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at
Description

Returns the result type of at [6] .

Synopsis 
template<
    typename Seq,
    typename N>
struct at
{
    typedef unspecified type;
};

Table 1.25. Parameters

Parameter Requirement Description
Seq A model of Forward Sequence Argument sequence
N An MPL Integral Constant Index of element
Expression Semantics 
result_of::at<Seq, N>::type

Return type: Any type.

Semantics: Returns the result type of using at to access the Nth element of Seq.

Header 
#include <boost/fusion/sequence/intrinsic/at.hpp>
Example 
typedef vector<int,float,char> vec;
BOOST_MPL_ASSERT((boost::is_same<result_of::at<vec, boost::mpl::int_<1> >::type, float&>));

[6] result_of::at reflects the actual return type of the function at. _sequence_s typically return references to its elements via the at function. If you want to get the actual element type, use result_of::value_at

Copyright © 2001-2005 Joel de Guzman, Dan Marsden
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