qt 6.5.1 original

tests/manual/wasm/eventloop/main_exec/CMakeLists.txt

@@ -0,0 +1,11 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+qt_internal_add_manual_test(main_exec
+    GUI
+    SOURCES
+        main.cpp
+    LIBRARIES
+        Qt::Core
+        Qt::Gui
+)

tests/manual/wasm/eventloop/main_exec/main.cpp

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+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+#include <QtGui>
+
+// This example demonstrates how the standard Qt main()
+// pattern works on Emscripten/WebAssambly, where exec()
+// does not return.
+
+class ClickWindow: public QRasterWindow
+{
+public:
+    ClickWindow() {
+        qDebug() << "ClickWindow constructor";
+    }
+    ~ClickWindow() {
+        qDebug() << "ClickWindow destructor";
+    }
+
+    void paintEvent(QPaintEvent *ev) override {
+        QPainter p(this);
+        p.fillRect(ev->rect(), QColorConstants::Svg::deepskyblue);
+        p.drawText(50, 100, "Application has started. See the developer tools console for debug output");
+    }
+
+    void mousePressEvent(QMouseEvent *) override {
+        qDebug() << "mousePressEvent(): calling QGuiApplication::quit()";
+        QGuiApplication::quit();
+    }
+};
+
+int main(int argc, char **argv)
+{
+    qDebug() << "main(): Creating QGuiApplication object";
+    QGuiApplication app(argc, argv);
+
+    QObject::connect(&app, &QCoreApplication::aboutToQuit, [](){
+        qDebug() << "QCoreApplication::aboutToQuit";
+    });
+
+    ClickWindow window;
+    window.show();
+
+    qDebug() << "main(): calling exec()";
+    app.exec();
+
+    // The exec() call above never returns; instead, a JavaScript exception
+    // is thrown such that control returns to the browser while preserving
+    // the C++ stack.
+
+    // This means that the window object above is not destroyed, and that
+    // shutdown code after exec() does not run.
+
+    qDebug() << "main(): after exit"; // <- will not be printed
+}
+
+// Global variables are created before main() as usual, but not destroyed
+class Global
+{
+public:
+    Global() {
+        qDebug() << "Global constructor";
+    }
+    ~Global() {
+        qDebug() << "Global destructor"; // <- will not be printed
+    }
+};
+Global global;