C

Platform Migration Guide to Qt for MCUs 3.0

Here are the changes to be aware of when porting a platform or an application from Qt for MCUs 2.x to Qt for MCUs 3.0 or higher.

Application-owned main loop

The application now always owns the Qt Quick Ultralite main loop. It calls Application::update() to run the Qt Quick Ultralite engine and passes the returned timestamp to Application::waitUntil():

while (true) {
    uint64_t nextUpdate = app.update();
    app.waitUntil(nextUpdate);
}

Qul::Application::exec() is removed. Replace calls to it with this loop.

See Running Qt Quick Ultralite in applications for more information.

Removed platform APIs

Removed API	Replacement
`Qul::Platform::PlatformContext::exec()`	No direct replacement. The application owns the loop.
`Qul::Platform::PlatformContext::update()`	Move periodic platform work to PlatformContext::process(). Application::update() routes the update directly.
`Qul::Platform::PlatformContext::scheduleEngineUpdate(uint64_t)`	For timer-based updates, use the timestamp returned by Application::update(). For interrupts and events, call PlatformContext::resume().
`Qul::PlatformInterface::updateEngine(uint64_t)`	Call Application::update() from the application's loop. To wake the loop from an interrupt service routine, such as a hardware timer, call PlatformContext::resume().

Removed C API

qul_app_exec() is removed. Replace it with the loop that uses the functions declared in qul_run.h:

while (true) {
    uint64_t nextUpdate = qul_update_engine();
    qul_wait_until(nextUpdate);
}

Waiting and resuming

Implement PlatformContext::waitUntil() and PlatformContext::resume() in the platform to suspend between updates and to wake up early. See Waiting for the next update for details.

Migration guide to Qt for MCUs 2.3

Available under certain Qt licenses.
Find out more.