测试代码如下：
// a.h #ifndef A_H #define A_H #include <QObject> #include <QDebug> class A : public QObject { Q_OBJECT public: explicit A(QObject *parent = nullptr); ~A(); void print(); int a; signals: }; class B : public QObject { public: explicit B(QObject *parent = nullptr); ~B(); A *a; }; #endif // A_H // a.cpp #include "a.h" A::A(QObject *parent) : QObject(parent) { a = 10; } A::~A() { qDebug() << "This is A destructor..."; } void A::print() { //下面这两行，同时存在时，程序会出现段错误 //这句单独存在时，此函数无效 qDebug() << "This is A print method, a = " << a; //这句单独存在时，可以完美执行，打印能够完成 qDebug() << "This is A print method;"; } B::B(QObject *parent) : QObject(parent) { a = new A(this); } B::~B() { qDebug() << "This is B destructor...."; } // main.cpp #include <QCoreApplication> #include "a.h" int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); B *b = new B(); qDebug() << "b delete start"; delete b; qDebug() << "b delete end"; A *c = b->a; c->print(); return a.exec(); } /* * 执行结果为： * b delete start * This is B destructor.... * This is A destructor... * b delete end * This is A print method; */执行结果说明了，继承自QObject的对象，在使用了 Q_OBJECT 宏之后，父对象（通过parent关联，并非继承关系）在被析构时，其子对象会一并析构。
