i have a problem with a small program (I am a beginner with c++ and qt).
On button press it starts a cli application with qprocess and the output should be displayed in a text field as soon as the cli app writes it to stdout or stderr.
i read that its a good idea to use signals and slots for this but it isnt working.
the compiler throws an error that in my slot getOutput() the "process" object isn't declared (C2065)
here is the code.
processgui.cpp:
#include "processgui.h"
#include "ui_processgui.h"
#include <QProcess>
processGui::processGui(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::processGui)
{
ui->setupUi(this);
}
processGui::~processGui()
{
delete ui;
}
void processGui::on_startProcess_clicked() {
QProcess *process = new QProcess(this);
QString program = "tracert";
QString arguments = "";
process->setReadChannelMode(QProcess::MergedChannels);
process->start(program, QStringList() << arguments);
process->waitForStarted();
QObject::connect(process, SIGNAL(readyReadStandardOutput()), this, SLOT(getOutput()));
}
void processGui::getOutput() {
QByteArray strdata = process->readAllStandardOutput();
ui->textLog->append(strdata);
}
processgui.h :
#ifndef PROCESSGUI_H
#define PROCESSGUI_H
#include <QMainWindow>
namespace Ui {
class processGui;
}
class processGui : public QMainWindow
{
Q_OBJECT
public:
explicit processGui(QWidget *parent = 0);
~processGui();
private slots:
void on_startProcess_clicked();
void getOutput();
private:
Ui::processGui *ui;
};
#endif // PROCESSGUI_H
thanks in advance
Move QProcess *process to your header and initialize it with process = new QProcess(this) in your constructor. That way you can access it in your slot.
QProcess *process = new QProcess(this);
is declared in:
void processGui::on_startProcess_clicked()
it's a scope problem, process is a local variable not available in the whole class.
You can access QProcess object inside a slot with sender(), like this:
void processGui::getOutput()
{
QProcess* process = qobject_cast<QProcess*>(sender());
QByteArray strdata = process->readAllStandardOutput();
}
Related
=====================OUTDATE=======================
I have a vector which contains threads, each thread is doing a while loop, for some reason, i need to delete the thread in the vector, to do this, i referenced this blog and write a test demo online. But when i write pthread_cancel() in Qt, it reports error: use of undeclared identifier 'pthread_cancel'. I have added LIBS += -lpthread in my .pro file and added #include <thread> in my .cpp file, this error still exists.
=====================UPDATE=====================
Afterwards, i trid to use QThread to achieve my goal. In brief, to start a qthread, i create a Worker class, then instantiate it and move it to QThread, connect &QThread::started with &Worker::process, process is the time consuming method, finnaly call thread->start();; to stop a qthread, i use a bool flag, and i store it with thread id in QMap, if the bool flag is set to false, qthread will break while loop, and emit a finished() signal and this signal will trigger &QThread::quit; to delete the qthread, i connect finished() signal with &Worker::deleteLater and &QThread::deleteLater.
