QtConcurrent-run-free-function

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To call a free function using QtConcurrent::run, simply pass the function name.

form.h

#ifndef FORM_H
#define FORM_H

#include "ui_form.h"

class Form : public QWidget, private Ui::Form
{
Q_OBJECT

public slots:

void on_btnOpen_clicked();

public:
 Form(QWidget *parent = 0);

};

#endif

form.cpp

#include <QtGui>
#include <QImage>

#include "form.h"

#include <iostream>

Form::Form(QWidget *parent)
 : QWidget(parent)
{
 setupUi(this);
}

void LongFunction()
{
 for( int count = 0; count < 5; count++ )
 {
 sleep( 1 );
 std::cout << "Ping long!" << std::endl;
 }
}

void Form::on_btnOpen_clicked()
{
 QFuture<void> result = QtConcurrent::run ( LongFunction );
 //result.waitForFinished();

std::cout << "exit." << std::endl;
}

form.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>Form</class>
 <widget class="QWidget" name="Form">
 <property name="geometry">
 <rect>
 <x>0</x>
 <y>0</y>
 <width>400</width>
 <height>300</height>
 </rect>
 </property>
 <property name="windowTitle">
 <string>Form</string>
 </property>
 <layout class="QVBoxLayout" name="verticalLayout">
 <item>
 <widget class="QPushButton" name="pushButton">
 <property name="text">
 <string>PushButton</string>
 </property>
 </widget>
 </item>
 </layout>
 </widget>
 <resources/>
 <connections/>
</ui>

main.cpp

#include <QApplication>
#include <QObject>
#include <QThread>
#include <iostream>

#include "form.h"

int main(int argc, char*argv[])
{
 QApplication app(argc, argv);
 Form form;
 form.show();
 return app.exec();
}