Paralel Thread do not work

yczo

Hello, I am trying to make a thread app to read serial port and connect through signals to a text browser. I have an object created for these purpose, that in theory, in paralel with the main window, must a debug text in console show, but i dont know what happens, that the main window do not run, like if the the Thread do not work.

I will appreciate any help, thanks in avance

//main.cpp

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();

return a.exec();

}
//*************************************************

//hilo.h

#ifndef HILO_H
#define HILO_H

#include<QThread>

class hilo : public QThread{
Q_OBJECT
public:

hilo();
~hilo();
void run();

signals:
void xtring(QString xtr);
};

#endif // HILO_H
//*************************************************

//hilo.cpp

#include "hilo.h"
#include <iostream>

using namespace std;
hilo::hilo()
{

}
//**********************************************
hilo::~hilo(){

}
//**********************************************
void hilo::run(){
for(;;){
cerr << "show debug\n";
}
// emit xtring("cadena xtring");
}
//**********************************************

//MainWindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

private slots:
void on_MainWindow_customContextMenuRequested(const QPoint &pos);

private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H
//**************************************************
//MainWindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <hilo.h>

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
// hilo h();
hilo *pH = new hilo();
pH->run();
}

MainWindow::~MainWindow()
{
delete ui;
}

JohanSolo

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
// hilo h();
hilo *pH = new hilo();
pH->run();
}

The call to pH->run() never returns, therefore your constructor never returns, thus leading to everything frozen.

VRonin

use pH->start(); instead of pH->run();

run should be declared protected and virtual

change hilo constructor to call the base class

hilo::hilo(QObject * parent)
:QThread(parent)
{

}

also you have a memory leak there if you do not give a parent to ph : hilo *pH = new hilo(this);

yczo

Thank you very much for your help.
pH->start(); Did work

I don't understand the another variant and why must the pointer this use (I am total newbie), If somebody want explain a little more, will be well received

Greetings and thank you again

hilo::hilo(QObject * parent)
:QThread(parent)
{

}

also you have a memory leak there if you do not give a parent to ph : hilo *pH = new hilo(this);//your code here

mrjj

Hi
About the "this" pointer

Normally if you do
ClassX * mine= new ClassX;

you will need to call
delete mine;

to clean up .

In Qt we have a parent/child system. The parents will also delete/clean up all childs it
owns.

so when you do
hilo *pH = new hilo(this);

You are indirectly saying,
"I transfer ownership of pH to the parent" ( parent = this)

So when "this" is deleted it will also delete pH as you gave it as child.

yczo

Thank you very much for your help