gcc __thread关键字

https://blog.csdn.net/xj178926426/article/details/54345449

EventLoop.cpp

__thread EventLoop* t_loopInThisThread = 0;
EventLoop::EventLoop() {
    if (t_loopInThisThread) {
        LOG(INFO)<<"Another EventLoop " << t_loopInThisThread << " exists in this thread " << threadId_;
    } else {
        t_loopInThisThread = this;
    }
}