QProcess, child and setWorkingDirectory, for Windows process...

[wysota]

I'm not sure what you mean... Even if Windows launches the application, it does it on behalf of the current user. I don't know if this is the case on Windows, but on Linux I can manipulate a running instance of Firefox through a small app that is bundled with the browser.

Isn't your problem that you form an endless loop between firefox and your app? When mailto: is called, your app i launched and it starts firefox and probably passes it the mailto: address, which again calls your app, etc.

[Nyphel]

I think that works well : my application is launched only when the user clic the milto link.
I've controled it, and - lucky me - there is no such loop

I'm very interested in this small application you use : you can control Firefox ?!
Have you made this application, or is it coming with Firefox ?
If it comes with Firefox, what is the name of this application ?
What sort of control have you ?

In my case, if I launch my application manually, a new tab is open in Firefox.
If I launch it with a Batch script : the same.
If my application is launched by Windows : it's a new Firefox that is opened.

Moreover I've controled where the application is executed.
If I launch it, it's executed from its directory in C:/Program Files.
When Windows launch it, it's executed from a strange root disk M:///

Thanks for your answers, that really help me

[wysota]

I'm very interested in this small application you use : you can control Firefox ?!

Yes, sort of.

Have you made this application, or is it coming with Firefox ?

It's part of Firefox distribution for Linux.

If it comes with Firefox, what is the name of this application ?

mozilla-xremote-client

What sort of control have you ?

You can open new windows and urls.

[Nyphel]

Ups...
That was only because I didn't gave arguments to my QProces Firefox.
If we don't give an argument (the URL to be opened), Firefox open a new window instead of opening a new tab in the current window.