Proposed resolution:

This wording is relative to N4861.

1. Modify [ios.base.cons] as indicated:

   [Drafting note: Wording modeled on container requirements]

   ~ios_base();
   

   -2- Effects: Calls each registered callback pair (fn, idx) ([ios.base.callback]) as (*fn)(erase_event, *this, idx) at such time that any ios_base member function called from within fn has well-defined results. Then, any memory obtained is deallocated.

[ 2020-11-09 Approved In November virtual meeting. Status changed: Tentatively Ready → WP. ]

[ 2020-07-17; Reflector prioritization ]

Set priority to 0 and status to Tentatively Ready after six votes in favour during reflector discussions.

According to [ios.base.storage] the class ios_base allocates memory, represented by two exposition-only pointers, iarray and parray in response to calls to iword and pword. However, the specification for the destructor in [ios.base.cons] says nothing about reclaiming any allocated memory.