Question

I understand that the TPL does not necessarily create a new thread for every task in a parallel set, but does it always create at least one? eg:

private void MyFunc()
{
    Task.Factory.StartNew(() =>
    {
        //do something that takes a while   
    });

    DoSomethingTimely();   //is this line guaranteed to be hit immediately?
}

EDIT: To clarify: Yes, I mean is it guaranteed that the thread executing MyFunc() is not going to be used to execute //do something that takes a while.

Answer 1

It depends on what you mean by “immediately” but I think it’s reasonable to assume that the TPL isn’t going to hijack your currently executing thread to synchronously run the code in your task, if that’s what you mean. At least not with the normal scheduler… you could probably write your own scheduler which does do so, but you can normally assume that StartNew will schedule the task rather than just running it inline.