Size winSize=Director::getInstance()->getWinSize();

    Label *label=Label::createWithSystemFont("时钟界面","",48);

    label->setPosition(Vec2(winSize.width/2,winSize.height*3/4));

    label->setColor(Color3B(255,0,0));

    this->addChild(label);

改成

Label *label=Label::createWithTTF("clcok","fonts/Maker Felt.ttf",48);

    Size size1=Director::getInstance()->getWinSize();

    label->setPosition(Vec2(size1.width/2,size1.height*3/4));

    this->addChild(label);

为什么编译通过后在运行中报内存错误？