TITLE: exceptions in constructors

(Newsgroups: comp.lang.c++.moderated, 21 Jan 98)

HOPPS: "Kevin J. Hopps" <khopps@Adobe.COM>

>[...] consider this:
>  { Thing* array = new Thing[3]; delete [] array; }
>When delete is called, the destructor for array[2] is called, then
>array[1] and array[0], and finally the memory is released.  What if the
>destructor for array[2] throws?  Are the other objects destroyed?  Is
>the memory released?


BELL: abell@mindspring.com (Andrew Bell)

Section 15.2 of the draft is quite clear on this:
2 An object that is partially constructed will have destructors
executed only for its fully constructed sub-objects.  Should a
constructor for an element  of  an  automatic array throw an
exception, only the constructed elements of that array will be
destroyed.  If the  object  or  array  was  allocated  in a
new-expression and the new-expression does not   contain   a
new-placement,    the    deallocation    function
(_basic.stc.dynamic.deallocation_, _class.free_) is called to free the
  storage occupied by the object; the deallocation function is chosen
as specified  in  _expr.new_.   If the object or array was allocated
in a new-expression and the new-expression contains  a  new-placement,
the storage  occupied  by the object is deallocated only if an
appropriate placement operator delete is found, as specified in
_expr.new_