When declaring a class/struct/union the compiler will generate the default methods (rule of three). This also will happen when = default'ing these methods.
How do the default methods exactly look like?
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It isn't that simple. If you `default`, say, the copy constructor, you don't get a default constructor any more. There are also rules concerning move constructors and move assignment operators. – juanchopanza Jun 06 '14 at 12:59
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For example let consider the default constructor. According to the C++ Standard
An implicitly-declared default constructor is an inline public member of its class.
and
The implicitly-defined default constructor performs the set of initializations of the class that would be performed by a user-written default constructor for that class with no ctor-initializer (12.6.2) and an empty compound-statement.
So it looks like
struct A
{
A() {}
};
except that it is not explicitly declared and defined.
About copy constructor you can read at my personal forum
http://cpp.forum24.ru/?1-1-0-00000021-000-0-0-1388485669
Though it is written in Russian but you can translate it for example using google service translate.
Vlad from Moscow
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For each of these methods, the compiler defines default inline methods that call the default methods of each attribute of the object. (so a pointer won't be initialized neither any built-in type).
hl037_
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Those method will do the minimum necessary to initialize the class.
Default construtor - do nothing with simple members but call the constructors of more complex members (class/struct) as well as call the ctor of its super class.
Copy constructor will perform a shallow copy (memcpy).
egur
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