Informix 4gl program hanging

[sameer_11]

I have written one program to transfer the data from remote servers to central server .
Its working properly in all conditions except one that whenever we remove the network cable from server during the process , program gets hang and when we again connect the cable to the server , program resumed the remaining process .

And because there are continous 53 remote servers are there , these program fails in this situation .

In such situation , program suppose to inform about connection failed for remote server and it should connect to next remote server.


Please let me know is there is any solution for above problem .

OS : True64 UNIX
Programming Language : Informix 4gl 7.20 UE1

[Ravi_8]

Hi Sameer

when you remove the network naturally all the connections will be lost hence the data transfer.

when the process is already running and if you disconnect, system wouldn't inform you of network connection. if you remove the network cable before starting the operation (data transfer)system would definately inform you about connection fail like other programs such as ftp,rcp does

[Ralf Puchner]

If reading and understanding network programming handbooks you will get the information that TCP/IP will not detect automatically connection lost states.

So your connections will hang forever if not developed for "socket timeout" behaviours and signal handling. Keyword: TCP keepalive, socket() function call

UDP requires own mechanism to detect network outages.