c++: constructor template

[Boris Kolpackov]

Good day,


There is this interesting technique (or idiom, if you please) that
I found a really elegant example of. The code explains it:

  class auto_lock
  {
    template <typename x>
    static void
    unlock (void* p)
    {
      reinterpret_cast<x*> (p)->unlock ();
    }

  public:
    template <typename x>
    auto_lock (x& m)
      : m_ (reinterpret_cast<void*>(&m), unlock_ (&unlock<x>)
    {
      m.lock ();
    }

    ~auto_lock ()
    {
      unlock_ (m_);
    }

  private:
    void* m_;
    void (*unlock_) (void*);
  };



-boris
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