RE: General socket question: Would server knows the connection has beenbroken if client drop the connection without calling close()

Thanks.  Implementer #3 and #5. 

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Larry Ducie
Sent: Wednesday, January 18, 2006 3:35 PM
To: rpg400-l@xxxxxxxxxxxx
Subject: General socket question: Would server knows the connection has
beenbroken if client drop the connection without calling close()

Hi Lim,
 
<snip>
If I've a socket program that connected to a server and the program
ended abnormally without calling the close() to close the connection,
would the server knows that the connection has been broken and auto drop
the connection?
</snip>
 
I'm sure you will get lots of advice on how TCP/IP is used across
network works, but your question suggests one problem you can solve
without going outside your application: Namely - make sure your
application DOES call
close() when the program ends abnormally. Here are a few suggestions you
could use to achieve this.
 
1) You can do this by registering a call-back procedure to be called if
an activation group ends (normally or abnormally) and call close()
within that.
Do that with CEE4RAGE.
 
2) You could register a condition handler within your program and simply
call close() and percolate the error within that. Do that with CEEHDLR.
 
3) You could register a cancel handler within your program to be called
if your program ends (removed fom the call stack). If the end was
abnormal you can call close() wihin the cancel handler. Do that with
CEERTX/CEEUTX.
 
4) You could put your whole RPG program code within a monitor group and
call
close() within the on-error block.
 
5) You could code a *PSSR subroutine within your program and call
close() within that.
 
Although a well written server program should handle any and all client
or network glitches, you do have many options to ensure you tidy up
after yourself when things go wrong.
 
HTH
 
Larry Ducie