标签:lin not from zha detail 需要 bug archive timer
为何只能在其关联的线程内启动timer?
在QTimer源码分析(以Windows下实现为例) 一文中,我们谈到:
QTimer的是通过QObject的timerEvent()实现的,开启和关闭定时器是通过QObject的startTimer()和killTimer完成的。
startTimer最终调用对象关联线程的eventDispatcher来注册定时器:
int QObject::startTimer(int interval) { Q_D(QObject); return d->threadData->eventDispatcher->registerTimer(interval, this);
在Win32平台下:
void QEventDispatcherWin32::registerTimer(int timerId, int interval, QObject *object) { if (timerId < 1 || interval < 0 || !object) { qWarning("QEventDispatcherWin32::registerTimer: invalid arguments"); return; } else if (object->thread() != thread() || thread() != QThread::currentThread()) { qWarning("QObject::startTimer: timers cannot be started from another thread"); return; } ...
在Linux平台下:
void QEventDispatcherGlib::registerTimer(int timerId, int interval, QObject *object) { #ifndef QT_NO_DEBUG if (timerId < 1 || interval < 0 || !object) { qWarning("QEventDispatcherGlib::registerTimer: invalid arguments"); return; } else if (object->thread() != thread() || thread() != QThread::currentThread()) { qWarning("QObject::startTimer: timers cannot be started from another thread"); return; } ...
在这两个平台下,它都会检查当前线程和dispatcher的线程是否一致。不一致则直接返回。
为什么要这么设计。我不太清楚。或许是因为:注册定时器要用到回调函数,而回调函数需要在注册的线程执行(fix me)。
http://blog.csdn.net/lynfam/article/details/7081545
为何只能在其关联的线程内启动timer?(Qt会检查一致性,否则就不执行)
标签:lin not from zha detail 需要 bug archive timer
原文地址:http://www.cnblogs.com/findumars/p/6696924.html