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Section: 23.6.4 [istreambuf.iterator] Status: C++17 Submitter: Jonathan Wakely Opened: 2016-11-09 Last modified: 2017-07-30
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Addresses GB 59There is no specification for istreambuf_iterator::operator->. This operator appears to have been added for C++11 by LWG issue 659, which gave the signature, but also lacked specification.
[2016-11-08, Jonathan comments and suggests wording]
There is no good option here, and implementations either return nullptr, or return the address of a temporary, or don't even provide the member at all. We took polls to decide whether to remove istreambuf_iterator::operator->, or specify it to return nullptr, and the preferred option was to remove it. It was noted that in the Ranges TS input iterators no longer require operator-> anyway, and the library never tries to use it.
[Issues Telecon 16-Dec-2016]
Move to Review
This wording is relative to N4606.
This reverts LWG 659.
Remove the note in paragraph 1 of 23.6.4 [istreambuf.iterator]:
The class template istreambuf_iterator defines an input iterator (24.2.3) that reads successive characters from the streambuf for which it was constructed. operator* provides access to the current input character, if any.
[Note: operator-> may return a proxy. — end note]Each time operator++ is evaluated, the iterator advances to the next input character. […]
Remove the member from the class synopsis in 23.6.4 [istreambuf.iterator]:
charT operator*() const;
pointer operator->() const;istreambuf_iterator& operator++(); proxy operator++(int);