Text box is not refreshing content on window.

[jenya7]

int main(int argc, char *argv[])
{
    uint32_t discovered = 0;

    QApplication a(argc, argv);

    MainWindow w;
    w.show();

    QObject::connect(&m_sys, &SYS::SendMessage, &w, &MainWindow::DisplayTerminalMessage);
    QObject::connect(&m_comparser, &COMPARSER::SendMessage, &w, &MainWindow::DisplayTerminalMessage);
    QObject::connect(&m_commands, &COMMANDS::SendMessage, &w, &MainWindow::DisplayTerminalMessage);
    QObject::connect(&m_sensor, &SENSOR::SendMessage, &w, &MainWindow::DisplayTerminalMessage);
    QObject::connect(&m_script, &SCRIPT::SendMessage, &w, &MainWindow::DisplayTerminalMessage);

    //load parameters+script from a default file location
    m_sys.ParamInit(nullptr);
    m_sys.ScriptInit(sys_params.script_file);

    rt_params.connected = wifi_udp.Start(sys_params.local_ip, sys_params.local_port);
    if (rt_params.connected )
        m_sys.Print("UDP - OK\n");
    else
       m_sys.Print("UDP - FAIL\n");

    w.repaint();  //does not help
    w.update();  //does not help

   discovered = m_sensor.DiscoverConcurrent(0, 4, SYS_DISC_MODE_ALL);
   
    QFuture<void> future = QtConcurrent::run(&ScriptRun);

    return a.exec();
}

The function m_sensor.DiscoverConcurrent - runs concurrent - a separated thread and should not block the GUI thread.
If I comment m_sensor.DiscoverConcurrent - all functions (m_sys.ParamInit, m_sys.ScriptInit) print some messages in a text box and I see it and it's OK.
But if m_sensor.DiscoverConcurrent runs - it blocks the text box and I don't see any prints (it captures a part of the desktop). After m_sensor.DiscoverConcurrent finishes - all prints available in the text box.
It doesn't affect functionality but looks ugly to a user.

[jsulm]

@jenya7 said in Text box is not refreshing on window.:

But if m_sensor.DiscoverConcurrent runs - it blocks the text box and I don't see any prints

Sounds like m_sensor.DiscoverConcurrent is a blocking call and does NOT run concurrently.

[jenya7]

@jsulm said in Text box is not refreshing on window.:

@jenya7 said in Text box is not refreshing on window.:

But if m_sensor.DiscoverConcurrent runs - it blocks the text box and I don't see any prints

Sounds like m_sensor.DiscoverConcurrent is a blocking call and does NOT run concurrently.

May be.

uint32_t SENSOR::DiscoverConcurrent(uint8_t min, uint8_t max, uint8_t mode)
{
    QFuture<uint32_t> future;

     rt_params.service = 1;

     switch (mode)
     {
         case SYS_DISC_MODE_ALL:
             future = QtConcurrent::run(this, &SENSOR::DiscoverByIndexAll, max);
         break;
         case SYS_DISC_MODE_RANGE:
               future = QtConcurrent::run(this, &SENSOR::DiscoverByIndexRange, min, max);
         break;
         case SYS_DISC_MODE_FILE:
               future = QtConcurrent::run(this, &SENSOR::DiscoverByList);
         break;
     }

    rt_params.service = 0;

    return future;
}

At least I try. I get no exceptions or run time messages. How can I be sure another thread was created?
The function is executed - I see result on finish.

[jsulm]

@jenya7 Why is the return type uint32_t and not QFuture<uint32_t>?

[J.Hilk]

@jenya7
I assume

uint32_t SENSOR::DiscoverConcurrent(uint8_t min, uint8_t max, uint8_t mode)
{
    QFuture<uint32_t> future;
....
   return future;
}

does an implicit call to result() to return the uint32_t value,

which will wait until the concurrent has run its course.

Congratulations, you turned it back into a synchronous program :P

give the QFuture object to an QFutureWatcher instance and listen to the finished signal there.

[jsulm]

@J-Hilk said in Text box is not refreshing content on window.:

does an implicit call to result() to return the uint32_t value

Yes, this is also what I think is happeneing, but can't find anything related to this in QFuture documentation.

[J.Hilk]

@jsulm probably this one ?

https://doc.qt.io/qt-5/qfuture.html#operator-T

[jenya7]

@jsulm said in Text box is not refreshing on window.:

@jenya7 Why is the return type uint32_t and not QFuture<uint32_t>?

I fixed it. But the issue stays.

[jsulm]

@jenya7 said in Text box is not refreshing content on window.:

I fixed it

I bet you did not, because discovered variable is still uint32_t, right?
Please read what @J-Hilk wrote.

[jenya7]

@jsulm said in Text box is not refreshing content on window.:

@jenya7 said in Text box is not refreshing content on window.:

I fixed it

I bet you did not, because discovered variable is still uint32_t, right?
Please read what @J-Hilk wrote.

Now it is
in main.cpp

QFuture<uint32_t>  discovered;

in sensor.cpp

QFuture<uint32_t> SENSOR::DiscoverConcurrent()........

Still the same.

Wait a minute... SENSOR::DiscoverConcurrent calls

future = QtConcurrent::run(this, &SENSOR::DiscoverByIndexAll, max);

so SENSOR::DiscoverByIndexAll - should be also QFuture<uint32_t> ?

well..the problem is only on start up. If I call SENSOR::DiscoverConcurrent() from another place (after return a.exec();) it works good.

[jenya7]

What if I want to invoke SENSOR::DiscoverConcurrent() after return a.exec();?
What event to connect?

QObject::connect(&a, a.???

[jsulm]

@jenya7 said in Text box is not refreshing content on window.:

What event to connect?

Why do you need an event/signal for that?
Just call it after a.exec()...

[jenya7]

@jsulm said in Text box is not refreshing content on window.:

@jenya7 said in Text box is not refreshing content on window.:

What event to connect?

Why do you need an event/signal for that?
Just call it after a.exec()...

what is "after"?

int main(int argc, char *argv[])
{
   ............
  return a.exec();

  discovered = m_sensor.DiscoverConcurrent(0, 4, SYS_DISC_MODE_ALL);
}

code will never be executed.

[jsulm]

@jenya7 said in Text box is not refreshing content on window.:

code will never be executed

Well, it is really not hard to change this code in a way it does what you want.
But I will let this simple exercise to you...