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Returns the result type of at[6].
template< typename Seq, typename M> struct at { typedef unspecified type; };
Table 1.29. Parameters
|
Parameter |
Requirement |
Description |
|---|---|---|
|
|
A model of Random Access Sequence |
Argument sequence |
|
|
Index of element |
result_of::at<Seq, M>::type
Return type: Any type.
Semantics: Returns the result type of
using at to access the Mth element of Seq.
#include <boost/fusion/sequence/intrinsic/at.hpp> #include <boost/fusion/include/at.hpp>
typedefvector<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