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template<
      bool C
    >
struct bool_
{
    // unspecified
    // ...
};
typedef bool_<true>  true_;
typedef bool_<false> false_;
A boolean Integral Constant wrapper.
#include <boost/mpl/bool.hpp>
| Parameter | Requirement | Description | 
|---|---|---|
| C | A boolean integral constant | A value to wrap. | 
The semantics of an expression are defined only where they differ from, or are not defined in Integral Constant.
For arbitrary integral constant c:
| Expression | Semantics | 
|---|---|
| bool_<c> | An Integral Constant x such that x::value == c and x::value_type is identical to bool. | 
BOOST_MPL_ASSERT(( is_same< bool_<true>::value_type, bool > )); BOOST_MPL_ASSERT(( is_same< bool_<true>, true_ > )); } BOOST_MPL_ASSERT(( is_same< bool_<true>::type, bool_<true> > )); BOOST_MPL_ASSERT_RELATION( bool_<true>::value, ==, true ); assert( bool_<true>() == true );