Path: utzoo!utgpu!water!watmath!clyde!att!pacbell!ditka!stb!michael
From: michael@stb.UUCP (Michael)
Newsgroups: comp.sys.amiga.tech
Subject: Re: pipe: stuff
Keywords: put that in your pipe: and smoke it!
Message-ID: <10435@stb.UUCP>
Date: 19 Jun 88 18:26:48 GMT
References: <10440@ames.arc.nasa.gov>
Reply-To: michael@stb.UUCP (Michael)
Organization: STB BBS, La, Ca, Usa, +1 213 459 7231
Lines: 41

Which pipe device are you using? There are at least 2 public domain ones,
a third was on the 1.2 disks (non working, alas), there's probably another
one on the 1.3 disks (which are still gamma, so it may be bugged).

In general, pipes work by having a reader and a writter. The reader will
block on reads until either
	A: A writter writes data,
	B: All writters close the file
Since AmigaDos does not allow duplicating file handles, this really only
allows for a single reader and single writter.

From your discription, it sounds like the pipe: you are using will only
support one pipe at any given time, and as such, your descriptions
sound reasonably correct--the reader blocks until data is written, once
the writter closes the file and exits, the reader receives length 0
reads, and additional opens are not allowed until the first pipe:
is gone.

You might want to get one of the other pipe handlers and see if they allow
a pipe to be opened multiple times for writting. In any event, the
reader will block if there are no writters (at least for any pipe
device that wants to maintain resonable compatibility with the
definition of unix pipes).

(Remember: A pipe should look to a program like a file. When a program reads
length 0 from a file, it hits end of file. You haven't hit end-of-pipe
until no more writters exist).

Hmm, here's something you might try (might work):
RUN WAIT > PIPE: 32766 MIN
RUN MONITOR
COMMAND1 > PIPE:
COMMAND2 > PIPE:
etc. This might work, or it might not.

				Michael
: --- 
: Michael Gersten			 uunet.uu.net!denwa!stb!michael
:				sdcsvax!crash!gryphon!denwa!stb!michael
: What would have happened if we had lost World War 2. Well, the west coast
: would be owned by Japan, we would all be driving foreign cars, hmm...