🚀 go-pugleaf

In article <BtCqCG.DMw@usenet.ucs.indiana.edu> jackson@daimler.ucs.indiana.edu (Jeff Jackson) writes:
>
>In the client, after the server has timed out and closed the socket,
>I expected to get a SIGPIPE signal the next time I tried a write to 
>the socket. What I am finding is that the first write that I do to
>the socket completes normally - returning the number of bytes that
>were written. Sometimes even the second write will appear to succeed.
>Usually however the second or third write causes the SIGPIPE signal, which
>is trapped and closes the socket. 
>
>What needs to be done to get the SIGPIPE signal the FIRST time I write
>to the socket? 

You are encoutnering TCP's half-close.  The server's closing of its
socket causes its TCP to send a FIN.  That only closes the data flow
from the server to the client.  As far as the client's TCP is concerned,
it can still *send* data to the server.  Your first write will be OK,
but the server's TCP will respond with a RST (since the server really
terminated and didn't do a real half-close), which causes the second
client write to get SIGPIPE.  You can't change this--it's a TCP feature.

What you need to do is call select from the client--then the socket
will be marked readable in the client when the server terminates and
your read will receive an EOF.  Use that to not write anything else
to the server.

	Rich Stevens  (rstevens@noao.edu)