
in this package between the program and the Xwindow graphic driver is
handled with fifo files.  We have a monitorcap file that defines how
the fifo files should connect. eg:

APOLLO:driver/APOLLO:Apollo X graphics display:/dev/fifo.a /dev/fifo.b::any terminal

To get this to work we are supposed to create two devices with the
command:

mknod -p /dev/fifo.a
mknod -p /dev/fifo.b

This command is however not availble in 9.7.  I looked in the standard
library and found the mknod(2).  I wrote this program:

main()
{
   int mode;
   mode = 0010000;
   mknod("/dev/fifo.a",mode);
   mknod("/dev/fifo.b",mode);
}

and after that chmod 7777 fifo.a and fifo.b to be able to open those
from our program.  That didn't work however.  What have I done wrong.
I not too experienced in interporcess programming so I don't want to
rewrite this with sockets which I tried once before.  I would be very
glad for advice and hints how to get around this.

When we chance to OS 10.1, (we just have it on 1 out 8 nodes now)
I've seen there is a command mknod(8) with the syntax:

/etc/mknod name [b] / [c] major minor

I suppose that I want to create a character device with c
but what do I set major and minor to.  The system source file
conf.c is something I can't find.  Nither can the Stockholm
Apollo office support group.  HELP !!!!.

Lars Schylberg                       Email: larss@fmi.kth.se
Department of Photogrammetry         (Internet)
Royal Institute of Technolgy
S-100 44  STOCKHOLM                  Tel. +46 8 790 86 33 (office)
SWEDEN                               Fax. +46 8 10 91 99
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