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template<class... T> struct disjunction;
Inherits: Inherits from the first type
U in the list for which
bool(U::value) is true,
or the last type in the list if there is no such type. If sizeof...(T)
is 0 then inherits from false_type.
Header: #include
<boost/type_traits/disjunction.hpp>
Compiler Compatibility: All current compilers
are supported by this trait. In the absence of variadic-template support,
disjunction has only 2 parameters.
Examples:
Given:
template<int N> struct Int { static const int value = N };
disjunction<>inherits fromfalse_type.
disjunction<Int<1> >inherits fromInt<1>.
disjunction<Int<1>, Int<2>, Int<3> >inherits fromInt<1>.
disjunction<Int<0>, Int<2>, Int<3> >inherits fromInt<2>.