App dissapears from Task Manager when running a QProcess

[INeedADollar]

Hello! I have a problem. When I run a QProcess for the first time, my app is shown in Task Manager with all processes.
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When I run the same QProcess second time my app dissapears from Task Manager.
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When the QProcess is finished after started second time, app is shown again in Task Manager but without its process.
13263

My code:

mainwindow.h


#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QWidget>
class mainWindow : public QWidget
{
Q_OBJECT
public:
mainWindow(QWidget *parent = 0);
~mainWindow();
void createUI();
void process();
QProcess *process = new QProcess(this);

private slots:
void ReadOutput(int, QProcess::ExitStatus);

};
#endif // MAINWINDOW_H


mainwindow.cpp


#include <QWidget>
#include <QPushButton>
#include <QProcess>
#include <QByteArray>
#include <QTextCodec>
#include <QString>
#include <QDebug>
#include "mainwindow.h"

mainWindow::mainWindow(QWidget *parent) : QWidget(parent)
{
createUI();
connect(process, SIGNAL(finished(int, QProcess::ExitStatus)), this, SLOT(ReadOutput(int, QProcess::ExitStatus)));
}


mainWindow::~mainWindow()
{

}
void mainWindow::createUI(){
QPushButton buttonsearch = new QPushButton("Start process", this);
buttonsearch->setToolTip("Start process");
buttonsearch->setGeometry(200, 290, 100, 30);
connect(buttonsearch, &QPushButton::clicked, [this]() {process(); });
}

void mainWindow::process(){
process->setProcessChannelMode(QProcess::MergedChannels);
process->start("\"D:\\YTDownloader\\youtube-dl.exe\" -e --no-playlist https://www.youtube.com/watch?v=6V-wwfuxZxw");

void readOutput(int exitCode, QProcess::ExitStatus exitStatus){
qDebug() << exitCode;
qDebug() << exitStatus;
QByteArray a = process->readAllStandardOutput();
QTextCodec* utfCodec = QTextCodec::codecForName("UTF-8");
processStdout = utfCodec->toUnicode(a);
qDebug() << processStdout;
}


main.cpp


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

int main(int argl,char *argv[])
{
QApplication app(argl,argv);

mainWindow *window = new mainWindow();
window->setWindowTitle("Test");
window->setFixedSize(700, 335);
window->show();

return app.exec();
}


How can this be solved? Thank you!

[d_stranz]

It may not be the reason, but you are calling QProcess::start() incorrectly. The preferred way is to specify the first argument as a QString containing the name of the program to be executed (your youtube-dl.exe), and the second argument a QStringList where each item in the list is one of the individual command line arguments. In your case, this should be:



QString program = "D:\\YTDownloader\\youtube-dl.exe";
QStringList args;
args << "-e" << "--no-playlist" << "https://www.youtube.com/watch?v=6V-wwfuxZxw";
process->start( program, args );


Also, Task Manager has a default update rate. (View->Update speed) If your process starts and ends in less time than the update interval, it may not show up.

[INeedADollar]

It may not be the reason, but you are calling QProcess::start() incorrectly. The preferred way is to specify the first argument as a QString containing the name of the program to be executed (your youtube-dl.exe), and the second argument a QStringList where each item in the list is one of the individual command line arguments. In your case, this should be:



QString program = "D:\\YTDownloader\\youtube-dl.exe";
QStringList args;
args << "-e" << "--no-playlist" << "https://www.youtube.com/watch?v=6V-wwfuxZxw";
process->start( program, args );


Also, Task Manager has a default update rate. (View->Update speed) If your process starts and ends in less time than the update interval, it may not show up.

Thank you very much!