Re: [Boost-users] thread running many times

creating thread group for(i=0; i < iterations; ++i) {        run threadgroup for parallel part, till all threads finished        run serial part }

So I would like to ask for, if the thread group is created, and I call the join_all within the loop, each "join_all" starts the full group again on each iteration or need I create a new threadgroup on each iteration (join_all can be called only once on a group)?

join_all() waits (blocks) until the execution of all the threads in the group is complete - *that's all*. In other words: join_all(), like thread::join(), does not start anything. It just waits until thread completes. So at the end of every iteration you don't have threads anymore -- if you need them again, you have to create another ones.