gistfile1.cpp

#include <boost/thread/thread.hpp>

#define CHECK(x) if (!x) { abort(); }

struct State {
  State()
    : x(0) {
  }

  boost::mutex m;
  boost::condition_variable c;
  int x;
};

void Notifier(State* s) {
  for (int i = 0; i <= 10000; i++) {
    boost::unique_lock<boost::mutex> l(s->m);
    s->x = i;
    s->c.notify_one();
  }
}

int main(int argc, char** argv) {
  State s;
  boost::thread n(&Notifier, &s);

  boost::unique_lock<boost::mutex> l(s.m);
  while (s.x < 10000) {
    int old_val = s.x;
    if (s.c.timed_wait(l, boost::posix_time::microseconds(1))) {
      // Return true, we should assume that old_val incremented
      CHECK(s.x > old_val);
    } else {
      // Timed out waiting on notify, so must not have incred
      CHECK(s.x == old_val);
    }
  }
}