boost_condition

  1 #include <boost/thread/thread.hpp>
  2 #include <boost/thread/mutex.hpp>
  3 #include <boost/thread/condition.hpp>
  4 #include <iostream>
  5 using namespace std;
  6 
  7 const int BUF_SIZE = 10;
  8 const int ITERS    = 100;
  9 
 10 boost::mutex io_mutex;
 11 typedef boost::mutex::scoped_lock SCOPE_LOCK;
 12 
 13 class buffer
 14 {
 15 public:    
 16     buffer():p(0),c(0),full(0){ }
 17 
 18     void put(int m)
 19     {
 20         SCOPE_LOCK lock(mutex);
 21         if(full == BUF_SIZE)
 22         {
 23             {
 24                 SCOPE_LOCK locl(io_mutex);
 25                 cout<<"Buffer is full.Wait..."<<endl;
 26             }
 27             while(full == BUF_SIZE)
 28             {
 29                 cond.wait(lock);
 30             }
 31         }
 32         buf[p] = m;
 33         p = (p+1) % BUF_SIZE;
 34         ++full;
 35         cond.notify_one();
 36         //cond.notify_all();
 37     }
 38 
 39     int get()
 40     {
 41         SCOPE_LOCK lock(mutex);
 42         if(full == 0)
 43         {
 44             {
 45                 SCOPE_LOCK locl(io_mutex);
 46                 cout<<"Buffer is empty.Wait..."<<endl;
 47             }
 48             while(full == 0)
 49             {
 50                 cond.wait(lock);
 51             }
 52         }
 53 
 54         int i = buf[c];
 55     
 56         c = (c+1) % BUF_SIZE;
 57         --full;
 58         cond.notify_one();
 59         return i;
 60     }
 61 
 62 
 63 private:
 64     boost::mutex     mutex;
 65     boost::condition cond;
 66     unsigned int p,c,full;
 67     int              buf[BUF_SIZE];
 68 };
 69 
 70 buffer buf;
 71 
 72 void writer()
 73 {
 74     for(int n = 0; n < ITERS;n++)
 75     {
 76         {
 77             SCOPE_LOCK(io_mutex);
 78             cout<<"sending:"<<n<<endl;
 79         }
 80         buf.put(n);
 81     }
 82 }
 83 
 84 void reader()
 85 {
 86     for(int i = 0;i < ITERS;i++)
 87     {
 88         int n = buf.get();
 89         {
 90             SCOPE_LOCK lock(io_mutex);
 91             cout<<"receive:"<<n<<endl;
 92         }
 93     }
 94 }
 95 
 96 int main(int argc, char const *argv[])
 97 {
 98     boost::thread t1(&reader);
 99     boost::thread t2(&writer);
100     t1.join();
101     t2.join();
102 
103     return 0;
104 }