Hi Boris,
I have a similar problem with running a Qt application from a second thread. In my case it segfaulted after QApplication::app.
Christian gave me a hint I wasn't able to try yet, but maybe it could be helpful for you, too.
On Mon, Oct 16, 2017 at 01:42:04PM +0200, Johannes Kliemann wrote:
I tried to create a provide an input session from a libc (in this case an Qt application). If I just run it from the Main struct it will correctly announce the session but since Main never returns, no client will be able to use it. I tried to circumvent this by putting the application into a separate thread but this led to the following error:
Error: void Libc::Kernel::run(Libc::Application_code&) called from non-kernel context
Running this Qt application without wrapping it into with_libc makes it segfault on initialization.
What is the correct way to do this? My current main is at [1].
Unfortunately, there is no "correct" way of implementing tasks like the described currently. I must admit that with_libc() is the most confusing function in Genode currently and we therefore will remove it from the API soon. In fact, I myself did not expect that with_libc() is needed in your context but there may be dependencies unknown to me.
I'd suggest a careful look into libports/src/app/avplay which provides an input session too. The approach there is to create a second Genode entrypoint for the input service and execute Qt code in the component thread. I strongly encourage you not just to copy the avplay code as it uses the older, low-level Rpc_entrypoint but use Genode::Entrypoint.
Regards, Johannes
On 10/23/17 15:51, Boris Mulder wrote:
Dear Genode folks,
I have built an application with Qt5. I want it to also be able to read ROM modules from a report_rom server and to be able to handle updates to that ROM using signals.
When I run QApplication::exec() however, it does not return and the entrypoint cannot listen to signals, causing them to be ignored.
So I created another QThread and run my QApplication in there. Now I get the following error:
   WARNING: QApplication was not created in the main() thread.
And the application does not do anything and does not react to events.
What can I do to be able to run both the qt event loop and the genode event loop?
regards,
Boris