about the longest elapsed time in Qt

[jsulm]

@opengpu said in about the longest elapsed time in Qt:

qint64 is only about 214783 seconds

What?
max(qint64) == 9223372036854775807
Divede that number by 1000 and you get the number of seconds.
So, why do you think it is 214783 seconds?

[opengpu]

@jsulm
ok, that's INT_MAX, int32.
ok, so max(int64) is about 292471208 years...that's enough

[opengpu]

@jsulm is the code above right? is it the best and efficient way?

[jsulm]

@opengpu said in about the longest elapsed time in Qt:

ok, that's INT_MAX, int32

This is wrong as well: max(int) = 2,147,483,647. Devide it by 1000 and you get 2,147,483sec

"is the code above right? is it the best and efficient way?" - looks fine

[aha_1980]

@opengpu

Why don't you use QTimer? Seems like the optimal tool for your case (run code every xxx seconds).

Elapsed timer is for measurement.

[opengpu]

@aha_1980 i neet: donot emit signal within the time-interval

[jsulm]

@opengpu Then emit it AFTER the time interval - for that you can use QTimer.

[opengpu]

@jsulm

void SendEmail()
{
    if ( !m_ElapsedTimer.isValid() ||  m_ElapsedTimer.hasExpired(timeout))
    {
    emit signalSendEmail();
    m_ElapsedTimer.restart();
    }
}

SendEmail() is called at some situation, it's not called every time-interval. i just have to control inside the time-interval from last SendEmail another SendEmail is forbidden.
ie. SendEmail's minimun time interval, the time between two SendEmails >= this interval

[jsulm]

@opengpu
?

[KroMignon]

@opengpu said in about the longest elapsed time in Qt:

m_ElapsedTimer.restart();

Attention: QElapsedTimer::restart() only works if QElapsedTimer instance is valid ==> QElapsedTimer::start() has been called before!
If you don't use the return value (which is the elapsed timer since last start or restart), it is better to use start():

void MyClass::SendEmail()
{
    if ( !m_ElapsedTimer.isValid() ||  m_ElapsedTimer.hasExpired(timeout))
    {
        emit signalSendEmail();
        m_ElapsedTimer.start();
    }
}

[opengpu]

@KroMignon thanks so much!, so start when expired is ok?
because i donot when the 1st time call SendMail, so i use isValid to let me know it's the 1st time SendEmail is called.
after that it's actually check by the hasExpired.
right?

[KroMignon]

@opengpu said in about the longest elapsed time in Qt:

so start when expired is ok?

Yes, of course. QElapsedTimer::hasEpired() is only a kind of helper function,
==> m_ElapsedTimer.hasExpired(timeout) is almost the same as m_ElapsedTimer.elapsed() > timeout. This does not affect QElapsedTimer state.

The difference is only that hasExpired() will test if timer has been started (is valid).

[opengpu]

@KroMignon thank you, and i will write as follow:

QElapsedTimer m_ElapsedTimer;
...
void MyClass::SendEmail()
{
    if ( !m_ElapsedTimer.isValid() ||  m_ElapsedTimer.hasExpired(timeout))
    {
        emit signalSendEmail();
        m_ElapsedTimer.start();
    }
}