I have several gambas programmes that I display on my desktop (Kubuntu 24.04, Gambas3 v3.19.4).
For some reason I find multiple instances of a program are being opened so how can I prevent more than one instance being loaded?

I don't know if :? this page can help you:
   Impedire l'avvio di un programma.gambas già avviato - Gambas-it.org - Wikipedia

You can use DBus and DBus.Unique
See attached project.
if the program is running it sends the arguments to the running process instead of launching the program again.
You can test it in a terminal by running it, then running it a second time with args

Also I have just added this exact thing to my GambasProcWatch program add DBus Quit and Activate commands and auto activate running program if attempted to run again (d08d1bd9) · Commits · Bruce Steers / gambasprocwatch · GitLab
I added a DBus Activate() and Quit() method

Now if you run GambasProcWatch a second time it activates the first one instead.

This way also gives you a way to control your programs from other programs using their interfaces, commands like Activate/ Quit / open some window / run some function / etc

Now from another program i can simply do this to activate GambasProcWatch…

Or quit it…


or you can simply use pgrep to check more than one instance but it is not as useful (and i think not as reliable) as using DBus.

 Thanks for the ideas, have been fiddling with this on and off for a while now without success.
The pgrep check doesn't always work, neither does vuott's suggestion.
Can't quite get my head around the SingleBus example yet.  The example works fine, if I change the name pf the project then I get an error "-1 unable to create dbus interface" because the dbBus registration(line 19) fails with error message "Cannot enable observer".
Regards
Bill

bill-lancaster said

Thanks for the ideas, have been fiddling with this on and off for a while now without success.
The pgrep check doesn't always work, neither does vuott's suggestion.
Can't quite get my head around the SingleBus example yet.  The example works fine, if I change the name pf the project then I get an error "-1 unable to create dbus interface" because the dbBus registration(line 19) fails with error message "Cannot enable observer".
Regards
Bill

there are some chars that cannot be used in a DBus interface name (I only replace spaces for underscore) so the problem may be in what you name the application.

Just change the "Application.Name" in SingleInstance.class:_new() to the name of your choice then the Application.Name will not matter.

I am not up to speed with the dark art of working with DBus either. Here is a bit of code I put together that returns the number of instances of the same program running.