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From: jhc@m2jhc.uucp (James H. Coombs)
Newsgroups: comp.unix.questions
Subject: Re: How can a server tell if a client is gone?
Message-ID: <48479@brunix.UUCP>
Date: 28 Aug 90 20:33:55 GMT
References: <26DAAE36.74D6@wilbur.coyote.trw.com>
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In article <26DAAE36.74D6@wilbur.coyote.trw.com> rudoff@mdi.com writes:
>I am writing an application that uses a client-server model. I want the
>server to be able to tell if the client has disappeared unexpectedly.
>
>I have been using RPC for interprocess communication on a Sun3 and Sun4
>running 4.0.3.

I agree that your need is fundamental and that RPC should provide some
direct support.

In the meantime, you can consider the keepalive option on sockets.
Also, if a socket read succeeds with 0 bytes read, you can reasonably
infer that the other end has died.  Others have better explanations and
would probably recommend the use of a select().  Finally, if you
attempt a write on a disconnected socket, the SIGPIPE signal will be
raised.  I don't know of any straightforward way to apply these
techniques with RPC.

--Jim