...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Returns the result type of at_c [7] .
template< typename Seq, int M> struct at_c { typedef unspecified type; };
Table 1.26. Parameters
Parameter |
Requirement |
Description |
---|---|---|
Seq |
A model of Forward Sequence |
Argument sequence |
M |
Positive integer index |
Index of element |
result_of::at_c<Seq, M>::type
Return type: Any type
Semantics: Returns the result type of using at_c to access the Mth element of Seq.
/sequence/intrinsic/at.hpp>
typedef vector<int,float,char> vec; BOOST_MPL_ASSERT((boost::is_same<result_of::at_c<vec, 1>::type, float&>));
[7] result_of::at_c reflects the actual return type of the function at_c. Sequence(s) typically return references to its elements via the at_c function. If you want to get the actual element type, use result_of::value_at_c