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2.å¦ä½è®© Qt ç¨åº Sleep
3.Qt——QThread源码浅析
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QTime t;
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while(t.elapsed()<);
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QElapsedTimer t;
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QTest::qWait
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namespace QTest
{
inline static void qWait(int ms)
{
Q_ASSERT(QCoreApplication::instance());
QElapsedTimer timer;
timer.start();
do {
QCoreApplication::processEvents(QEventLoop::AllEvents, ms);
QTest::qSleep();
} while (timer.elapsed() < ms);
}
...
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QEventLoop eventloop;
QTimer::singleShot(, &eventloop, SLOT(quit()));
eventloop.exec();
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void QTest::qSleep(int ms)
{
QTEST_ASSERT(ms > 0);
#ifdef Q_OS_WIN
Sleep(uint(ms));
#else
struct timespec ts = { ms / , (ms % ) * * };
nanosleep(&ts, NULL);
#endif
}
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[cpp] view plain copy
/* /internal
helper function to do thread sleeps, since usleep()/nanosleep()
aren't reliable enough (in terms of behavior and availability)
*/
static void thread_sleep(struct timespec *ti)
{
pthread_mutex_t mtx;
pthread_cond_t cnd;
pthread_mutex_init(&mtx, 0);
pthread_cond_init(&cnd, 0);
pthread_mutex_lock(&mtx);
(void) pthread_cond_timedwait(&cnd, &mtx, ti);
pthread_mutex_unlock(&mtx);
pthread_cond_destroy(&cnd);
pthread_mutex_destroy(&mtx);
}
void QThread::sleep(unsigned long secs)
{
struct timeval tv;
gettimeofday(&tv, 0);
struct timespec ti;
ti.tv_sec = tv.tv_sec + secs;
ti.tv_nsec = (tv.tv_usec * );
thread_sleep(&ti);
}
å¦ä½è®© Qt ç¨åº Sleep
使ç¨å¹³å°ç¸å ³ç Sleep æ nanosleep 以åï¼çé¢ä¸ºä»ä¹æ²¡æååºï¼QThread ä¸æä¾äºprotected æéç sleep å½æ°ï¼å¦ä½ç¨å°ä¸»çº¿ç¨ä¸ï¼ä½¿ç¨QTest ä¸ç qSleepï¼å¨windowsä¸å¦ä½éèæ§å¶å°ï¼è¿äºé®é¢å ¶å®å½ç»ä¸ºä¸ç¹ï¼å¨ä¸»çº¿ç¨ä¸ä½¿ç¨è¿äºå½æ°æ¯ä¸ç§é误ï¼è¿ä¼ç´æ¥å¯¼è´çé¢æ æ³å·æ°ï¼ç¨æ·ä¸ç¨åºæ æ³äº¤äºãQtä¸æä¾ï¼æ¯å ä¸ºä½ ä¸éè¦å¨ä¸»çº¿ç¨ä¸ä½¿ç¨ sleep å½æ°ãå¦ä½è®©ç¨åºçå¾ ä¸æ®µæ¶é´QTimeQTime t; t.start(); while(t.elapsed()<);è¿ç§æ»å¾ªç¯ä¹æ¯ä¸ç§å¸¸è§é误ç¨æ³ãä½æ¹ææ£ç¡®çè¿æ¯æ¯è¾ç®åçï¼QTime t; t.start(); while(t.elapsed()<) QCoreApplication::processEvents();ä¸åå°å¤çäºä»¶ï¼ä»¥ä½¿å¾ç¨åºä¿æååºãQElapsedTimerè¿æ¯Qt4.7å¼å ¥çæ°çç±»ï¼åQTimeç¸æ¯ï¼å®æä¾äºæ´å¿«çè®¡ç® elapsed æ¶é´çæ¹æ³ãQElapsedTimer