decltype() with dereference operator.

[Hashirama senju]

I have started learning C++ from the book C++ primer. In that book, the autor says that decltype will return a reference with dereference operator. Sorry if I am confusing here. I will give a code:

 int v = 1;
 int *p = &v;
 // decltype(*p) will yeild the type int& not int.  

I am confused. The book does not really tell the issue here. Dereferencing the pointer p will give the object v which has a type int. Why is it returning type int& then? In which cases will it return types like that?

[JLBorges]

int main()
{
    int v = 0 ;
    int*p = &v ;

    decltype(v) a = 0 ; // v is the name of an object of type int; type is int

    decltype( (v) ) b = a ; // (v) is an expression of type int; value category of the expression is lvalue
                            // type is lvalue reference to int (int&)

    decltype(*p)  c = a ; // (*p) is an expression of type int; value category of the expression is lvalue
                          // type is lvalue reference to int (int&)

    decltype( +*p )  d = b+c ; // (+*p) is an expression of type int; value category of the expression is prvalue
                               // type is int

    int foo() ;
    decltype( foo() )  e = c+d ; // foo() is an expression of type int; value category of the expression is prvalue
                                 // type is int

    int& bar() ;
    decltype( bar() )  f = a ; // bar() is an expression of type int; value category of the expression is lvalue
                               // type is lvalue reference to int (int&)

    int&& baz() ;
    decltype( baz() ) g = a + 8 ; // baz() is an expression of type int; value category of the expression is xvalue
                                  // type is rvalue reference to int (int&&)
}

See: http://en.cppreference.com/w/cpp/language/decltype

[Hashirama senju]

The book has not introduced value category yet. I think that's what is making me confused.