WSJT-X/boost/libs/iterator/doc/func_output_iter_abstract.rst

.. Copyright David Abrahams 2006. Distributed under the Boost
.. Software License, Version 1.0. (See accompanying
.. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

The function output iterator adaptor makes it easier to create custom
output iterators. The adaptor takes a unary function and creates a
model of Output Iterator. Each item assigned to the output iterator is
passed as an argument to the unary function.  The motivation for this
iterator is that creating a conforming output iterator is non-trivial,
particularly because the proper implementation usually requires a
proxy object.