qt lamdba 表达式书写

connect(ui->pushButton, &QPushButton::clicked, [=](){     //注意：若在lambda中访问类成员变量，[]号里面必须有=或&，否则编译不过，报错this指针错误。
if (m_td != NULL)
{
m_td->terminate();
m_td->quit();
m_td->wait();
delete m_td;
m_td = NULL;
}
m_td = new mythread;
m_td->str1 = ui->pushButton->text();
m_td->start();

});