The code are:
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "worker.h"
#include <QThread>
#include <QMap>
#include <QDebug>
QMap<int, bool> stateController;
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
ui->tableWidget->setSelectionBehavior(QAbstractItemView::SelectRows);
ui->tableWidget->setSelectionMode(QAbstractItemView::SingleSelection);
qDebug()<<"Main UI thread id is"<<(int)QThread::currentThreadId();
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_add_clicked()
{
int row = ui->tableWidget->rowCount();
ui->tableWidget->insertRow(row);
ui->tableWidget->setItem(row,0,new QTableWidgetItem());//hold a place for blank item, in order to uniformly determine whether its text is empty afterwards
QTableWidgetItem *ckx = new QTableWidgetItem;
ckx->setCheckState(Qt::Unchecked);
ui->tableWidget->setItem(row,1,ckx);
}
void MainWindow::on_tableWidget_cellClicked(int row, int column)
{
if(column == 1){
bool state = ui->tableWidget->item(row,1)->checkState();
if(state){
if(ui->tableWidget->item(row,0)->text().isEmpty()){//only if there is not thread id, then create the thread
QThread* thread = new QThread();
qDebug()<<"New created thread id is"<<(int)thread->currentThreadId(); //I found this thread id will equal to main ui thread id, so i use a sigal/slot to update thread id
Worker* worker = new Worker(row);
worker->moveToThread(thread);
connect( worker, &Worker::updateQThreadIDSignal, this, &MainWindow::updateQThreadID);
connect( thread, &QThread::started, worker, &Worker::process);
connect( worker, &Worker::finished, thread, &QThread::quit);
// automatically delete thread and worker object when work is done:
connect( worker, &Worker::finished, worker, &Worker::deleteLater);
connect( thread, &QThread::finished, thread, &QThread::deleteLater);
//start the thread
thread->start();
}
}else{
if(!ui->tableWidget->item(row,0)->text().isEmpty()){//only if there is already the thread, then stop it
int thread_id = ui->tableWidget->item(row,0)->text().toInt();
// qDebug()<<"get thread id is"<<thread_id;
QMutexLocker locker(&mx);
stateController[thread_id] = false;
ui->tableWidget->setItem(row,0,new QTableWidgetItem());//Because thread will be delete later, so clear its thread id
}
}
}
}
void MainWindow::on_pushButton_delete_clicked()
{
QItemSelectionModel* selectionModel = ui->tableWidget->selectionModel();
QModelIndex index = selectionModel->currentIndex();
if(index.isValid()){
int row = index.row();
if(!ui->tableWidget->item(row,0)->text().isEmpty()){//Before stop the thread, ensure it exist
int thread_id = ui->tableWidget->item(row,0)->text().toInt();
if(ui->tableWidget->item(row,1)->checkState() == Qt::Checked){
//If not stopped yet, firstly stop it
QMutexLocker locker(&mx);
stateController[thread_id] = false;
}
stateController.remove(thread_id);
}
ui->tableWidget->removeRow(row);
}
}
void MainWindow::updateQThreadID(int row, QString id)
{
ui->tableWidget->setItem(row,0,new QTableWidgetItem(QString::number(id.toInt())));
}
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QMutex>
#include <vector>
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
private slots:
void on_pushButton_add_clicked();
void on_tableWidget_cellClicked(int row, int column);
void on_pushButton_delete_clicked();
public slots:
void updateQThreadID(int row, QString id);
private:
Ui::MainWindow *ui;
QMutex mx;
};
#endif // MAINWINDOW_H
worker.cpp
#include "worker.h"
#include <QThread>
#include <QDebug>
#include <QMutexLocker>
extern QMap<int, bool> stateController;
Worker::Worker(int row) : row_index(row) {
qDebug()<<"Create new worker at thread "<<(int)QThread::currentThreadId();
}
Worker::~Worker() {
qDebug()<<"Destroy the worker instance";
}
void Worker::process() {
thread_id = (int)QThread::currentThreadId();
stateController.insert(thread_id, true);
// qDebug()<<"set thread id is"<<thread_id;
emit updateQThreadIDSignal(row_index,QString("%1").arg(thread_id)); //execute once, because if delete row happen, the row index will change
while(true)
{
count++;
QThread::sleep(2);//simulate time consuming operations
qDebug()<<thread_id<<"processing"<<count;
{//life scope of locker
QMutexLocker locker(&mx);
if(!stateController[thread_id])//In every loop, determine whether it can run, if not, exit the loop
{
return;
}
}
}
emit finished();
}
worker.h
#ifndef WORKER_H
#define WORKER_H
#include <QObject>
#include <QMutex>
class Worker : public QObject {
Q_OBJECT
public:
Worker(int row);
~Worker();
public slots:
void process();
signals:
void finished();
void updateQThreadIDSignal(int, QString);
private:
int thread_id;
int row_index;
QMutex mx;
int count = 0;
};
#endif // WORKER_H
To watch the demo video, click here.
If you have any advice, please let me know, thanks !
