Databases
StackOverflow2013
Postsdbo
POWhy does the application crash when I try to start the same thread a second time?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POWhy does the application crash when I try to start the same thread a second time?
    primarykey
    data
    text
    <p>main.cpp:</p> <pre><code>#include "mainwindow.h" #include &lt;QApplication&gt; int main(int argc, char *argv[]) { QApplication a(argc, argv); MainWindow w; w.show(); return a.exec(); } </code></pre> <p>mainwindow.cpp:</p> <pre><code>#include "mainwindow.h" #include "ui_mainwindow.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui-&gt;setupUi(this); cThread = new QThread(this); cObject = new MyObject(); cObject-&gt;moveToThread(cThread); QObject::connect(ui-&gt;pushButton_3, SIGNAL(clicked()), this, SLOT(close()) ); QObject::connect(cThread, SIGNAL(started()), cObject, SLOT(doWork()) ); QObject::connect(ui-&gt;pushButton_4, SIGNAL(clicked()), this, SLOT(runThreadSlot()) ); QObject::connect(cThread, SIGNAL(finished()), cThread, SLOT(deleteLater()) ); QObject::connect(cThread, SIGNAL(finished()), cObject, SLOT(deleteLater()) ); QObject::connect(cObject, SIGNAL(setStatusBarSignal(QString)), this, SLOT(setStatusBarSlot(QString)) ); } MainWindow::~MainWindow() { delete ui; } void MainWindow::runThreadSlot() { cThread-&gt;start(); } void MainWindow::setStatusBarSlot(QString text) { ui-&gt;statusBar-&gt;showMessage(text); } </code></pre> <p>myobject.cpp:</p> <pre><code>#include "myobject.h" MyObject::MyObject(QObject *parent) : QObject(parent) { } void MyObject::doWork() { emit setStatusBarSignal(QString::number((qint32) QThread::currentThreadId())); QThread::currentThread()-&gt;quit(); return; } </code></pre> <p>mainwindow.h:</p> <pre><code>#ifndef MAINWINDOW_H #define MAINWINDOW_H #include &lt;QMainWindow&gt; #include "myobject.h" namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); private slots: void runThreadSlot(); void setStatusBarSlot(QString); private: Ui::MainWindow *ui; QThread* cThread; MyObject* cObject; }; #endif // MAINWINDOW_H </code></pre> <p>myobject.h:</p> <pre><code>#ifndef MYOBJECT_H #define MYOBJECT_H #include &lt;QtCore&gt; class MyObject : public QObject { Q_OBJECT public: explicit MyObject(QObject *parent = 0); signals: void setStatusBarSignal(QString); public slots: void doWork(); }; #endif // MYOBJECT_H </code></pre> <p>So the pattern is:</p> <p>pushButton_4 clicked() ---> runThreadSlot() ---> cThread start()</p> <p>The thread immediately kills itself with <code>QThread::currentThread()-&gt;quit();</code>, but when I click on pushButton_4 again, the application crashes.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USuser2317537
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload