I want to issue an event from catch_CtrlC to every running threads to exit elegantly(release resources before exit). How to realise this in the threads?

It depends what those threads are doing and what resources they need to release?

There are several approaches to the problem, and which is appropriate is dependent upon the code in question, so post your code.

The one approach I cannot recommend at all, is using the Threads signalling mechanism which is entirely redundant.

Thanks! Can we define signal of our own?

Can we define signal of our own?

No. Signals and threading do not mix; and as you've found out, even the "threads signals" apparently intended for use with threads don't work for any reasonable definition of the term.

For example, With SAFE_SIGNALS in force, a signal, even a kill, will not interrupt a join. (That's the first problem with the code you posted in your new thread.)

And even if you worked your way around that; you'll end up having to poll in your threads and that's a nonsense.

Far simpler to set a shared variable true in your main thread signal handler and have your threads poll on that.

But simpler even than that is to just detach your threads -- either when you create them or when you receive the kill signal -- and then exit your main thread. The kids will then just go away silently without any polling or other special considerations, regardless of what they are doing at the time.

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