Even though the codes seems to work fine, but i still have a question : Why i wrote &Worker::deleteLater, but I never see the destructor of Worker is called ?
I'm new in QT and I ran into a problem.
I decided to try writing a small application using Qt and QSystemTrayIcon. To start, I decided to reproduce the example from the official site of Qt.
https://doc.qt.io/qt-5/qtwidgets-desktop-systray-example.html?
This is my header file:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QSystemTrayIcon>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = nullptr);
~MainWindow();
private:
Ui::MainWindow *ui;
QMenu *trayIconMenu;
QAction *launchAction;
QAction *quitAction;
QSystemTrayIcon *trayIcon;
public slots:
void changeEvent(QEvent*);
void trayIconActivated(QSystemTrayIcon::ActivationReason reason);
void trayActionExecute();
void setTrayIconActions();
void showTrayIcon();
};
#endif // MAINWINDOW_H
This is my source code file:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QMessageBox>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
this->setTrayIconActions();
this->showTrayIcon();
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::showTrayIcon() {
trayIcon = new QSystemTrayIcon(this);
QIcon trayImage(":/images/trayIcon.png");
trayIcon->setIcon(trayImage);
trayIcon->setContextMenu(trayIconMenu);
connect(trayIcon,
SLOT(activated(QSystemTrayIcon::ActivationReason)),
this,
SLOT(trayIconActivated(QSystemTrayIcon::ActivationReason)));
trayIcon->show();
}
void MainWindow::trayActionExecute() {
QMessageBox::information(this, "TrayIcon", "Info text");
}
void MainWindow::trayIconActivated(QSystemTrayIcon::ActivationReason
reason) {
switch (reason) {
case QSystemTrayIcon::Trigger:
case QSystemTrayIcon::DoubleClick:
this->trayActionExecute();
break;
default:
break;
}
}
void MainWindow::showMsg() {
QMessageBox::information(this, "Tray message", "Hello world!");
}
void MainWindow::setTrayIconActions() {
launchAction = new QAction("Launch", this);
quitAction = new QAction("Exit", this);
connect (launchAction, SIGNAL(triggered()), this, SLOT(showMsg()));
connect (quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
// Setting system tray's icon menu
trayIconMenu = new QMenu(this);
trayIconMenu -> addAction (launchAction);
trayIconMenu -> addAction (quitAction);
}
void MainWindow::changeEvent(QEvent *event) {
QMainWindow::changeEvent(event);
if (event->type() == QEvent::WindowStateChange) {
if (isMinimized()) {
this->hide();
}
}
}
When I perform any action in the context menu, the application simply closes.
I thought that the point was to override the method QCloseEvent and that would fix the situation. So, i reimplent it:
void MainWindow::closeEvent(QCloseEvent *event) {
#ifdef Q_OS_OSX
if (!event->spontaneous() || !isVisible()) {
return;
}
#endif
if (trayIcon->isVisible()) {
QMessageBox::information(this, tr("Systray"),
tr("The program will keep running in the "
"system tray"));
hide();
event->ignore();
}
}
What can be wrong?
Thanks.
The issue can be reproduced by minimizing the main window, which hides it as per your changeEvent() implementation, and subsequently clicking "Launch" in the system tray icon menu. The message box is displayed, and afterwards the application simply closes.
This is caused by a "feature" of QT called QuitOnLastWindowClosed which is enabled by default. If it is enabled, the application quits when the last non-hidden window is closed - in your example, this is the message box spawned by the "Launch" command (which counts as a window)!
You can solve the issue by calling QApplication::setQuitOnLastWindowClosed(false); at some point after creating the QApplication, e.g. in the main.cpp which likely sets up your application:
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
a.setQuitOnLastWindowClosed(false);
MainWindow w;
w.show();
return a.exec();
}
On a side note, your connect() syntax in showTrayIcon() is wrong: It should spell SIGNAL(activated(QSystemTrayIcon::ActivationReason)) instead of SLOT(activated(QSystemTrayIcon::ActivationReason)).
