函数 指针

connect(sender, &QObject::destroyed, this, &MyObject::objectDestroyed);

宏

  connect(sender, SIGNAL(destroyed(QObject*)), this, SLOT(objectDestroyed(Qbject*)));
  connect(sender, SIGNAL(destroyed(QObject*)), this, SLOT(objectDestroyed()));
  connect(sender, SIGNAL(destroyed()), this, SLOT(objectDestroyed()));

函数 的 参数可忽略。

lambda

connect(sender, &QObject::destroyed, [=](){ this->m_objects.remove(sender); });

[=] 表示用到的任何外部变量都隐式按值捕获。