Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
| Front Page / Sequences / Intrinsic Metafunctions / is_sequence |
template<
typename X
>
struct is_sequence
{
typedef unspecified type;
};
Returns a boolean Integral Constant c such that c::value == true if and only if X is a model of Forward Sequence.
#include <boost/mpl/is_sequence.hpp>
| Parameter | Requirement | Description |
|---|---|---|
| X | Any type | The type to query. |
typedef is_sequence<X>::type c;
| Return type: | Boolean Integral Constant. |
|---|---|
| Semantics: | Equivalent to typedef not_< is_same< begin<T>::type,void_ > >::type c; |
Amortized constant time.
struct UDT {};
BOOST_MPL_ASSERT_NOT(( is_sequence< std::vector<int> > ));
BOOST_MPL_ASSERT_NOT(( is_sequence< int > ));
BOOST_MPL_ASSERT_NOT(( is_sequence< int& > ));
BOOST_MPL_ASSERT_NOT(( is_sequence< UDT > ));
BOOST_MPL_ASSERT_NOT(( is_sequence< UDT* > ));
BOOST_MPL_ASSERT(( is_sequence< range_c<int,0,0> > ));
BOOST_MPL_ASSERT(( is_sequence< list<> > ));
BOOST_MPL_ASSERT(( is_sequence< list<int> > ));
BOOST_MPL_ASSERT(( is_sequence< vector<> > ));
BOOST_MPL_ASSERT(( is_sequence< vector<int> > ));