CODEWITHSUNDEEP
c++11rvalue-reference
devil
devil

Reputation: 1839

For move assignment, will memory leak occur if destruction is left to the rvalue?

With reference to this MSDN article , at the end (Section: Robust Programming) it states,

To prevent resource leaks, always free resources (such as memory, file handles, and sockets) in the move assignment operator.

What will happen if the move assignment is instead implemented as:

MemoryBlock& operator=(MemoryBlock&& other)
{
   if (this != &other)
   {
      std::swap(_data, other._data);
      std::swap(_length, other._length);
   }
   return *this;
}

Wouldn't the "_data" of the rvalue that "other" references be freed when it goes out of scope?

Upvotes: 3

Views: 397

Answers (1)

Howard Hinnant
Howard Hinnant

Reputation: 218780

Yes, other._data will be freed when it goes out of scope (assuming a good destructor of course). However there is one item to consider: If other._data refers to a resource that needs a timely destruction, it may be destructed late in this design. An example might be the locked state of a mutex.

Upvotes: 2

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