> To kill the thread, set the stop flag and cond_signal the condvar This is a race condition. When you "spin" on a condition variable, the stop flag you check

> To kill the thread, set the stop flag and cond_signal the condvar This is a race condition. When you "spin" on a condition variable, the stop flag you check must be guarded by the same mutex you give to cond_wait. See this article for a thorough explanation: https://zeux.io/2024/03/23/condvars-atomic/ https://zeux.io/2024/03/23/condvars-atomic/