calling member functions from an initialiser list

[John Harrison]

What are the rule concerning calling member functions from an initialiser
list? Suppose I have

class C : public B
{
public:
C() : x(), y(f()), z() {}
private:
Y f();
X x;
Y y;
Z z;
};

B, X, Y, Z are other classes.

What am I allowed to do in C::f()? Presumably I'm not allowed to access C::y
or C::z since they haven't been constructed yet, what about C::x, and what
about members of the base class B? Any other gotchas in this situation?

thanks,
john

 

[Victor Bazarov]

What are the rule concerning calling member functions from an initialiser
list? Suppose I have

class C : public B
{
public:
C() : x(), y(f()), z() {}
private:
Y f();
X x;
Y y;
Z z;
};

B, X, Y, Z are other classes.

What am I allowed to do in C::f()? Presumably I'm not allowed to access C::y
or C::z since they haven't been constructed yet, what about C::x, and what
about members of the base class B? Any other gotchas in this situation?

The rule is that you may do that, but (a) it will resolve statically
(no virtual calls), and (b) the function should not try to use any
parts of the object (members and base classes) that haven't been
constructed yet.

Perhaps in your case it's better to make 'f' static?.. And if you need
to use 'x' there, just pass it as an argument...

Victor

 

[=?iso-8859-1?Q?Juli=E1n?= Albo]

John Harrison escribió:

class C : public B
{
public:
C() : x(), y(f()), z() {}
private:
Y f();
X x;
Y y;
Z z;
};

B, X, Y, Z are other classes.

What am I allowed to do in C::f()? Presumably I'm not allowed to accessC::y
or C::z since they haven't been constructed yet, what about C::x, and what
about members of the base class B? Any other gotchas in this situation?

The base class is constructed before any members. x is constructed, then
you can use it.

Regards.