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Class optional_last_value<void>

boost::signals2::optional_last_value<void> — Evaluate an InputIterator sequence.


// In header: <boost/signals2/optional_last_value.hpp>

class optional_last_value<void> {
  // types
  typedef unspecified result_type;

  // invocation
  template<typename InputIterator> 
    result_type operator()(InputIterator, InputIterator) const;


This specialization of optional_last_value is provided to cope with the fact that there is no such thing as an optional<void>, which optional_last_value would otherwise try to use as its result_type. Therefore, this specialization leaves the result_type unspecified.

optional_last_value invocation

  1. template<typename InputIterator> 
      result_type operator()(InputIterator first, InputIterator last) const;


    Attempts to dereference every iterator in the sequence [first, last).