use_category

Overrides the category of conversion of a type.

Synopsis

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

template<
    class T,
    class Ctx = void,
    class Enable = void>
struct use_category;

Description

Specializations should provide the static member constant value that is equal to an enumerator of conversion_category that represents the suitable conversion category of T in context Ctx.

The primary template’s value is equal to conversion_category::unknown.

Use void for Ctx (the default) if the category should apply regardless of context.

The third template parameter can be used for conditional specializations.

Usage example:

namespace boost {
namespace json {

template <>
struct conversion_category<your::string> : string_category
{ };

} // namespace boost
} // namespace json

See Also

Custom Conversions, value_from, value_to.

Convenience header <boost/json.hpp>.

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