This is how mutex class looks like

#include class mutex:    boost::noncopyable { public:    mutex();    ~mutex();    void lock();    bool try_lock();    void unlock();    typedef platform-specific-type native_handle_type;    native_handle_type native_handle();    typedef unique_lock<mutex> scoped_lock;

   typedef unspecified-type scoped_try_lock;

};

Please help me figure out what purpose does 'unspecified-type' serve below.

Note that this is just documentation, not the real class definition.

Abbhishek Misra writes:

Please help me figure out what purpose does 'unspecified-type' serve below.

typedef unspecified-type scoped_try_lock;

It means that the implementation provides a real type, the name of which you're not being told, and which may therefore change. The documentation below tells you what properties this type has. Anthony -- Author of C++ Concurrency in Action http://www.stdthread.co.uk/book/ just::thread C++0x thread library http://www.stdthread.co.uk Just Software Solutions Ltd http://www.justsoftwaresolutions.co.uk 15 Carrallack Mews, St Just, Cornwall, TR19 7UL, UK. Company No. 5478976