为什么 Qt 在加载窗口图标时崩溃？

Question

以下应用程序崩溃mainWindow->show();

#include <QApplication>
#include <QFrame>
#include <QPixmap>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Q_INIT_RESOURCE(resources);

    QPixmap pix;
    pix.load(":/resources/images/app/icon_glow.png");

    QFrame *mainWindow = new QFrame;
    mainWindow->setWindowIcon(QIcon(pix));
    mainWindow->show();

    return a.exec();
}

注释掉后mainWindow->setWindowIcon(QIcon(pix));，一切正常。否则，回溯（SEGFAULT，试图取消引用 0x8；似乎某处缺少 nullptr 检查）是：

0   ??  /usr/local/Qt32/5.3/gcc/plugins/platforms/libqxcb.so        0xf4991138  
1   ??  /usr/local/Qt32/5.3/gcc/plugins/platforms/libqxcb.so        0xf4982d4c  
2   ??  /usr/local/Qt32/5.3/gcc/plugins/platforms/libqxcb.so        0xf498e7e3  
3   ??  /usr/local/Qt32/5.3/gcc/plugins/platforms/libqxcb.so        0xf498f0f4  
4   QWindowPrivate::applyCursor()   /usr/local/Qt32/5.3/gcc/lib/libQt5Gui.so.5      0xf7517942  
5   QWindowPrivate::setCursor(QCursor const*)   /usr/local/Qt32/5.3/gcc/lib/libQt5Gui.so.5      0xf75179f7  
6   QWindow::setCursor(QCursor const&)  /usr/local/Qt32/5.3/gcc/lib/libQt5Gui.so.5      0xf7517b16  
7   ??  /usr/local/Qt32/5.3/gcc/lib/libQt5Widgets.so.5      0xf7ad5d65  
8   QWidgetPrivate::show_sys()  /usr/local/Qt32/5.3/gcc/lib/libQt5Widgets.so.5      0xf7ad60b6  
9   QWidgetPrivate::show_helper()   /usr/local/Qt32/5.3/gcc/lib/libQt5Widgets.so.5      0xf7abab35  
10  QWidget::setVisible(bool)   /usr/local/Qt32/5.3/gcc/lib/libQt5Widgets.so.5      0xf7abb005  
11  QWidget::show() /usr/local/Qt32/5.3/gcc/lib/libQt5Widgets.so.5      0xf7aad77e  
12  main    main.cpp    17  0x804a21f   

我尝试按如下方式加载资源：

QLabel *mainLabel = new QLabel;
mainLabel->setPixmap(pix);
mainLabel->show();

这毫无问题。任何帮助是极大的赞赏。Ubuntu 14.04 x64，编译32位，Qt 5.3

更新：我重新安装了 ubuntu-desktop（我将桌面从 32 位恢复为 64 位），现在出现错误：

The X11 connection broke: Maximum allowed requested length exceeded (code 4)
XIO:  fatal IO error 2 (No such file or directory) on X server ":0"
      after 409 requests (409 known processed) with 0 events remaining.

Answer 1

我也遇到过这种情况。原因是图标太大。调整为更小的尺寸，例如 256x256。