QtConcurrent::run() starts a new thread after not being run for 30s

Grand_Titan

qDebug() << "called from Physical Thread ID: " << QThread::currentThreadId();
futureWatcher.setFuture(QtConcurrent::run([this]() {
    qDebug() << "Physical Thread ID: " << QThread::currentThreadId();
    //some code
}

I observed that this code consistently runs on the same thread if executed within 30 seconds of the last run. After this time threshold, it switches to a new thread. I discovered this behavior through console monitoring and a timer.

I want to know if this behavior could lead to issues, as I previously encountered a problem with thread exhaustion due to accidentally placing threads in an infinite loop. Why does this happen, and is there a way to disable this behavior to ensure that the futureWatcher doesn't switch threads every time it's called?

Christian Ehrlicher

After 30 sec of inactivity the thread is killed to save resources.

Grand_Titan

@Christian-Ehrlicher Could you answer this please?

I want to know if this behavior could lead to issues, as I previously encountered a problem with thread exhaustion due to accidentally placing threads in an infinite loop. Is there a way to disable this behavior to ensure that the futureWatcher doesn't switch threads every time it's called?

Christian Ehrlicher

@Grand_Titan I already have. The thread is cleaned up after a certain time of inactivity to save resources.