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From: Phil Endecott (spam_from_boost_dev_at_[hidden])
Date: 2008-05-09 09:05:19

vicente.botet wrote:
> {
> unique_lock<mutex> lock(smtx);
> // ... some writing operations
> { // non locked block
> reverse_lock< unique_lock<mutex> > rlock(lock);
> // ... some code not needing the mutex to be locked
> } // locked again
> // ...
> }

I wrote something like this to use inside my condition variable
implementation and called it "unlock". I think I prefer the name
"unlock" to "reverse_lock", personally. In my case I have only a
subset of the proposed C++0x mutex and lock functionality, making the
implementation simpler and the potential for errors low.

template <typename MUTEX_T>
struct Unlock: boost::noncopyable {

   typedef MUTEX_T mutex_t;

   mutex_t& m;

   explicit Unlock(mutex_t& m_): m(m_) {

   ~Unlock() {

   mutex_t* mutex(void) {
     return &m;

Once you have recursive mutexes, shared locks and the other features,
the possible interactions start to get interesting. I have wondered
whether a subset of the C++0x features, closer to the old Boost.Threads
API, could be useful as a "threads-for-beginners" package.


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