2576. istream_iterator and ostream_iterator should use std::addressof

Section: 24.6 [stream.iterators] Status: C++17 Submitter: Tim Song Opened: 2016-01-01 Last modified: 2017-07-30

Priority: 0

View all other issues in [stream.iterators].

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Discussion:

To defend against overloaded unary &. This includes the constructors of both iterators, and istream_iterator::operator->.

Note that {i,o}stream_type are specializations of basic_{i,o}stream, but the constructors might still pick up an overloaded & via the traits template parameter. This change also provides consistency with std::experimental::ostream_joiner (which uses std::addressof).

[2016-02, Issues Telecon]

P0; move to Tentatively Ready.

Proposed resolution:

This wording is relative to N4567.

1. Edit 24.6.2.2 [istream.iterator.cons]/3+4 as indicated:

   istream_iterator(istream_type& s);
   

   -3- Effects: Initializes in_stream with &saddressof(s). value may be initialized during construction or the first time it is referenced.

   -4- Postcondition: in_stream == &saddressof(s).

2. Edit 24.6.2.3 [istream.iterator.ops]/2 as indicated:

   const T* operator->() const;
   

   -2- Returns: &addressof(operator*()).

3. Edit 24.6.3.2 [ostream.iterator.cons.des]/1+2 as indicated:

   ostream_iterator(ostream_type& s);
   

   -1- Effects: Initializes out_stream with &saddressof(s) and delim with null.

   ostream_iterator(ostream_type& s, const charT* delimiter);
   

   -2- Effects: Initializes out_stream with &saddressof(s) and delim with delimiter.