Cheers, yes your patch was returning the right path.
It did work.

Before asking I was looking into the message in pd console : 'pd-gui' connecting to 'pd' on localhost 41969
& I thought there was a way to use this port for opening the gui.

( sorry for off-list mail ! I noticed this too late )

From: IOhannes m zmölnig via Pd-list <pd-list@lists.iem.at>
Sent: 28 August 2025 16:26
To: pd-list@lists.iem.at <pd-list@lists.iem.at>
Subject: [PD] Re: Opening gui of running -nogui pure data instance
 
On 28/08/2025 17:10, Yogi data wrote:
> Something is unclear to me.
>
> I'm on linux, with command line, my path to pd-gui is /usr/local/lib/pd/tcl/pd-gui.tcl
>
> So the message is " vis /usr/local/lib/pd/tcl/pd-gui.tcl "


no.
it's "vis /usr/local/lib/pd/".

this is what my patch should have produced.

>
> In order to send this to pd,
> Should I use 'pdsend' and create a netreceive in my patch ?
> ( this worked fine)

yes, that's one way.
another is to listen on the serial port for a given event.
or, whatever.

but [netreceive] is a good start :-)

>
> Or find the port "pd" already opened ?
>

there's none.

gfmsadr
IOhannes

PS: sorry for my off-list mail; i didn't see your reply to the mailing
list at first.