Question

I am wondering if the following concept is known as a programming pattern.

Imagine a worker queue, but instead of each queue entry beeing removed when processed, it should be removed when another thread has catched the remove-event or when a remove-event was triggered.

So it would go like this:

• command gets into the queue
• 2nd command gets into the queue
• 3rd …
• first command gets processed
• first command waits to be removed
• 2nd command gets processed
• remove-event for first command was fired
• first command gets removed
• 2nd command waits to be removed
• …

I hope, I made this clear enough to understand.

Now is there a boost library, which has implemented such behaviour? Is there a pattern representing this behaviour?

Answer 1

As far as I can see, you’re just talking about two queues – the “novel” one being the queue of pending removals. Standard queues (deque) should be fine. You’d need a mutex, and a condition variable to signal the removal events. Wanting a name for such a pattern is a bit gradiose (people expect that too much these days)… if I were describing it I might say we have a decoupled removal thread (assuming that’s how you implement it), an asynchronous removal process (similarly), or even delayed element removal (which is true even if not done in a separate thread).