[LV2] Plugin instance ID

[David Robillard]

On Tue, 2020-08-25 at 19:41 +0200, Hermann Meyer wrote:
> Am 25.08.20 um 19:11 schrieb Iurie Nistor:
> > Hi,
> > 
> > I think there would be a problem if I'll save this kind of data
> > into
> > the state (as mentioned by Hanspeter Portner).
> > 
> > When this state is saved as a preset by the host it will become
> > shareable, and this data is not relevant to be shared.
> > 
> 
> Just ensure that your plug could handle unreasonable data (unsolvable
> path) from a saved state.

Hosts must not mess around with plugin state itself like this.

This conversation seems to be confusing LV2 state, as used by the
plugin itself, and host-specific things.  Pretty much any non-trivial
host needs to store things about a plugin instance aside from the
plugin state itself.  This stuff is host-specific and needs to live
somewhere else.  For example Ardour stores things about plugin
instances in the session XML file, Ingen stores it in the graph Turtle
file, etc.

There is no standard identifier for a plugin instance in LV2.  Hosts
can use whatever.  For example, Ardour uses 64-bit integers, Ingen uses
paths, etc.  The plugin itself doesn't need to know about this.

-- 
dr