But I would highly recommend to use the new signal/slot syntax (https://wiki.qt.io/New_Signal_Slot_Syntax) instead:
connect(trayIcon, &QSystemTrayIcon::activated, this, &MainWindow::trayIconActivated);
This has the advantage of showing you any mistakes (like unknown signals/slots or incompatible parameters) at compile-time instead of runtime.
I create a player for audiobooks - when you open a folder with mp3 file, whole list of them is added to playlist and List View. And i have a Label, which suppose to show duration of the whole book. But player->duration returns only a duration of current track, and if i go through the loop and do playlist->next() every step, player->duration returns 0. I know about Phonon and file metadata, but i need to do this without using it.
I am attaching a source code of a working project, you can use. When the player changes the file, the duration is changed and printed out. To loop within files, there is a need to wait till the decoder completes reading the media file. See the code below and the comments.
This is mainwindow.cpp
#include "mainwindow.h"
#include "mainwindow.h"
#include "ui_mainwindow.h"
bool done =false;
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
player = new QMediaPlayer(this);
playlist = new QMediaPlaylist(player);
playlist->setPlaybackMode(QMediaPlaylist::Sequential);
player->setPlaylist(playlist);
connect(player, &QMediaPlayer::durationChanged, this, &MainWindow::on_durationchanged);
//connect(player,&QMediaPlayer::)
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_clicked()
{
playlist->addMedia(QUrl::fromLocalFile("Ar_today.mp3"));
playlist->addMedia(QUrl::fromLocalFile("Ar_sunday.mp3"));
playlist->setCurrentIndex(0); //set the first file
while (done == false) //wait till the duration is read
{
QApplication::processEvents();
}
done = false; playlist->setCurrentIndex(1); //change to the second file
while (done == false) //wait till the duration is read
{
QApplication::processEvents();
} //this way you can loop through files
player->setVolume(80);
player->play();
qDebug() << player->errorString();
}
void MainWindow::on_pushButton_2_clicked()
{
player->stop();
}
void MainWindow::on_durationchanged(qint64 duration)
{
done = true;
qDebug() << "duration = " << player->duration();
}
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QMediaPlayer>
#include <QMediaPlaylist>
#include <QDebug>
extern bool done;
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = nullptr);
~MainWindow();
private slots:
void on_pushButton_clicked();
void on_pushButton_2_clicked();
void on_durationchanged(qint64 duration);
private:
Ui::MainWindow *ui;
QMediaPlayer* player;
QMediaPlaylist* playlist;
};
#endif // MAINWINDOW_H
In the form, create 2 buttons, one called pushbutton to play and the other is pushButton_2 to stop
I am using Qt and I am unable to get output of a exe file using readyReadStandardOutput.
Here is my code.
mainwindow.cpp
void MainWindow::on_pushButton_24_clicked()
{
myprocess = new QProcess(this);
myprocess->start("files\\helloworld.exe");
connect(myprocess, SIGNAL(readyReadStandardOutput ()), this, SLOT(outlog()));
}
void MainWindow::outlog()
{
QString abc;
abc = myprocess->readAllStandardOutput();
emit outlogtext(abc);
ui->lineEdit_4->setText(abc);
}
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QtGui>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
QProcess *myprocess;
signals:
void outlogtext(QString ver);
private slots:
void outlog();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
The helloworld.exe will just give a output "Hello world" but I cannot see it in the textEdit, whats wrong with my code? I am very new to Qt. Thank you
I got the program working. Below is the code.
