c++ - how to block and wake a boost thread? -

how can block boost thread , wake thread? thread doing work, if work finished should block or sleep, if new work ready main thread should weake worker thread. tried blocking read on boost ipc message_queue not performant solution.

something this:

void thread() {    uint8_t ret=0;    for(;;) //working loop    {       ret=dowork();       if(ret==work_complete)       {          blockorsleep();       }    } } 

with pthreads can block on semaphore not platform independent.

one solution problem condition variable, is, name implies, way of waiting in thread until condition reached. requires mutual co-operation between threads.

from example in documentation linked above:

thread 1:

boost::condition_variable cond; boost::mutex mut; bool data_ready;  void process_data();  void wait_for_data_to_process() {     boost::unique_lock<boost::mutex> lock(mut);     while(!data_ready)     {         cond.wait(lock);     }     process_data(); } 

thread 2:

void retrieve_data(); void prepare_data();  void prepare_data_for_processing() {     retrieve_data();     prepare_data();     {         boost::lock_guard<boost::mutex> lock(mut);         data_ready=true;     }     cond.notify_one(); }