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From: les@chinet.chi.il.us (Leslie Mikesell)
Newsgroups: comp.unix.questions
Subject: Re: Help: pipe accross two processes
Message-ID: <1990Dec04.050117.7239@chinet.chi.il.us>
Date: 4 Dec 90 05:01:17 GMT
References: <1510@ulowell.ulowell.edu>
Organization: Chinet - Public Access UNIX
Lines: 24

In article <1510@ulowell.ulowell.edu> mchetan@hawk.ulowell.edu (Munisuvratha Chetan) writes:
>I have a problem with "pipe"s, which might have appeared earlier.

>I have two processes - a server and a client.
>The server runs in an infinite loop untill killed.
>After the server is brought up, clients wil be forked, from a
>different shell.  If the clients know the process id of the
>server, how can I establish a communication channel between the
>two using pipes (and signals, if necessary) only.
>I know how to create pipes between a parent and child.

If your system supports FIFOs  (named pipes) just let the server create
on using a name known to the clients.  All clients can write to
the single FIFO read by the server (with some care to keep things that
must not be interleaved in a single write()), and this will automatically
schedule the requests.  Communicating back to the client is a different
problem.  Depending on the circumstances, you might want the client to
create a FIFO as well and pass its name in the request to the server, or
you might use shared memory or ordinary files with the server sending a
signal to the client when the output is completed and safe to read.
(See the man page for mknod to find out if you have named pipes.)

Les Mikesell
  les@chinet.chi.il.us