error: no matching function for call to QtConcurrent::run()

[been_1990]

I forgot to mention that loadMenuItems() is a Widget private method.
I get the same error if I do

QFuture<bool> future = QtConcurrent::run(this, &Widget::loadMenuItems);

And the blocking part is just what came with the example, I intend to remove it.

[ChrisW67]

I forgot to mention that loadMenuItems() is a Widget private method.

Not if it is defined like your example.

QtConcurrent does not know about your default parameter, just that the signature is "bool f(bool)" so you must provide a value in your call to QtConcurrent::run(). This, for example, compiles:

class Widget: public QWidget {
    Q_OBJECT
public:
    explicit Widget(QWidget *p = 0): QWidget(p) {
        QFuture<bool> future = QtConcurrent::run(this, &Widget::loadMenuItems, true);
    }
private:
    bool loadMenuItems(bool flag = false) {
        return flag;
    }
};

class Widget: public QWidget {
    Q_OBJECT
public:
    explicit Widget(QWidget *p = 0): QWidget(p) {
        QFuture<bool> future = QtConcurrent::run(this, &Widget::loadMenuItems, true);
    }
private:
    bool loadMenuItems(bool flag = false) {
        return flag;
    }
};

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And the blocking part is just what came with the example, I intend to remove it.

If you do not block at that point then the variable future will go out of scope immediately and you will no have access to the state or return of the thread.

Your loadMenuItems() function will run in another thread. Be careful if you try to access the parent object, allocate memory you expect to use in the GUI thread, or do things that are only supported in the GUI thread.

[been_1990]

Ah, I thought it knew about the default value for the parameter, that fixes it.
My use case is that i have to load many items from a list stored on file, I imagine I can read the file into a QList and then pass it back to the main thread by emitting a signal?

[ChrisW67]

Yes, I guess you can.