Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!nosc!cod!waagen
From: waagen@cod.NOSC.MIL (Don E. Waagen)
Newsgroups: comp.unix.questions
Subject: end of file characters and open file descriptors
Message-ID: <1345@cod.NOSC.MIL>
Date: 29 Dec 88 19:06:28 GMT
Reply-To: waagen@cod.nosc.mil.UUCP (Don E. Waagen)
Organization: Naval Ocean Systems Center, San Diego
Lines: 23


   I'm trying to have two processes communicate via a pipe (stdout), like 

			A | B

but with a small difference.  Process A will never die (i.e. the connection 
will never be closed).  What I would like to do is have the fread and getchar()
calls of process B sense or think that it is seeing the pipe close (i.e. an EOF
character returned by the calls) without closing the connection.

I have tried flushing EOT characters (^D) to process B, but this doesn't help.
The fread call in process B remains blocked.  

I've also tried having process A's standard out dup'd and then closing standard
out, and then duping the duplicate back to 1 (standard out); no luck.  It 
seems the dup'd file descriptors share status fields.

My Question: What do the standard library calls use to determine end-of-file.
I really need to be able to do this, for a process to know when an end of 
transmission has occured.

Thanks in advance --
Don Waagen