Qt threading - Basic use of QThread.

main.cpp

#include <QThread>
#include "mythread.h"

int main(int argc, char *argv[])
{
  QCoreApplication a(argc, argv);
  
  QThread thread;      //Thread object
  MyThread cObject;    //My class object
  
  //Set it up
  cObject.DoSetup(thread);
  
  //This is where the real work happens
  //Take the cObject and move it to the thread (So we don't have to sublass it)
  cObject.moveToThread(&thread);  //Takes a pointer so we add the address of the thread
  
  //Start the thread
  thread.start();
  
  /**********************************************************/
  //You can set a priority for the thread. Ex:
  thread.start(QThread::HighestPriority);   //or LowestPriority
  /**********************************************************/
    
  return a.exec();
}

mythread.cpp

#include "mythread.h"

MyThread::MyThread(QObject *parent) : 
    QObject(parent)
{
}

void MyThread::DoSetup(QThread &cThread)
{
  connect(&cThread,SIGNAL(started()),this,SLOT(DoWork()));
}

void MyThread::DoWork()
{
  //Once the thread is started, all the work will be done here
  
  /**********************************************************/
  //Preventing deadlocks in threads when accessing global variables
  //You need to allow only 1 thread to change the global variable by locking the access
  //Ex:
  QMutex mutex;
  mutex.lock();
  //....Update your variable(s)
  mutex.unlock();
  /**********************************************************/
  
  /**********************************************************/
  //Slowing the thread down. For UI friendly reasons or for CPU reasons.
  this->sleep(2);       //in secods
  this-<msleep(100);    //in milliseconds
  /**********************************************************/
}

mythread.h

//Create a class (ex. myThread) and subclass it to QObject

#include <QObject>
#include <QDebug>
#include <QThread>

class MyThread : public QObject
{
  Q_OBJECT

  public:
      explicit MyThread(QObject *parent = 0);

      //This passes a reference to the thread and will connect signals and slots
      //When the thread is started, DoWork will be emmited.
      void DoSetup(QThread &cThread);

  signals:

  public slots:
      //
      void DoWork();

};
}