c++ - Using boost::mutex as a private member of class -

i have class contains boost::mutex private member. becomes locked when call 1 of public functions , unlocks when function exits. provide synchronous access object's internals.

class stringdeque {   boost::mutex mtx;   std::deque<string> string_deque; public:   stringdeque() { }    void addtodeque(const string& str_to_add)   {     boost::lock_guard<boost::mutex> guard(mtx);     string_deque.push(str_to_add);   }    string popfromdeque()   {     boost::lock_guard<boost::mutex> guard(mtx);     string popped_string = string_deque.front();     string_deque.pop();     return popped_string;   } }; 

this class isn't meant particularly useful playing around mutexes , threads.

i have main() has function defined pops strings class , prints them in thread. repeat 10 times , return function. once again, purely testing purposes. looks this:

void printthestrings(stringdeque& str_deque) {     int = 0;     while(i < 10)     {       string popped_string = str_deque.popfromdeque();       if(popped_string.empty())       {         sleep(1);         continue;       }       cout << popped_string << endl;       ++i;     } }  int main() {   stringdeque str_deque;   boost::thread the_thread(printthestrings, str_deque);   str_deque.addtodeque("say prayers");   str_deque.addtodeque("little one");   str_deque.addtodeque("and don't forget son");   str_deque.addtodeque("to include everyone");   str_deque.addtodeque("i tuck in");   str_deque.addtodeque("warm within");   str_deque.addtodeque("keep free sin");   str_deque.addtodeque("until sandman comes");   str_deque.addtodeque("sleep 1 eye open");   str_deque.addtodeque("gripping pillow tight");   the_thread.join(); } 

the error keep getting boost::mutex noncopyable. printthestrings() function takes reference little confused why trying copy object.

i have read bit on , 1 solution keep reading make boost::mutex static private member of object. however, defeats purpose of mutex since want on object-by-object basis rather class variable.

is bad use of mutexes? should rethinking entire application?

edit:

i discovered condition_variable should serve purpose lot better have thread wait until there in deque before waking pop deque , print it. examples see define these mutexes , condition_variable objects @ global scope. seems very... not object-oriented in opinion. examples straight boost show done in way. how other people use these objects?

you correct printtostring takes stringqueue reference. problem boost::thread take arguments value. force take arguments reference need modify things to:

boost::thread the_thread(printthestrings, boost::ref(str_deque)); 

as aside, c++11 onwards, threads part of standard library. should use std::thread instead