11 Classes [class]

11.9 Member access control [class.access]

11.9.1 Access specifiers [class.access.spec]

Member declarations can be labeled by an access-specifier ([class.derived]):

_{o p t}

An access-specifier specifies the access rules for members following it until the end of the class or until another access-specifier is encountered.

[Example

class X {
  int a;            // X::a is private by default: class used
public:
  int b;            // X::b is public
  int c;            // X::c is public
};

— end example

]

Any number of access specifiers is allowed and no particular order is required.

[Example

struct S {
  int a;            // S::a is public by default: struct used
protected:
  int b;            // S::b is protected
private:
  int c;            // S::c is private
public:
  int d;            // S::d is public
};

— end example

]

[Note

The effect of access control on the order of allocation of data members is specified in [expr.rel].

— end note

]

When a member is redeclared within its class definition, the access specified at its redeclaration shall be the same as at its initial declaration.

[Example

struct S {
  class A;
  enum E : int;
private:
  class A { };                  // error: cannot change access
  enum E: int { e0 };           // error: cannot change access
};

— end example

]

[Note

In a derived class, the lookup of a base class name will find the injected-class-name instead of the name of the base class in the scope in which it was declared.

The injected-class-name might be less accessible than the name of the base class in the scope in which it was declared.

— end note

]

[Example

class A { };
class B : private A { };
class C : public B {
  A* p;             // error: injected-class-name A is inaccessible
  ::A* q;           // OK
};

— end example

]