template<typename RefStringType> class json_pointer;
A JSON pointer defines a string syntax for identifying a specific value within a JSON document. It can be used with functions at and operator[]. Furthermore, JSON pointers are the base for JSON patches.
RefStringType : the string type used for the reference tokens making up the JSON pointer
Deprecation
For backwards compatibility RefStringType may also be a specialization of basic_json in which case string_t will be deduced as basic_json::string_t. This feature is deprecated and may be removed in a future major version.
basic_json to string type in version 3.11.0.