RE: question on socket connection

["Ranga Reddy M - CTD ,Chennai." <rangareddym@ctd.hcltech.com>]

Error -1: because of recv/send fail.
Error EGAIN: this is because of MSG_DONTWAIT.

Client and Server Both are running on different systems.What if client
crashes or powered off.How does the underlaying TCP/IP layer works
here,There is no time for TCP/IP to say socket close to server.

Client does not give any indication of socket close.Then, I think server
will does not know about the status of the client.

I have read the article about the "Nagles allgoritham" . It sets a default
time out of 2 hours. If there is not data on the socket for 2 hrs this will
disconnect the socket.

Is there any way to trace???


-----Original Message-----
From: ronkhu [mailto:ronkhu@ntsp.nec.co.jp]
Sent: Monday, May 26, 2003 1:04 PM
To: linux-c-programming
Subject: Re: question on socket connection


i think
recv() would still return 0 if the remote side of the socket connection 
has disconnected...

if ur using MSG_DONTWAIT... -1 will be returned if there is no data to 
be read...(as well as EGAIN)....
thus, making it possible to differentiate from "no data" from 
"disconnection event"






Ranga Reddy M - CTD ,Chennai. wrote:

>If the socket is non-blocking mode, I mean if MSG_DONTWAIT send/recv of
>flag is set....
>If , the other end is no proper socket closing is done (system crash or
>power down).
>Then how to find the socket connection....?????
>
>
>-----Original Message-----
>From: Glynn Clements [mailto:glynn.clements@virgin.net]
>Sent: Monday, May 26, 2003 11:28 AM
>To: Lejanson C. Go
>Cc: linux-c-programming
>Subject: Re: question on socket connection
>
>
>
>Lejanson C. Go wrote:
>
>  
>
>>how do you check if the socket has been disconnected?
>>    
>>
>
>Try reading from it; if read/recv return zero bytes, it's closed.
>
>  
>



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