Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!rex!mb
From: mb@rex.cs.tulane.edu (Mark Benard)
Newsgroups: comp.unix.questions
Subject: Re: Can a parent process determine its child's status ?
Message-ID: <2377@rex.cs.tulane.edu>
Date: 6 Mar 90 23:29:08 GMT
References: <5090.25e135aa@mva.cs.liv.ac.uk>
Reply-To: mb@rex.UUCP (Mark Benard)
Organization: Computer Science Dept., Tulane Univ., New Orleans, LA
Lines: 18

In article <5090.25e135aa@mva.cs.liv.ac.uk> adh@mva.cs.liv.ac.uk writes:
>...... The children are executing simultaneously, so the parent uses
>non-blocking reads, polling each pipe to see if anything has arrived.
>Unfortunately, a call to 'read' returns zero if the child hasn't
>sent any new data *OR* if the child has terminated so the parent cannot
>distinguish between EOF on a pipe and a pipe that temporarily has no
>data in it.

If you have BSD, you can use select instead of polling.  Then do a
blocking read on the selected channels, which will either have data or
an EOF condition.

-Mark
-- 
Mark Benard
Department of Computer Science     INTERNET & BITNET: mb@cs.tulane.edu
Tulane University                  USENET:   rex!mb
New Orleans, LA 70118