Macros to disallow class copy and assignment. Google -vs- Qt

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To disallow copying or assigning a class it's common practice to make the copy constructor and assignment operator private. Both Google and Qt have macros to make this easy and visible. These macros are:

Google:

#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
  TypeName(const TypeName&);   \
  void operator=(const TypeName&)

Qt: 

#define Q_DISABLE_COPY(Class) \
  Class(const Class &); \     
  Class &operator=(const Class &);

Questions: Why are the signatures of the two assignment operators different? It seems like the Qt version is correct. What is the practical difference between the two?

c++
11 Answers

In practice I would say that both should not be used anymore if you have a C++11 compiler.

You should instead use the delete feature , see here

Meaning of = delete after function declaration

and here

http://www.stroustrup.com/C++11FAQ.html#default

Why : essentially because compiler message is much more clearer. When the compiler need one of the copy or copy assignment operator, it immediately points out to the line where the =delete was coded.

Better and complete explanations can also be found in Item 11: Prefer deleted functions to private undefined ones from Effective Modern C++ book by Scott Meyers

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