mainwindow.hpp
#ifndef MAINWINDOW_HPP
#define MAINWINDOW_HPP
#include <QtGui>
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
signals:
void outlogtext(QString ver);
private slots:
void outlog();
void on_pushButton_24_clicked();
private:
QPushButton* pushButton_24;
QLineEdit* lineEdit_4;
QProcess *myprocess;
};
#endif // MAINWINDOW_HPP
main.cpp
#include <QtCore>
#include <QtGui>
#include <QDebug>
#include "mainwindow.hpp"
MainWindow::MainWindow(QWidget* parent)
: QMainWindow(parent)
{
pushButton_24 = new QPushButton;
connect(pushButton_24, SIGNAL(clicked()),
this, SLOT(on_pushButton_24_clicked()));
lineEdit_4 = new QLineEdit;
QWidget* central = new QWidget;
QLayout* layout = new QVBoxLayout();
layout->addWidget(pushButton_24);
layout->addWidget(lineEdit_4);
central->setLayout(layout);
setCentralWidget(central);
}
MainWindow::~MainWindow()
{
}
void MainWindow::on_pushButton_24_clicked()
{
myprocess = new QProcess(this);
connect(myprocess, SIGNAL(readyReadStandardOutput()),
this, SLOT(outlog()));
myprocess->start("./helloworld.exe");
// For debugging: Wait until the process has finished.
myprocess->waitForFinished();
qDebug() << "myprocess error code:" << myprocess->error();
}
void MainWindow::outlog()
{
QString abc = myprocess->readAllStandardOutput();
emit outlogtext(abc);
lineEdit_4->setText(abc);
}
int main(int argc, char* argv[])
{
QApplication app(argc, argv);
MainWindow win;
win.show();
return app.exec();
}
helloworld.cpp
#include <iostream>
int main()
{
std::cout << "Hello World!" << std::endl;
}
Some things I changed:
After constructing an object, I always connect signals and slots before performing the
actual operation on the object, which might be calling show() for widgets or calling
start() for threads. So I can be sure that I do not miss a signal like started(),
for example.
I ran the program on Linux. There I had to make sure that helloworld.exe was on my
path and I changed the command to ./helloworld.exe. I didn't create the sub-directory
called files as in your example.
The character to separate directories in Qt is the slash /. There are special functions to convert between the Qt-style and the native-style, when you want to display something to the user. Internally always make use of slashes. This even works for Windows programs (many console commands can cope with a slash instead of a backslash, too).
Adding debug output is really, really valuable during development. If the Makefile is
not set up correctly or something breaks, the helloworld.exe might end up in a directory, where it is not expected. Thus, I added code to wait for some time until the process has finished. This does not hurt because helloworld.exe needs just some milliseconds to run. Afterwards, I print the error code of QProcess just to be sure that the program has been found and could be executed. So I can be sure that the executable is on my path, that the executable flag is set, that I have permissions for executing the file etc.
I don't know exactly what causes the problem on your machine. However, comparing your solution to mine, having a look at the error code of QProcess and setting break points inside the slots should help you finding the error.
I am working on building a GUI around a console application. I would like to be able to click a button to run the console app and show the console output inside of the GUI itself. How might I accomplish this? I am working in Linux.
You could also try QProcess. It provides a Qt interface to launching external processes, reading their I/O and waiting, or not, on their completion.
For your purpose, it sounds like you want the process to run asynchronously, so code might look like :
myprocessstarter.h :
#include <QObject>
#include <QProcess>
#include <QDebug>
class MyProcessStarter : public QObject
{
Q_OBJECT
public:
MyProcessStarter() : QObject() {};
void StartProcess();
private slots:
void readStandardOutput();
private:
QProcess *myProcess;
};
main.cpp:
#include "myprocessstarter.h"
void MyProcessStarter::StartProcess()
{
QString program = "dir";
QStringList arguments;
// Add any arguments you want to be passed
myProcess = new QProcess(this);
connect(myProcess, SIGNAL(readyReadStandardOutput()), this, SLOT(readStandardOutput()));
myProcess->start(program, arguments);
}
void MyProcessStarter::readStandardOutput()
{
QByteArray processOutput;
processOutput = myProcess->readAllStandardOutput();
qDebug() << "Output was " << QString(processOutput);
}
void main(int argc, char** argv)
{
MyProcessStarter s;
s.StartProcess();
}
I wanted to do something similar in one of my applications. I redirected all output from the standard stream (cout) to my console window. To periodically read out the stream contents I use a timer loop. Works fine for me.
