[erlang-questions] 2 (unrelated) questions.

[Paul Barry]

Thanks Geoff and Ahmed for those answers.  :-)

I'm interested to know why register() doesn't support remote PIDs, but
I guess that's a question for the language implementers.  Of course,
that said, it looks like the "global" library is what I'm after: "In
this module, the equivalent of the register/2 and whereis/1 BIFs (for
local name registration) are implemented, but for a network of Erlang
nodes." - so there's my answer right there.

Thanks for that pointer (Geoff) and thanks for also for the link to
the list archive (Ahmed).  I'll be sure to check there *first* from
now on.

Regards.

Paul.



On 26 October 2011 21:34, Geoff Cant <nem@REDACTED> wrote:
> On 2011-10-26, at 08:25 , Paul Barry wrote:
>> Q2. Being able to register a spawned process is cool, but why can't I
>> register a process that is spawned remotely?  That is, why does this
>> line of code give me a "badarg"?
>>
>>     register(the_board, spawn('server@REDACTED', displayboard,
>> putmessage, [])).
>
>
> You can only register local pids and ports. I'm not sure why this restriction is enforced - maybe the erts people have more information.
>
> In practice it's easy to work around. Register the name on the remote node and then use the {the_board, 'server@REDACTED'} ({RegisteredName, Node}) form instead of using a bare registered name or pid. This form is a valid argument to the ! send function.
>
> As others have mentioned there are other process registries you can use (gproc, ngproc, proc_reg, global) that allow the registration of remote pids (and usually allow names to be terms instead of just atoms).
>
> Cheers,
> --
> Geoff Cant
>
>
>
>
>



-- 
Paul Barry, w: http://paulbarry.itcarlow.ie - e: paul.barry@REDACTED
Lecturer, Computer Networking: Institute of Technology, Carlow, Ireland.