Boost C++ Libraries

Determine if T can be treated like null during conversions.

Synopsis

Defined in header <boost/json/conversion.hpp>

template<
    class T>
struct is_null_like :
    public false_type

Description

Primary template instantiations provide the member constant value that is equal to false. Users can specialize the trait for their own types if they do want them to be treated as nulls. For example:

namespace boost {
namespace json {

template <>
struct is_null_like<your::null_type> : std::true_type
{ };

} // namespace boost
} // namespace json

Types satisfying the trait

std::nullptr_t.

See Also

value_from, value_to

Convenience header <boost/json.hpp>