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title: Timers pending at shutdown | daily.dev
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# Timers pending at shutdown

**[Rambling Comments](https://daily.dev/sources/lenholgate)** · 10 min read · 1 upvotes · 1 comments

## Summary

This installment of a long-running C++ testing series details a redesign of a timer queue system used in The Server Framework to allow clean shutdown without requiring callers to pre-cancel pending timers. The change fires all pending timers at shutdown with a new 'shutdown induced' flag via a new OnTimerEx() function, keeping backwards compatibility with the existing OnTimer(). It walks through splitting the IManageTimerQueue interface into IHandleTimerQueueTimeouts and a new ISupportTimerQueueFacade to preserve correct lock-free dispatch semantics during shutdown, and renaming HandleTimeout() to HandleTimeouts(). Full source is published on GitHub under the MIT license, buildable with Visual Studio 2022 and 2026.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://lenholgate.com/blog/2026/09/practical-testing-44-timers-pending-at-shutdown.html>

## Community discussion

Top comments from developers on daily.dev.

**@nark3d** · 0 upvotes

> Is there a way for a caller to distinguish a shutdown induced timer from a real one without checking the flag at every site, because the flag only helps if the handler is already written to care.  The split into IHandleTimerQueueTimeouts and ISupportTimerQueueFacade reads well, and firing pending timers rather than cancelling them keeps the shutdown path free of caller bookkeeping.  Does HandleTimeouts ever run twice for the same timer when a real timeout and the shutdown race each other?

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---

Tags: [#general-programming](https://daily.dev/tags/general-programming), [#testing](https://daily.dev/tags/testing), [#c++](https://daily.dev/tags/c++)

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