Request for comments about synchronized queue using boost

I am currently designing a synchronized queue used to communicate
between threads. Is the code given below a good solution? Am I
using mutex lock/unlock more than needed?

Are there any resources out there on the Internet on how to design
*thread-safe* *efficient* data-
structures?

/Nordl=F6w

The file synched_queue.hpp follows:

#ifndef PNW__SYNCHED_QUEUE_HPP
#define PNW__SYNCHED_QUEUE_HPP

/*!
 * @file synched_queue.hpp
 * @brief Synchronized (Thread Safe) Container Wrapper on std:queue
 * using Boost::Thread.
 */

#include <queue>
#include <iostream>

#include <boost/bind.hpp>
#include <boost/thread/thread.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/condition.hpp>

//
==========================
==========================
==========================
=

template <typename T>
class synched_queue
{
    std::queue<T> q; ///< Queue.
    boost::mutex m; ///< Mutex.
public:
    /*!
     * Push @p value.
     */
    void push(const T & value) {
        boost::mutex::scoped_lock sl(m); // NOTE: lock mutex
        q.push(value);
    }

    /*!
     * Try and pop into @p value, returning directly in any case.
     * @return true if pop was success, false otherwise.
     */
    bool try_pop(T & value) {
        boost::mutex::scoped_lock sl(m); // NOTE: lock mutex
        if (q.size()) {
            value = q.front();
            q.pop();
            return true;
        }
        return false;
    }

    /// Pop and return value, possibly waiting forever.
    T wait_pop() {
        boost::mutex::scoped_lock sl(m); // NOTE: lock mutex
        // wait until queue has at least on element()
        c.wait(sl, boost::bind(&std::queue<T>::size, q));
        T value = q.front();
        q.pop();
        return value;
    }

    size_type size() const {
        boost::mutex::scoped_lock sl(m); // NOTE: lock mutex
        return q.size();
    }

    bool empty() const {
        boost::mutex::scoped_lock sl(m); // NOTE: lock mutex
        return q.empty();
    }

};

//
==========================
==========================
==========================
=

#endif