Sleep problem without QThread class

[ahmed kato]

how to make my program sleep for 100 ms without using Qthread class??

[broadpeak]

maybe:
-#include <qwaitcondition.h>-

-QWaitCondition sleep;-
-sleep.wait(1000); // one seconds-

ahh, sorry this was ok for Qt 3, but for Qt 4 the wait() function is changed... (you need a mutex too)

[lgeyer]

You either use QTest
@
QTest::qSleep(100); // no event processing
QTest::qWait(100); // event processing
@
or you use QWaitCondition / QMutex
@
QWaitCondition waitCondition;
QMutex mutex;

waitCondition.wait(&mutex, 100);
@
or you use QThread.
@
class Thread : public QThread
{
public:
static void msleep(int ms)
{
QThread::msleep(ms);
}
};

Thread::msleep(100);
@

However, having to do so in an event-driven application is usually a clear indicator for a broken design.

[joonhwan]

Is there any specific reason not to use QThread::sleep() ?

[lgeyer]

Yes, it is protected.

[broadpeak]

[quote author="Lukas Geyer" date="1325612918"]
or you use QThread
[/quote]

Hm... What about the (pure virtual) run() function?

[lgeyer]

[quote author="broadpeak" date="1325618245"]
Hm... What about the (pure virtual) run() function?[/quote]

It is indeed virtual, but not pure. The default implementation simply calls exec() (which doesn't even matter in our case, as the thread isn't started). QThread::msleep() causes the current thread to sleep.

[goetz]

On unix like machins (including the Mac):

@
#include <unistd.h>

// sleep for 5 seconds
sleep(5);

// sleep for another 5 seconds (5,000,000 microseconds)
usleep(5000000);
@

On Windows:
@
// sleep for 5 seconds (5000 milliseconds)
Sleep(5000);
@

Or copy the implementation of QTest::qSleep():

@
#ifdef Q_OS_WIN
#include <windows.h> // for Sleep
#else
#include <time.h>
#endif

void mySleep(int ms)
{
if(ms <= 0)
return

#ifdef Q_OS_WIN
Sleep(uint(ms));
#else
struct timespec ts = { ms / 1000, (ms % 1000) * 1000 * 1000 };
nanosleep(&ts, NULL);
#endif
}
@