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From: terryl@sail.LABS.TEK.COM
Newsgroups: comp.unix.questions
Subject: Re: reading on sockets when connection breaks
Message-ID: <8592@tekgvs.LABS.TEK.COM>
Date: 13 Dec 90 19:28:05 GMT
References: <25205@adm.brl.mil> <1990Dec6.055353.23846@Think.COM> <5727@navy40.UUCP> <1990Dec12.060545.7673@Think.COM>
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Reply-To: terryl@sail.LABS.TEK.COM
Organization: Tektronix, Inc., Beaverton,  OR.
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In article <1990Dec12.060545.7673@Think.COM> barmar@think.com (Barry Margolin) writes:
>In article <5727@navy40.UUCP> damenf@motcid.UUCP (Frederick Damen) writes:
>>1) After reading some related information on SIGPIPE and running a test program
>>   it seems as though SIGPIPE is only raised on a pipe/socket that has been 
>>   written to.
>
>Someone please correct me if I'm wrong (my answers are mostly educated
>guesses), but I think Unix keepalives are implemented by periodically
>retransmitting a packet with the sequence number of the last one sent.  The
>other host acknowledges having received all bytes up to that point, and
>this acknowledgement serves as the indication that it is still alive.  But
>if you haven't yet written anything, then there is nothing to retransmit


     OK, consider yourself corrected!!! (-:

     What actually happens is that sends out a packet with a sequence number
of send unacknowledged - 1, which should have been the last byte sent and
already acknowledged, which is what I guess Barry was trying to say.....

__________________________________________________________
Terry Laskodi		"There's a permanent crease
     of			 in your right and wrong."
Tektronix		Sly and the Family Stone, "Stand!"
__________________________________________________________