Boost.Fusion define struct array member

How do you do it?

using char10 = char[10];  
BOOST_FUSION_DEFINE_STRUCT(
    (demo), employee,
    (char10, name))

doesn't work:
main.cpp:8:1: error: incompatible types in assignment of 'boost::call_traits::param_type {aka const char* const}' to 'char10 {aka char [10]}'

using char10 = char[10];
BOOST_FUSION_DEFINE_STRUCT(
    (demo), employee,
    (decltype(char10{}), name))

doesn't work either:
main.cpp:8:1: error: value-initialization of reference type 'char (&)[10]'

That's not possible for C-style arrays because of the infamous array-to-pointer-decay property that C has (and still binds C++ for backwards compatibility).

This breaks, since the Fusion macro generates code like:

namespace demo {
    struct employee {
        typedef employee self_type;
        char10 name;
        employee() : name() {}
        employee(self_type const &) = default;
        employee(self_type &&) = default;
        template <typename Seq>
            employee(Seq const &seq, typename boost::disable_if<boost::is_convertible<Seq const &, char10> >::type * = 0)
            : name(boost::fusion::deref(boost::fusion::advance_c<0>(boost::fusion::begin(seq)))) {}
        self_type &operator=(self_type const &) = default;
        self_type &operator=(self_type &&) = default;
        template <typename Seq> self_type &operator=(Seq const &seq) {
            typedef typename boost::fusion::result_of::begin<Seq const>::type I0;
            I0 i0 = boost::fusion::begin(seq);
            name = boost::fusion::deref(i0);
            return *this;
        }
        explicit employee(boost::call_traits<char10>::param_type arg) : name(arg) {}
    };
} // namespace demo

In the constructor's initializer list:

explicit employee(boost::call_traits<char10>::param_type arg) : name(arg) {}

the type of arg will be char const* which is not a valid initializer for the string (a char const(&)[10] would be, but would need

Solution

Go the C++ way:

Live On Coliru (c++11)

#include <boost/fusion/include/define_struct.hpp>

using char10 = std::array<char, 10>;

BOOST_FUSION_DEFINE_STRUCT(
    (demo), employee,
    (char10, name))

#include <boost/core/demangle.hpp>
#include <iostream>
int main() {
    demo::employee emp;
    emp.name = {{'I',' ','a','m',' ','G','r','o','o','t'}};
}

If you're stuck in the dark ages, you can use boost::array instead:

Live On Coliru (c++03)