t; t.start(); while(t.elapsed()<) QCoreApplication::processEvents();QTest::qWaitè¿æ¯QTest模åæä¾ççå¾ å½æ°ä¸é¢æ¯å ¶æºä»£ç ï¼åæ们åé¢ç代ç å¾åå§ï¼ï¼ï¼namespace QTest { inline static void qWait(int ms) { Q_ASSERT(QCoreApplication::instance()); QElapsedTimer timer; timer.start(); do { QCoreApplication::processEvents(QEventLoop::AllEvents, ms); QTest::qSleep(); } while (timer.elapsed() < ms); } ...å ¶å®æ²¡ä»ä¹éå,对å§ï¼ä½æ¯å 为å®QTest模åï¼æ以å¨ç¨åºä¸æ们ä¸è¦ä½¿ç¨å®ãQEventLoopé åQTimer使ç¨å±é¨ç eventLoop ä¹æ¯ä¸ä¸ªä¸éçéæ©ãä¾åï¼ QEventLoop eventloop; QTimer::singleShot(, &eventloop, SLOT(quit())); eventloop.exec();QTimer å QBasicTimerè¿ä¸¤ä¸ªåæ¬æ没æä»ä¹ç´æ¥å ³ç³»ï¼QTimer估计大家é½å¾çäºãèQBasicTimer估计å¾å°æ人ç¨ãä¸QTimerç¸æ¯ï¼QBasicTimeræ´å¿«éãè½»éãåºå±ãä¸QTimerç¸æ¯ï¼å®ä¸æ¯QObjectçæ´¾çç±»ã跨平å°çsleep尽管ä¸å¼å§æ们就说äºï¼ä¸éè¦è¿ä¸ªä¸è¥¿ãä½ä¸æé¤æç§åºåä¸ï¼ä½ ç¡®å®éè¦è¿ä¸ªä¸è¥¿ã橹械æ®��èè»ã£â³indowsä¸è°ç¨Sleepï¼å ¶ä»å¹³å°è°ç¨ nanosleepï¼ï¼void QTest::qSleep(int ms) { QTEST_ASSERT(ms > 0); #ifdef Q_OS_WIN Sleep(uint(ms)); #else struct timespec ts = { ms / , (ms % ) * * }; nanosleep(&ts, NULL); #endif }çQThreadçæºç ï¼windowsä¸åæ ·ç´æ¥è°ç¨Sleepï¼ä½éwindowsçå®ç°æ¯è¿ä¸ªå°±å¤æå¤äºï¼/* \internal helper function to do thread sleeps, since usleep()/nanosleep() aren't reliable enough (in terms of behavior and availability)*/staticvoidthread_sleep(structtimespec *ti){ pthread_mutex_tmtx;pthread_cond_tcnd;pthread_mutex_init(&mtx, 0);pthread_cond_init(&cnd, 0);pthread_mutex_lock(&mtx); (void) pthread_cond_timedwait(&cnd, &mtx, ti);pthread_mutex_unlock(&mtx);pthread_cond_destroy(&cnd);pthread_mutex_destroy(&mtx);}voidQThread::sleep(unsignedlongsecs){ structtimevaltv;gettimeofday(&tv, 0);structtimespecti;ti.tv_sec = tv.tv_sec + secs;ti.tv_nsec = (tv.tv_usec * );thread_sleep(&ti);}
Qt——QThread源码浅析
在探索Qt的多线程处理中,QThread类的实现源码历经变迁。在Qt4.0.1和Qt5.6.2版本中,尽管QThread类的声明相似,但run()函数的php源码thinkphp实现有所不同。从Qt4.4开始,杨幂视频源码国产一区QThread不再是抽象类,这标志着一些关键调整。
QThread::start()函数在不同版本中的核心代码保持基本一致,其中Q_D()宏定义是一个预处理宏,用于获取QThread的私有数据。_beginthreadex()函数则是创建线程的核心,调用QThreadPrivate::start(this),通达信实时量比指标源码即执行run()函数并发出started()信号。
QThread::run()函数在Qt4.4后的版本中,不再强制要求重写,而是附近手机号码采集源码可以通过start启动事件循环。在Qt5.6.2版本中,run函数的定义更灵活,可以根据需要进行操作。
关于线程停止,中颖51单片机ISP源码QThread提供了quit()、exit()和terminate()三种方式。quit()和exit(0)等效,用于事件循环中停止线程,而terminate()则立即终止线程,但不推荐使用,因为它可能引发不稳定行为。
总结起来,QThread的核心功能包括线程的创建、run函数的执行以及线程的结束控制。从Qt4.4版本开始,QThread的使用变得更加灵活,可以根据需要选择是否重写run函数,以及如何正确地停止线程。不同版本间的细微差别需要开发者注意,以确保代码的兼容性和稳定性。