StdRedirector.cpp
#include "StdRedirector.h"
QMutex coutMutex;
void outcallback(const char* ptr, std::streamsize count, void* bufferString)
{
string *b = (string *) bufferString;
string t;
for (int i=0; i < count; i++)
{
if (ptr[i] == '\n')
{
t = t + "\n";
} else {
t = t + ptr[i];
}
}
coutMutex.lock();
*b = *b + t;
coutMutex.unlock();
}
void ConsoleWindow::updateTimer(void)
{
coutMutex.lock();
if (bufferString.size() > 0)
{
consoleBox->insertPlainText(QString(bufferString.c_str()));
bufferString.clear();
QScrollBar *sb = consoleBox->verticalScrollBar();
sb->setValue(sb->maximum());
}
coutMutex.unlock();
}
ConsoleWindow::ConsoleWindow(QWidget *parent) : QWidget(parent)
{
consoleBox = new QTextEdit(this);
consoleBox->setReadOnly(true);
stdRedirector = new StdRedirector<>(std::cout, outcallback, &bufferString);
QVBoxLayout *vb = new QVBoxLayout();
vb->addWidget(consoleBox);
vb->setMargin(0);
vb->setSpacing(0);
setLayout(vb);
QTimer *timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(updateTimer()));
timer->start(100);
}
ConsoleWindow::~ConsoleWindow()
{
delete stdRedirector;
}
StdRedirector.h
#ifndef STD_REDIRECTOR
#define STD_REDIRECTOR
#include <QWidget>
#include <QTextEdit>
#include <QString>
#include <QVBoxLayout>
#include <QTimer.h>
#include <QMutex>
#include <QScrollBar>
#include <iostream>
#include <string>
using namespace std;
template<class Elem = char, class Tr = std::char_traits<Elem>>
class StdRedirector : public std::basic_streambuf<Elem, Tr>
{
typedef void (*pfncb) ( const Elem*, std::streamsize _Count, void* pUsrData );
public:
StdRedirector(std::ostream& a_Stream, pfncb a_Cb, void* a_pUsrData) :
m_Stream(a_Stream),
m_pCbFunc(a_Cb),
m_pUserData(a_pUsrData)
{
m_pBuf = m_Stream.rdbuf(this);
}
~StdRedirector()
{
m_Stream.rdbuf(m_pBuf);
}
std::streamsize xsputn(const Elem* _Ptr, std::streamsize _Count)
{
m_pCbFunc(_Ptr, _Count, m_pUserData);
return _Count;
}
typename Tr::int_type overflow(typename Tr::int_type v)
{
Elem ch = Tr::to_char_type(v);
m_pCbFunc(&ch, 1, m_pUserData);
return Tr::not_eof(v);
}
protected:
std::basic_ostream<Elem, Tr>& m_Stream;
std::streambuf* m_pBuf;
pfncb m_pCbFunc;
void* m_pUserData;
};
class ConsoleWindow : public QWidget
{
Q_OBJECT
public:
ConsoleWindow(QWidget *parent = 0);
~ConsoleWindow();
public slots:
void updateTimer(void);
public:
QTextEdit *consoleBox;
StdRedirector<> *stdRedirector;
string bufferString;
};
#endif
The StdRedirector class is based on code from this forum post: http://www.qtforum.org/article/24554/displaying-std-cout-in-a-text-box.html
Take a look at the popen() function, it might do what you need.
Then you could pass the FILE * to a QTextStream and work in Qt style with it.
I suggest, rather than showing stdout in GUI, having own console output, which essentially means all messages you want to show to users you are sending to your own output.
This way you can have debug messages and such still available from console, wtih potential errors with connections and whatever that can happen and have fully controlled console output in GUI application. Of course this output can also be outputted to stdout so it is visible in console, but it also allows you to append a prefixs like WARNING LOG NOTICE NO_THIS_WENT_WRONG or whatever you want to show to users as your console entry.