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
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
That looks like a good start. So far I added (among others) the following lines to my program:
Genode::Entrypoint ep { env, 64*1024, "signal_ep" };
Genode::Signal_handler<MyClass> _status_handler(ep, *this, &MyClass::_handle_update);
_status_ds.sigh(_status_handler);
However, when the _status_ds ROM dataspace content changed (verified using verbose=yes in the report_rom), the function _handle_update is not invoked. I can see that the initial content of the dataspace at initialization time is correct.
What else do I need to do for my Qt program to be able to receive signals?
On 24-10-17 17:11, Johannes Kliemann wrote:
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
Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ genode-main mailing list genode-main@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/genode-main
Nevermind, I apparently made a mistake and it does work correctly now with the new entrypoint. Thanks for the hint, Johannes.
Met vriendelijke groet / kind regards,
Boris Mulder
Cyber Security Labs B.V. | Gooimeer 6-31 | 1411 DD Naarden | The Netherlands +31 35 631 3253 (office)
-
Boris Mulder -
Johannes Kliemann