null_category
Conversion category for null types.
Synopsis
Defined in header <boost/json/conversion.hpp>.
using null_category = std::integral_constant< conversion_category, conversion_category::null >;Description
Null types are represented in JSON as the null literal.
By default only the types std::nullptr_t and std::monostate are considered null types.
Users can specialize conversion_category_of for their own types if they want them to be treated as nulls. For example:
namespace boost { namespace json {
template <>
struct conversion_category_of<your::null> : null_category
{ };
} }Matching Types
Convenience header <boost/json.hpp>.