.. Iterators/Iterator Metafunctions//deref |50

deref

Synopsis

.. parsed-literal::

template<
      typename Iterator
    >
struct deref
{
    typedef |unspecified| type;
};

Description

Dereferences an iterator.

Header

.. parsed-literal::

#include <boost/mpl/deref.hpp>

Parameters

+---------------+---------------------------+-----------------------------------+ | Parameter | Requirement | Description | +===============+===========================+===================================+ | Iterator | |Forward Iterator| | The iterator to dereference. | +---------------+---------------------------+-----------------------------------+

Expression semantics

For any |Forward Iterator|\ s iter:

.. parsed-literal::

typedef deref<iter>::type t; 

:Return type: A type.

:Precondition: iter is dereferenceable.

:Semantics: t is identical to the element referenced by iter. If iter is a user-defined iterator, the library-provided default implementation is equivalent to

.. parsed-literal::

    typedef iter::type t;

Complexity

Amortized constant time.

Example

.. parsed-literal::

typedef vector<char,short,int,long> types;
typedef begin<types>::type iter;

BOOST_MPL_ASSERT(( is_same< deref<iter>::type, char > ));

See also

|Iterators|, |begin| / |end|, |next|

.. copyright:: Copyright 2001-2009 Aleksey Gurtovoy and David Abrahams 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)