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Thread: How to start a thread (inline)

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    Default How to start a thread (inline)

    I am aware that to execute something in a separate thread, one can simply extend QThread, implement run(), and write the pertinent code in the run method. But is there a way to execute an arbitrary block of code in a separate thread w/o having to create a whole new class? For example, maybe when I click a button I want a task to be executed in a separate thread, etc. Thanks.

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    Default Re: How to start a thread (inline)

    Quote Originally Posted by DiamonDogX View Post
    I am aware that to execute something in a separate thread, one can simply extend QThread, implement run(), and write the pertinent code in the run method. But is there a way to execute an arbitrary block of code in a separate thread w/o having to create a whole new class? For example, maybe when I click a button I want a task to be executed in a separate thread, etc. Thanks.
    Use OpenMP
    Qt Code:
    1. #pragma omp parallel default(none) shared(n,a,b,c,d) private(i)
    2. {
    3. #pragma omp for nowait
    4. for (i=0; i<n-1; i++) b[i] = (a[i] + a[i+1])/2;
    5.  
    6. #pragma omp for nowait
    7. for ( i=0; i<n; i++ ) d[i] = 1./c[i];
    8.  
    9. } /* -- End of parallel region -- */
    To copy to clipboard, switch view to plain text mode 

    Or google search for QtConcurrent

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    Default Re: How to start a thread (inline)

    See QRunnable and QThreadPool or better yet QtConcurrent::run.
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    Default Re: How to start a thread (inline)

    While we're on the subject, if I am executing code in another thread (i.e. a thread that is not the UI thread), is there a way to manually execute a piece of code on the UI thread?

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    Default Re: How to start a thread (inline)

    Yes. Either post an event to the main thread and catch it from within QObject::customEvent() of the object living in the main thread or use QMetaObject::invokeMethod() with Qt::QueuedConnection as the last parameter. The method you call has to be a slot.
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