variant_category

Conversion category for variants.

Synopsis

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

struct variant_category;

Description

Variants are serialised the same way their active alternative is serialised. The opposite conversion selects the first alternative for which conversion succeeds.

By default a type T is considered a variant if given t, a glvalue of type const T, t.valueless_by_exception() is well-formed.

Users can specialize conversion_category_for for their own types if they want them to be treated as variants. For example:

namespace boost {
namespace json {

template <>
struct conversion_category_for<your::variant>
{
    using type = variant_category;
};

} // namespace boost
} // namespace json

Mathcing Types

std::variant, boost::variant2::variant.

Convenience header <boost/json.hpp>.

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