Compilation errors with Qt6 and QtConcurrent::run

[Dvassily]

Hello !

In my project, i try to execute a member function asynchronously with the help of QtConcurrent::run :

	ulong histogramId = histogramWidget->allocate();
	QFuture<void> future = QtConcurrent::run(&HistogramWidget::computeHistogram, histogramWidget, std::cref(image), histogramId);
	QFutureWatcher<void>* watcher = new QFutureWatcher<void>();
	
	 connect(watcher, &QFutureWatcher<Histogram>::finished, this, [this, histogramId]() {
		histogramWidget->drawHistogram(histogramId);
	 });

	 watcher->setFuture(future);

Therefore, i included the following header in my source file :

#include <QtConcurrentRun>

Which generates the following errors at compilation time :

I compile with MSVC 2019 64 bits, and i included the core and concurrent modules.

Could you help me?

[Christian Ehrlicher]

I would start with a clean simple main.cpp and include the header to see if it compiles.

[Dvassily]

I just tried this and yes, it does compile.

One more detail : the project compiled fine some hours ago, and the changes i made since don't concern the class containing the QtConcurrent::run call.

[jsulm]

@Dvassily Try a complete rebuild: delete build folder, run qmake and build

[Dvassily]

I already tried the complete rebuild : nothing changed.

By the way, i don't use qmake.

[jsulm]

@Dvassily What is the very first error message you get?

[Dvassily]

The first error message is "missing type spcifier - int assumed. Note: C++ does not support default-int" in qfuture_impl.h at line 175.

[Christian Ehrlicher]

Move the header up until the error no longer occurs. Daily programming business...

[Dvassily]

It solved the problem. Thank you !

[Christian Ehrlicher]

@Dvassily I think it would be interesting for others what the problem was. And don't forget to mark the thread as solved then.

[sarthak031]

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