Hello, I would like to ask the group if you know of an efficient and clean way to stop a thread. What I've been using till now was a while loop in the function operator()() given to the boost::thread when created, whose condition was a boolean data member. This boolean was the means to stop the thread, such that when it was turned off, the child thread would exit the while loop and join the main thread. I am seeing now that this data member is being held twice (one copy for the main thread and one copy for the child thread) and there's no synch between the two copies; so when the main thread turns it off / false, the child thread goes on (since its copy is still on / true) and hell breaks loose. I am using VC7 in debug mode, so I started looking for some kind of flag/optimization I might be inadvertently using that makes data members into registers (thus explaining the copies), but couldn't find anything of the sort. Any help will be greatly appreciated... Dan --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.805 / Virus Database: 547 - Release Date: 03-Dec-04