How to make a thread finish its work before being free'd?

Question

I\'m writing a thread which writes event logs. When the application is closed (gracefully), I need to make sure this thread finishes its job saving the logs before it\'s fre

Answer 1

If I call Free directly to the thread, it shouldn't immediately be destroyed, it should wait until the thread is done and there's no more work left to do.

I think you have a slight mis-understanding of what happens when you destroy a thread. When you call Free on a TThread, the following happens in the destructor:

1. Terminate is called.
2. WaitFor is called.
3. The remainder of the thread's destructor then runs.

In other words, calling Free already does what you ask for, namely notifying the thread method that it needs to terminate, and then waiting for it to do so.

Since you are in control of the thread's Execute method, you can do as much or as little work there once you detect that the Terminated flag has been set. As Remy suggests, you could override DoTerminate and do your last pieces of work there.

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For what it is worth, this is a poor way to implement a queue. That call to Sleep(1) jumps right out at me. What you need is a blocking queue. You empty the queue and then wait on an event. When the producer adds to the queue the event is signaled so that your thread can wake up.