chatty@cenatls.cena.dgac.fr (Stephane Chatty) writes:

>Until now, I assumed that operator new was called right before
>the constructor, so that:
>
>new B (new A)
>
>resulted in the following sequence:
>
>A::new, A::A, B::new, B::B
>
>but I just discovered that g++ has a different behaviour:
>
>B::new, A::new, A::A, B::B
>
>Is this legal?

Yes, this is legal.

>Is anything said in the standard about this?

No, since there's no standard yet.
The latest draft of the working paper says the following:

  Whether the  allocation  function  is  called  before  evaluating  the
  constructor  arguments, after evaluating the constructor arguments but
  before entering the constructor,  or  by  the  constructor  itself  is
  unspecified.   It  is  also  unspecified  whether  the  arguments to a
  constructor are evaluated if the allocation function returns the  null
  pointer or throws an exception.

--
Fergus Henderson - fjh@munta.cs.mu.oz.au

I could not find anything precise in the ARM about
the time when operator new is called. I understand that
it can be called by the constructor or before the constructor.
But in the latter case, nothing is said about when it can happen.

Until now, I assumed that operator new was called right before
the constructor, so that:

new B (new A)

resulted in the following sequence:

A::new
A::A
B::new
B::B


but I just discovered that g++ has a different behaviour:

B::new
A::new
A::A
B::B

Is this legal? Is anything said in the standard about this?

>>>>> Stephane Chatty <chatty@cenatls.cena.dgac.fr> writes:

> Is this legal?

Yes.

> Is anything said in the standard about this?

Yes:

10Whether the  allocation  function  is  called  before  evaluating  the
  constructor  arguments, after evaluating the constructor arguments but
  before entering the constructor,  or  by  the  constructor  itself  is
  unspecified.   It  is  also  unspecified  whether  the  arguments to a
  constructor are evaluated if the allocation function returns the  null
  pointer or throws an exception.

Jason