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From: Karl Pielorz <karl@skynet.co.uk>
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Checking Socket validity under BSD
Date: Thu, 06 Mar 1997 16:05:01 +0000
Organization: Enterprise PLC - Internet Services
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Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:36649
Hi,
I've written a program that creates & connects a socket to a remote
machine, and quite happily reads & writes data to it, mostly in a
do{}while loop.
The only problem I've got is trying to check to see if the remote
machine has closed it's socket... According to the man pages a SIGPIPE
would be generated if the socket gets closed / becomes invalid, which
will cause most normal threads (that aren't looking for signals like
SIGPIPE) to exit, this does happen - but only after you try to write()
some data to the socket that's closed...
The program uses non-blocking IO and spends most of it's time in a loop
like:
transferred = read( mysocket, buffer, sizeof( buffer ));
if( transferred >0 ){
write( mydestination, buffer, transferred );
}
transferred = read( mydestination, buffer, sizeof( buffer ));
if( transferred >0 ){
write( mysocket, buffer, transferred );
}
(the above is sort of in pseudo code :(
What I'd really like to do is have something like:
if( is_still_valid( mysocket ){
read
...
}
The closest I can get is using select() - but it's a bit messy to say
the least...
If anyone can suggest a better method, any help would be gratefully
received...
Regards,
Karl Pielorz