"Igor R" writes:

This's rather basic question, but I couldn't find any example in the docs.

typedef boost::shared_lockboost::shared_mutex shared_lock; shared_mutex mutex_; /// { shared_lock lock(mutex_); // reading locked data...

// here I want to midify the data, how can I upgrade the lock to be exclusive? }

You can't change a shared_lock to an unique_lock. If you want to do this, use an upgrade_lock. There can be at most one upgrade_lock held at any one time on a shared_mutex, but an upgrade_lock can share ownership with any number of shared_locks. You can then upgrade the lock by transferring ownership from the upgrade_lock to a unique_lock: { upgrade_lock lock(mutex_); // reading locked data if(want_to_upgrade) { unique_lock lock2(boost::move(lock)); // access with unique ownership } } Anthony -- Anthony Williams | Just Software Solutions Ltd Custom Software Development | http://www.justsoftwaresolutions.co.uk Registered in England, Company Number 5478976. Registered Office: 15 Carrallack Mews, St Just, Cornwall, TR19 7UL