[erlang-questions] Scoped group leaders

Yurii Rashkovskii yrashk@REDACTED
Tue Jul 5 17:31:36 CEST 2011

Right now there is no way to remove a group leader from process, but
it is not inherently impossible to do so, just was out of scope of
this prototype.

On Tue, Jul 5, 2011 at 8:05 AM, Eric Merritt <ericbmerritt@REDACTED> wrote:
> I understand and that makes sense, but it does raise a potential
> problem. That is group leaders are created but never destroyed. In the
> case of the process itself, this is probably ok. The developer will
> have to create some mechanism to know when his group leader is no
> longer useful and have it die on its own. However, I didn't see any
> mechanisms to unregister group leaders and reclaim the memory alloced
> when they are created. That could be me missing something when I was
> looking at the code, if so then the point is moot, however if not
> that's something that would probably need to be added to make this
> workable. Of course, that still leaves the problem that if a group
> leader dies unexpectedly, or the user mis-codes his application and
> forgets to unregister a group leader when it dies, then he has a
> memory leak. You could say that its a users problem and go from there,
> but leaving around unreferenced memory just doesn't smell right. (I
> know, we do that already with the atom table, but it doesn't make it a
> good thing)
> On Mon, Jul 4, 2011 at 6:57 PM, Robert Virding
> <robert.virding@REDACTED> wrote:
>> ----- "Eric Merritt" <ericbmerritt@REDACTED> wrote:
>>> >
>>> >
>>> >> Just out of curiosity does a group leader go away when a group
>>> dies?
>>> >
>>> > Define group death?
>>> >
>>> When when all processes in a group have terminated, either normally
>>> or
>>> abnormally.
>> Today there is nothing in the system which keeps track of the processes in a group, process groups don't really exist at all. A "process group" is those processes which have the same group leader. The group leader has no information about which processes have it as group leader. You can make any process a group leader by setting it as group leader.
>> Process groups were explicitly added in such a way as NOT to impose any structure or hierarchy on processes, process space is flat.
>> Robert

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