Re: Example socket program to send data to a non IBM i device

Alan,

I'd like to reply to some of the things in your message, I'll put my comments inline.

The hanging thing is a new one. Are other people using this socket server?
It doesn't sound like the socket server is not responding, it sounds like
you are connecting and then being hung up.

"Socket" is a set of routines that can be used for many different things...   I assume this example is TCP?

It is an extremely frequent issue with TCP that they "hang" when a firewall is blocking the connection, or when the network connection gets broken, etc.  TCP is meant to be completely reliable, so the receiving side will send acknowledgements of the data received, and the sender will re-send anything that wasn't acknowledged, basically it'll get stuck re-sending indefinitely if it gets no response.

For that reason, you should always implement a time out mechanism in a TCP application.

Normally socket attempts to make a connection. That connection is either
accepted or rejected. If there is nothing to connect to it just returns an
error.

...but that error can only be received if the network connection is open and working.  If something is blocking it (a firewall, or something like an unplugged cable, power turned off, etc... anything that would prevent the error message being sent back) instead of an error, you'll sit and wait indefinitely.


If by "socket server" (hate that term) you don't mean a TCP server but you mean something else, then my comments above may not apply. It'd help me out a lot if you'd be more specific rather than using terms like "socket server" or "socket client".  Say TCP if you mean TCP.  If you can be even more specific (like Telnet, FTP, HTTP, SMTP, PPTP, etc) then please do.