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Forum Topic - Re: Multiple instances of TCP/IP stack and socket communication: Page 1 of 2 (2 Items)
   
 
 
Re: Multiple instances of TCP/IP stack and socket communication  
Thanks Weijie and Robert for your responses.

If a process X started on SOCK=/sock2, wants to talk to another process Y
started on SOCK=/sock3, how can process X talk to process Y using socket
communication. As I understand process X can only send messages to processes
with environment var SOCK=/sock2 (unless the environment variable is changed
in process X to SOCK=/sock 3 before using socket comm to process Y and then
change back to SOCK=/sock2 before using sock communication to other process
started on SOCK=/sock2) , but they should be better ways of
doing this.

Regarding Robert's question:
"To get these two stacks to talk to one another using IP,

there'd have to be a common IP interface between them and this normally
doesn't happen when you have two different stacks instantiated on the
same machine (which is what I assume you are talking about), so I'd have
to see exactly what sort of configuration you were thinking of before
commenting on if it's possible.  "


Process X (sock2) wants to another process Y (sock3) on the same machine,
using socket communication. Is this not feasible?

Thanks
Cheng-Yin

On Fri, Mar 6, 2009 at 2:53 PM, Yin Lee <c.yin.lee@gmail.com> wrote:

> Hello,
>
> If a SOCK environment variable is set to the same “prefix” name used to
> start a TCP/IP stack, then:
>
>
>
> From a FAQ in QNX developer web site "The SOCK environment variable is set
> so that QNX libsocket can identify which stack instance to use"
>
> I cannot find any other official QNX document validating this information.
> Can someone please confirm this or point to more detailed information on how
> the SOCK environment variable is used within QNX, and if there are any
> caveats to this.
>
>
> Also I would like to confirm that a socket in a process (e.g. telnet
> client) started using a specific SOCK environment will communicate with
> another socket in a process  (e.g. telnetd) started using the same SOCK
> environment variable, and no code changes is required in the processes (e.g.
> telnet and telnetd), and no other parameters, or functions need to be set
> for this to happen.
>
>
> If for some reason,  a process started on SOCK=/sock2, wants to talk to
> another process started on SOCK=/sock3, what is the recommended way of doing
> this?
>
>
>
> Thanks
>
> Cheng-Yin
>